Dermatology: Practical and Conceptual Original Article | Dermatol Pract Concept. 2024;14(3):e2024183 1 Microneedling with Topical Insulin Versus Microneedling with Non-Cross-Linked Hyaluronic Acid for Atrophic Post-Acne Scars: A Split-Face Study Shaimaa Hassan Mohamed1, Ghada Abd-Elbadea Omar1, Aliaa El-Sayed Hamdy1 1 Dermatology and Venereology Department, Faculty of Medicine for Girls, Al-Azhar University. Cairo, Egypt Key words: acne scars, microneedling, insulin, non-cross-linked hyaluronic acid Citation: Mohamed SH, Omar GAE, Hamdy AES. Microneedling With Topical Insulin Versus Microneedling With Non-cross-linked Hyaluronic Acid for Atrophic Post-Acne Scars: A Split-Face Study. Dermatol Pract Concept. 2024;14(3):e2024183. DOI: https://doi. org/10.5826/dpc.1403a183 Accepted: March 22, 2024; Published: July 2024 Copyright: ©2024 Mohamed et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Dr. Shaimaa Hassan Mohamed ,MD, Lecturer at Dermatology and Venereology Department, Faculty of Medicine for Girls, Al-Azhar university, Al-Zahraa Hospital, Box 11517 Al-Abbasia Cairo, Egypt. Telephone number +2 01021106064. E-mail: shaimaadiab08@gmail.com Introduction: Post-acne scars are a prevalent cosmetic complaint that usually require multi-modality treatment to achieve accepted results. Objectives: The target of this research was to evaluate and compare the efficacy and safety of mi- croneedling with topical insulin versus microneedling with non-cross-linked hyaluronic acid in atro- phic post-acne scar treatment. Methods: The current comparative split-face research included 30 patients with atrophic facial acne scars. Each patient received six sessions of microneedling with topical insulin on one side of the face and microneedling with non-cross-linked hyaluronic acid on the other side. Sessions were done three weeks apart, and digital photographs were taken before and three months after the last treatment session. Goodman and Baron qualitative and quantitative grading system was used to evaluate the improvement across both sides of the face, along with patient satisfaction. Results: Three months after the last session, a statistically significant improvement in qualitative acne scar grading on both sides of the face (P < 0.001) was reported, with non-significant difference be- tween the two sides (P = 0.864). Moreover, the mean percentage of improvement in quantitative acne scar grading was 49.18 ± 13.22 on the insulin side and 47.72 ± 15.08 on the hyaluronic acid side, with non-significant difference between the two sides after treatment (P = 0.235). Conclusion: Both microneedling with topical insulin and with non-cross-linked hyaluronic acid achieved comparable significant improvement of atrophic post-acne scars. ABSTRACT 2 Original Article | Dermatol Pract Concept. 2024;14(3):e2024183 Introduction Acne scarring is a common cosmetic problem. Normal tissue replacement with fibrous scars occurs due to acne’s inflamma- tory process [1]. Despite the presence of various treatment op- tions for acne scars, a standard treatment that will permanently improve the condition has not been established, and combined methods should be used to obtain ideal cosmetic results [2]. Microneedling is a well-established option for scar man- agement, especially when combined with topical agents. It is a transdermal collagen induction and trans-epidermal medi- cation delivery technique in which very tiny needles are rolled into the skin to penetrate it superficially and controllably [3]. Blood glucose concentration is balanced by insulin. Be- cause of insulin’s roles in metabolism, cellular proliferation, protein synthesis, and growth, it is considered a potent factor in the healing process. Insulin also controls the proliferation, growth, migration, and development of fibroblasts, keratino- cytes, and endothelial cells [4]. Hyaluronic acid (HA) is a mucopolysaccharide found in high concentration in the epidermis and dermis in order to maintain skin hydration. Non-cross-linked HA can promote collagen deposition via enhancing the anabolic activity of dermal fibroblasts, and it plays a critical role in the wound healing process [5]. Objective A few studies have evaluated the efficacy of topical insulin for acne scar treatment. Thus, the target of this research was to evaluate microneedling with topical insulin versus with non-cross-linked HA in atrophic acne scar treatment. Methods The current prospective split-face comparative research en- rolled 30 cases diagnosed clinically with atrophic acne scars who were randomly selected from the Al-Zahraa Hospital Dermatology Outpatient Clinic. The study was approved by The Research Ethics Committee (REC) of the Faculty of Medicine for Girls, Al-Azhar University, Cairo, Egypt, with approval code 202104792. Before enrollment in this research study, the procedure details were discussed with the patients, and informed writ- ten consent was obtained from them. The presence of atro- phic facial acne scars, age between 18 and 45 years, and the absence of post-acne scar treatment in the previous three months were required for inclusion. Exclusion criteria were pregnancy, lactation, keloidal tendency, coagulation disor- ders or bleeding tendency, active inflammatory acne lesions, active infection such as viral warts or herpes simplex in the treatment area, and uncontrolled blood glucose level. Treatment Protocol A sufficient layer of topical anesthetic cream (pridocaine cream, formed of prilocaine 2.5% + lidocaine 2.5%) was applied to the face 30 minutes before the procedure, then the face was washed with water and disinfected with alcohol. The whole face was treated with microneedling using a dermapen (Dr. Pen Ultima A6; Bjheyetec Electronic Technology Co., Guangzhou, China) with 36 disposable needles at 1.5 mm depth and ad- justed speed. The dermapen device was applied over the skin with one hand while the other hand stretched the skin to ex- pose the scar’s base for the dermapen. The device was moved vertically until uniform pinpoint bleeding was seen. To avoid encrustation, sterile saline was used to wipe the blood away. After the needling process, 1-2 ml of topical insulin (Hu- man Actrapid 100 IU/ml solution; Novo Nordisk Pharma- ceuticals Ltd, Bagsvμrd, Denmark) was applied to one side of the face and 1-2 ml of topical non-cross-linked HA solution (Presensa fullnesse 3.5% Persensa Spain) was applied to the other side. Side selection for either insulin or HA was done randomly by sealed envelope method. After the procedure, the patients were advised to use photo-protective measures and apply topical fusidic acid cream twice a day for 3–5 days. Acyclovir 400 mg /8 hours was prescribed for one week (especially to patients with a history of recurrent herpes labialis). Blood glucose level was measured before and after the procedure for all the patients. This treatment protocol was repeated every three weeks for a total of six sessions, Assessment of the Responses Evaluation was done at baseline, monthly after the last ses- sion, and the final evaluation three months after the last treatment session by Goodman and Baron qualitative and quantitative acne scarring grading systems [6,7]. a. The qualitative change in the grading of acne scarring was considered excellent, good, or poor, as proposed by Majid [8]. b. The quantitative change in the grading of acne scarring was considered very good, good, moderate, or minimal reduction, as proposed by Chandrashekar et al [9]. Patient Satisfaction The patients were asked to rate their improvement in acne scars on both sides of the face in comparison to pre- treatment condition using the quartile scale [210]. Grade 0: Slight improvement < 25% Grade 1: Moderate improvement 25%–49% Grade 2: Considerable improvement 50%–74% Grade 3: Marked improvement ≥ 75% Original Article | Dermatol Pract Concept. 2024;14(3):e2024183 3 Side Effects Erythema, edema, post-inflammatory hypo or hyperpigmen- tation, hypoglycemia, and pain were discussed verbally with the cases and evaluated by the doctor throughout the study. The patients were asked to rate their pain according to a numeric rating scale (NRS) ranging from 0–10 [11]. Statistical Analysis Data collection, editing, coding, and entry were all accom- plished with IBM SPSS version 23. When the variables were parametric or non-parametric, the quantitative data are presented as means, ranges, and standard deviations with inter-quartile ranges (IQR). The error margin was established at 5% based on a 95% confidence interval This indicates that a P value of 0.05 was used for statistical significance. Results The present research included 21 females (70%) and 9 males (30%), with a mean age of 30.63 ± 4.72 years. Eight cases were of skin phototype III (26.7%), and 22 cases were of type IV (73.3%). The duration of post-acne scars ranged from two to 18 years with a median (IQR) of 5.25 (4–12) years (Table 1). Clinical Assessment Before treatment, a non-significant difference was noticed between both sides of the face regarding both qualitative and quantitative Goodman and Baron scoring system; after treat- ment, the qualitative grading of acne scars was significantly improved on insulin side and HA side (P < 0.001), with a non-significant difference between both sides (P = 0.864). Also, the quantitative Goodman and baron scoring system was lower after treatment on the insulin side, from 15.80 ± 3.91 to 7.87 ± 2.30, with a 49.18% improvement; on the HA side, it decreased from 14.07 ± 2.83 to 7.30 ± 2.34, with a 47.72% improvement. This improvement is consid- ered significant on both sides of the face (P < 0.001), with a non-significant difference between both sides after treatment (P = 0.348) (Tables 2 and 3). On comparing the degree of reduction in quantitative grading after treatment, a non-significant difference was noticed between both sides of the face (P = 0.235). On the insulin side, moderate improvement was achieved in 12 cases (40%), good improvement in eight cases (26.7%), minimal improvement in eight cases (26.7%), and very good improvement in two cases (6.7%). On the HA side, moderate improvement was achieved in 17 cases (56.7%), good improve- ment in four cases (13.3%), minimal improvement in nine cases (30%); no case had very good improvement (0.0%) (Table 4). Quantitative Grading After Treatment for Each Scar Type Boxcar scars showed significant improvement after treat- ment, with improvement percentages of 54.87% and Table 1. Demographic Data of the Studied Patients. No. = 30 Age Mean±SD 30.63 ± 4.72 Range 23 – 38 Sex Female 21 (70.0%) Male 9 (30.0%) Skin phototype III 8 (26.7%) IV 22 (73.3%) Scar duration (Years) Median (IQR) 5.25 (4 – 12) 2 – 18 IQR = interquartile range; SD = standard deviation. Table 2. Comparison between the Insulin- and HA-Treated Sides, Qualitative Grading Before and After Treatment. Qualitative Insulin side HA side Test value* PNo. % No. % Before II: mild 1 3.3% 1 3.3% 1.137 0.566 III: moderate 15 50.0% 19 63.3% IV: sever 14 46.7% 10 33.3% After I: macular 1 3.3% 1 3.3% 0.293 0.864 II: mild 17 56.7% 19 63.3% III: moderate 12 40.0% 10 33.3% IV: sever 0 0.0% 0 0.0% Chi-square test 29.556 29.993 P-value <0.001 (HS) <0.001 (HS) P > 0.05: Nonsignificant (NS); P < 0.05: Significant (S); P < 0.01: highly significant (HS). *Chi-square test HA = hyaluronic acid. 4 Original Article | Dermatol Pract Concept. 2024;14(3):e2024183 of the face was noticed in one patient only. The pain score ranged from 2 to 6, and none of the patients had clinical or lab evidence of hypoglycemia. Discussion Management of atrophic acne scars represents a therapeu- tic challenge for dermatologists, with no available standard effective treatment option [12]. Microneedling has gained marked popularity in the dermatology field for acne scar management, especially in the skin-of-color population. The microneedling process can stimulate new collagen, elastin, and new capillary formation in the papillary dermis. Several clinical studies have documented the efficacy of micronee- dling in acne scar management regardless of scar type or severity [13]. In the current research, the qualitative scoring of Good- man and Baron was significantly improved in the insulin side, with P <0.001, and the quantitative scoring decreased from 15.80 ± 3.91 to 7.87 ± 2.30, with 49.18% improvement. On reviewing the literature, a few published studies have evaluated the efficacy of microneedling with topical insulin 54.80% on the insulin side and HA side, respectively. Rolling scars also showed significant improvement after treatment, with improvement percentages of 60.63% and 50.26% on the insulin and HA side, respectively. Ice pick scars had the least percentage of improvement, 37.06% and 34.44% on the insulin and HA sides, respectively. On comparing the quantitative scoring after treatment in terms of improvement according to scar type, a non-significant difference was no- ticed between both sides of the face (Table 5). Patient Satisfaction Grade 3 improvement on the insulin side was reported by 14 patients and 12 on the HA side, grade 2 by eight patients on the insulin side and nine on the HA side, grade 1 by four patients on the insulin side and four on the HA side, and grade 0 by four patients on the insulin side and five on the HA side, with non-significant difference between the insulin and HA sides regarding patient satisfaction (P = 0.616). Side Effects All the cases had erythema on the first day after the pro- cedure. Post-inflammatory hyperpigmentation on both sides Table 4. Comparison between the Insulin- and HA-treated Sides, Reduction Degree in Quantitative Grading. Quantitative Insulin Side HA Side Test value PNo. = 30 No. = 30 Reduction Minimal 8 (26.7%) 9 (30.0%) 4.254 0.235 Moderate 12 (40.0%) 17 (56.7%) Good 8 (26.7%) 4 (13.3%) Very good 2 (6.7%) 0 (0.0%) P > 0.05: Nonsignificant (NS); P < 0.05: Significant (S); P < 0.01: highly significant (HS)*: Chi-square test HA = hyaluronic acid. Table 3. Comparison between the Insulin- and HA-treated Sides, Quantitative Grading Before and After Treatment and Percentage of Improvement. Quantitative Insulin side HA side Test value PNo. = 30 No. = 30 Before Mean ± SD 15.80 ± 3.91 14.07 ± 2.83 1.968• 0.054 Range 9 – 24 8 – 19 After Mean ± SD 7.87 ± 2.30 7.30 ± 2.34 0.947• 0.348 Range 3 – 12 2 – 12 Percentage of improvement Mean ± SD 49.18 ± 13.22 47.72 ± 15.08 0.400• 0.691 Range 21.43 – 80 20 – 83.33 Paired t-test -13.840 -13.664 P <0.001 (HS) <0.001 (HS) P > 0.05: Nonsignificant (NS); P < 0.05: Significant (S); P < 0.01: highly significant (HS) *: Chi-square test; •: Independent t-test HA = hyaluronic acid. Original Article | Dermatol Pract Concept. 2024;14(3):e2024183 5 that are present in the skin, thus increasing re-epithelialization, collagen content, granulation tissue formation, and insulin-like growth factor production by fibroblasts [16]. In diabetic foot management, topical application of insulin im- proved re-epithelization rates [17]. This effect is achieved via regulation of the inflammatory process, reduction in reactive oxygen species (ROS) levels in the tissue, and induction of chemotaxis [16]. Moreover, intralesional injection and top- ical insulin spray prevented hypertrophic scar development after wound injuries in susceptible individuals [18]. On the HA-treated side in our study, the qualitative scoring of Goodman and Baron was significantly improved, with P < 0.001, and the quantitative scoring decreased from 14.07 ± 2.83 to 7.30 ± 2.34, with a 47.72% improvement. The efficacy of microneedling with non-cross-linked hyaluronic acid was assessed by Amer et al. [19], who com- pared combined microneedling with PRP on the right side against microneedling and non-cross-linked hyaluronic acid on the left side of the face. The cases received four sessions at consecutive monthly intervals, showiing an for treatment of post-acne scars. Pawar and Singh [14] used PRP with microneedling on the left side of the face and top- ical insulin with microneedling on the right side of the face (Actrapid insulin 40 IU/ml). The treatment protocol included four sessions at monthly intervals. To measure the progress, a qualitative grading system was used, with 45% improve- ment on the right side of the face (insulin) and only 26% improvement on the left (PRP). They concluded that both treatment modalities were associated with significant reduc- tion in atrophic acne scars. Also, Abbas et al. [15] conducted a split-face study to compare topical vitamin C with microneedling versus topi- cal insulin (human Actrapid insulin 100 IU/ml solution) with microneedling for atrophic post-acne scar treatment. They did four sessions at monthly intervals. Statistically signifi- cant improvement in the value of ASAS on both sides of the face, with a slightly more improvement on the side treated with vitamin C, was noticed in their study. Insulin is recognized now an as important factor in the wound healing process. It acts on growth hormone receptors Table 5. Comparison between the Insulin- and HA-treated Sides Quantitative Grading Before and After Treatment in Each Scar Type. Quantitative Before After Percentage of Improvement Test value• P Box scar Insulin side Mean ± SD 17.00 ± 3.65 7.71 ± 2.06 54.87 ± 5.20 –12.433 0.000 Range 11 – 22 5 – 10 44.44 – 60 HA side Mean ± SD 15.29 ± 2.29 7.00 ± 2.65 54.80 ± 16.11 –9.578 0.000 Range 12 – 19 2 – 9 40 – 83.33 P 0.313 (NS) 0.583 (NS) 0.992 (NS) Ice pick scar Insulin side Mean ± SD 11.67 ± 2.08 7.33 ± 1.53 37.06 ± 7.81 –6.500 0.023 Range 10 – 14 6 – 9 30 – 45.45 HA side Mean ± SD 13.00 ± 1.73 8.67 ± 2.89 34.44 ± 12.51 –6.500 0.023 Range 12 – 15 7 – 12 20 – 41.67 P 0.442 (NS) 0.519 (NS) 0.774 (NS) Rolling scar Insulin side Mean ± SD 20.00 ± 4.24 8.00 ± 2.71 60.63 ± 9.66 –9.798 0.002 Range 15 – 24 4 – 10 50 – 73.33 HA side Mean ± SD 14.00 ± 3.83 7.25 ± 3.30 50.26 ± 13.13 –9.000 0.003 Range 9 – 17 3 – 11 35.29 – 66.67 P 0.081 (NS) 0.738 (NS) 0.250 (NS) Mixed Insulin side Mean ± SD 15.00 ± 3.25 8.00 ± 2.58 46.10 ± 14.51 –10.340 0.000 Range 9 – 21 3 – 12 21.43 – 80 HA side Mean ± SD 13.75 ± 3.00 7.19 ± 2.01 46.47 ± 14.78 –8.656 0.000 Range 8 – 18 3 – 11 22.22 – 70.59 P 0.267 (NS) 0.328 (NS) 0.944 (NS) P > 0.05: Non significant (NS); P < 0.05: Significant (S); P < 0.01: highly significant (HS) •: Paired t-test HA = hyaluronic acid. 6 Original Article | Dermatol Pract Concept. 2024;14(3):e2024183 rolling scars but had limited efficacy in dealing with ice pick scars [21]. The current study is the first of its kind to compare microneedling with topical insulin and microneedling with non-cross-linked HA for atrophic facial post-acne scar treatment. As measured by the Goodman and Baron grad- ing system and patient satisfaction, both sides of the face showed a statistically significant decrease in the severity of post-acne scars and significant patient satisfaction. Limitations Our study’s strengths include the use of combination therapy, a treatment protocol composed of six sessions at three-week intervals, and all types of scars included in the treatment pro- tocol except hypertrophic scars. Our limitations include the absence of a control group (microneedling alone) and the relatively short follow-up period. improvement of 85.4% on the right side and 82.9% on the left side. This demonstrates that microneedling with non- cross-linked hyaluronic acid is effective in treating atrophic post-acne scars. The suggested mechanisms of acne scar improvement with topical HA include maintenance of skin hydration, increased keratinocyte proliferation, migration, differentia- tion, and increased epidermal thickness [20]. Regarding clinical improvement according to scar type in the current study, box car and rolling scars showed highly significant improvement after treatment on both sides of the face, while ice pick scars showed the least percentage of improvement. This is in agreement with Chawla, who con- ducted a split-face comparative study of microneedling with PRP versus microneedling with vitamin C in treating  atrophic post-acne scars. He concluded that microneedling combined with PRP or vitamin C was effective in treating boxcar and Figure 1. A 29-year-old woman with acne scars of 5 years’ duration. (A) Insulin side before treatment. (B) Insulin side 3 months after the last session. (C) Hyaluronic acid side before treatment. (D) Hyaluronic acid side 3 months after the last session. Original Article | Dermatol Pract Concept. 2024;14(3):e2024183 7 2. Huang Y, Yu H, Wang L. et al. Research progress on cosmetic microneedle systems: preparation, property and application. Eur. Polym. J. 2021; 110942.https://doi.org/10.1016/j.eurpolymj .2021.110942. 3. Ziaeifar E, Ziaeifar F, Mozafarpoor S. et al. Applications of mi- croneedling for various dermatologic indications with a special focus on pigmentary disorders: A comprehensive review study. Dermatol ther. 2021;34(6), e15159. https://doi.org/10.1111/ dth.15159. 4. Bhittani MK, Rehman M, Altaf HN, et al. Effectiveness of topical insulin dressings in management of diabetic foot ulcers. World J Surg. 2020; 44(6), 2028-2033. https://doi.org/10.1007 /s00268-019-05321-3. 5. Ghatak S, Maytin EV, Mack JA, A et al. Roles of proteoglycans and glycosaminoglycans in wound healing and fibrosis. Int J Cell Biol. 2015; 2015:834893. https://doi.org/10.1155/2015 /834893. Conclusion Both microneedling with topical insulin and with non-cross- linked HA is an efficient and safe therapy for atrophic post- acne scars, with a slight predilection for insulin due to its low cost and availability. Topical insulin can be considered an anti-scarring drug, but further studies on a larger scale with longer follow-up periods are required. References 1. Salameh F, Shumaker PR, Goodman G. J et al. Energy‐based devices for the treatment of Acne Scars: International consensus recommendations. Lasers Surg Med. 2022;54(1),10-26. https:// doi.org/10.1002/lsm.23484. Figure 2. A 32-year-old man with mixed acne scars of 8 years’ duration. (A) Insulin side before treatment. (B) Insulin side 3 months after the last session. (C) Hyaluronic acid side before treatment. (D) Hyaluronic acid side 3 months after the last session. 8 Original Article | Dermatol Pract Concept. 2024;14(3):e2024183 comparative research. J. Am. Acad. Dermatol. 2021;84(3): 810-811. https://doi.org/10.1016/j.jaad.2020.05.152. 15. Abbas MA, Elgamal EEAE, Zaky MS, et al. Microneedling with topical vitamin C versus microneedling with topical in- sulin in the treatment of atrophic post-acne scars: A split-face research. Dermat therap. 2022 May;35(5):e15376. doi: 10.1111 /dth.15376. Epub 2022 Feb 21. 16. Wang J, Xu J. Effects of topical insulin on wound healing: a review of animal and human evidences. Diabetes, metabolic syndrome and obesity: targets and therapy. 2020 Mar 13;13:719-727. doi: 10.2147/DMSO.S237294. 17. Scimeca CL, Bharara M, Fisher TK, et al. Novel use of insulin in continuous-instillation negative pressure wound therapy as “wound chemotherapy”. J Diabetes Sci Technol. 2010;4(4): 820-824. https://doi.org/10.1177/1938640010371121. 18. Reddy C, Chittoria RK, Aggrawal A, et al. Role of insulin in pre- vention of hypertrophic scars. Adv Pharmacol Clin Trials. 2020; 5(1):000173. DOI: 10.23880/apct-16000173. 19. 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Wound J. 2021 Oct;18(5):577-585. doi: 10.1111/iwj.13559. 13. Casabona, G., Alfertshofer, M. G., Kaye, K. O., et al. (2021). Safety and efficacy of microneedling technology in the treat- ment of acne scars. J. Cosmet. Dermatol. 2021 Nov;20(11): 3482-3491. doi: 10.1111/jocd.14502. Epub 2021 Oct 1. 14. Pawar M, Singh M. Microneedling with autologous platelet- rich plasma versus microneedling with topical insulin in the treatment of postacne atrophic scars: A simultaneous split-face