A Controlled Clinical Trial With Pirfenidone in the Treatment of Pathological Skin Scarring Caused by Burns in Pediatric Patients

Pirfenidone use in fibrotic diseases: What do we know so far?

BACKGROUND

Pirfenidone has demonstrated significant anti-inflammatory and antifibrotic effects in both animal models and some clinical trials. Its potential for antifibrotic activity positions it as a promising candidate for the treatment of various fibrotic diseases. Pirfenidone exerts several pleiotropic and anti-inflammatory effects through different molecular pathways, attenuating multiple inflammatory processes, including the secretion of pro-inflammatory cytokines, apoptosis, and fibroblast activation.

OBJECTIVE

To present the current evidence of pirfenidone's effects on several fibrotic diseases, with a focus on its potential as a therapeutic option for managing chronic fibrotic conditions.

FINDINGS

Pirfenidone has been extensively studied for idiopathic pulmonary fibrosis, showing a favorable impact and forming part of the current treatment regimen for this disease. Additionally, pirfenidone appears to have beneficial effects on similar fibrotic diseases such as interstitial lung disease, myocardial fibrosis, glomerulopathies, aberrant skin scarring, chronic liver disease, and other fibrotic disorders.

CONCLUSION

Given the increasing incidence of chronic fibrotic conditions, pirfenidone emerges as a potential therapeutic option for these patients. However, further clinical trials are necessary to confirm its therapeutic efficacy in various fibrotic diseases. This review aims to highlight the current evidence of pirfenidone's effects in multiple fibrotic conditions.

Modulation of the Sirtuin-1 signaling pathway in doxorubicin-induced nephrotoxicity (synergistic amelioration by resveratrol and pirfenidone)

The current study was conducted to determine the precise mechanisms of Sirtuin-1 (Sirt-1), TGF- β (Transforming Growth Factor-β), and long non-coding RNA Metastasis Associated Lung Adenocarcinoma Transcript 1 (LncRNA MALAT-1) in signaling pathways in doxorubicin (DOX)-induced nephrotoxicity. The potential therapeutic effect of Resveratrol and Pirfenidone in DOX toxicity was also assessed. Thirty-six male adult rats were evenly distributed into four groups: Group 1: control rats. Group 2: DOX exposed rats' group, each animal received 7.5 mg/kg DOX as a single intravenous dose, Group 3: DOX exposed group subjected to oral resveratrol (20 mg/kg/daily for two weeks), Group 4: DOX exposed group subjected to oral Pirfenidone (200 mg/kg once daily for 10 days). At the planned time, animals were sacrificed. Renal tissue was collected to assess matrix metalloproteinase-9 (MMP9), inflammatory and apoptotic markers: tumor necrosis factor-alpha (TNF- β, caspase-3, cyclo-oxygenase-2 (COX-2), and oxidative stress markers: nitric oxide (NO), Glutathione (GSH), malondialdehyde (MDA), and superoxide dismutase (SOD). Sirtuin-1 (Sirt-1), TGF-β, and LncRNA MALAT-1 were quantitatively assessed by real-time RT-PCR in the whole blood. Results showed that the DOX group exhibited a significant increase in oxidative stress markers, and inflammatory, and apoptotic markers in the renal tissue. Histologically, the renal tubule lining cells exhibited vacuolar alterations in the cytoplasm, glomerular atrophy, and vascular congestion. Furthermore, renal degeneration was evident, as confirmed by the heightened immuno-expression of MMP9. Exposure to DOX resulted in a significant decrease in Sirtuin-1 (Sirt-1) with a significant increase in the TGFβ, and LncRNA MALAT-1 gene expression. However, pre-treatment with either resveratrol/or Pirefenidone ameliorated the histological renal alterations, regulated the pathways of Sirt-1, TGFβ, and LncRNA MALAT-1, and decreased all oxidative stress, inflammatory and apoptotic markers. In conclusion, DOX exposure leads to renal toxicity by inducing renal degeneration, oxidative stress, and apoptosis. Administration of either resveratrol or Pirfenidone counteracted these changes and protected the kidney against DOX-induced renal damage.

Drugs targeting TGF-β/Notch interaction attenuate hypertrophic scar formation by optic atrophy 1-mediated mitochondrial fusion

Hypertrophic scar (HS) formation is a cutaneous fibroproliferative disease that occurs after skin injuries and results in severe functional and esthetic disability. To date, few drugs have shown satisfactory outcomes for the treatment of HS formation. Transforming growth factor-beta (TGF-β)/Notch interaction via small mothers against decapentaplegic 3 (Smad3) could facilitate HS formation; therefore, targeting TGF-β/ Notch interaction via Smad3 is a potential therapeutic strategy to attenuate HS formation. In addition, optic atrophy 1 (OPA1)-mediated mitochondrial fusion contributes to fibroblast proliferation, and TGF-β/Smad3 axis and the Notch1 pathway facilitate OPA1-mediated mitochondrial fusion. Thus, the aim of this study was to investigate whether drugs targeting TGF-β/Notch interaction via Smad3 suppressed fibroblast proliferation to attenuate HS formation through OPA1-mediated mitochondrial fusion. We found that the TGF-β pathway, Notch pathway, and TGF-β/Notch interaction via Smad3 were inhibited by pirfenidone, the gamma- secretase inhibitor DAPT, and SIS3 in human keloid fibroblasts (HKF) and an HS rat model, respectively. Protein interaction was detected by co-immunoprecipitation, and mitochondrial morphology was determined by electron microscopy. Our results indicated that pirfenidone, DAPT, and SIS3 suppressed the proliferation of HKFs and attenuated HS formation in the HS rat model by inhibiting TGF-β/Notch interaction via Smad3. Moreover, pirfenidone, DAPT, and SIS3 hindered OPA1-mediated mitochondrial fusion through inhibiting TGF-β/Notch interaction, thereby suppressing the proliferation of HS fibroblasts and HS formation. In summary, these findings investigating the effects of drugs targeting TGF-β/Notch interaction on HS formation might lead to novel drugs for the treatment of HS formation.

Scars

Wound healing occurs as a response to disruption of the epidermis and dermis. It is an intricate and well-orchestrated response with the goal to restore skin integrity and function. However, in hundreds of millions of patients, skin wound healing results in abnormal scarring, including keloid lesions or hypertrophic scarring. Although the underlying mechanisms of hypertrophic scars and keloid lesions are not well defined, evidence suggests that the changes in the extracellular matrix are perpetuated by ongoing inflammation in susceptible individuals, resulting in a fibrotic phenotype. The lesions then become established, with ongoing deposition of excess disordered collagen. Not only can abnormal scarring be debilitating and painful, it can also cause functional impairment and profound changes in appearance, thereby substantially affecting patients' lives. Despite the vast demand on patient health and the medical society, very little progress has been made in the care of patients with abnormal scarring. To improve the outcome of pathological scarring, standardized and innovative approaches are required.

Electrospun Fibers Loaded with Pirfenidone: An Innovative Approach for Scar Modulation in Complex Wounds

Hypertrophic scars (HTSs) are pathological structures resulting from chronic inflammation during the wound healing process, particularly in complex injuries like burns. The aim of this work is to propose Biofiber PF (biodegradable fiber loaded with Pirfenidone 1.5 w/w), an electrospun advanced dressing, as a solution for HTSs treatment in complex wounds. Biofiber has a 3-day antifibrotic action to modulate the fibrotic process and enhance physiological healing. Its electrospun structure consists of regular well-interconnected Poly-L-lactide-co-poly-ε-caprolactone (PLA-PCL) fibers (size 2.83 ± 0.46 µm) loaded with Pirfenidone (PF, 1.5% w/w), an antifibrotic agent. The textured matrix promotes the exudate balance through mild hydrophobic wettability behavior (109.3 ± 2.3°), and an appropriate equilibrium between the absorbency % (610.2 ± 171.54%) and the moisture vapor transmission rate (0.027 ± 0.036 g/min). Through its finer mechanical properties, Biofiber PF is conformable to the wound area, promoting movement and tissue oxygenation. These features also enhance the excellent elongation (>500%) and tenacity, both in dry and wet conditions. The ancillary antifibrotic action of PF on hypertrophic scar fibroblast (HSF) for 3 days downregulates the cell proliferation over time and modulates the gene expression of transforming growth factor β1 (TGF-β1) and α-smooth muscle actin (α-SMA) at 48-72 h. After 6 days of treatment, a decrement of α-SMA protein levels was detected, proving the potential of biofiber as a valid therapeutic treatment for HTSs in an established wound healing process.

A Soft Skin Adhesive (SSA) Patch for Extended Release of Pirfenidone in Burn Wounds

As much as half or more of deep partial-thickness burn wounds develop hypertrophic scarring and contracture. Once formed, treatments are only minimally effective. Pirfenidone (Pf), indicated for treatment of idiopathic pulmonary fibrosis, is an anti-inflammatory and anti-fibrotic small molecule that potentially can be repurposed as a preventative against scarring in burn wounds. We present a drug-in-matrix patch with a soft skin adhesive (SSA) wound-contacting layer for multi-day drug delivery of Pf into burn wounds at the point of injury. Our patch construction consists of an SSA adhesive layer (Liveo™ MG7-9850, Dupont, Wilmington, DE, USA) for wound fixation, an acrylic co-polymer drug matrix (DURO-TAK 87-2852, Henkel, Düsseldorf, Germany) as the drug (Pf) reservoir, and an outermost protective polyurethane backing. By employing a drug-in-matrix patch design, Pf can be loaded as high as 2 mg/cm². Compared to the acrylic co-polymer adhesive patch preparations and commercial films, adding an SSA layer markedly reduces skin stripping observed under scanning electron microscopy (SEM). Moreover, the addition of varying SSA thicknesses did not interfere with the in vitro release kinetics or drug permeation in ex vivo porcine skin. The Pf patch can be easily applied onto and removed from deep partial-thickness burn wounds on Duroc pigs. Continuous multi-day dosing of Pf by the patches (>200 μg/cm²/day) reduced proinflammatory biomarkers in porcine burn wounds. Pf patches produced by the manual laboratory-scale process showed excellent stability, maintaining intact physical patch properties and in vitro biological activity for up to one year under long-term (25 °C at 60% RH) and 6 months under accelerated (40 °C at 75% RH) test conditions. To manufacture our wound safe-and-extended-release patch, we present scale-up processes using a machine-driven automated roll-to-roll pilot scale coater.

Pirfenidone Protects from UVB-Induced Photodamage in Hairless Mice

Background: Ultraviolet radiation (UV) is the main environmental factor that causes histological degenerative changes of the skin giving rise to a chronic process called photodamage. Non-melanoma skin cancer induced by UVB radiation is a result of a cascade of molecular events caused by DNA damage in epidermis cells, including persistent inflammation, oxidative stress, and suppression of T cell-mediated immunity. Retinoids such as tretinoin have been widely used in skin to treat photoaging and photodamage, though its secondary adverse effects have been recognized. Pirfenidone (PFD) has emerged as an antifibrogenic, anti-inflammatory and antioxidant agent, and in this work its efficacy was evaluated in a model of UVB-induced photodamage. Methods: Epidermal, dermal, and inflammatory changes were measured by histomorphometric parameters. In addition, gene, and protein expression of key molecules in these processes were evaluated. Results: Our results revealed an anti-photodamage effect of topical PFD with absence of inflammatory skin lesions determined by dermoscopy. In addition, PFD reduced elastosis, improved organization, arrangement, and deposition of dermal collagens, downregulated several pro-inflammatory markers such as NF-kB, IL-1, IL-6 and TNFα, and decreased keratinocyte damage. Conclusion: Topical pirfenidone represents a promising agent for the treatment of cell photodamage in humans. Clinical trials need to be carried out to explore this premise.

New Antifibroblastic Medication in Dermatology: Could Nintedanib Treat Scarring?

There are a wide variety of disfiguring dermatological conditions whose pathologic substrate is represented by the unwanted deposition of collagen from dermal fibroblasts. Pirfenidone has demonstrated efficiency in the treatment of disordered collagen production when applied topically. Due to a similar mechanism of action, we also hypothesize that a similar medication, nintedanib, might have similar applications. We also propose that a liposomal technology may assist in the penetration of nintedanib and enhance its clinical effects.

A Review of Hypertrophic Scar and Keloid Treatment and Prevention in the Pediatric Population: Where Are We Now?

Significance: This body of work gives a concise and comprehensive overview for the clinician and scientist on the latest treatment modalities for hypertrophic scars (HTS) and keloids in the pediatric population, as well as the most promising methods of prevention currently being investigated. This review will serve as a guide to the clinician for treatment selection and as an efficient tool for the scientist to achieve a comprehensive overview of the scientific literature to guide their future experiments aimed at pathologic scar prevention. Recent Advances: Current studies in the literature suggest carbon dioxide (CO₂) laser and E-light (bipolar radiofrequency, intense pulsed light, and cooling) are two of the most effective treatment modalities for HTS, while surgical excision+CO₂ laser+triamcinolone injection was one of the most successful treatments for keloids. In animal models, drug impregnated electrospun nanofiber dressings offer encouraging results for HTS prevention, while Kelulut honey showed promising results for keloid prevention. Critical Issues: Treatment outcome reproducibility is hindered by small cohorts of patients, inadequate-follow up, and variability in assessment tools. Prevention studies show multiple ways of achieving the same result, yet fall short of complete prevention. Furthermore, some studies that have purported full prevention have not been validated. Future Directions: To establish a standard of care, large clinical trials of the most successful modalities in small cohorts are needed. The key for prevention will be validation in animal models of the most successful methods, followed by translational and clinical studies.

Local Delivery of Pirfenidone by PLA Implants Modifies Foreign Body Reaction and Prevents Fibrosis

Peri-implant fibrosis (PIF) increases the postsurgical risks after implantation and limits the efficacy of the implantable drug delivery systems (IDDS). Pirfenidone (PF) is an oral anti-fibrotic drug with a short (<3 h) circulation half-life and strong adverse side effects. In the current study, disk-shaped IDDS prototype combining polylactic acid (PLA) and PF, PLA@PF, with prolonged (~3 days) PF release (in vitro) was prepared. The effects of the PLA@PF implants on PIF were examined in the rabbit ear skin pocket model on postoperative days (POD) 30 and 60. Matching blank PLA implants (PLA⁰) and PLA⁰ with an equivalent single-dose PF injection performed on POD0 (PLA⁰+injPF) served as control. On POD30, the intergroup differences were observed in α-SMA, iNOS and arginase-1 expressions in PLA@PF and PLA⁰+injPF groups vs. PLA⁰. On POD60, PIF was significantly reduced in PLA@PF group. The peri-implant tissue thickness decreased (532 ± 98 μm vs. >1100 μm in control groups) approaching the intact derma thickness value (302 ± 15 μm). In PLA@PF group, the implant biodegradation developed faster, while arginase-1 expression was suppressed in comparison with other groups. This study proves the feasibility of the local control of fibrotic response on implants via modulation of foreign body reaction with slowly biodegradable PF-loaded IDDS.

Kinase inhibition in autoimmunity and inflammation

Despite recent advances in the treatment of autoimmune and inflammatory diseases, unmet medical needs in some areas still exist. One of the main therapeutic approaches to alleviate dysregulated inflammation has been to target the activity of kinases that regulate production of inflammatory mediators. Small-molecule kinase inhibitors have the potential for broad efficacy, convenience and tissue penetrance, and thus often offer important advantages over biologics. However, designing kinase inhibitors with target selectivity and minimal off-target effects can be challenging. Nevertheless, immense progress has been made in advancing kinase inhibitors with desirable drug-like properties into the clinic, including inhibitors of JAKs, IRAK4, RIPKs, BTK, SYK and TPL2. This Review will address the latest discoveries around kinase inhibitors with an emphasis on clinically validated autoimmunity and inflammatory pathways.

Unmet medical needs in the treatment of autoimmune and inflammatory diseases still exist. This Review discusses the activity of kinases that regulate production of inflammatory mediators and the recent advances in developing inhibitors to target such kinases.

Inflammation as an orchestrator of cutaneous scar formation: a review of the literature

Inflammation is a key phase in the cutaneous wound repair process. The activation of inflammatory cells is critical for preventing infection in contaminated wounds and results in the release of an array of mediators, some of which stimulate the activity of keratinocytes, endothelial cells, and fibroblasts to aid in the repair process. However, there is an abundance of data suggesting that the strength of the inflammatory response early in the healing process correlates directly with the amount of scar tissue that will eventually form. This review will summarize the literature related to inflammation and cutaneous scar formation, highlight recent discoveries, and discuss potential treatment modalities that target inflammation to minimize scarring.

Efficacy and Safety of Pirfenidone in Patients with Second-Degree Burns: A Proof-of-Concept Randomized Controlled Trial

OBJECTIVE

Several studies suggest that pirfenidone may have a potential off-label use for wound healing. However, the effectiveness of this medication in patients with burns remains uncertain. Accordingly, investigators sought to assess wound re-epithelialization in patients with second-degree burns after adding pirfenidone to usual care.

DESIGN AND SETTING

Single-center pilot, proof-of-concept, single-blind randomized controlled trial.

PATIENTS AND INTERVENTION

Eight patients with second-degree burns were treated with occlusive hydrocolloid dressings and were randomly allocated to receive either no additional treatment or pirfenidone.

OUTCOME MEASURES

The primary outcome of the study was to evaluate wound healing between groups based on the thickness of the re-epithelialized epidermis at day 7. Secondary outcomes were to qualitatively assess the development of fibrotic tissue in the dermis, anomalies in the basal membrane, and the development of collagen fibers by histologic analysis. Liver and renal functions were measured daily to assess the overall safety of oral pirfenidone.

MAIN RESULTS

Patients treated with pirfenidone showed a remarkable improvement in wound re-epithelialization at day 7 (148.98 ± 13.64 vs 119.27 ± 15.55 μm; P = .029; 95% confidence interval, 4.14-55.29). Histologic evaluations showed less wound fibrosis in the pirfenidone group.

CONCLUSIONS

A decrease in wound healing time by enhancing wound re-epithelialization was observed with pirfenidone. Larger clinical trials are needed to reach more reliable conclusions.

Pirfenidone inhibits epithelial-mesenchymal transition in keloid keratinocytes

Background

Keloids are benign fibroproliferative skin lesions that are difficult to treat and become a lifetime predicament for patients. Several treatment modalities have been put forth, but as yet no satisfactory approach to the prevention or treatment of keloids has been identified. The process of epithelial-to-mesenchymal transition (EMT) has been implicated in keloid scarring, as keloid keratinocytes display an EMT-like phenotype. This study investigated the potential of pirfenidone, an antifibrotic agent, to counteract EMT-like alterations in keloid keratinocytes, including gene expression, cell migratory and proliferative functions.

Methods

Normal and keloid keratinocytes were isolated from discarded normal skin tissues and from resected keloid tissues, respectively. Cells were quiesced for 24 h without epidermal growth factor DS-Qi1MCDigital and were exposed to transforming growth factor-beta1 (TGF-β1; 10 ng/mL), with or without pirfenidone (400 μg/mL), for an additional 24 h. The effects of pirfenidone on cytotoxicity, cell migration, cell proliferation, and on expression of genes and proteins involved in EMT were assayed. Statistical significance was determined by two-way ANOVA using Sigma Plot.

Results

We found that pirfenidone did not elicit any cytotoxic effect at concentrations up to 1000 μg/mL. A statistically significant dose-dependent decrease in basal cell proliferation rate was noted in both normal and keloid keratinocytes when exposed to pirfenidone at concentrations ranging from 200 to 1000 μg/mL. Pirfenidone significantly decreased basal cell migration in both normal and keloid keratinocytes, but a significant decrease in TGF-β1-induced cell migration was seen only in keloid keratinocytes. Significant inhibition of the expression of TGF-β1-induced core EMT genes, namely hyaluronan synthase 2, vimentin, cadherin-11, and wingless-type MMTV integration site family, member 5A along with fibronectin-1, was observed in both normal and keloid keratinocytes treated with pirfenidone. In addition, the protein levels of vimentin and fibronectin were significantly reduced by pirfenidone (400 μg/mL) in both normal and keloid keratinocytes.

Conclusions

For the first time, this study shows the efficacy of pirfenidone in inhibiting the EMT-like phenotype in keratinocytes derived from keloids, suggesting that pirfenidone may counteract a critical contributor of keloid progression and recurrence.

Current Approaches Targeting the Wound Healing Phases to Attenuate Fibrosis and Scarring

Cutaneous fibrosis results from suboptimal wound healing following significant tissue injury such as severe burns, trauma, and major surgeries. Pathologic skin fibrosis results in scars that are disfiguring, limit normal movement, and prevent patient recovery and reintegration into society. While various therapeutic strategies have been used to accelerate wound healing and decrease the incidence of scarring, recent studies have targeted the molecular regulators of each phase of wound healing, including the inflammatory, proliferative, and remodeling phases. Here, we reviewed the most recent literature elucidating molecular pathways that can be targeted to reduce fibrosis with a particular focus on post-burn scarring. Current research targeting inflammatory mediators, the epithelial to mesenchymal transition, and regulators of myofibroblast differentiation shows promising results. However, a multimodal approach addressing all three phases of wound healing may provide the best therapeutic outcome.

Pirfenidone attenuates the profibrotic contractile phenotype of differentiated human dermal myofibroblasts

Dysregulated wound healing after burn injury frequently results in debilitating hypertrophic scarring and contractures. Myofibroblasts, the main effector cells for dermal fibrosis, develop from normal fibroblasts via transforming growth factor beta 1 (TGF-β1). During wound healing, myofibroblasts produce extracellular matrix (ECM) proteins, modulate ECM stability, and contract the ECM using alpha smooth muscle actin (α-SMA) in contractile stress fibers. The antifibrotic pirfenidone has previously been shown to inhibit the initial differentiation of fibroblasts into myofibroblasts in vitro and act as a prophylactic measure against hypertrophic scar development in a mouse burn model. To test whether pirfenidone affects differentiated myofibroblasts, we investigated the in vitro effects of pirfenidone treatment after three to five days of stimulation with TGF-β1. In assays for morphology, protein and gene expression, and contractility, pirfenidone treatment produced significant effects. Profibrotic gene expression returned to near-normal levels, further α-SMA protein expression was prevented, and cell contraction within a stressed collagen matrix was reduced. These in vitro results promote pirfenidone as a promising antifibrotic agent to treat existing scars and healing wounds by mitigating the effects of differentiated myofibroblasts.

Abnormal scar identification with spherical-nucleic-acid technology

The accurate diagnosis of scar type and severity relies on histopathology of biopsied tissue, which is invasive and time-consuming, causes discomfort and may exacerbate scarring. Here, we show that imaging nanoprobes for the live-cell detection of intracellular messenger RNA (mRNA) (also known as NanoFlares) enable measurements of the expression of connective tissue growth factor (CTGF) as a visual indicator of hypertrophic scars and keloids. During cell culture, NanoFlares enabled the distinction of hypertrophic and keloidal fibroblasts from normal fibroblasts, and the detection of changes in CTGF expression resulting from the regulatory effects of transforming growth factor-β (TGF-β) agonists and TGF-β antagonists. We also applied the NanoFlares topically to the skin of live mice and rabbits, and to ex vivo human skin models. Transepidermal penetration of the NanoFlares enabled the visual and spectroscopic quantification of underlying abnormal fibroblasts on the basis of CTGF mRNA expression. Our proof-of-concept studies of topically applied NanoFlare technology as a means of biopsy-free scar diagnosis may eventually inform therapeutic decisions on the basis of the mRNA-expression patterns of skin disorders.

Advancements in Regenerative Strategies Through the Continuum of Burn Care

Burns are caused by several mechanisms including flame, scald, chemical, electrical, and ionizing and non-ionizing radiation. Approximately half a million burn cases are registered annually, of which 40 thousand patients are hospitalized and receive definitive treatment. Burn care is very resource intensive as the treatment regimens and length of hospitalization are substantial. Burn wounds are classified based on depth as superficial (first degree), partial-thickness (second degree), or full-thickness (third degree), which determines the treatment necessary for successful healing. The goal of burn wound care is to fully restore the barrier function of the tissue as quickly as possible while minimizing infection, scarring, and contracture. The aim of this review is to highlight how tissue engineering and regenerative medicine strategies are being used to address the unique challenges of burn wound healing and define the current gaps in care for both partial- and full-thickness burn injuries. This review will present the current standard of care (SOC) and provide information on various treatment options that have been tested pre-clinically or are currently in clinical trials. Due to the complexity of burn wound healing compared to other skin injuries, burn specific treatment regimens must be developed. Recently, tissue engineering and regenerative medicine strategies have been developed to improve skin regeneration that can restore normal skin physiology and limit adverse outcomes, such as infection, delayed re-epithelialization, and scarring. Our emphasis will be centered on how current clinical and pre-clinical research of pharmacological agents, biomaterials, and cellular-based therapies can be applied throughout the continuum of burn care by targeting the stages of wound healing: hemostasis, inflammation, cell proliferation, and matrix remodeling.

Development of a Topical 48-H Release Formulation as an Anti-scarring Treatment for Deep Partial-Thickness Burns

The purpose of this study was to develop pirfenidone (PF) ointment formulations for a dose finding study in the prophylactic treatment of deep partial-thickness burns in a mouse model. A preformulation study was performed to evaluate the solubility of PF in buffers and different solvents and its stability. Three different formulations containing 1, 3.5, and 6.5% w/w PF were prepared and optimized for their composition for testing in mice. Optimized formulations showed promising in vitro release profiles, in which 20-45% of PF was released in the first 7 h and 70-90% released within 48 h. The rheological properties of the ointment remained stable throughout storage at 25 ± 2°C/60% RH. Animal studies showed treatments of burn wounds during the inflammatory stage of wound healing with PF ointments at different drug concentrations had no adverse effects on reepithelization. Moreover, 6.5% PF ointment (F3) reduced the expression of pro-inflammatory cytokines IL-12p70 and TNFα. This study suggests that hydrocarbon base ointment could be a promising dosage form for topical delivery of PF in treatment of deep partial-thickness burns.

Pirfenidone reduces profibrotic responses in human dermal myofibroblasts, in vitro

Pirfenidone (PFD) is a synthetic small molecule inhibitor with demonstrated anti-inflammatory and antifibrotic properties in vitro and in vivo. The exact mechanism(s) of PFD action remain unclear, due in part to the broad effects of this drug on the complex processes involved in inflammation and fibrosis. While PFD is FDA-approved for the treatment of idiopathic pulmonary fibrosis, the efficacy of this compound for the treatment of dermal fibrosis has not yet been fully characterized. Dermal fibrosis is the pathological formation of excess fibrous connective tissue of the skin, usually the result of traumatic cutaneous injury. Fibroproliferative scarring, caused by delayed wound healing and prolonged inflammation, remains a major clinical concern with considerable morbidity. Despite efforts to identify a therapeutic that targets the fibrotic pathways involved in wound healing to mitigate scar formation, no satisfactory dermal antifibrotic has yet been identified. We aim to better elucidate the antifibrotic mechanism(s) of PFD activity using an in vitro model of dermal fibrosis. Briefly, cultured human dermal fibroblasts were stimulated with TGF-β1 to induce differentiation into profibrotic myofibroblast cells. A dose-dependent reduction in cellular proliferation and migration was observed in TGF-β1-stimulated cells when treated with PFD. We observed a clear inhibition in the development of essential myofibroblast mechanoregulatory machinery, including contractile F-actin stress fibers containing α-SMA and large super-mature focal adhesions. PFD treatment significantly reduced protein levels of major ECM components type I and type III collagen. PFD targeted the p38 MAPK signaling pathway and mitigated profibrotic gene expression profiles. This in vitro data promotes PFD as a potential therapeutic agent for the treatment of dermal fibrosis.

Abnormal scar identification with spherical-nucleic-acid technology

The accurate diagnosis of scar type and severity relies on histopathology of biopsied tissue, which is invasive and time-consuming, causes discomfort and may exacerbate scarring. Here, we show that imaging nanoprobes for the live-cell detection of intracellular messenger RNA (mRNA) (also known as NanoFlares) enable measurements of the expression of connective tissue growth factor (CTGF) as a visual indicator of hypertrophic scars and keloids. During cell culture, NanoFlares enabled the distinction of hypertrophic and keloidal fibroblasts from normal fibroblasts, and the detection of changes in CTGF expression resulting from the regulatory effects of transforming growth factor-β (TGF-β) agonists and TGF-β antagonists. We also applied the NanoFlares topically to the skin of live mice and rabbits, and to ex vivo human skin models. Transepidermal penetration of the NanoFlares enabled the visual and spectroscopic quantification of underlying abnormal fibroblasts on the basis of CTGF mRNA expression. Our proof-of-concept studies of topically applied NanoFlare technology as a means of biopsy-free scar diagnosis may eventually inform therapeutic decisions on the basis of the mRNA-expression patterns of skin disorders.

Pathophysiologic Mechanisms and Current Treatments for Cutaneous Sequelae of Burn Wounds

Burn injuries are a pervasive clinical problem. Extensive thermal trauma can be life-threatening or result in long-lasting complications, generating a significant impact on quality of life for patients as well as a cost burden to the healthcare system. The importance of addressing global or systemic issues such as resuscitation and management of inhalation injuries is not disputed but is beyond the scope of this review, which focuses on cutaneous pathophysiologic mechanisms for current treatments, both in the acute and long-term settings. Pathophysiological mechanisms of burn progression and wound healing are mediated by highly complex cascades of cellular and biochemical events, which become dysregulated in slow-healing wounds such as burns. Burns can result in fibroproliferative scarring, skin contractures, or chronic wounds that take weeks or months to heal. Burn injuries are highly individualized owing to wound-specific differences such as burn depth and surface area, in addition to patient-specific factors including genetics, immune competency, and age. Other extrinsic complications such as microbial infection can complicate wound healing, resulting in prolonged inflammation and delayed re-epithelialization. Although mortality is decreasing with advancements in burn care, morbidity from postburn deformities continues to be a challenge. Optimizing specialized acute care and late burn outcome intervention on a patient-by-patient basis is critical for successful management of burn wounds and the associated pathological scar outcome. Understanding the fundamentals of integument physiology and the cellular processes involved in wound healing is essential for designing effective treatment strategies for burn wound care as well as development of future therapies. Published 2018. Compr Physiol 8:371-405, 2018.

Anti-fibrotic action of pirfenidone in Dupuytren's disease-derived fibroblasts

BACKGROUND

Dupuytren's disease (DD) is a complex fibro-proliferative disorder of the hand that is often progressive and eventually can cause contractures of the affected fingers. Transforming growth factor beta (TGF-β1) has been implicated as a key stimulator of myofibroblast activity and fascial contraction in DD. Pirfenidone (PFD) is an active small molecule shown to inhibit TGF-β1-mediated action in other fibrotic disorders. This study investigates the efficacy of PFD in vitro in inhibiting TGF-β1-mediated cellular functions leading to Dupuytren's fibrosis.

METHODS

Fibroblasts harvested from (DD) and carpal tunnel (CT)- tissues were treated with or without TGF-β1 and/or PFD and were subjected to cell migration, cell proliferation and cell contraction assays. ELISA; western blots and real time RT-PCR assays were performed to determine the levels of fibronectin; p-Smad2/Smad3; alpha-smooth muscle actin (α-SMA), α2 chain of type I collagen and α1 chain of type III collagen respectively.

RESULTS

Our results show that PFD effectively inhibits TGF-β1-induced cell migration, proliferation and cell contractile properties of both CT- and DD-derived fibroblasts. TGF-β1-induced α-SMA mRNA and protein levels were inhibited at the higher concentration of PFD (800 μg/ml). Interestingly, TGF-β1 induction of type I and type III collagens and fibronectin was inhibited by PFD in both CT- and DD- derived fibroblasts, but the effect was more prominent in DD cells. PFD down-regulated TGF-β1-induced phosphorylation of Smad2/Smad3, a key factor in the TGF-β1 signaling pathway.

CONCLUSION

Taken together these results suggest the PFD can potentially prevent TGF-β1-induced fibroblast to myofibroblast transformation and inhibit ECM production mainly Type I- and Type III- collagen and fibronectin in DD-derived fibroblasts. Further in-vivo studies with PFD may lead to a novel therapeutic application in preventing the progression or recurrence of Dupuytren's disease.

Pirfenidone inhibits the proliferation of fibroblasts from patients with active Crohn's disease

OBJECTIVE

One-third of Crohn's disease (CD) patients develop intestinal strictures that require repeated surgical intervention. Current anti-inflammatory therapies have limited effect on stricture development, which necessitates the exploration of new pharmacological approaches. Pirfenidone (PFD), a novel anti-fibrotic agent, was recently approved in Europe for the treatment of idiopathic pulmonary fibrosis (IPF). We hypothesized that observations in IPF could be transferable to intestinal fibrosis and that PFD inhibits the proliferation and extracellular matrix (ECM) turnover of gut-derived fibroblasts from CD patients.

MATERIAL AND METHODS

Fibroblasts were isolated from biopsies of inflamed (n = 8) and non-inflamed (n = 5) colonic mucosa. Expression of CD90 and alpha-smooth muscle actin (αSMA) expression was determined by flow cytometry. The fibroblasts were cultured with PFD (0.5, 1.0 and 2.0 mg/ml). Proliferation was evaluated with CellTiter 96(®) AQueous One Solution Cell Proliferation Assay. Production of matrix metalloproteinase-3 (MMP-3), tissue inhibitor of metalloproteinases-1 (TIMP-1) and collagen were assessed using ELISA and calorimetric assays, respectively.

RESULTS

The majority of the fibroblasts were αSMA-positive myofibroblasts. PFD inhibited fibroblast proliferation [0.94 (PFD 0.5 mg/ml); 0.76 (1.0 mg/ml); 0.58 (2.0 mg/ml)] and production of MMP-3 [0.85 (0.5 mg/ml); 0.74 (1.0 mg/ml); 0.63 (2.0 mg/ml)] dose-dependently (both p = 0.0001). The anti-proliferative effect of PFD was reversible (p = 0.0001), indicating that PFD does not act by an irreversible cytotoxic mechanism. PFD did not influence neither TIMP-1 nor collagen production.

CONCLUSION

PFD inhibited the proliferation and the production of MMP-3 dose-dependently in gut-derived fibroblast from CD patients. Our observations support further studies on PFD in stricturing CD.

Decreased Fibrogenesis After Treatment with Pirfenidone in a Newly Developed Mouse Model of Intestinal Fibrosis

BACKGROUND

Fibrosis as a common problem in patients with Crohn's disease is a result of an imbalance toward excessive tissue repair. At present, there is no specific treatment option. Pirfenidone is approved for the treatment of idiopathic pulmonary fibrosis with both antifibrotic and anti-inflammatory effects. We subsequently investigated the impact of pirfenidone treatment on development of fibrosis in a new mouse model of intestinal fibrosis.

METHODS

Small bowel resections from donor mice were transplanted subcutaneously into the neck of recipients. Animals received either pirfenidone (100 mg/kg, three times daily, orally) or vehicle.

RESULTS

After administration of pirfenidone, a significantly decreased collagen layer thickness was revealed as compared to vehicle (9.7 ± 1.0 versus 13.5 ± 1.5 µm, respectively, **P < 0.001). Transforming growth factor-β and matrix metalloproteinase-9 were significantly decreased after treatment with pirfenidone as confirmed by real-time PCR (0.42 ± 0.13 versus 1.00 ± 0.21 and 0.46 ± 0.24 versus 1.00 ± 0.62 mRNA expression level relative to GAPDH, respectively, *P < 0.05). Significantly decreased transforming growth factor-β after administration of pirfenidone was confirmed by Western blotting.

CONCLUSION

In our mouse model, intestinal fibrosis can be reliably induced and is developed within 7 days. Pirfenidone partially prevented the development of fibrosis, making it a potential treatment option against Crohn's disease-associated fibrosis.

Pirfenidone gel in patients with localized scleroderma: a phase II study

Introduction

Localized scleroderma is an inflammatory disease in its first stages and a fibrotic process in later stages, principally mediated by the transforming growth factor β. To date, there is no standard treatment. The objective of this study was to determine the effectiveness and safety of 8% pirfenidone gel in patients with localized scleroderma.

Methods

This was an open phase II clinical trial that included 12 patients. Treatment with pirfenidone was indicated, three times daily for 6 months. Patients were evaluated clinically with the modified Localized Scleroderma Skin Severity Index (mLoSSI), as well with a durometer and histologically using hematoxylin and eosin stain and Masson’s trichrome stain.

Results

The baseline mLoSSI average scores were 5.83 ± 4.80 vs. 0.83 ± 1.75 (P = 0.002) at 6 months. The initial durometer induration of the scleroderma plaques was 35.79 ± 9.10 vs. 32.47 ± 8.97 at 6 months (P = 0.05). We observed histopathological improvement with respect to epidermal atrophy, inflammation, dermal or adipose tissue fibrosis and annex atrophy from 12.25 ± 3.25 to 9.75 ± 4.35 (P = 0.032). The 8% pirfenidone gel application was well tolerated, and no side effects were detected.

Conclusions

This is the first study on the therapeutic use of pirfenidone gel in localized scleroderma. It acts on both the inflammatory and the fibrotic phases. Considering its effectiveness, good safety profile and the advantage of topical application, pirfenidone is a treatment option in this condition.

Pharmacological treatment for keloids

INTRODUCTION

Keloids are fibroproliferative disorders that are characterized by histological accumulation of collagens and fibroblasts, refractory clinical symptoms such as itching, topical invasiveness, and frequent postsurgical recurrence. At present, to treat or prevent keloids, new drugs are currently being designed and the pharmaceutical indications of known drugs are being expanded.

AREAS COVERED

The current pharmacological interventions for keloids are mainly described on the basis of the various hypotheses on keloid etiology and the keloid ingredients that are targeted. These interventions include angiotension-converting enzyme inhibitors and calcium-channel blockers (based on hypertension hypothesis), selective estrogen receptor modulator (based on endocrinological hypothesis), vitamins and essential fatty acids (based on immunonutritional hypothesis), and transglutaminase inhibitor (based on metabolic hypothesis). Drugs that directly target the reduction or destruction of the major extracellular matrix or cellular constituents of keloids are also included. Besides, drugs that indirectly modulate the biochemical microenvironment are described. These include growth factors, immunomodulators, and anti-inflammation and anti-allergy drugs.

EXPERT OPINION

Due to the unclear etiology of keloids and the lack of animal models, efficient, reliable, and specific pharmaceutical interventions for keloids continue to be lacking. The reliability of current data and clinical observations must be strengthened by large-scale, randomized, controlled clinical trials.

Genotoxic evaluation of pirfenidone using erythrocyte rodent micronucleus assay

Pirfenidone is a non-steroidal antifibrotic compound that has been proposed in clinical protocols and experimental studies as a pharmacological treatment for fibroproliferative diseases. The objective of this study was to determine the genotoxicity or cytotoxicity of three doses of pirfenidone using the micronuclei test in peripheral blood erythrocytes of rodent models. Pirfenidone was administered orally to Balb-C mice for 3 days, and also was administered topically to hairless Sprague Dawley rats during the final stage of gestation. Mice were sampled every 24 h over the course of 6 days; pregnant rats were sampled every 24 h during the last 6 days of gestation, and pups were sampled at birth. Blood smears were analyzed and the frequencies of micronucleated erythrocytes (MNEs), micronucleated polychromatic erythrocytes (MNPCEs), and the proportion of polychromatic erythrocytes (PCEs), were recorded in samples from mice, pregnant rats and rat neonates. Increases in MN frequencies (p<0.03) were noted only in the positive control groups. No genotoxic effects or decreased PCE values were observed neither in newborn rats transplacentally exposed to pirfenidone, or in two adult rodent models when pirfenidone was administered orally or topically.