Am J Stem Cells 2023;12(2):23-36 www.AJSC.us /ISSN:2160-4150/AJSC0146642 Original Article Safety and feasibility of autologous adipose-derived stromal vascular fraction in the treatment of keloids: a phase one randomized controlled pilot trial Ronald Mbiine1, Anthony Kayiira2, Misaki Wayengera3, Munabi Ian Guyton4, Noah Kiwanuka5, Rose Alenyo1, Edris Wamala Kalanzi6, Haruna Muwonge7, Cephas Nakanwagi8, Moses Joloba9, Moses Galukande1 1Department of Surgery, Makerere University College of Health Sciences, Kampala, Uganda; 2Life Sure Fertil- ity and Gynaecology Centre, Kampala, Uganda; 3Department of Immunology and Molecular Biology, School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda; 4Department of Human Anatomy, School of Biomedical Sciences, Makerere University College of Health Science, Kampala, Uganda; 5School of Public Health, Makerere University College of Health Sciences, Kampala, Uganda; 6Department of Plastic Surgery, Kirruddu National Referral Hospital, Kampala, Uganda; 7Department of Physiology, Makerere University College of Health Sciences, Kampala, Uganda; 8Mulago National Referral Hospital, Kampala, Uganda; 9School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda Received September 22, 2022; Accepted April 22, 2023; Epub April 25, 2023; Published April 30, 2023 Abstract: Introduction: Autologous adipose-derived stromal vascular fraction (SVF) has been described to have ther- apeutic benefits in the treatment of keloids. However, most of the evidence on its efficacy is based on observational studies the majority of which are conducted in high-income countries and yet the highest burden of keloids is in low- and middle-income countries (LMICs). Objectives: We set out to determine the safety and feasibility of using autologous adipose derived stromal vascular fraction in the treatment of keloids in LMICs. Methods: In this phase II randomized controlled pilot clinical trial conducted in the Plastic Surgery Unit of Kirruddu National Referral Hospital in Kampala Uganda, 8 patients were assigned a 1:1 ratio to either SVF or triamcinolone acetonide (TAC) arms. In the SVF arm, a median (Inter quartile range) amount of stromal cell infiltration of 2.7×106 (11×106) was administered, while the controls received 10 mg/ml TAC at a ratio of 1:1 TAC to keloid volume. Primary endpoints were adverse event development based on the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 tool and feasibility assessment based on ≥ 70% recruitment feasibility and ≥ 80% interventional feasibility rates. Results: The par- ticipants’ mean age was 27.9 (±6.5) years, with a female predilection of 5 (63%). Overall, no adverse events were reported in the SVF arm, while ulceration in a single patient in the TAC arm, which was a grade II adverse event, was reported. Recruitment feasibility of 80% and interventional feasibility with 100% completion were reported. Conclu- sion: Based on our findings, an autologous adipose-derived stromal vascular fraction is feasible and safe for the treatment of keloids in LMICs. Keywords: Stromal vascular fraction, adipose stem cells, keloids, scars, low middle-income countries Introduction Keloids are one of the most common benign skin disorders [1], occurring mostly in indivi- duals with coloured skin, especially among Africans. They are estimated to affect up to 16% of the African population [1, 2]. To date, there is no curative treatment for these keloids, as all existing therapies have varied treatment responses and invariably result in recurrence [3-5]. Several therapies for managing keloids exist of which the most widely used is Triamcinolone acetonide (TAC). TAC is a synthetic glucocorti- coid with anti-inflammatory properties and is traditionally used either as monotherapy or in combination with other therapies such as surgi- cal excision, cryotherapy often with significant treatment response [6]. Other therapies used in Keloid management such as 5-Fluorouracil, Verapamil, radiothera- http://www.AJSC.us Adipose derived stromal vascular fraction in keloid treatment: a pilot study 24 Am J Stem Cells 2023;12(2):23-36 py, Silicone gel among others have been described globally being used in combination or in isolation and with varying dosing strate- gies [7-9]. These are however not routinely used in Uganda or other Low-income count- ries. All the above therapies have been described to have varying degrees of satisfactory response with the majority described to result in keloid volume regression ranging from 30 to 100% [6, 10]. Despite the majority of therapies reporting more than 50% satisfactory volume regression for keloids [11, 12], Triamcinolone acetonide (TAC) is the most widely used therapy in keloid management especially in LMICs. This is partly due to its low cost, universal availability and ease of administration. It can either be used as single or combination therapy [13, 14]. Despite its efficacy in causing keloid volume regression, the biggest limitation of Triamcinolone and the other existing therapies is the high keloid recur- rence rates which range between 20 to 100% following successful treatment [10, 14-18]. To compound this limitation, optimal treatment responses for TAC often require multiple ses- sions of therapies often on a monthly basis with no predefined limit but until the desired outcome is obtained. This coupled with the pain associated with these injections makes TAC are less desirable treatment for keloids. Because of the high recurrence rates associat- ed with the existing therapies coupled with the several and cumbersome treatment sessions required to achieve the desired treatment out- comes, there is a need to explore other thera- pies that can augment the existing therapies or provide entirely alternative options that maybe more tolerable. Autologous adipose derived stromal vascular fraction (SVF) is one new promising therapy that is increasingly being recognised to have therapeutic potential in treating keloids and hypertrophic scars. Human adipose tissue which is usually obtained through liposuction contains vast amounts of cells collectively referred to as stromal cells or the stromal vascular fraction (SVF) [19]. This heterogenous cell population contains mesen- chymal stem cells, pericytes and other cell pre- cursors as well nucleated cells [20]. Charac- teristically, these cells exhibit multi-lineage dif- ferentiation potential and are therefore de- scribed to be a rich source of adult stem cells very similar to those obtained from bone mar- row [21]. Unlike bone marrow aspirate, the lipoaspirate is a lot easier to extract and pro- vides are richer and yet similar quality of mes- enchymal stem cells [19, 21]. Through either enzymatic or mechanical processing, the cells in the adipose tissue are extracted and con- centrated through centrifugation [19, 22]. The SVF cells obtained after processing the fat have been demonstrated to possess immense therapeutic and regenerative properties [20, 22]. These cells promote wound healing and hence used in the treatment of chronic wounds [23, 24], arthritis [25], neurological diseases [26] among other conditions. Specifically, SVF has been described to improve scar outcomes [27-30] with mouse models demonstrating significant reduction in the hypertrophic scar volumes. The SVF cells have been described to exert their therapeutic effects through paracrine based signalling mechanisms that modulate excess inflammatory processes [31] as well as suppression keloid fibroblast proliferation and gene expression [20, 32-34]. Specifically in scar therapy, SVF is described to inhibit scar fibrosis through the suppression of the p38/ MAPK signalling pathway [35] as well as fibrosis inhibition via the Transforming growth factor- beta (TGF-β) pathway [36]. This results in SVF mediated inhibition of collagen deposition th- rough the suppression of the col1, col3 and α-SMA (Smooth muscle actin) genes [35, 37]. This is described to result in faster healing with more organised scar tissue. The SVF is constituted either as a point of care therapy or it’s sent to the laboratory for culture expansion to yield more cell volumes [38, 39]. Despite this growing evidence of the effective- ness of SVF in scar healing, the majority of studies have a low level of evidence with pau- city of well-organized clinical trials to com- pare the efficacy of SVF to existing therapies. Similarly, most studies are conducted in high income countries and yet the biggest burden of keloids is in Low-income countries. In order to benefit from this potential therapy, there is a need to understand the feasibility of Adipose derived stromal vascular fraction in keloid treatment: a pilot study 25 Am J Stem Cells 2023;12(2):23-36 utilising this therapy as well as describe the safety of the therapy in a low-income country setting. Without designed randomized controlled clini- cal trials, it is difficult to objectively determine the benefits of SVF therapy in scar manage- ment and this may subsequently deter future potential utilization as standard therapy. Point of care stromal vascular fraction is a lot cheap- er and safer to use as the cells are processed and used at the same sitting. Utilization of the adipose-derived stromal vascular fraction is highly technical and demanding, and before conducting a clinical trial to assess efficacy, it is important that a pilot study be conducted. In this study, we assessed the feasibility of con- ducting a clinical trial using the stromal vascu- lar fraction in keloid treatment. Second, we evaluated the safety of using the SVF in com- parison to standard triamcinolone acetonide (TAC). The findings of this pilot study will be used to develop a phase II clinical trial that will evaluate the efficacy of using the stromal vascular frac- tion in the treatment of keloids. Materials and methods Trial design This was a parallel group single centre random- ized controlled pilot trial with a ratio of 1:1 con- ducted at the plastic surgical unit of Kirruddu National Referral Hospital in Kampala, Uganda, from March to July 2021. The trial was approved by the “The AIDS Support Organization (TASO) Research Ethics Committee (TASOREC/060/ 19-UG-REC-009) and the Kirruddu National Referral Hospital Research Ethics Committee and was also registered in the ClinicalTrials.gov under the registration number NCT04553159”. The trial reporting followed the CONSORT Extended checklist for pilot clinical trials [40] and TIDier guidelines [41]. Eligibility criteria We included patients with a single keloid of ≤ 4 cm3 as these have the highest response to any treatment administered. Patients had to be between the age of 18-65 years. Participants were excluded if they had are BMI less than 18.5. As these would have an insufficient fat pad. Participants who had received an intra- lesional steroid injection therapy or radiothera- py in the three months prior to the study were also excluded. Any participant with an active or ongoing systemic illness demonstrated by the presence of are fever or comfirmatory labora- tory results were also excluded. Likewise pa- tients with ulcerated keloids or infected keloids were also excluded from the study. Included participants were provided with com- plete oral and written information ahead of their consent on the clinic visit. Informed con- sent was then obtained on the scheduled day of the procedure usually not less than 2 days from the booking date. Intervention Once participants were included in the study, baseline characteristics were obtained. The participants were then randomly allocated into one of the two treatment groups. Group 1 was the group that received the SVF while group 2 received the Triamcinolone Acetonide as described below. The autologous adipose-derived stromal vascu- lar fraction (SVF) group Participants in this arm received a single dose of intralesional infiltration of the autologous adipose-derived stromal vascular fraction. The dosage depended on the total number of viable SVF cells in the cellular suspension and was expressed as total viable cells per ml of sus- pension. The final cell suspension volume was constituted in a 1:1 ratio of the keloid volume with 1 ml of cell suspension per cubic centime- tre of keloid tissue. To obtain the stromal vascular fraction, the steps described below were followed. Harvesting adipose tissue: Tumescence lipo- suction was performed aseptically on the ou- ter thigh following the infiltration of 300 ml of tumescent solution (constituted as 20 ml of 2% lignocaine, 1 ml of 1:1000 epinephrine, 12.5 ml of 8.4% sodium bicarbonate in 1 litre of nor- mal saline). Through a 3-4 mm skin incision, liposuction into a 10 ml Leuer lock syringe attached to a 3 mm Coleman liposuction can- nula was performed with 100 to 150 ml of Adipose derived stromal vascular fraction in keloid treatment: a pilot study 26 Am J Stem Cells 2023;12(2):23-36 Figure 1. Liposuction process being aseptically performed. Figure 2. Lipoaspirate processing to obtain the stromal vascular fraction. A. The lipoaspirate after centrifugation. B. Digested lipoaspirate following 0.075% collagensase incubation. C. Stromal vascular fraction pellet (SVF). lipoaspirate and collected into 50 ml sterile Falcon centrifuge tubes (see Figure 1). The lipo- suction cannula entry incision was closed with a 6/0 Monocryl absorbable suture, and a pres- sure bandage was placed. Standard operation theatre aseptic protocols were followed, and the procedures were con- ducted in a dedicated plastic surgery operation theatre by qualified plastic surgeons. Extraction of stromal vascular fraction: The harvested lipo- aspirate (see Figure 2A) was processed aseptically from a designated sterile unit in the operating theatre. The lipoas- pirate was washed using 1X Dulbecco’s phosphate buff- ered saline-PBS (Lonza, Wal- kersville, MD, USA) and then subsequently enzymatically di- gested using 0.075% Type 1A collagenase (MERCK Millipore, USA). Enzyme stop media com- prising 10% foetal bovine serum-FBS (Sigma St. Louis, MO, USA) in Dulbecco’s modi- fied Eagle’s medium (DMEM)- high glucose (Sigma St. Louis, MO, USA) was used to neutral- ize the enzymatic process (see Figure 2B). The stromal vascu- lar fraction pellet (Figure 2C) was subsequently incubated in 10 ml of red cell lysis buffer (Sigma St. Louis, MO, USA) at room temperature for 10 min- utes and later washed in 1X PBS. Through a 100 µm nylon cell strainer (BD Falcon, NJ, USA), the mixture was filtered to remove any unwanted tis- sue debris. Centrifugation at 1200 g resulted in the stromal vascular fraction (SVF) pellet, which was then resuspended in 1.5 mL of Ringer’s lactate solution. To determine the cell count and viability, 10 µl of the cell suspension was added to an equal volume of 0.4% Trypan blue (Sigma St. Louis, MO, USA) and then mounted into a Neubauer counting chamber as per Strober’s guidelines [42]. Cells were count- ed at 40× magnification, as shown in Figure 3. Total nucleated cells per 10 µl were used to determine the final cell dosing, while viability was determined using the Trypan blue exclu- sion test [42]. The total number of viable cells Adipose derived stromal vascular fraction in keloid treatment: a pilot study 27 Am J Stem Cells 2023;12(2):23-36 Figure 3. Stromal vascular fraction cells following staining using Trypan blue ready for cell counting. Cell suspension mounted on a Neubauer counting chamber and cells counted at ×40 magnification (Scale bar of 250 µm). Figure 4. Infiltration of the stromal vascular fraction into keloid tissue. in the Neubauer counting chamber was used to calculate the total number of cells in the 1.5 ml suspension factoring in the two times dilution factor during trypan blue staining. The stromal vascular fraction dosing was constituted by diluting the SVF suspension to a 1:1 ratio of SVF volume to keloid volume. Hence, for a 4 cm3 keloid, 1.5 ml of original SVF suspension was constituted to make 4 ml by the addition of 1X phosphate buffered saline (PBS). The final infiltration cellular dosing cal- culation per millilitre was com- puted, and medication was placed into hypodermic syring- es ready for infiltration. The triamcinolone acetonide (TAC) group For this arm, one ampoule of triamcinolone acetonide (TAC) containing 40 mg in 1 ml was used for each patient. To each ml of triamcinolone, 1 ml of 2% lidocaine and 2 ml of water were added for injection to constitute 4 ml of TAC suspen- sion at a concentration of 10 mg per ml. The suspension was placed in hypodermic syringes for subsequent infil- tration into the keloid tissue. For each patient, a maximum of 40 mg of triamcinolone could be infiltrated into the keloid under study. The standard dosing for tri- amcinolone for keloid volume was described by Rahban and Ganner [43]. Injection of the SVF and TAC into the keloid The selected keloid was pre- pped with 10% povidone io- dine and then appropriately draped. Infiltration into the keloid depended on the keloid mor- phology, volume and shape. Each keloid, where applicable, was divided into four quadrants, and the infiltration dose was equally divided into the four quadrants. An infil- tration volume of 0.1 ml per cubic millimetre or 1 ml for every cubic centimetre was targeted. This was based on estimates from Rahban [43] and Rables [44] studies. See Figure 4. In some instances, the keloid tissues were thick, and it was impossible to enable infiltra- Adipose derived stromal vascular fraction in keloid treatment: a pilot study 28 Am J Stem Cells 2023;12(2):23-36 Table 1. Common terminology criteria for adverse events (CTCAE) v5.0 tool Grade Grade 1 Mild Mild symptoms, no intervention required. Grade 2 Moderate Minimal or local non-invasive intervention needed. Grade 3 Severe or medically significant Severe but not immediately life threatening. Requires hospitalization, disabling. Grade 4 Life threatening consequences Urgent intervention indicated. Grade 5 Death tion of the appropriate dosage. In such cases, ‘needling’ was performed. ‘Needling’ is when a 22-gauge needle is used to create a mesh/net- work of interconnecting tunnels 2 mm apart into the keloid. Following this, infiltration of the treatment was instituted into the created tunnels. General trial procedure Patients who were included and consented to the trial underwent standard preoperative care, including informed consent for surgery. The research assistants enrolled the partici- pants, obtained baseline characteristics, and then randomized and allocated them into ei- ther treatment arm. The intervention was ad- ministered by a qualified surgeon who had pre- viously been trained on the standards and practices of the procedures. Following the pro- cedure, postprocedural analgesics were pro- vided to participants based on the hospital guidelines for day-care surgery. At follow-up, patients were reassessed clinically at the plas- tic surgical clinic. The reviews were scheduled at one week and one month while a final follow- up at the end of three months upon which the participants exited the study. The project principal investigator undertook the follow-up reviews. Participants were provided with a transport refund during the follow-up visits. Outcome The primary outcome variables were safety and feasibility of using autologous adipose- derived stromal vascular fraction in the treat- ment of keloids in comparison to Triamcinolone Acetanoide. Safety Adverse events were defined based on the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 tool as any unfavoura- ble and unintended symptom, sign or disease associated with the use of a medical treatment or procedure that may or may not be directly an intended result of the procedure. These adverse events experienced by the participants were documented based on CTCAE v5.0 [45] and were reported on a running daily basis for the entire study period. Specific assessments for adverse event development were conducted on day 0 (immediate post procedure), day 1, days seven, one and three months. The partici- pants were asked to spontaneously report any adverse events to the study principal inves- tigator through a phone call at any time during the follow-up period, and the principal investi- gator would then follow-up with the necessary intervention. Adverse events were graded as seen in Table 1, and the adverse event grade at each assess- ment time was recorded. The adverse events looked out for included. Donor site adverse events: Among patients in the SVF arm. The development of haematoma, bleeding, infections and pain, delayed wound healing, and keloid development at the liposuc- tion site. The nature and severity of the adverse events were graded using the CTCAE v5.0 tool. Infiltration/recipient site adverse events: In both arms, the keloid and surrounding skin, adverse events were observed, including bleed- ing, excessive pain, infection, and ulceration. These were also graded using the CTCAE v5.0 tool. Feasibility The criteria for feasibility were based on four parameters that had to be met for the proce- dure to be considered feasible. All four param- eters had to be feasible for the procedures to be classified as feasible. Recruitment feasibility: This referred to the enrolment and acceptability to participate Adipose derived stromal vascular fraction in keloid treatment: a pilot study 29 Am J Stem Cells 2023;12(2):23-36 appropriateness of this follow-up was evaluat- ed to establish the optimal timing before sub- sequent follow-up therapy. This was based on the duration of symptom remission or symp- tom-free duration. Secondary outcomes Clinical outcomes were the mean change in the Patient and Observer Scar Assessment Scores (POSAS) from baseline to one month and three months. Monitoring treatment fidelity Because this was the first time this kind of study was being conducted, it was important that treatment fidelity be monitored. Specifi- cally, fidelity adherence checklists were devel- oped, and each key step in the study implemen- tation was compared to the described protocol to evaluate the degree of deviation. Deviations from the protocol were identified, and the rea- sons were reported. For each procedural step, the investigator was asked to rate how compli- ant they were in keeping with the trial protocols. Second, standardization training of the partici- pants and research assistants was performed to ensure consistency in trial procedures. Sample size estimation This was a phase one study intended to explore the safety, feasibility and refine the trial pro- cess and not establish an effect. Therefore, hypothesis testing to establish a sample size was not necessary. This was based on the rec- ommendations of Arain [46]. To establish the sample size, we used the for- mula by Lackey et al where they proposed that the pilot study sample size comprised 10% of the main trial size. Based on this recommenda- tion, a pilot sample size of 8 participants, which is 10% of the main clinical trial sample size, was established with 4 participants allocated to each arm. Randomization and allocation concealment Randomization was performed using STATA command ralloc by a statistician who was not directly involved in the study. Block randomiza- tion using block size 2 was used to allocate patients following a 1:1 ratio. among those who were found to be eligible. Obtaining consent in 70% of the first 10 res- pondents was described as feasible for recruit- ment. For those who declined, reasons for the decline were sought out. Intervention feasibility: As a day-care proce- dure: Here we looked at two variables which were the procedure time and the procedure completion rates. The procedure time was defined as the total procedure time it took the whole procedure to be performed in hours. Durations of equal to or less than 5 hours were described as feasible. The procedure comple- tion rates and general anaesthesia conversion rates: The procedure was intended to be con- ducted under local anesthesia with optional opioid analgesia addition. Completion, as de- scribed above without the need for conversion to general anaesthesia or procedural abandon- ment, was described as feasible. Suitability of outcome measurements: We in- tended to describe the keloid thickness mea- surement as are key outcome measurement. Keloid height/thickness was determined in millimeters using high-frequency ultrasound (Healcerion SONON portable ultrasound model 300 L). This ultrasound scan device has a capacity for length measurement with up to two decimal point accuracy. Suitability was described as the interobserver ability to con- sistently reproduce three ultrasound thickness measurements at the same site with a varia- tion of ≤ ±0.03. The feasibility of assessing the primary out- come measures of the main trial of Patients and Observer Scar Assessment Score (POSAS) and keloid volume calculation were also as- sessed. Completion rates and challenges in assessing each of these outcomes were evaluated. Follow up feasibility: We also assessed the feasibility of following up the participants. Specifically, we looked at the assessment for co-intervention, appropriateness of timing for the next intervention. In the first case, partici- pant utilisation of any other treatment during the follow-up period, the timing of use and the reason were determined. For the appropriate- ness of timing for the next intervention, the study follow-up of three months was used. The Adipose derived stromal vascular fraction in keloid treatment: a pilot study 30 Am J Stem Cells 2023;12(2):23-36 Sequentially numbered opaque envelopes were used to conceal the allocation sequences, and these were prepared by the same statistician that generated the randomization. The enve- lopes were stapled and handed to the recruit- ment nurse who only interfaced with the patients during the allocation of treatment the day of the procedure and did not interact with the enrolling research assistant. At the time of allocation into the different study arms, the recruiting nurse would detach the sequential envelope to identify the allocation and subsequently keep the envelope. Blinding The nature of the study procedure made it impossible to blind the patients and the sur- geons, as liposuction instantly revealed which arm the patient was allocated. The outcome assessors, on the other hand, who followed up patients for review were blinded, as they did not know what intervention the participants had received. Statistical methods Data analysis for the participant demograph- ics, baseline characteristics, safety, and feasi- bility took on a descriptive approach with all data being exported and analysed in STATA 15.0. Continuous data are reported as the means (± SD), while categorical data are reported as pro- portions with their percentages. Categorical data analysis was performed for the first primary endpoint of safety. Proportions with the percentages of the different Common Terminology Criteria for Adverse Events (CTCAE) v5.0 grades were obtained. Broadly, two cate- gories of “adverse events” and “no adverse events” were analysed and compared bet- ween the two treatment arms using chi square tests. For the second primary endpoint of feasibility, variables were categorized into feasible or not feasible, and the proportions were determined. Comparison between the two treatment arms was performed using chi square tests. For the secondary outcomes, efficacy end- points were merely exploratory; therefore, ana- lytical assessments were not performed. These were continuous variables and were reported as the means with standard deviations. We evaluated for the presence of mean differences in the two treatment arms at one week, one month and three months and at baseline. Patient & public involvement Patients and participants were not involved in the development of the research question, choice of outcome measures, design of the trial, recruitment of participants or conduct of the trial. The results of the trial were dissemi- nated to the study participants through direct consultation. Results Characteristics of the study participants Eight participants were recruited during the months of March and April 2021 and were fol- lowed up for three months with the last follow- up taking place in July 2021. Their mean age was 27.9 (±6.5) years, while five of the participants were female. Despite the randomization, all the participants that were allocated into the intervention arm were female, while one female was allocated into the control arm. The mean BMI was 27.9 (±6.0), with a BMI generally higher among the intervention arm. The mean keloid duration was 4.4 (±5.5) years, and none of these par- ticipants had received any therapy in the last three months. Details of the keloid distribution can be found in (Table 2). In the SVF arm, participants selectively pre- ferred the liposuction point to be the outer thigh out of three options of the abdominal, inner thigh, and outer thigh. The mean infiltrat- ed volume of tumescence fluid was 387.5 (±114) ml, with a mean lipoaspirate volume of 137.5 (±37.7) ml. The total cell counts among the participants were found to be skewed. Particularly one par- ticipant had an outlier value. Because these data were not normally distributed, we used medians with their interquartile ranges (IQRs) instead of means with standard deviations. Adipose derived stromal vascular fraction in keloid treatment: a pilot study 31 Am J Stem Cells 2023;12(2):23-36 Table 2. Baseline characteristics of study participants Participant Age Sex BMI Location of keloid Duration of keloid (years) Treatment intervention 001 24 Male 23.3 Sternal 1 TAC 002 26 Female 32.4 Sternal 1 SVF 003 24 Female 35.3 Sub-mandibular 18 SVF 004 39 Female 35.9 Epigastric 2 SVF 005 25 Male 19.8 Sternal 6 TAC 006 20 Female 21.6 Earlobe 5 SVF 007 25 Male 23.9 Lateral infrapatellar 2 TAC 008 36 Female 31.2 Breast 1 TAC Mean 27.9 (±6.5) NA 27.9 (±6.0) Not applicable 4.4 (±5.5) NA Following processing, the mean total number of viable stromal cells in the entire lipoaspirate was estimated to be 9.9×106 (±13.8×106) cells with a mean dosing of 3.2×106 (±4.6×106) cells/ml of infiltrating suspension. The median total number of stromal cells was 2.7×106 cells with an interquartile range of 11×106 cells. Overall cellular viability was reported at 94%. For details see Table 3. Comparison of safety profile On the day of intervention, there were no ad- verse events that were reported, and all pa- tients were subsequently discharged as had been intended. There were still no adverse events at the 24-hour follow-up. Overall, no serious adverse events were recorded. One participant in the triamcinolone group report- ed the development of an ulcer at the infiltra- tion site that developed on day five following the intervention. This required administration of oral antibiotics and analgesics and a topical antibacterial cream but no surgical interven- tion or hospitalization. Subsequently, the ulcer healed by the second week of follow-up. Among the SVF group, there were no reported adverse events in the entire follow-up period. Feasibility of adipose-derived stromal vascular fraction Overall, both treatments were feasible with comparable differences. Recruitment feasibility Among the first 8 eligible participants who were reached out to participate, two declined to par- ticipate in the study after they had received information about the clinical trial. This prompt- ed us to reach out to the next two eligible par- ticipants who agreed to participate in the study. Based on this, overall, recruitment feasibility stood at 80%. The reason for the decline was the unwillingness to have another site away from the keloid operated upon, while the sec- ond respondent strictly wanted to undergo sur- gical excision. Intervention feasibility Duration of procedure: On average, the proce- dure time for triamcinolone was 30 minutes to one hour, while that of the SVF took a mean time of 5 hours. All interventions were success- fully conducted as day-care procedures, and no patient required hospitalization. Table 3. Characteristics of participants in SVF arm No. Tumescence fluid infiltrated Lipoaspirate volume Processed lipoaspirate Total viable cell count harvested Infiltration volume (ml) Infiltration dose cells/ml Cellular viability 002 500 200 110 4.5×106 5 9×105 98 004 500 130 70 33.6×106 3 11.2×106 98 004 300 120 57 6×105 3 2×105 85 007 250 100 52 8.4×105 1.5 5.6×105 95 Mean (±SD) 387.5 (±114) 137.5 (±37.7) 72.3 (±22.8) 9.9×106 (±13.8×106) 3.25 (±1.1) 3.2×106 (±4.6×106) 94 (±5.3) Median (IQR) 400 (212.5) 125 (32.5) 63.5 (24.3) 2.7×106 (11×106) 3 (0.75) 7.3×105 (3×106) 96.5 (5.5) Adipose derived stromal vascular fraction in keloid treatment: a pilot study 32 Am J Stem Cells 2023;12(2):23-36 Procedure completion rates: All intended pro- cedures had a completion rate of 100%. This means that no procedure was abandoned once it had been started. Second, there was no con- version to general anaesthesia, as all patients tolerated the procedure. In the SVF arm, one patient needed supple- mental opioid analgesia and was given IV fen- tanyl 50 mcg, which sufficiently controlled the break-through pain during the liposuction pro- cess. Suitability of outcome measurements Keloid thickness: Two independent radiologists performed cutaneous ultrasound to determine keloid scar thickness. The interobserver vari- ability was within the stipulated margin of ±0.03. Surface area estimation using photography when compared to surface area mapping using tracing paper was found to be more unreliable with variability in establishing focal length and angles. Surface area mapping using tracing paper proved a more reliable measurement estimate. Follow up feasibility Co-intervention: All patients but one did not seek additional therapy during the first two months of therapy. The patient who developed the ulcer had to seek extra therapy, and she received a topical antibacterial cream. Secondary outcome: All participants’ Patient and Observer Scar Assessment Scores (POSAS) improved (reduced) by a mean of 12.5 (±7.2) and 7.6 (±3.1) at one month and three months, respectively, when compared to baseline. The one-month mean difference in the improve- ment of POSAS scores between SVF and TAC was 14.8 (±8.6) and 10.3 (±4.6), respectively. At three months, the mean difference in POSAS scores when compared to baseline was 7.8 (±3.3) and 7.5 (±2.9) in the SVF and TAC arms, respectively. All patients in all arms reported resolution of itching and noted scar softening. Treatment fidelity: To ensure adherence to treatment fidelity, all study staff were trained on strict adherence to the research protocol. In all participants in both arms, adherence to the protocol was followed. Discussion To date, there a few clinical trials comparing autologous adipose-derived stromal vascular fractions to other keloid therapies with the majority of existing studies being observational [27, 47-49]. Secondly, most published studies in high-income countries cast uncertainty on the feasibility of conducting similar trials in low- and middle-income countries, where the great- est burden of keloids is found [47, 50]. To the best of our knowledge, no clinical trial has been published, particularly in sub-Saharan Africa exploring this therapy. This trial therefore provides critical information on the feasibility of conducting this study in a resource-limited setting in addition to describ- ing its safety while also comparing it to the widely used therapy of triamcinolone aceto- nide. With the broader goal of conducting a phase II clinical trial to evaluate the efficacy of SVF in keloid treatment, a preliminary phase I trial was required to provide preliminary feasibility and safety data. Feasibility of SVF To appropriately determine the feasibility, key steps of the study were identified and evaluat- ed. As a new therapy, the willingness of partici- pants to enrol was unknown, yet this would fun- damentally determine the success of the trial. Therefore, recruitment feasibility was assess- ed. With recruitment feasibility at 80%, the pilot scored well above the minimum feasibility score of 70%. Among the two participants who declined, one had previously been scheduled for surgical excision and had missed surgery and therefore opting for the earlier treatment plan. The second patient expressed her scepti- cism about being involved in an entirely new therapy that had not been practiced in the country earlier. This recruitment feasibility rate is comparable to studies conducted elsewhere where SVF use is described as feasible [47, 51]. For interventional feasibility testing, key techni- cal aspects of the procedures were assessed, including completion rates. All treatment arms passed the set interventional feasibility test. Specifically, for SVF, a five-hour duration en- abled the procedure to be performed as a day care procedure. This was comparable to other Adipose derived stromal vascular fraction in keloid treatment: a pilot study 33 Am J Stem Cells 2023;12(2):23-36 studies with treatment durations of 4 hours [52] and three hours [51]. In one study by Karina, a shorter time of 2-3 hours excluded the infiltration and observation time. The fact that no patients required conversion of anaes- thesia to general and the completion rates of 100% clearly demonstrated the feasibility of the trial procedure, especially as a day care therapy. Other centres similarly conduct SVF as a day care procedure with the use of tumes- cence liposuction [51, 52]. Safety For the safety of the procedure, overall, pa- tients who received the SVF intervention did not report any adverse events during the entire study period. These findings are in keeping wi- th reports described elsewhere [51, 53, 54]. According to one systematic review by Gentile, there were no particular adverse events asso- ciated with SVF treatment in scar tissues [55] besides the pain that comes with the proce- dure. Overall, SVF therapy for intralesional scar treatment is safe. In contrast, the Triamcino- lone arm registered one case of a grade II adverse event. Ulceration following infiltration of TAC has been described and is a well- known side effect [56]. The development of this adverse event highlights the limitation of TAC as the most used keloid treatment. This forms a justification for the need for alternative therapies. In both treatment arms, there were improve- ments in the POSAS scores at both one month and three months. The difference was most marked at one month, with the decline in scar improvement possibly explainable by the wan- ing treatment effect. All patients in both arms described symptom resolution of itching in addition to softening of the scars. However, despite the promising improvement in POSAS scores, this study was neither intended nor powered to draw any such conclusions on effi- cacy, as this is the primary objective of the anticipated phase II trial. Strengths and limitations One strength of this trial is that patients were randomized to minimize bias. Second, the real- time evaluation of treatment fidelity ensured adherence to developed protocols. The des- cription of the SVF arm as feasible is a streng- th of this study, as it forms the foundation for conducting a phase II clinical trial. This is the first randomized clinical trial evaluating stromal vascular fraction in sub-Saharan Africa and will play a role in advancing practice on the continent. Some limitations in our study included the allo- cation of one gender into the intervention arm despite block randomization. This was due to the small sample size as well as predominantly female attendance in the plastic surgical clinic. This may be due to the cosmetically disfiguring nature associated with keloids. The gender skew limited the SVF characterisation among the males. This, however, will guide the ran- domization of the phase II trial with specific incorporation of stratification for sex during the randomization process. Conclusion Based on our findings, autologous adipose- derived stromal vascular fraction is feasible and safe as a therapy in the treatment of keloids. The trial demonstrates that SVF the- rapy can be safely performed as a day care procedure. Although not designed to assess efficacy, the trial describes promising improve- ment in the POSAS scores and symptom relief for all participants during the follow-up time. Recommendations Based on this pilot trial, we recommend that a phase II randomized controlled trial comparing efficacy in SVF and TAC be conducted. Acknowledgements We wish to acknowledge the staff of the Department of Plastic Surgery at Kirruddu National Referral Hospital Kampala for the commitment during the implementation of the study. We also wish to acknowledge the De- partment of Physiology at Makerere University College of Health Sciences for the provision of laboratory space and key equipment needed during this study. Research reported in this publication was supported by the Fogarty International Centre of the National Institutes of Health, U.S. Department of State’s Office of the U.S. Global AIDS Coordinator and Health Diplomacy (S/GAC), and President’s Emergency Adipose derived stromal vascular fraction in keloid treatment: a pilot study 34 Am J Stem Cells 2023;12(2):23-36 Plan for AIDS Relief (PEPFAR) under Award Number 1R25TW011213. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Additional funding was obtained from the Makerere University Research Innovation Fund (MakRIF) grant reg- istration: MAK/DVCFA/113/20. Disclosure of conflict of interest None. Abbreviations CTCAE, Common Terminology Criteria for Adverse Events; POSAS, Patient and Observer Scar Assessment Score; SVF, Stromal Vascular Fraction; TAC, Triamcinolone Acetonide. Address correspondence to: Ronald Mbiine, De- partment of Surgery, Makerere University College of Health Sciences, P.O. Box 7072, Kampala, Uganda. Tel: +256-774-338585; ORCID: 0000-0003-2403- 1656; E-mail: mbiineron@gmail.com References [1] McGinty S and Siddiqui WJ. Keloid. In: Stat- Pearls [Internet]. Treasure Island (FL): Stat- Pearls Publishing; 2020. [2] Rockwell WB, Cohen IK and Ehrlich HP. Keloids and hypertrophic scars: a comprehensive re- view. Plast Reconstr Surg 1989; 84: 827-837. [3] Betarbet U and Blalock TW. Keloids: a review of etiology, prevention, and treatment. J Clin Aesthet Dermatol 2020; 13: 33-43. [4] Ekstein SF, Wyles SP, Moran SL and Meves A. Keloids: a review of therapeutic management. Int J Dermatol 2021; 60: 661-671. [5] Robles DT and Berg D. Abnormal wound heal- ing: keloids. Clin Dermatol 2007; 25: 26-32. [6] Wong TS, Li JZ, Chen S, Chan JY and Gao W. The efficacy of triamcinolone acetonide in ke- loid treatment: a systematic review and meta- analysis. Front Med (Lausanne) 2016; 3: 71. [7] Shah VV, Aldahan AS, Mlacker S, Alsaidan M, Samarkandy S and Nouri K. 5-fluorouracil in the treatment of keloids and hypertrophic scars: a comprehensive review of the litera- ture. Dermatol Ther (Heidelb) 2016; 6: 169- 183. [8] Li Z and Jin Z. Comparative effect and safety of verapamil in keloid and hypertrophic scar treatment: a meta-analysis. Ther Clin Risk Manag 2016; 12: 1635-1641. [9] Barara M, Mendiratta V and Chander R. Cryo- therapy in treatment of keloids: evaluation of factors affecting treatment outcome. J Cutan Aesthet Surg 2012; 5: 185-189. [10] Morelli Coppola M, Salzillo R, Segreto F and Persichetti P. Triamcinolone acetonide intrale- sional injection for the treatment of keloid scars: patient selection and perspectives. Clin Cosmet Investig Dermatol 2018; 11: 387-396. [11] Tan E, Chua S and Lim J. Topical silicone gel sheet versus intralesional injections of triam- cinolone acetonide in the treatment of keloids - a patient-controlled comparative clinical trial. J Dermatolog Treat 1999; 10: 251-254. [12] Davison SP, Dayan JH, Clemens MW, Sonni S, Wang A and Crane A. Efficacy of intralesional 5-fluorouracil and triamcinolone in the treat- ment of keloids. Aesthet Surg J 2009; 29: 40- 46. [13] Mustoe TA, Cooter RD, Gold MH, Hobbs FD, Ra- melet AA, Shakespeare PG, Stella M, Téot L, Wood FM and Ziegler UE; International Adviso- ry Panel on Scar Management. International clinical recommendations on scar manage- ment. Plast Reconstr Surg 2002; 110: 560- 571. [14] Jacobs C and Wilmink J. Combined versus sin- gle treatment regimens for keloid therapy us- ing serial intralesional corticosteroid injec- tions, surgical excision, silicone- and/or cry- otherapy. JPRAS Open 2021; 29: 157-166. [15] Miles OJ, Zhou J, Paleri S, Fua T and Ramak- rishnan A. Chest keloids: effect of surgical exci- sion and adjuvant radiotherapy on recurrence, a systematic review and meta-analysis. ANZ J Surg 2021; 91: 1104-1109. [16] Berman B and Flores F. Recurrence rates of excised keloids treated with postoperative tri- amcinolone acetonide injections or interferon alfa-2b injections. J Am Acad Dermatol 1997; 37: 755-757. [17] Limmer EE and Glass DA. A review of current keloid management: mainstay monotherapies and emerging approaches. Dermatol Ther (Hei- delb) 2020; 10: 931-948. [18] Ojeh N, Bharatha A, Gaur U and Forde AL. Ke- loids: current and emerging therapies. Scars Burn Heal 2020; 6: 2059513120940499. [19] Zuk PA, Zhu M, Ashjian P, De Ugarte DA, Huang JI, Mizuno H, Alfonso ZC, Fraser JK, Benhaim P and Hedrick MH. Human adipose tissue is a source of multipotent stem cells. Mol Biol Cell 2002; 13: 4279-4295. [20] Nguyen A, Guo J, Banyard DA, Fadavi D, Toran- to JD, Wirth GA, Paydar KZ, Evans GR and Wid- gerow AD. Stromal vascular fraction: a regen- erative reality? Part 1: current concepts and review of the literature. J Plast Reconstr Aes- thet Surg 2016; 69: 170-179. [21] Zuk PA, Zhu M, Mizuno H, Huang J, Futrell JW, Katz AJ, Benhaim P, Lorenz HP and Hedrick mailto:mbiineron@gmail.com Adipose derived stromal vascular fraction in keloid treatment: a pilot study 35 Am J Stem Cells 2023;12(2):23-36 MH. Multilineage cells from human adipose tissue: implications for cell-based therapies. Tissue Eng 2001; 7: 211-228. [22] Pak J, Lee JH, Pak NJ, Park KS, Jeon JH, Jeong BC and Lee SH. Clinical protocol of producing adipose tissue-derived stromal vascular frac- tion for potential cartilage regeneration. J Vis Exp 2018; 58363. [23] Deng C, Wang L, Feng J and Lu F. Treatment of human chronic wounds with autologous extra- cellular matrix/stromal vascular fraction gel: a STROBE-compliant study. Medicine (Baltimore) 2018; 97: e11667. [24] Deptuła M, Brzezicka A, Skoniecka A, Zieliński J and Pikuła M. Adipose-derived stromal cells for nonhealing wounds: emerging opportuni- ties and challenges. Med Res Rev 2021; 41: 2130-2171. [25] Boada-Pladellorens A, Avellanet M, Pages-Boli- bar E and Veiga A. Stromal vascular fraction therapy for knee osteoarthritis: a systematic review. Ther Adv Musculoskelet Dis 2022; 14: 1759720x221117879. [26] Siennicka K, Zolocinska A, Stepien K, Lubina- Dabrowska N, Maciagowska M, Zolocinska E, Slysz A, Piusinska-Macoch R, Mazur S, Zdano- wicz U, Smigielski R, Stepien A and Pojda Z. Adipose-derived cells (stromal vascular frac- tion) transplanted for orthopedical or neuro- logical purposes: are they safe enough? Stem Cells Int 2016; 2016: 5762916. [27] Lee JW, Park SH, Lee SJ, Kim SH, Suh IS and Jeong HS. Clinical impact of highly condensed stromal vascular fraction injection in surgical management of depressed and contracted scars. Aesthetic Plast Surg 2018; 42: 1689- 1698. [28] Stachura A, Paskal W, Pawlik W, Mazurek MJ and Jaworowski J. The use of adipose-derived stem cells (ADSCS) and stromal vascular frac- tion (SVF) in skin scar treatment-a systematic review of clinical studies. J Clin Med 2021; 10: 3637. [29] Behrangi E, Moradi S, Ghassemi M, Goodarzi A, Hanifnia A, Zare S, Nouri M, Dehghani A, Sei- fadini A, Nilforoushzadeh MA and Roohanina- sab M. The investigation of the efficacy and safety of stromal vascular fraction in the treat- ment of nanofat-treated acne scar: a random- ized blinded controlled clinical trial. Stem Cell Res Ther 2022; 13: 298. [30] Chen H, Hou K, Wu Y and Liu Z. Use of adipose stem cells against hypertrophic scarring or ke- loid. Front Cell Dev Biol 2021; 9: 823694. [31] Borovikova AA, Ziegler ME, Banyard DA, Wirth GA, Paydar KZ, Evans GRD and Widgerow AD. Adipose-derived tissue in the treatment of der- mal fibrosis: antifibrotic effects of adipose-de- rived stem cells. Ann Plast Surg 2018; 80: 297-307. [32] Xie F, Teng L, Xu J, Lu J, Zhang C, Yang L, Ma X and Zhao M. Adipose-derived mesenchymal stem cells inhibit cell proliferation and migra- tion and suppress extracellular matrix synthe- sis in hypertrophic-scar and keloid fibroblasts. Exp Ther Med 2021; 21: 139. [33] Li L, Zhang S, Zhang Y, Yu B, Xu Y and Guan Z. Paracrine action mediate the antifibrotic effect of transplanted mesenchymal stem cells in a rat model of global heart failure. Mol Biol Rep 2009; 36: 725-731. [34] Fujita M, Matsumoto T, Hayashi S, Hashimoto S, Nakano N, Maeda T, Kuroda Y, Takashima Y, Kikuchi K, Anjiki K, Ikuta K, Onoi Y, Tachibana S, Matsushita T, Iwaguro H, Sobajima S, Hi- ranaka T and Kuroda R. Paracrine effect of the stromal vascular fraction containing M2 mac- rophages on human chondrocytes through the Smad2/3 signaling pathway. J Cell Physiol 2022; 237: 3627-3639. [35] Li Y, Zhang W, Gao J, Liu J, Wang H, Li J, Yang X, He T, Guan H, Zheng Z, Han S, Dong M, Han J, Shi J and Hu D. Adipose tissue-derived stem cells suppress hypertrophic scar fibrosis via the p38/MAPK signaling pathway. Stem Cell Res Ther 2016; 7: 102. [36] Li J, Li Z, Wang S, Bi J and Huo R. Exosomes from human adipose-derived mesenchymal stem cells inhibit production of extracellular matrix in keloid fibroblasts via downregulating transforming growth factor-β2 and Notch-1 ex- pression. Bioengineered 2022; 13: 8515- 8525. [37] Stevenson AW, Deng Z, Allahham A, Prêle CM, Wood FM and Fear MW. The epigenetics of ke- loids. Exp Dermatol 2021; 30: 1099-1114. [38] Williams SK, Morris ME, Kosnik PE, Lye KD, Gentzkow GD, Ross CB, Dwevidi AJ and Klein- ert LB. Point-of-care adipose-derived stromal vascular fraction cell isolation and expanded polytetrafluoroethylene graft sodding. Tissue Eng Part C Methods 2017; 23: 497-504. [39] Smakaj A, De Mauro D, Rovere G, Pietramala S, Maccauro G, Parolini O, Lattanzi W and Li- uzza F. Clinical application of adipose derived stem cells for the treatment of aseptic non- unions: current stage and future perspectives- systematic review. Int J Mol Sci 2022; 23: 3057. [40] Eldridge SM, Chan CL, Campbell MJ, Bond CM, Hopewell S, Thabane L and Lancaster GA; PAFS consensus group. CONSORT 2010 state- ment: extension to randomised pilot and feasi- bility trials. BMJ 2016; 355: i5239. [41] Hoffmann TC, Glasziou PP, Boutron I, Milne R, Perera R, Moher D, Altman DG, Barbour V, Macdonald H, Johnston M, Lamb SE, Dixon- Adipose derived stromal vascular fraction in keloid treatment: a pilot study 36 Am J Stem Cells 2023;12(2):23-36 Woods M, McCulloch P, Wyatt JC, Chan AW and Michie S. Better reporting of interventions: template for intervention description and repli- cation (TIDieR) checklist and guide. BMJ 2014; 348: g1687. [42] Strober W. Trypan blue exclusion test of cell viability. Curr Protoc Immunol 2015; 111: A3.B.1-A3.B.3. [43] Rahban SR and Garner WL. Fibroproliferative scars. Clin Plast Surg 2003; 30: 77-89. [44] Robles DT, Moore E, Draznin M and Berg D. Ke- loids: pathophysiology and management. Der- matol Online J 2007; 13: 9. [45] Freites-Martinez A, Santana N, Arias-Santiago S and Viera A. Using the common terminology criteria for adverse events (ctcae - version 5.0) to evaluate the severity of adverse events of anticancer therapies. Actas Dermosifiliogr (Engl Ed) 2021; 112: 90-92. [46] Arain M, Campbell MJ, Cooper CL and Lancast- er GA. What is a pilot or feasibility study? A re- view of current practice and editorial policy. BMC Med Res Methodol 2010; 10: 67. [47] Mattei A, Bertrand B, Jouve E, Blaise T, Philan- drianos C, Grimaud F, Giraudo L, Aboudou H, Dumoulin C, Arnaud L, Revis J, Galant C, Velier M, Veran J, Dignat-George F, Dessi P, Sabatier F, Magalon J and Giovanni A. Feasibility of first injection of autologous adipose tissue-derived stromal vascular fraction in human scarred vocal folds: a nonrandomized controlled trial. JAMA Otolaryngol Head Neck Surg 2020; 146: 355-363. [48] Mattei A, Magalon J, Bertrand B, Grimaud F, Revis J, Velier M, Veran J, Dessi P, Sabatier F and Giovanni A. Autologous adipose-derived stromal vascular fraction and scarred vocal folds: first clinical case report. Stem Cell Res Ther 2018; 9: 202. [49] Negenborn VL, Groen JW, Smit JM, Niessen FB and Mullender MG. The use of autologous fat grafting for treatment of scar tissue and scar- related conditions: a systematic review. Plast Reconstr Surg 2016; 137: 31e-43e. [50] Huang C, Wu Z, Du Y and Ogawa R. The epide- miology of keloids. In: Téot L, Mustoe TA, Mid- delkoop E, Gauglitz GG, editors. Textbook on Scar Management: State of the Art Manage- ment and Emerging Technologies. Cham: Springer International Publishing; 2020. pp. 29-35. [51] Karina K, Rosliana I, Rosadi I, Schwartz R, So- bariah S, Afini I, Widyastuti T, Remelia M, Wa- hyuningsih KA and Pawitan JA. Safety of tech- nique and procedure of stromal vascular fraction therapy: from liposuction to cell ad- ministration. Scientifica (Cairo) 2020; 2020: 2863624. [52] Park Y, Lee YJ, Koh JH, Lee J, Min HK, Kim MY, Kim KJ, Lee SJ, Rhie JW, Kim WU, Park SH, Moon SH and Kwok SK. Clinical efficacy and safety of injection of stromal vascular fraction derived from autologous adipose tissues in systemic sclerosis patients with hand disabili- ty: a proof-of-concept trial. J Clin Med 2020; 9: 3023. [53] Aronowitz JA, Lockhart RA, Hakakian CS and Hicok KC. Clinical safety of stromal vascular fraction separation at the point of care. Ann Plast Surg 2015; 75: 666-671. [54] Mazur S, Zołocińska A, Siennicka K, Janik-Ko- sacka K, Chrapusta A and Pojda Z. Safety of adipose-derived cell (stromal vascular fraction - SVF) augmentation for surgical breast recon- struction in cancer patients. Adv Clin Exp Med 2018; 27: 1085-1090. [55] Gentile P, Sterodimas A, Calabrese C and Garc- ovich S. Systematic review: advances of fat tis- sue engineering as bioactive scaffold, bioac- tive material, and source for adipose-derived mesenchymal stem cells in wound and scar treatment. Stem Cell Res Ther 2021; 12: 318. [56] Schetman D, Hambrick GW Jr and Wilson CE. Cutaneous changes following local injection of triamcinolone. Arch Dermatol 1963; 88: 820- 828.