Plasminogen activator inhibitor-1 is elevated, but not essential, in the development of bleomycin-induced murine scleroderma

Clinical, Histologic, and Transcriptomic Evaluation of Sequential Fat Grafting for Morphea: A Nonrandomized Controlled Trial

Importance

Morphea is a rare disease of unknown etiology without satisfactory treatment for skin sclerosis and soft tissue atrophy.

Objective

To provide clinical, histologic, and transcriptome evidence of the antisclerotic and regenerative effects of sequential fat grafting with fresh fat and cryopreserved stromal vascular fraction gel (SVF gel) for morphea.

Design, Setting, and Participants

This single-center, nonrandomized controlled trial was conducted between January 2022 and March 2023 in the Department of Plastic and Reconstructive Surgery of Nanfang Hospital, Southern Medical University and included adult participants with early-onset or late-onset morphea who presented with varying degrees of skin sclerosis and soft tissue defect.

Interventions

Group 1 received sequential grafting of fresh fat and cryopreserved SVF gel (at 1 and 2 months postoperation). Group 2 received single autologous fat grafting. All patients were included in a 12-month follow-up.

Main Outcome and Measures

The primary outcome included changes in the modified Localized Scleroderma Skin Severity Index (mLoSSI) and Localized Scleroderma Skin Damage Index (LoSDI) scores as evaluated by 2 independent blinded dermatologists. The histologic and transcriptome changes of morphea skin lesions were also evaluated.

Results

Of 44 patients (median [IQR] age, 26 [23-33] years; 36 women [81.8%]) enrolled, 24 (54.5%) were assigned to group 1 and 20 (45.5%) to group 2. No serious adverse events were noted. The mean (SD) mLoSSI scores at 12 months showed a 1.6 (1.50) decrease in group 1 and 0.9 (1.46) in group 2 (P = .13), whereas the mean (SD) LoSDI scores at 12 months showed a 4.3 (1.34) decrease in group 1 and 2.1 (1.07) in group 2 (P < .001), indicating that group 1 had more significant improvement in morphea skin damage but not disease activity compared with group 2. Histologic analysis showed improved skin regeneration and reduced skin sclerosis in group 1, whereas skin biopsy specimens of group 2 patients did not show significant change. Transcriptome analysis of skin biopsy specimens from group 1 patients suggested that tumor necrosis factor α signaling via NFκB might contribute to the immunosuppressive and antifibrotic effect of sequential fat grafting. A total of 15 hub genes were captured, among which many associated with morphea pathogenesis were downregulated and validated by immunohistochemistry, such as EDN1, PAI-1, and CTGF.

Conclusions and Relevance

The results of this nonrandomized trial suggest that sequential fat grafting with fresh fat and cryopreserved SVF gel was safe and its therapeutic effect was superior to that of single autologous fat grafting with improved mLoSSI and LoSDI scores. Histological and transcriptomic changes further support the effectiveness after treatment.

Trial Registration

Chinese Clinical Trial Registry identifier: ChiCTR2200058003.

Cardiovascular-renal complications and the possible role of plasminogen activator inhibitor: a review

Since angiotensin increases the expression of plasminogen activator inhibitor (PAI), mechanisms associated with an actively functioning renin–angiotensin–aldosterone system can be expected to be associated with increased PAI-1 expression. These mechanisms are present not only in common conditions resulting in glomerulosclerosis associated with aging, diabetes or genetic mutations, but also in autoimmune disease (like scleroderma and lupus), radiation injury, cyclosporine toxicity, allograft nephropathy and ureteral obstruction. While the renin–angiotensin–aldosterone system and growth factors, such as transforming growth factor-beta (TGF-β), are almost always part of the process, there are rare experimental observations of PAI-1 expression without their interaction. Here we review the literature on PAI-1 and its role in vascular, fibrotic and oxidative injury as well as work suggesting potential areas of intervention in the pathogenesis of multiple disorders.

PAI-1 in tissue fibrosis

Fibrosis is defined as a fibroproliferative or abnormal fibroblast activation-related disease. Deregulation of wound healing leads to hyperactivation of fibroblasts and excessive accumulation of extracellular matrix (ECM) proteins in the wound area, the pathological manifestation of fibrosis. The accumulation of excessive levels of collagen in the ECM depends on two factors: an increased rate of collagen synthesis and or decreased rate of collagen degradation by cellular proteolytic activities. The urokinase/tissue type plasminogen activator (uPA/tPA) and plasmin play significant roles in the cellular proteolytic degradation of ECM proteins and the maintenance of tissue homeostasis. The activities of uPA/tPA/plasmin and plasmin-dependent MMPs rely mostly on the activity of a potent inhibitor of uPA/tPA, plasminogen activator inhibitor-1 (PAI-1). Under normal physiologic conditions, PAI-1 controls the activities of uPA/tPA/plasmin/MMP proteolytic activities and thus maintains the tissue homeostasis. During wound healing, elevated levels of PAI-1 inhibit uPA/tPA/plasmin and plasmin-dependent MMP activities, and, thus, help expedite wound healing. In contrast to this scenario, under pathologic conditions, excessive PAI-1 contributes to excessive accumulation of collagen and other ECM protein in the wound area, and thus preserves scarring. While the level of PAI-1 is significantly elevated in fibrotic tissues, lack of PAI-1 protects different organs from fibrosis in response to injury-related profibrotic signals. Thus, PAI-1 is implicated in the pathology of fibrosis in different organs including the heart, lung, kidney, liver, and skin. Paradoxically, PAI-1 deficiency promotes spontaneous cardiac-selective fibrosis. In this review, we discuss the significance of PAI-1 in the pathogenesis of fibrosis in multiple organs.

Lapachol suppresses cell proliferation and secretion of interleukin-6 and plasminogen activator inhibitor-1 of fibroblasts derived from hypertrophic scars

Objectives

The pathogenesis and therapy of hypertrophic scar have not yet been established. Our aim was to investigate the antiproliferative and antisecretory effects of lapachol, isolated from the stem bark of Avicennia rumphiana Hall. f., on hypertrophic scar fibroblasts.

Methods

The effects of lapachol on hypertrophic scar fibroblast proliferation were measured using the MTT assay, cell-cycle analyses and lactate dehydrogenase assays. The type I collagen α-chain (COL1A1), interleukin-6 (IL-6) and plasminogen activator inhibitor-1 (PAI-1) mRNA and/or protein levels of hypertrophic scar-fibroblasts were quantitated by real-time PCR and ELISA.

Key findings

Lapachol at 25 and 50 µm significantly inhibited the in vitro proliferation of hypertrophic scar fibroblasts, but not fibroblasts from non-lesional skin sites. In addition, lapachol had no apparent effect on cell cycle and lactate dehydrogenase activity in conditioned medium from lapachol-treated hypertrophic scar fibroblasts was nearly equal to that in medium from vehicle-treated cells. Lapachol treatment also inhibited COL1A1 and PAI-1 mRNA levels in hypertrophic scar fibroblasts, but did not affect IL-6 mRNA levels. The protein levels of IL-6 and PAI-1 in conditioned medium from hypertrophic scar fibroblasts treated with 50 µm lapachol were lower than those from vehicle-treated hypertrophic scar fibroblasts.

Conclusions

Lapachol decreased the proliferation rate of hypertrophic scar fibroblasts. As IL-6 and PAI-1 secretion was also lowered in lapachol-treated hypertrophic scar fibroblasts, our findings suggested that lapachol may have suppressed extracellular matrix hyperplasia in wound healing and possibly alleviated the formation of hypertrophic scar.

Prevention of excessive collagen accumulation by human intravenous immunoglobulin treatment in a murine model of bleomycin-induced scleroderma

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrotic changes in skin and other organs involving excessive collagen deposition. Here we investigated the effect of intravenous immunoglobulin (IVIG) on fibrosis in a murine model of bleomycin (BLM)-induced scleroderma. Scleroderma was induced in C3H/He J mice by subcutaneous BLM injections daily for 35 days. The collagen content in skin samples from the BLM-injected group (6·30 ± 0·11 mg/g tissue) was significantly higher than the PBS group (5·80 ± 0·10 mg/g tissue), and corresponded with dermal thickening at the injection site. In contrast, mice treated with IVIG for 5 consecutive days after initiating BLM injection showed lesser collagen content significantly (IVIG group, 5·61 ± 0·09 mg/g tissue; BLM vs. IVIG). In order to investigate the cellular and protein characteristics in the early stage of the model, the skin samples were obtained 7 days after the onset of experiment. Macrophage infiltration to the dermis, monocyte chemoattractant protein (MCP-1)-positive cells, and increased TGF-β1 mRNA expression were also observed in the BLM group. IVIG inhibited these early fibrogenic changes; MCP-1 expression was significantly lesser for the IVIG group (1·52 ± 0·19 pg/mg tissue) than for the BLM group (2·49 ± 0·26 pg/mg tissue). In contrast, TGF-β1 mRNA expression was significantly inhibited by IVIG. These results suggest that IVIG treatment may inhibit macrophage recruitment to fibrotic sites by down regulating MCP-1 and TGF-β production, and thus could be a potential drug for managing fibrotic disorders such as SSc.

The Plasminogen Activator System in Fibroblasts from Systemic Sclerosis

Systemic sclerosis (SSc) is characterized by excessive fibrosis throughout the body. There are two major subsets of SSc, diffuse cutaneous Systemic sclerosis (dSSc) and limited cutaneous Systemic sclerosis (ISSc). Fibroblasts play a key role in SSc. The expression and function of the urokinase (uPA)-mediated plasminogen activation (PA) system, a well-characterized system of serine-proteases involved in several pathological processes, has been investigated in SSc fibroblasts. The expression of the components of the PA system, including uPA, its type-1 and type-2 inhibitors (PAI-1 and PAI-2) and its receptor (uPAR), was examined by Western blot in fibroblasts from patients affected by limited and diffuse forms of SSc. uPA and PAI-1 secretion increased only in fibroblasts from ISSc lesions compared to normal fibroblasts. PAI-2 levels were decreased in fibroblasts from both SSc forms. Interestingly, fibroblasts from areas not adjacent to the lesions (not-affected) of the diffuse form showed reduced levels of PAI-1 and increased uPAR expression. Adhesion experiments showed reduced adherence to VN of fibroblasts from ISSc lesions and from non-affected areas of the diffuse form, as compared to normal controls. These results suggest a role for uPA and PAI-1 in the ISSc form, likely related to the activation of latent forms of cytokines and to the accumulation of ECM components, whereas a role for uPAR can be hypothesized in the evolvement of the diffuse form, based on its up-regulation in the non-affected areas.

Investigation of sensory neurogenic components in a bleomycin-induced scleroderma model using transient receptor potential vanilloid 1 receptor- and calcitonin gene-related peptide-knockout mice

OBJECTIVE

Along with their classic afferent function (nociception), capsaicin-sensitive transient receptor potential vanilloid 1 (TRPV1) receptor-expressing sensory nerve terminals exert local and systemic efferent activities. Activation of TRPV1 causes sensory neuropeptide release, which modulates the inflammation process. The aim of the present study was to examine the role of this modulatory role of TRPV1 receptor and that of calcitonin gene-related peptide (CGRP) in bleomycin-induced scleroderma, using transgenic mice.

METHODS

Cutaneous sclerosis was induced with daily subcutaneous injections of bleomycin for 30 days. Control groups were treated with phosphate buffered saline (PBS). TRPV1 receptor gene-deficient (TRPV1(-/-)) mice and CGRP-knockout (CGRP(-/-)) mice and their wild-type (WT) counterparts were investigated. A composite sclerosis score was calculated on the basis of thickening, leukocyte infiltration, and the amount/orientation of collagen bundles. Dermal thickness and the number of alpha-smooth muscle actin (alpha-SMA)-positive cells were also determined. The quantity of the collagen-specific amino acid hydroxyproline was measured by spectrophotometry.

RESULTS

Bleomycin treatment induced marked cutaneous thickening and fibrosis compared with that observed in control mice treated with PBS. The composite sclerosis score was 18% higher, dermal thickness was 19% higher, the number of alpha-SMA-positive cells was 47% higher, and the amount of hydroxyproline was 57% higher in TRPV1(-/-) mice than in their WT counterparts. Similarly, the composite sclerosis score was 47% higher, dermal thickness was 29% higher, the number of alpha-SMA-positive cells was 76% higher, and the amount of hydroxyproline was 30% higher in CGRP(-/-) mice than in the respective WT groups.

CONCLUSION

These results suggest that activation of the TRPV1 receptor by mediators of inflammation induces sensory neuropeptide release, which might exert protective action against fibrosis. We confirmed the protective role of CGRP in the development of cutaneous sclerosis.