Ahead of Print

Introduction

Hypertrophic scarring represents a pathological variant of skin healing that occurs after injury, characterised by excessive collagen deposition within the dermal layer. Unlike normal scars, hypertrophic scars remain confined to the original wound margins, yet they often appear thick, raised, and discolored. The underlying pathophysiology involves key biological processes, including fibroblast proliferation, extracellular matrix (ECM) deposition, and angiogenesis, all of which contribute significantly to scar formation.^1-6 Furthermore, elucidating the molecular and cellular mechanisms of hypertrophic scarring is crucial for developing targeted therapies that effectively reduce scar formation and improve clinical outcomes.^7-9

The clinical impact of hypertrophic scars extends beyond cosmetic concerns, as they can also cause functional impairments, pain and pruritus. Although these scars often regress over time, they rarely resolve completely, leading to long-term complications, such as contractures and deformities.¹⁰ In addition, hypertrophic scars may predispose individuals to keloid formation, which is characterised by tissue proliferation beyond the boundaries of the original wound.¹¹ The psychological burden is also considerable, frequently resulting in diminished quality of life.¹²

Given their substantial clinical and psychosocial burden, effective treatment strategies are urgently needed. Current management options include silicone gel sheets, corticosteroid injections, laser therapy, cryotherapy and surgical excision. Silicone sheets are most effective when applied early and significantly reduce scar volume.¹³ Corticosteroid injections, such as triamcinolone acetonide, help reduce inflammation and collagen synthesis; however, long-term use may cause adverse effects, such as skin atrophy.^14,15 Laser therapies, including pulsed dye and fractional CO₂ lasers, can improve scar appearance but are costly and require multiple sessions.¹⁶ Cryotherapy is useful for smaller scars but may result in hypopigmentation.¹⁴ Surgical excision is considered when conservative treatments fail, though it carries risks such as infection and recurrence.¹⁷ While each of these treatments has demonstrated efficacy, their limitations often necessitate the use of combination approaches.⁹

Immunomodulatory drugs, particularly the calcineurin inhibitors tacrolimus and pimecrolimus, have shown promise in preventing or reducing hypertrophic scarring.¹⁸ Tacrolimus effectively inhibits fibroblast proliferation and excessive collagen deposition.^19,20 Similarly, pimecrolimus, a non-steroidal topical agent, has demonstrated efficacy in treating inflammatory skin conditions and preventing scarring through the inhibition of mast cell degranulation and cytokine release.^21,22

However, the long-term effectiveness of these agents remains under investigation, with evidence suggesting that intermittent use may be preferable to maintain efficacy.^23,24 Concerns also exist regarding safety, particularly the reported increased risk of lymphoma associated with prolonged use.²⁵ Thus, while they offer a less invasive alternative to steroids and surgery, their application requires careful management.

The therapeutic potential of pimecrolimus in hypertrophic scar prevention remains insufficiently explored, underscoring the need for further research. This study aims to address existing gaps in scar management by evaluating the effects of pimecrolimus in a validated animal model of hypertrophic scarring, thereby contributing to the development of safer and more effective therapeutic options.

Methods

This in-vivo experimental trial was designed to evaluate the effects of pimecrolimus 1% cream in preventing hypertrophic scarring. The study was conducted at the Kerman University of Medical Sciences. The protocol was approved by the Ethics Committee of Kerman University of Medical Sciences (IRB approval: IR.KMU.AH.REC.2023.024). The pathologist who performed the histopathological analysis was blinded to the treatment groups; personnel who collected tissue samples were also blinded to each animal’s treatment to minimise bias.

Subjects

Ten female New Zealand rabbits (age 6–8 months; weight 2.0–2.5kg) were used. Rabbits were selected for their consistent wound-healing characteristics and were housed in a controlled environment. Animals were acclimatised for three hours prior to the experiment to reduce acute handling stress.

Preparation and wound production

Anesthesia was administered by intramuscular ketamine (35mg/kg; Alfasan, Netherlands) and xylazine (5mg/kg; Alfasan, Netherlands) in a 7:1 ratio. A single full-thickness wound was created on the ventral surface of each ear of every rabbit. A sterile circular stencil (1cm diameter) was used to standardise wound size. The wound was made using a No.15 sterile scalpel blade to excise the epidermis and dermis down to the perichondrium; the perichondrium served as the anatomical endpoint for consistent full-thickness injury. The same trained researcher created all wounds, and visual confirmation was used to verify full-thickness excision.

Hemostasis was achieved by gentle compression with sterile gauze; if bleeding persisted, epinephrine-soaked gauze (1:100,000) was applied briefly until hemostasis. Each wound was covered with a 2cm×2cm sterile gauze pad pre-moistened with saline to reduce adherence during dressing changes. Dressings were secured with hypoallergenic adhesive tape and changed daily. Before each dressing change, saline was applied to moisten the gauze and facilitate gentle removal. Sterile gauze was chosen for this study due to budgetary constraints.

Intervention and comparator

After wound creation, topical treatments were applied daily. Approximately 0.1g of pimecrolimus 1% cream (Elidel®; molecular formula: C₄₃H₆₈ClNO₁₁) was applied to each wound on the left ear, while an equal amount of placebo (Vaseline) was applied to the right ear. The formulations were gently spread over the entire wound surface using sterile cotton swabs. Treatment continued for 6 weeks, resulting in approximately 4.2g of each formulation used per animal (0.1g/day×42 days) (Figure 1).

 

Figure 1. The chemical structure in Figure 1 was derived from the PubChem Database: PubChem Compound Summary for Geraniol, CID 637566, National Center for Biotechnology Information (NCBI).

 

Regarding the use of pimecrolimus, although it is not traditionally recommended for open wounds due to potential adverse effects, such as immunosuppression or delayed healing, recent studies have explored the therapeutic potential of calcineurin inhibitors in scar modulation. In our research, Elidel^® 1% cream was applied in a controlled amount (~0.1g per wound) under close daily observation. No signs of infection, delayed healing, or systemic side effects were detected, supporting the safe and well-tolerated use of this compound in our model under the described conditions.

Postoperative analgesia, monitoring and euthanasia

Postoperative analgesia consisted of meloxicam (0.2mg/kg, subcutaneously; Boehringer Ingelheim) given immediately after surgery and once daily for three days. All animals were monitored twice daily for signs of distress, infection or systemic reactions. Monitored parameters included food and water intake, activity level, body temperature, respiratory rate, and local wound appearance (erythema, discharge, edema). No systemic adverse events (such as fever, lymphadenopathy) or treatment-related systemic side effects were observed. A small number of animals showed mild erythema and pruritus during the first week, which resolved spontaneously without additional intervention. At study end, animals were humanely euthanised by cervical dislocation under anesthesia and scar tissues were excised and fixed in 10% formalin for histopathological examination.

Although peri-scar tissues and baseline skin biopsies were not collected in this study, we acknowledge that pre-manipulation skin samples would provide a useful histological baseline for future work.²⁶

Outcome measures

The primary outcome was scar diameter, measured weekly with a manual vernier caliper (Mitutoyo; accuracy±0.02mm). Secondary outcomes, assessed at the study endpoint, included histopathological parameters: collagen deposition, inflammatory cell infiltration, fibroblast count and vascularisation. Collagen was assessed using hematoxylin & eosin (H&E) and Masson’s Trichrome staining, quantified in 10 random high-power fields (HPFs) per sample.

Inflammatory cells (neutrophils, lymphocytes, plasma cells, and macrophages) were counted collectively on H&E-stained slides under light microscopy by a blinded pathologist in 10 random HPFs per sample. Fibroblasts and blood vessels were also manually counted in 10 random HPFs. Scar tissue maturation into fibrotic tissue was evaluated at seven weeks post-injury to indicate the transition from the acute remodeling phase to a mature, stable (chronic) scar stage.

Statistical analysis

All continuous data are expressed as mean±SD. Scar diameter data were paired within each animal (left ear versus right ear) and analysed at each time point using a paired Student’s t-test. Repeated measures ANOVA (with Greenhouse–Geisser correction) was applied only to scar diameter over time. Secondary histopathological outcomes, measured once at euthanasia, were analysed using standard t-tests for intervention versus. control. Statistical significance was set at p<0.05.

Results

Scar diameter

In Week 1 and Week 2, there were no significant differences in wound diameter between the two groups (1.35±0.10mm versus 1.35±0.11mm; p>0.05 and 1.11±0.09mm versus 1.11±0.13mm; p>0.05, respectively). Similarly, Week 3 showed no significant difference (0.88±0.08mm versus 0.87±0.11mm; p>0.05).

Starting from Week 4, wounds treated with pimecrolimus (Elidel^® cream, left ear) exhibited a significantly greater reduction in diameter compared to those treated with Vaseline (right ear) (0.48±0.09mm versus 0.53±0.08mm; p<0.05). This significant trend continued in Week 5 (0.37±0.09 mm versus 0.44±0.08mm; p<0.01) and Week 6 (0.29±0.06mm versus 0.35±0.05 mm; p<0.001). These findings indicate that pimecrolimus accelerated scar contraction, resulting in smaller wound diameter from Week 4 onward.

Estimated marginal means of scar diameter over six weeks for both treatment groups are shown in Figure 2. Repeated measures ANOVA applied to diameter data demonstrated a significant reduction in scar size over time (Greenhouse–Geisser corrected F=1529.5, df=5, p<0.001). The interaction effect between time and treatment type was not statistically significant (Greenhouse–Geisser corrected F=2.32, df=2.92, p>0.05). Figure 2 illustrates these trends, highlighting the more pronounced reduction in the pimecrolimus-treated group by Week 6.

 

Table 1. Comparison of wound diameter between treatment groups over six weeks (mean ± SD)

 

 

Figure 2. Comparison of scar diameter (mm) over six weeks between the pimecrolimus-treated group (left ear, represented by the dashed line) and the placebo group (right ear, represented by the black line). The scar diameter progressively decreased in both groups, with no significant differences observed during the first five weeks. At Week 6, the pimecrolimus-treated group showed a significantly smaller scar diameter than the placebo group. Data are presented as mean±SD (n=10), ns=not significant, *p<0.05.

 

Secondary outcomes

Histopathological analysis showed no significant difference in inflammatory cell count (pooled neutrophils, lymphocytes, plasma cells, macrophages) between the pimecrolimus-treated group (56.3±29.8 cells/HPF) and the placebo group (69.8±29.9 cells/HPF; p>0.05).

However, fibroblast count (1282±275.7 cells/HPF versus 1475.6±286.2 cells/HPF; p<0.01), vascularisation (81.7±32.5 vessels/HPF versus 134.4±39.5 vessels/HPF; p<0.001), and collagen density (185.7±33.9 AU versus 128.2±54.9 AU; p<0.05) were significantly lower in the pimecrolimus group compared to placebo (Figure 3).

 

Figure 3. Histopathological comparison of scar tissue between the pimecrolimus-treated group (left ear) and the placebo group (right ear). Hematoxylin and eosin (H&E) staining shows differences in fibroblast density and inflammatory cell infiltration between the two groups, though only the former was statistically significant. Increased vascularisation is evident in the placebo-treated group. Masson’s Trichrome staining highlights reduced collagen deposition in the pimecrolimus-treated group, suggesting a lower degree of fibrotic tissue formation. Scale bar = 20μm.

 

Discussion

Hypertrophic scars’ current treatments highlight the need for safer alternatives.^9,27 In this regard, calcineurin inhibitors, such as pimecrolimus, modulate immune responses and may influence key processes in scar formation; yet, their role in preventing hypertrophic scars remains largely unexplored.^23,25

In this study, pimecrolimus reduced scar diameter, fibroblast proliferation, vascularisation, and collagen deposition, suggesting its potential as a non-invasive therapeutic option.

Here, “scar progression” refers to the increase or persistence of scar diameter over time, as measured in the rabbit ear model, rather than a clinical hypertrophic scar. The progressive reduction in scar diameter observed with pimecrolimus treatment suggests that it may modulate fibroblast-mediated contraction and extracellular matrix remodeling. Previous studies on calcineurin inhibitors such as pimecrolimus and tacrolimus have shown their ability to suppress fibroblast activation, collagen synthesis, and inflammatory signaling, critical components of hypertrophic scar formation. Although tacrolimus has been more extensively studied in the context of scar modulation, evidence for pimecrolimus in hypertrophic scars remains limited. However, its structural and functional similarities to tacrolimus suggest a potential role in scar prevention. For instance, one study demonstrated that intradermal tacrolimus significantly reduced scar hypertrophy in a rabbit ear model, showing clinical and histopathological improvement.²⁸ These findings align with the results of the present study, where pimecrolimus led to a significant reduction in scar size by the final time point.

Given the limitations of available non-invasive therapies, calcineurin inhibitors may offer a promising alternative to traditional therapies, particularly for individuals who are non-responsive to corticosteroids or silicone therapy. Besides, the delayed but significant reduction in scar diameter observed in this study suggests that pimecrolimus may gradually influence fibroblast-mediated contraction and collagen remodeling rather than exerting an immediate effect. Transforming growth factor-beta (TGF-β) signaling, a key regulator of scar formation, has been implicated in hypertrophic scar development, and previous research has shown that calcineurin inhibitors can suppress TGF–β–induced fibroblast activation and extracellular matrix deposition.²⁹ These findings suggest that Pimecrolimus may influence hypertrophic scarring by downregulating profibrotic pathways, warranting further investigation into its long-term therapeutic effects in clinical settings.

Quantitative fibroblast counts indicated a significant reduction in the pimecrolimus-treated group, whereas Figure 3 shows representative histological images only, supporting but not replacing the numerical data. By limiting fibroblast expansion, pimecrolimus may contribute to a more controlled healing process, consistent with previous reports on calcineurin inhibitors’ ability to suppress fibroblast activation and collagen synthesis.³⁰ A study highlighted that calcineurin inhibitors downregulate inflammatory and fibroproliferative responses in keratinocytes and hypertrophic scars, aligning with our findings on fibroblast reduction in the treated group.²⁸ Similarly, another study demonstrated that inhibiting fibroblast-driven collagen synthesis reduces extracellular matrix deposition in hypertrophic scars.³¹ These findings support the hypothesis that pimecrolimus exerts an inhibitory effect on fibroblast activity through similar immunomodulatory pathways.

Additionally, calcineurin inhibitors have been shown to modulate keratinocyte and dermal fibroblast interactions, further suppressing excessive fibrotic responses.^32,33 This suggests that the effects of pimecrolimus on fibroblast density may be mediated through the inhibition of TGF-β pathways, ultimately reducing hypertrophic scarring. These findings underscore the potential of pimecrolimus as a non-invasive therapeutic option for hypertrophic scars, particularly in cases where fibroblast hyperproliferation is a dominant pathological feature.

The reduction in vascularisation observed in this study also suggests that pimecrolimus may influence angiogenic signaling in hypertrophic scars, potentially contributing to a more regulated healing process. Angiogenesis plays a crucial role in scar maturation, with excessive vascular proliferation leading to increased metabolic demand, prolonged inflammation, and excessive extracellular matrix deposition. In hypertrophic scars, persistent neovascularisation supports fibroblast hyperactivity,^34,35 further exacerbating scar thickening. Therefore, by limiting aberrant vascular proliferation, pimecrolimus may alter the inflammatory and fibrotic environment, improving scar resolution.

Previous research has identified calcineurin inhibitors as modulators of angiogenic pathways, with pimecrolimus and tacrolimus demonstrating the ability to suppress endothelial activation and inhibit pro-angiogenic factors.^36,37 It has been highlighted that pimecrolimus disrupts endothelial adhesion and extracellular matrix remodeling, impairing the structural support for neovascularisation.³⁸ Moreover, calcineurin inhibitors potentially interfere with vascular endothelial growth factor (VEGF)-mediated angiogenesis, supporting the observed reduction in vascularisation in the present study.³⁹ These findings suggest that pimecrolimus exerts its vascular-modulating effects by interfering with VEGF signaling and endothelial-matrix interactions, leading to a less angiogenic environment within the scar tissue. Therefore, as pimecrolimus directly affects endothelial function, it can provide a distinct mechanism of action that may complement or serve as an alternative to traditional scar therapies, particularly in highly vascularised hypertrophic scars. However, given that angiogenesis is a dynamic and time-sensitive process, further studies are warranted to assess the optimal timing and dosing of pimecrolimus application and its long-term impact on scar remodeling and recurrence.

We also observed a reduced collagen deposition, suggesting that pimecrolimus influences extracellular matrix remodeling in hypertrophic scars, potentially preventing excessive fibrosis. Collagen accumulation is a key feature of hypertrophic scars, with an overproduction of type I and III collagen contributing to scar thickening and stiffness.^40,41 Therefore, pimecrolimus potentially helps regulate fibrotic tissue remodeling, leading to a more balanced wound healing response. Previous research has also highlighted the potential antifibrotic properties of calcineurin inhibitors.^42,43 In comparison, corticosteroids primarily suppress fibroblast proliferation but do not directly regulate collagen remodeling.^44,45 Pimecrolimus treatment in this study was associated with a reduction in scar diameter, fibroblast density, and collagen deposition, particularly evident at later stages (Week 6). While these findings suggest antifibrotic activity, the precise mechanisms underlying these effects remain unclear. We did not directly assess fibroblast–collagen interactions, and no early differences were observed compared with controls, indicating that the effects of pimecrolimus may emerge during later phases of scar remodeling rather than at the onset of scar formation. The observed reduction in collagen deposition is consistent with previous reports that calcineurin inhibitors can influence profibrotic pathways, such as TGF-β/Smad signaling, although this remains a hypothesis requiring further validation.⁴⁶ Given the multifactorial nature of hypertrophic scar development, including the roles of myofibroblasts,⁴⁷ mast cells,⁴⁸ glycosaminoglycans, fibronectin, proteoglycans, and altered MMP activity,^49-52 future studies should incorporate these parameters to provide a more comprehensive understanding of how pimecrolimus may modulate scar pathophysiology. In addition, evaluating collagen alignment and biomechanical properties could further elucidate its potential role in improving scar quality.

While this study provides valuable insights into the potential effects of pimecrolimus on hypertrophic scars, certain limitations should be acknowledged. One primary limitation is using an animal model, which does not fully replicate the complexities of human skin and scar physiology while providing controlled experimental conditions. The rabbit ear model is widely used for hypertrophic scar research;⁵³ however, differences in dermal thickness, fibroblast activity, and immune responses may affect the direct translatability of these findings to human subjects. Future studies should explore clinical trials in human patients to confirm the therapeutic potential of pimecrolimus in real-world settings.

High-frequency ultrasound and skin elasticity measurement methods provide valuable quantitative data on scar thickness, tissue stiffness, and collagen organisation. While these techniques were not available to us during the present study, they should be mentioned as important non-invasive modalities that could be incorporated in future investigations to enhance the accuracy and reproducibility of scar assessment.

Another limitation is the study duration. Although the study demonstrated significant differences in scar size, fibroblast activity, vascularisation, and collagen deposition, a more extended follow-up period would be beneficial to assess the long-term effects of pimecrolimus on scar remodeling and recurrence. Additionally, while histopathological evaluation provided qualitative data on collagen deposition, fibroblast density, and vascularisation, quantitative data were not presented in this study. Future studies should consider employing quantitative histological assessments to enhance the interpretation of these results and further elucidate the role of pimecrolimus in scar remodeling.

The mode of application and optimal dosing regimen for pimecrolimus in hypertrophic scar treatment remains an open question. This study applied pimecrolimus topically; however, different formulations, concentrations, and delivery systems may influence drug penetration and efficacy. Future research should investigate alternative delivery mechanisms, such as nanoparticle-based formulations, microneedle patches, or intradermal injections, to optimise bioavailability and therapeutic effects.

Finally, this study primarily focused on scar prevention and early-stage modulation. The effects of pimecrolimus on mature hypertrophic scars remain unclear. Future research should assess whether pimecrolimus can remodel existing hypertrophic scars or if its effects are limited to the early phases of wound healing and fibrosis prevention.

Despite these limitations, this study provides preliminary preclinical evidence suggesting that pimecrolimus may exert antifibrotic, anti-angiogenic and immunomodulatory effects during scar formation. However, these findings should be interpreted with caution, given the limited scope of the presented data. Future clinical trials and mechanistic studies are warranted to validate these observations in human subjects, optimise treatment regimens, and explore the long-term efficacy of pimecrolimus as a potential non-invasive therapeutic option for hypertrophic scar management.

Conclusions

Given the importance of wound healing and the subsequent development of hypertrophic scars, there are various methods to accelerate wound healing and reduce keloid formation. For this reason, choosing a method with appropriate effectiveness and fewer side effects is important. In the present study, the results of using Elidel cream on rabbit ears showed that this cream not only accelerates healing and wound healing but also effectively prevents the development of hypertrophic scars. Therefore, it is recommended that more studies be conducted on the effectiveness of this cream on human samples, so that this effective and low-complication method can be used in the treatment of wounds.

Acknowledgements

The authors would like to thank Kerman University of Medical Sciences for considering this manuscript.

Author contribution

Conceptualisation and methodology: Mahdiyeh and Farzaneh Lashkarizadeh. Formal analysis: Mahdiyeh Lashkarizadeh.Investigation: Mohammadreza Lashkarizadeh. Original draft preparation: Amin Karimzadeh. Writing, review and editing: Seyedeh Mahdieh Khoshnazar.

All authors read and approved the published version of the manuscript.

Conflict of interest

The authors declare no conflicts of interest.

Ethics statement

This study was approved by the Kerman University of Medical Sciences (License: IR.KMU.AH.REC.1402.024). Moreover, it followed the guidelines provided in the Declaration of Helsinki.

Funding

The authors received no funding for this study.

Author(s)

Farzaneh Lashkarizadeh¹, Seyedeh Mahdieh Khoshnazar², Amin Karimzadeh³,
Mohammadreza Lashkarizadeh¹, Mahdiyeh Lashkarizadeh⁴*
¹Department of General Surgery, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
²Gastroenterology and Hepatology Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran
³Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
⁴Department of Pathology, Pathology and Stem Cell Research Center, Afzalipour School of Medicine, Kerman, Iran

*Corresponding author email mh.lashkarizadeh@gmail.com

References

1. van der Veer WM, Bloemen MC, Ulrich MM, Molema G, van Zuijlen PP, Middelkoop E, et al. Potential cellular and molecular causes of hypertrophic scar formation. Burns. 2009;35(1):15–29.
2. Lian N, Li T. Growth factor pathways in hypertrophic scars: molecular pathogenesis and therapeutic implications. Biomed  Pharmacother. 2016;84:42-50.
3. Linares H. From wound to scar. Burns. 1996;22(5):339-52.
4. Hameedi SG, Saulsbery A, Olutoye OO. The pathophysiology and management of pathologic scarring—a contemporary review. Adv Wound Care. 2025;14(1):48–64.
5. Zhu Z, Ding J, Tredget EE. The molecular basis of hypertrophic scars. Burns Trauma. 2016;4:2.
6. Gauglitz GG, Korting HC, Pavicic T, Ruzicka T, Jeschke MG. Hypertrophic scarring and keloids: pathomechanisms and current and emerging treatment strategies. Molecular medicine. 2011;17:113–125.
7. Atiyeh BS. Nonsurgical management of hypertrophic scars: evidence-based therapies, standard practices, and emerging methods. Aesthetic Plast Surg. 2007;31:468–492.
8. Choi C, Mukovozov I, Jazdarehee A, Rai R, Sachdeva M, Shunmugam M, et al. Management of hypertrophic scars in adults: a systematic review and meta-analysis. Australas J Dermatol. 2022;63(2):172–189.
9. Ogawa R. The most current algorithms for the treatment and prevention of hypertrophic scars and keloids: a 2020 update of the algorithms published 10 years ago. Plast Reconstruct Surg. 2022;149(1):79e–94e.
10. Karppinen S-M, Heljasvaara R, Gullberg D, Tasanen K, Pihlajaniemi T. Toward understanding scarless skin wound healing and pathological scarring. F1000Res. 2019;8:Rev-787.
11. Berman B, Maderal A, Raphael B. Keloids and hypertrophic scars: pathophysiology, classification, and treatment. Dermatologic Surgery. 2017;43:S3–S18.
12. Brown B, McKenna S, Siddhi K, McGrouther D, Bayat A. The hidden cost of skin scars: quality of life after skin scarring. J Plast Reconstruct Aesthet Surg. 2008;61(9):1049–1058.
13. Mafong EA, Ashinoff R. Treatment of hypertrophic scars and keloids: a review. Aesthet Surg J. 2000;20(2):114–121.
14. Mokos ZB, Jović A, Grgurević L, Dumić-Čule I, Kostović K, Čeović R, et al. Current therapeutic approach to hypertrophic scars. Front Med. 2017;4:83.
15. Elsaie ML. Update on management of keloid and hypertrophic scars: a systemic review. J Cosmet Dermatol. 2021;20(9):2729–2738.
16. Grosu O-M, Perţea M, Onofrei P, Zamfir CL. Comparative preventive and curative treatment options for hypertrophic scars. Romanian Journal of Functional & Clinical, Macro & Microscopical Anatomy & of Anthropology/Revista Româna de Anatomie Functionala si Clinica, Macro si Microscopica si de Antropologie. 2022;21(4):223-230.
17. Ogawa R. The most current algorithms for the treatment and prevention of hypertrophic scars and keloids. Plast Reconstruct Surg. 2010;125(2):557–568.
18. Lane JE. Treatment of keloids. Textbook of Cosmetic Dermatology. CRC Press; 2017. p361–371.
19. Badea I, Taylor M, Rosenberg A, Foldvari M. Pathogenesis and therapeutic approaches for improved topical treatment in localized scleroderma and systemic sclerosis. Rheumatology. 2009;48(3):213–221.
20. Lan CC, Fang AH, Wu PH, Wu CS. Tacrolimus abrogates TGF – β1-induced type I collagen production in normal human fibroblasts through suppressing p38 MAPK signalling pathway: implications on treatment of chronic atopic dermatitis lesions. J Eur Acad Dermatol Venereol. 2014;28(2):204–215.
21. Simon D, Vassina E, Yousefi S, Braathen L, Simon HU. Inflammatory cell numbers and cytokine expression in atopic dermatitis after topical pimecrolimus treatment. Allergy. 2005;60(7):944–951.
22. Wellington K, Noble S. Pimecrolimus: a review of its use in atopic dermatitis. Am J Clin Dermatol. 2004;5:479–495.
23. Siegfried EC, Jaworski JC, Kaiser JD, Hebert AA. Systematic review of published trials: long-term safety of topical corticosteroids and topical calcineurin inhibitors in pediatric patients with atopic dermatitis. BMC Pediatrics. 2016;16:1–15.
24. Matas A. Calcineurin inhibitors: short-term friend, long-term foe? Clin Pharmacol Therapeut. 2011;90(2):209.
25. Devasenapathy N, Chu A, Wong M, Srivastava A, Ceccacci R, Lin C, et al. Cancer risk with topical calcineurin inhibitors, pimecrolimus and tacrolimus, for atopic dermatitis: a systematic review and meta-analysis. Lancet Child Adolesc Health. 2023;7(1):13–25.
26. Meingassner JG, Grassberger M, Fahrngruber H, Moore HD, Schuurman H, Stütz A. A novel anti-inflammatory drug, SDZ ASM 981, for the topical and oral treatment of skin diseases: in vivo pharmacology. Br J Dermatol. 1997;137(4):568–576.
27. Atiyeh B, Ibrahim A. Nonsurgical management of hypertrophic scars: Evidence-based therapies, standard practices, and emerging methods: An update. Aesthet Plast Surg. 2020;44(4):1345–1347.
28. Gisquet H, Liu H, Blondel W, Leroux A, Latarche C, Merlin J-L, et al. Intradermal tacrolimus prevent scar hypertrophy in a rabbit ear model: a clinical, histological and spectroscopical analysis. Skin Res Technol. 2011;17(2):160–166.
29. Kryger ZB, Sisco M, Roy NK, Lu L, Rosenberg D, Mustoe TA. Temporal expression of the transforming growth factor-Beta pathway in the rabbit ear model of wound healing and scarring. J Am Coll Surg. 2007;205(1):78–88.
30. Wolff K. Pimecrolimus 1% cream for the treatment of atopic dermatitis. Skin Therapy Lett. 2005;10(8):1–6.
31. Sidgwick G, Bayat A. Extracellular matrix molecules implicated in hypertrophic and keloid scarring. J Eur Acad Dermatol Venereol. 2012;26(2):141–52.
32. Al-Daraji WI, Grant KR, Ryan K, Saxton A, Reynolds NJ. Localization of calcineurin/NFAT in human skin and psoriasis and inhibition of calcineurin/NFAT activation in human keratinocytes by cyclosporin A. J Investig Dermatol. 2002;118(5):779–788.
33. Mammucari C, di Vignano AT, Sharov AA, Neilson J, Havrda MC, Roop DR, et al. Integration of Notch 1 and calcineurin/NFAT signaling pathways in keratinocyte growth and differentiation control. Developmental Cell. 2005;8(5):665–676.
34. Korntner S, Lehner C, Gehwolf R, Wagner A, Grütz M, Kunkel N, et al. Limiting angiogenesis to modulate scar formation. Adv Drug Deliv Rev. 2019;146:170–189.
35. DiPietro LA. Angiogenesis and scar formation in healing wounds. Curr Opin Rheumatol. 2013;25(1):87–91.
36. Grassberger M, Steinhoff M, Schneider D, Luger T. Pimecrolimus – an anti-inflammatory drug targeting the skin. Experimental Dermatol. 2004;13(12):721–730.
37. Arduino PG, Carbone M, Della Ferrera F, Elia A, Conrotto D, Gambino A, et al. Pimecrolimus vs. tacrolimus for the topical treatment of unresponsive oral erosive lichen planus: a 8 week randomized double-blind controlled study. J Eur Acad Dermatol Venereol. 2014;28(4):475–482.
38. Feng L-A, Shi J, Guo J-Y, Wang S-F. Recent strategies for improving hemocompatibility and endothelialization of cardiovascular devices and inhibition of intimal hyperplasia. J  Mater Chem B. 2022;10(20):3781–3792.
39. Baggott RR, Alfranca A, López-Maderuelo D, Mohamed TM, Escolano A, Oller J, et al. Plasma membrane calcium ATPase Isoform 4 inhibits vascular endothelial growth factor–mediated angiogenesis through interaction with calcineurin. Arterioscler  Thromb Vasc Biol. 2014;34(10):2310–2320.
40. Volk SW, Wang Y, Mauldin EA, Liechty KW, Adams SL. Diminished type III collagen promotes myofibroblast differentiation and increases scar deposition in cutaneous wound healing. Cells Tissues Organs. 2011;194(1):25–37.
41. Butzelaar L, Ulrich M, Van Der Molen AM, Niessen F, Beelen R. Currently known risk factors for hypertrophic skin scarring: A review. J Plast Reconstruct Aesthet Surg. 2016;69(2):163–169.
42. Lieberman A. The Role of Calcineurin/NFAT Signaling in Fibroblast Homeostasis and Activation: PhD Thesis. University of Pennsylvania; 2019.
43. Eberhardt W, Nasrullah U, Pfeilschifter J. Activation of renal profibrotic TGFβ controlled signaling cascades by calcineurin and mTOR inhibitors. Cellular Signalling. 2018;52:1–11.
44. Ketchum LD, Smith J, Robinson DW, Masters FW. The treatment of hypertrophic scar, keloid and scar contracture by triamcinolone acetonide. Plast Reconstr Surg. 1966;38(3):209–218.
45. Kiil J. Keloids treated with topical injections of triamcinolone acetonide (kenalog). Immediate and long-term results. Scand J Plast Reconstr Surg. 1977;11(2):169–72.
46. Tavakolpour S, Mahmoudi H, Abedini R, Hesari KK, Kiani A, Daneshpazhooh M. Frontal fibrosing alopecia: An update on the hypothesis of pathogenesis and treatment. Int J Womens Dermatol. 2019;5(2):116–123.
47. Zhu Z, Hou Q, Li M,  Fu X. Molecular mechanism of myofibroblast formation and strategies for clinical drugs treatments in hypertrophic scars. J Cellular Physiol. 2020;235(5):4109–4119.
48. Komi DEA, Khomtchouk K, & Santa Maria PLA. review of the contribution of mast cells in wound healing: involved molecular and cellular mechanisms. Clin Rev Allergy Immunol. 2020;58:298–312.
49. Jiang D, & Rinkevich Y. Scars or regeneration? Dermal fibroblasts as drivers of diverse skin wound responses. Int J Mol Sci. 2020;21(2):617.
50. Eremenko E, Ding J, Kwan P, & Tredget EE. The biology of extracellular matrix proteins in hypertrophic scarring. Adv Wound Care. 2020;11(5):234–254.
51. Mony MP, Harmon KA, Hess R, Dorafshar AH, & Shafikhani SH. An updated review of hypertrophic scarring. Cells. 2023;12(5):678.
52. Trace AP, Enos CW, Mantel A, Harvey VM. Keloids and hypertrophic scars: a spectrum of clinical challenges. Am J Clin Dermatol. 2016;17:201–223.
53. Wei Z, Zhang M, Chen M, Song Y, & Wang Y. Effects of cell-free fat extract and platelet-rich fibrin on scar maturation in an experimental rabbit ear wound model. Clin Cosmetic Invest Dermatol. 2024;2901–2909.