A brief overview of the pathogenesis of scleroderma (systemic sclerosis)

Human otopathology in scleroderma

Objective

Scleroderma is a complex chronic progressive immune-mediated disease that causes fibrosis of the skin and internal organs, and vasculopathy.Ear involvement has been poorly studied in patients with scleroderma. Vasculitic and autoimmune mechanisms are considered as possible etiologies on hearing impairment, however, this etiology still unclear.Herein, we reviewed three cases of scleroderma from a temporal bone repository.

Methods

The national temporal bone database was reviewed for cases with scleroderma. Clinical case review and correlative otopathologic analysis. Middle and inner ear otopathologic analysis was performed following hematoxylin and eosin staining under light microscopy. Findings were compared to three age-matched controls.

Results

Two patients (three cases) with a history of serologically confirmed scleroderma were identified. Both individuals reported tinnitus and demonstrated bilateral moderate to severe down-sloping sensorineural hearing loss on audiometry. Histologically, the incudomallear joint space was diminished and ossicles appeared demineralized. A loss of hyaline cartilage, and obliteration of the incudomallear and incudostapedial joint synovial spaces was observed. Decreased caliber and intimal hyperplasia of arteries adjacent to ossicles was also identified. Mild diffuse atrophy of stria vascularis in the middle and apical turns of cochlea were found. Hair cell populations were normal. Total spiral ganglion neurons were lower in cases of scleroderma (range 29%-51%) compared to age-matched controls.

Conclusion

Fibrosis, inflammation, and vascular changes were observed in the middle and inner ear in patients with scleroderma. Findings have implications for understanding hearing and vestibular dysfunction in this patient population.

Level of evidence

Retrospective study.

Connexin 37, 40, 43 and Pannexin 1 Expression in the Gastric Mucosa of Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of the skin and internal organs. Although its pathogenesis is not fully understood, connexins (Cxs) and pannexins (Panx) could be involved in the process of fibrosis. We analyzed the protein expression of Cx37, Cx40, Cx43, and Panx1 in the gastric mucosa of patients with SSc and healthy volunteers, using immunofluorescence staining. Protein levels of Cx37 were slightly increased, while the levels of Cx40 were significantly decreased in the lamina propria of the gastric mucosa of SSc patients compared to the controls. The changes were proportional to SSc severity, with the most prominent changes found in patients with severe diffuse cutaneous SSc. No differences in Cx43 or Panx1 levels were found between the analyzed groups of samples. The lack of changes in Cx43 expression, which has been previously associated with fibrosis, could be due to the weak expression of Cx43 in the gastric mucosa in general. Further studies on full-thickness gastric biopsies containing muscle layers and animal SSc models are needed to fully elucidate the role of Cxs and Panxs in SSc-associated fibrosis.

Significance of KIR like natural killer cell receptors in autoimmune disorders

Killer cell immunoglobulin-like receptors (KIRs), act as the regulators for the cytolytic activity of natural killer and certain T cells by interacting with the HLA class I ligands. KIRs have been shown to contribute to the pathogenesis of several autoimmune diseases. However, their specific roles are still not very clear. Autoimmune diseases are multifactorial in nature, highlighting the influence of both genetic and environmental factors. The innate immune response plays an important role in autoimmunity as it alters the self-glycans that mimic molecular patterns found on different intracellular pathogens. Natural killer (NK) cells have an important position in the innate immune response. NK cell receptors are encoded by the leukocyte receptor complex located on the chromosome 19q13.4 and lectin-like receptors on chromosome 12p13. This review focuses on the role of KIRs and their relationship with different autoimmune diseases.

Serum levels of anti-Fcγ receptor IIB/C antibodies are increased in patients with systemic sclerosis

Systemic sclerosis (SSc) is a systemic autoimmune disorder that results in fibrosis of the skin and multiple internal organs. Although the precise mechanism is unknown, it appears to result from the overproduction of extracellular matrix proteins and aberrant immune activations. Receptors for the Fc region of immunoglobulin (Ig)G (FcγR) are members of the Ig superfamily that modulate both activation and inhibition of immune responses. FcγRIIB is the sole inhibitory member, which has an intrinsic cytoplasmic immunoreceptor tyrosine-based inhibitory motif. The present study was undertaken to investigate the circulating concentrations of anti-FcγRIIB/C antibodies (Ab) in patients with SSc. Serum levels of anti-FcγRIIB/C Ab were significantly increased in patients with SSc compared to those in controls and in patients with localized scleroderma. Serum levels of anti-FcγRIIB/C Ab in patients with limited cutaneous SSc were similar to those in patients with diffuse cutaneous SSc. Among SSc patients, serum levels of anti-FcγRIIB/C Ab were increased in those with nail-fold bleeding and decreased in those with diffuse pigmentation and calcinosis. These findings support the notion that increased serum anti-FcγRIIB/C Ab levels are involved in aberrant immune responses in SSc.

Effect of Pentoxifylline Administration on Mast Cell Numbers and Degranulation in a Diabetic and Normoglycemic rat Model Wound Healing

BACKGROUND

Wound healing is a complicated and integrated process. Researches in the molecular level on human and animal models have indicated several molecular changes related to the effect of diabetes on wound healing process.

OBJECTIVES

Increasing number of researches implicates the influence of mast cells on skin wound repairing. In this study the effect of systemic pentoxifylline (PTX) administration (daily dose of 25mg/kg twice a day, for 7 consecutive days) on normoglycemic (NG) and diabetic (DB) wistar rat's wound healing by secondary intention was studied.

MATERIALS AND METHODS

In this study forty eight wistar rats (weighting 250-350g) were divided randomly in two groups: Normoglycemic and diabetic, each group was divided into experimental and control groups, experimental received intraperitoneal (PTX) and controls received distilled water (DW). The number and maturing process of mast cells was evaluated by counting the number of types of mast cells [1][2][3] microscopically and by stereological methods on day 3 and 7 after surgery.

RESULTS

In this study it was cleared that in wound healing process PTX caused increasing the number of type 2 mast cells in all experimental groups(P = 0.00). In normoglycemic experimental group, receiving PTX there was decrease in the number of type3 mast cells, comparing experimental NG groups (P = 0.00).

CONCLUSIONS

In all PTX treated groups delay in converting type 2 into type 3 mast cell was seen. Pentoxifylline causes decreasing mast cell degranulation in wound healing process.

Induction of matrix metalloproteinase-1 by small interfering RNA targeting connective tissue growth factor in dermal fibroblasts from patients with systemic sclerosis

We aimed to evaluate the effect of small interfering RNA (siRNA) targeting CTGF on extracellular matrices (ECMs) metabolism in normal and SSc fibroblasts. Normal and SSc fibroblasts were transfected with CTGF-specific siRNAs to silence CTGF synthesis. After silencing CTGF, production of type I collagen and matrix metalloproteinase (MMP)-1 by fibroblasts stimulated with TGF-beta was examined. Then quantitative analyses of protein production or mRNA expression of type I collagen, MMP-1,-2,-9 and tissue inhibitor of metalloproteinase (TIMP)-1 with TGF-beta stimulation were carried out. Furthermore, after silencing CTGF, proliferations of normal and SSc fibroblasts were investigated. CTGF-specific siRNA significantly reduced CTGF production. The production of type I collagen was significantly reduced by CTGF silencing in normal fibroblasts. The CTGF silencing significantly increased the production of MMP-1 and decreased the production of TIMP-1 in SSc fibroblasts. The mRNA expression of MMP-1 was increased in CTGF-silenced SSc fibroblasts, but not in normal fibroblasts. There were no significant changes in the production or mRNA expression of other ECM-related genes in normal and SSc fibroblasts. Fibroblast proliferations were suppressed by CTGF silencing in normal and SSc fibroblasts. Our data showed that MMP-1 was increased by CTGF-specific siRNA transfection only in SSc fibroblasts. RNAi targeting CTGF could be a novel therapeutic strategy for SSc.

Serum levels of soluble CD21 in patients with systemic sclerosis

Systemic sclerosis (SSc) is a systemic disorder that typically results in fibrosis of the skin and multiple internal organ systems. Although the precise mechanism is unknown, overproduction of extracellular matrix proteins, including collagens and fibronectins, and aberrant immune activation might be involved in the pathogenesis. The soluble cluster of differentiation 21 (sCD21) represents the extracellular portion of the CD21 glycoprotein that is released by shedding from the cell surfaces into plasma. sCD21 binds complement fragments and activates monocytes through binding to membrane CD23. The present study was undertaken to investigate the serum levels of sCD21 in patients with SSc. Serum sCD21 levels were reduced with age both in patients with SSc and normal controls. Serum sCD21 levels in patients with SSc were significantly decreased compared to those in control subjects. When we divided patients with SSc into limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc), patients with lcSSc had lower levels of serum sCD21 than those with dcSSc. Moreover, the prevalence of pulmonary fibrosis in the patients with dcSSc inversely correlated with serum sCD21 levels. Our finding may support the notion that B-cell activation is involved in the mechanism for pulmonary fibrosis and skin sclerosis.

Autocrine TGF-beta signaling in the pathogenesis of systemic sclerosis

Excessive extracellular matrix deposition in the skin, lung, and other organs is a hallmark of systemic sclerosis (SSc). Fibroblasts isolated from sclerotic lesions in patients with SSc and cultured in vitro are characterized by increased synthesis of collagen and other extracellular matrix components, consistent with the disease phenotype. Thus, cultured scleroderma fibroblasts serve as a principal experimental model for studying the mechanisms involved in extracellular matrix overproduction in SSc. The pathogenesis of SSc is still poorly understood, but increasing evidence suggests that transforming growth factor-beta (TGF-beta) is a key mediator of tissue fibrosis as a consequence of extracellular matrix accumulation in the pathology of SSc. TGF-beta regulates diverse biological activities including cell growth, cell death or apoptosis, cell differentiation, and extracellular matrix synthesis. TGF-beta is known to induce the expression of extracellular matrix proteins in mesenchymal cells and to stimulate the production of protease inhibitors that prevent enzymatic breakdown of the extracellular matrix. This review focuses on the possible role of autocrine TGF-beta signaling in the pathogenesis of SSc.

Hepatocyte growth factor ameliorates dermal sclerosis in the tight-skin mouse model of scleroderma

The tight-skin (TSK/+) mouse, a genetic model of systemic sclerosis (SSc), develops cutaneous fibrosis and defects in pulmonary architecture. Because hepatocyte growth factor (HGF) is an important mitogen and morphogen that contributes to the repair process after tissue injury, we investigated the role of HGF in cutaneous fibrosis and pulmonary architecture defects in SSc using TSK/+ mice. TSK/+ mice were injected in the gluteal muscle with either hemagglutinating virus of Japan (HVJ) liposomes containing 8 μg of a human HGF expression vector (HGF-HVJ liposomes) or a mock vector (untreated control). Gene transfer was repeated once weekly for 8 weeks. The effects of HGF gene transfection on the histopathology and expression of tumor growth factor (TGF)-β and IL-4 mRNA in TSK/+ mice were examined. The effect of recombinant HGF on IL-4 production by TSK/+ CD4⁺ T cells stimulated by allogeneic dendritic cells (DCs) in vitro was also examined. Histologic analysis revealed that HGF gene transfection in TSK/+ mice resulted in a marked reduction of hypodermal thickness, including the subcutaneous connective tissue layer. The hypodermal thickness of HGF-treated TSK/+ mice was decreased two-fold to three-fold compared with untreated TSK/+ mice. However, TSK/+ associated defects in pulmonary architecture were unaffected by HGF gene transfection. HGF gene transfection significantly inhibited the expression of IL-4 and TGF-β1 mRNA in the spleen and skin but not in the lung. We also performed a mixed lymphocyte culture and examined the effect of recombinant HGF on the generation of IL-4. Recombinant HGF significantly inhibited IL-4 production in TSK/+ CD4⁺ T cells stimulated by allogeneic DCs. HGF gene transfection inhibited IL-4 and TGF-β mRNA expression, which has been postulated to have a major role in fibrinogenesis and reduced hypodermal thickness, including the subcutaneous connective tissue layer of TSK/+ mice. HGF might represent a novel strategy for the treatment of SSc.

Insulin-like growth factor binding protein 5 induces skin fibrosis: A novel murine model for dermal fibrosis

OBJECTIVE

To determine the role of insulin-like growth factor binding protein 5 (IGFBP-5) in the development of skin fibrosis in vivo, by examining the effect of overexpression of IGFBP-5 in mouse skin.

METHODS

Wild-type C57BL/6J mice were injected subcutaneously with replication-deficient serotype 5 adenovirus expressing human IGFBP-3 (Ad3), IGFBP-5 (Ad5), or no complementary DNA (cAd). Mice were killed 3, 8, or 22 days postinjection. The dermal thickness and dermal collagen bundle thickness in skin sections were measured. The deposition of collagen in the extracellular matrix (ECM) was quantified using the Sircol assay. Expression of proliferating cell nuclear antigen (PCNA) and fibronectin, as determined by immunohistochemical analysis, was used to evaluate fibroblast activation, and vimentin and alpha-smooth muscle actin (alpha-SMA) were used to evaluate the fibroblast phenotype.

RESULTS

Adenovirally expressed IGFBP was detected in dermal fibroblasts, endothelial cells, epithelial cells, and muscle bundles in Ad3- and Ad5-injected mice. Increased collagen deposition, denser dermal connective tissue, and increased collagen bundle thickness were observed in IGFBP-5-overexpressing mice. Dermal thickness and collagen bundle thickness were significantly increased in Ad5-injected mice compared with cAd- and Ad3-injected mice. Treatment with Ad5 resulted in a dose-dependent increase in dermal and collagen bundle thickness. Increased deposition of collagen and fibronectin, increased numbers of PCNA-positive fibroblasts, as well as increased numbers of vimentin- and alpha-SMA-double-positive fibroblasts were detected in the dermis of IGFBP-5-overexpressing mouse skin.

CONCLUSION

IGFBP-5 is a key mediator of fibrosis. IGFBP-5 mediates its profibrotic effects through fibroblast activation, increased ECM deposition, and myofibroblastic transformation of dermal fibroblasts. Overexpression of IGFBP-5 provides a novel model for studying the pathogenesis of skin fibrosis in systemic sclerosis.

Increased levels of transforming growth factor beta receptor type I and up-regulation of matrix gene program: A model of scleroderma

OBJECTIVE

Previously published studies have demonstrated that a majority of systemic sclerosis (SSc) fibroblasts exhibit elevated levels of transforming growth factor beta type I receptor (TGFbetaRI). An experimental model that recapitulates this condition was established in control dermal fibroblasts by titrating the dose of adenovirus vector expressing TGFbetaRI (AdTGFbetaRI). The present study was undertaken to determine the functional consequences of increased levels of TGFbetaRI in SSc.

METHODS

Gene array analysis of control dermal fibroblasts transduced with AdTGFbetaRI was performed using GeneChip expression arrays. Gene validation was done by Northern blot, quantitative reverse transcriptase-polymerase chain reaction, and Western blot techniques. TGFbeta blockade was performed using soluble TGFbeta receptor. TGFbetaRI kinase/activin receptor-like kinase 5 was inhibited with pharmacologic inhibitors. TGFbetaRI and TGFbetaRII protein levels and collagen production were examined by Western blotting in primary dermal fibroblasts from 9 SSc patients and 9 healthy adults. Endogenous TGFbetaRI levels were suppressed in control and SSc fibroblasts using specific small interfering RNA (siRNA).

RESULTS

Global gene analysis indicated that a 2-fold increase in TGFbetaRI levels in control fibroblasts resulted in profibrotic changes that closely resembled the phenotype of SSc fibroblasts. A total of 125 genes were up-regulated, including COL1A1, COL1A2, and connective tissue growth factor, and 206 genes were down-regulated. Elevated production of collagen in cells transduced with AdTGFbetaRI was dependent on the autocrine TGFbeta, but not TGFbetaRI kinase activity. Eight of the 9 SSc strains exhibited increased levels of TGFbetaRI protein, which correlated with increased collagen synthesis. Treatment of SSc and matched control fibroblasts with siRNA that normalizes TGFbetaRI levels reverted collagen protein production in SSc fibroblasts to the levels observed in control fibroblasts.

CONCLUSION

Our findings demonstrate that aberrantly expressed TGFbetaRI may drive an autocrine loop involved in the up-regulation of collagen and other matrix-related genes in SSc fibroblasts.

Ultraviolet A1 phototherapy decreases inhibitory SMAD7 gene expression in localized scleroderma

Localized scleroderma (LS) is a connective skin disease with marked sclerosis of the skin as the most prominent feature. Transforming growth factor beta (TGF-beta) plays a central role in the pathogenesis of sclerotic skin diseases. Recently, special attention was contributed to a family of transcription factor proteins involved in TGF-beta signal transduction from cell surface to the nucleus, the so-called SMADs. Ultraviolet (UV) irradiation has been reported to alter TGF-beta/SMAD pathway in human skin. We sought to investigate the effects of UVA1 on the gene and protein expressions of the TGF-beta/SMAD pathway in LS. UVA1 phototherapy was performed in eight LS patients five times weekly for 8 weeks resulting in a total of 40 treatment sessions (single dose 50 J/cm(2), cumulative dose 2,000 J/cm(2)). TGF-beta1, SMAD3, SMAD4, and SMAD7 mRNA expressions were determined by semiquantitative real-time reverse transcription polymerase chain reaction in lesional and unaffected skin of patients with LS. Additionally, immunohistochemical staining was performed in lesional skin before and after irradiation. Skin status markedly improved in all patients, resulting in a significant reduction of the clinical score from baseline to the end of treatment. Inhibitory SMAD7 mRNA was significantly higher in lesional skin as compared to unaffected skin, and significantly decreased after UVA1 phototherapy. In contrast, SMAD7 mRNA levels remained unchanged in irradiated, healthy skin after UVA1. Both TGF-beta and SMAD3 mRNA levels decreased after UVA1, whereas SMAD4 mRNA increased. However, changes in TGF-beta, SMAD3, and SMAD4 mRNA after UVA1 did not reach statistical significance. Immunohistochemical investigation did not reveal significant changes in the protein expression of SMADs after UVA1. Similar to scleroderma, SMAD7-mediated negative regulation seems to be impaired in LS. UVA1 phototherapy demonstrated the alteration of SMAD7 gene expression in LS, as SMAD7 mRNA levels normalized after UVA1. The pathogenetic relevance of SMAD7 levels with respect to clinical improvement needs further investigation.

Autoantibody response against a novel testicular antigen protein highly expressed in testis (PHET) in SSc patients

Systemic sclerosis (SSc) is characterized by excessive fibrosis and autoantibody production. However, the pathogenesis of SSc is still under investigation. We have demonstrated that a novel testicular antigen, protein highly expressed in testis (PHET), is overexpressed in SSc dermal fibroblasts and targeted by autoantibodies. PHET was identified by screening of HepG2 cDNA library using an SSc serum and was found to belong to UniGene cluster of sperm associated antigen 9 (SPAG9) from its nucleotide sequence. PHET mRNA expression was examined by RT-PCR using mRNA panels of human tissues, and PHET mRNA was highly expressed only in testis in normal tissues. Anti-PHET antibodies were detected in 8.4% of sera of SSc patients by immunoblotting, and associated with diffuse scleroderma and lung involvement. Expression of PHET mRNA and protein was increased in cultured SSc dermal fibroblasts compared with control fibroblasts. These results suggest that ectopic expression of PHET in dermal fibroblasts induces autoantibody production against PHET in patients with SSc.

Upregulation of tenascin-C expression by IL-13 in human dermal fibroblasts via the phosphoinositide 3-kinase/Akt and the protein kinase C signaling pathways

In this study, we examined the genes targeted by IL-13 in human dermal fibroblasts using a cDNA microarray. We focused on the tenascin-C (TN-C) gene, which was identified as one of the genes induced by IL-13. IL-13 induced transcriptional activity of TN-C. IL-13-mediated TN-C expression was inhibited by treatment with wortmannin or LY294002, or Calphostin C. IL-13 induced the phosphorylation of the phosphoinositide 3-kinase (PI3K) regulatory subunit p85, induced tyrosine phosphorylation of Akt, upregulated Akt kinase activity, and activated protein kinase C (PKC)-delta and -epsilon. The IL-13-induced increase in TN-C protein expression was abrogated by the transfection of a dominant-negative mutant of Akt, PKC-delta, or PKC-epsilon. In conclusion, we showed that the PI3K/Akt and/or PKC signaling pathways are essential for the IL-13-mediated increase in TN-C. Both serum levels of IL-13 and the expression levels of TN-C in the dermis are increased in patients with systemic sclerosis. Our findings suggest that the expression of TN-C is upregulated in this disease due to IL-13 signaling, and that a blockade of the PI3K or PKC signaling pathway may also have therapeutic value by reducing the amount of TN-C produced during fibrosis.

Paclitaxel modulates TGFbeta signaling in scleroderma skin grafts in immunodeficient mice

BACKGROUND

Systemic sclerosis (SSc) is characterized by excessive fibrosis and obliterative vascular lesions. Abnormal TGFbeta activation is implicated in the pathogenesis of SSc. Aberrant TGFbeta/Smad signaling can be controlled by stabilization of microtubules with paclitaxel.

METHODS AND FINDINGS

SSc and healthy human skin biopsies were incubated in the presence or absence of paclitaxel followed by transplantation into severe combined immunodeficient mice. TGFbeta signaling, fibrosis, and neovessel formation were evaluated by quantitative RT-PCR and immunohistochemical staining. Paclitaxel markedly suppressed Smad2 and Smad3 phosphorylation and collagen deposition in SSc grafts. As a result, the autonomous maintenance/reconstitution of the SSc phenotype was prevented. Remarkably, SSc grafts showed a 2-fold increase in neovessel formation relative to normal grafts, regardless of paclitaxel treatment. Angiogenesis in SSc grafts was associated with a substantial increase in mouse PECAM-1 expression, indicating the mouse origin of the neovascular cells.

CONCLUSION

Low-dose paclitaxel can significantly suppress TGFbeta/Smad activity and lessen fibrosis in SCID mice. Transplantation of SSc skin into SCID mice elicits a strong angiogenesis-an effect not affected by paclitaxel. Although prolonged chemotherapy with paclitaxel at higher doses is associated with pro-fibrotic and anti-angiogenic changes, the findings described here indicate that low-dose paclitaxel may have therapeutic benefits for SSc via modulating TGFbeta signaling.

Constitutively phosphorylated Smad3 interacts with Sp1 and p300 in scleroderma fibroblasts

OBJECTIVE

To elucidate the role of transforming growth factor-beta (TGF-beta)/Smad signalling in the increased expression of the collagen gene in systemic sclerosis (SSc) fibroblasts.

METHODS

Dermal fibroblasts from seven patients with diffuse SSc of recent onset and from seven healthy individuals were studied. The expression levels of Smad2, Smad3 and Smad4 proteins were determined by immunoblotting. Smad3 phosphorylation and the interaction of Smad3 with Sp1 or p300 were analysed using immunoprecipitation. The effects of overexpression of Smad proteins or Sp1 on the human alpha2(I) collagen gene transcription were investigated with chloramphenicol acetyltransferase (CAT) assays using the -772 COL1A2/CAT construct.

RESULTS

Constitutive increased Smad3 phosphorylation was detected in SSc fibroblasts compared with normal fibroblasts. Increased interaction of Smad3 with Sp1 as well as p300 was also detected in SSc fibroblasts. The overexpression of Smad3 caused an increase of up to 5-fold in COL1A2 promoter activity in normal fibroblasts, while Smad3 caused a small increase in COL1A2 promoter activity in SSc fibroblasts. However, neither Smad2 nor Smad4 caused significant effects in COL1A2 promoter activity in normal fibroblasts or SSc fibroblasts. The overexpression of Sp1 caused further increase in COL1A2 promoter activity stimulated by TGF-beta in normal fibroblasts, but did not change COL1A2 promoter activity in the presence of TGF-beta in SSc fibroblasts. The combined overexpression of Smad3 and Sp1 significantly enhanced TGF-beta response in normal fibroblasts, but less markedly in SSc fibroblasts.

CONCLUSIONS

These results suggested that SSc fibroblasts are less sensitive to exogenous TGF-beta stimulation because they are already activated by the autocrine TGF-beta loop.

[Treatment of therapy-resistant acral ulcers with iloprost]

Patients with systemic sclerosis (SSc) develop often acral ulcers which are resistant to therapy and may result in gangrene and amputation. We investigated the effects of iloprost infusion on the acral ulcers and necrosis in patients with five patients with SSc and one with mixed connective tissue disease who had been previously treated with various modalities without improvement. All patients had Raynaud phenomenon, acral ulcers and necrosis. Iloprost 25 microg per day was administered intravenously daily over six hours for ten consecutive days. Eight weeks later all patients were treated with a second iloprost therapy cycle for five days. Two patients with severe ulceration received a third cycle until remission occurred. In all cases acral ulcers healed completely and no patient relapsed during an observation period of 6 months.

Sclerosing panniculitis is associated with pulmonary hypertension in systemic sclerosis

BACKGROUND

There have been no reports of patients with sclerosing panniculitis and systemic sclerosis (SSc).

OBJECTIVES

To evaluate the incidence of sclerosing panniculitis in patients with SSc, and to investigate the clinical features of such cases.

METHODS

In total, 128 patients with SSc treated at our clinic were investigated retrospectively.

RESULTS

SSc patients with sclerosing panniculitis had pulmonary hypertension (PH), especially isolated PH, at a significantly higher incidence than those without. Among the SSc patients with PH, those with sclerosing panniculitis had pulmonary infarctions at a higher incidence than those without.

CONCLUSIONS

Our results suggest that thrombosis caused by venous hypertension of the leg may be the main cause of PH in patients with SSc and sclerosing panniculitis. Sclerosing panniculitis may be a useful marker of PH in patients with SSc.

Recent advances in fibroblast signaling and biology in scleroderma

PURPOSE OF REVIEW

Systemic sclerosis is a complex disease manifesting itself by fibrosis of skin and other internal organs. Fibroblasts isolated from scleroderma lesions and cultured in vitro are characterized by increased synthesis of collagen and other extracellular matrix proteins, consistent with the disease phenotype. Cultured systemic sclerosis fibroblasts therefore serve as a principal experimental model for studying the molecular and cellular mechanisms involved in collagen overproduction in this disease. This review will discuss recent findings related to intracellular signal transduction pathways implicated in deregulated extracellular matrix deposition by systemic sclerosis fibroblasts.

RECENT FINDINGS

Recent findings suggest that constitutively elevated synthesis of extracellular matrix by cultured systemic sclerosis fibroblasts is, at least in part, due to the aberrant activation of the autocrine transforming growth factor-beta signaling. Enhanced constitutive transforming growth factor-beta signaling may result from the elevated levels of transforming growth factor-beta receptor type I and/or inappropriate activation of Smad3. These alterations of the transforming growth factor-beta signaling in systemic sclerosis fibroblasts may facilitate increased collagen production in vivo even under conditions of low ligand availability. However, there exist many inconsistencies among published reports regarding the detailed mechanisms of this pathway in systemic sclerosis fibroblasts, and additional studies in this area are needed. Other signaling molecules implicated in fibrotic phenotype include several members of the protein kinase C family, mammalian target of rapamycin, mitogen-activated protein kinase, necdin, reactive oxygen species, and sphingolipids. These signaling pathways may work in conjunction with transforming growth factor-beta signaling to regulate the behavior of systemic sclerosis fibroblasts.

SUMMARY

Alterations in multiple signaling pathways contribute to elevated extracellular matrix synthesis by systemic sclerosis fibroblasts. Improved understanding of the key signaling molecules may provide a novel avenue for therapeutic interventions.

An increased transforming growth factor beta receptor type I:type II ratio contributes to elevated collagen protein synthesis that is resistant to inhibition via a kinase-deficient transforming growth factor beta receptor type II in scleroderma

OBJECTIVE

Aberrant transforming growth factor beta (TGFbeta) signaling has been implicated in the pathogenesis of scleroderma (systemic sclerosis [SSc]), but the contribution of specific components in this pathway to SSc fibroblast phenotype remains unclear. This study was undertaken to delineate the role of TGFbeta receptor type I (TGFbetaRI) and TGFbetaRII in collagen overexpression by SSc fibroblasts.

METHODS

Primary dermal fibroblasts from SSc patients and healthy adults were studied (n = 10 matched pairs). Adenoviral vectors were generated for TGFbetaRI (AdTGFbetaRI), TGFbetaRII (AdTGFbetaRII), and kinase-deficient TGFbetaRII (AdDeltakRII). TGFbetaRI basal protein levels were analyzed by (35)S-methionine labeling/immunoprecipitation and immunohistochemistry. Type I collagen and TGFbetaRII basal protein levels were analyzed by Western blot and newly secreted collagen by (3)H-proline incorporation assay.

RESULTS

Analysis of endogenous TGFbetaRI and TGFbetaRII protein levels revealed that SSc TGFbetaRI levels were increased 1.7-fold (P = 0.008; n = 7) compared with levels in healthy controls, while TGFbetaRII levels were decreased by 30% (P = 0.03; n = 7). This increased TGFbetaRI:TGFbetaRII ratio correlated with SSc collagen overexpression. To determine the consequences of altered TGFbetaRI:TGFbetaRII ratio on collagen expression, healthy fibroblasts were transduced with AdTGFbetaRI or AdTGFbetaRII. Forced expression of TGFbetaRI in the range corresponding to elevated SSc TGFbetaRI levels increased basal collagen expression in a dose-dependent manner, while similar TGFbetaRII overexpression had no effect, although transduction of fibroblasts at higher multiplicities of infection led to a marked reduction of basal collagen levels. Blockade of TGFbeta signaling via AdDeltakRII resulted in approximately 50% inhibition of basal collagen levels in healthy fibroblasts and in 5 of 9 SSc cell lines. A subset of SSc fibroblasts (4 of 9 cell lines) was resistant to this treatment. SSc fibroblasts with the highest levels of TGFbetaRI were the least responsive to collagen inhibition via DeltakRII.

CONCLUSION

This study indicates that an increased TGFbetaRI:TGFbetaRII ratio may underlie aberrant TGFbeta signaling in SSc and contribute to elevated basal collagen production, which is insensitive to TGFbeta signaling blockade via DeltakRII.

A novel protein highly expressed in testis is overexpressed in systemic sclerosis fibroblasts and targeted by autoantibodies

Nearly all autoantibody specificities in sera from patients with systemic sclerosis (SSc) target proteins distributed ubiquitously, and Abs against proteins whose expression is restricted to the affected sites have not been identified. In this study we describe SSc-specific autoantibody to a novel testicular Ag, termed protein highly expressed in testis (PHET), which is ectopically overexpressed in SSc dermal fibroblasts. A partial cDNA encoding PHET was isolated by immunoscreening of a HepG2 cDNA library with an SSc serum. PHET appeared to be a member of the UniGene cluster Hs.129872, but had a unique exon composition and a characteristic mRNA expression profile restricted to the testis. Serum Abs to a recombinant PHET fragment were detected in nine (8.4%) of 107 SSc patients, but in none of 50 systemic lupus erythematosus patients or 77 healthy controls. In SSc patients, the presence of anti-PHET Abs was associated with diffuse cutaneous SSc and lung involvement (p = 0.02 and 0.01, respectively). PCR-based quantitative analysis of PHET mRNA expression in cultured dermal fibroblasts showed increased expression of PHET mRNA in SSc fibroblasts compared with control fibroblasts. PHET-reactive Abs purified from SSc sera stained the cytoplasm of SSc dermal fibroblasts, and the staining intensity tended to be more prominent on SSc compared with control fibroblasts. These findings suggest that the autoantibody response to PHET can be induced by ectopic overexpression of PHET in dermal fibroblasts in SSc patients.

Hepatocyte growth factor both prevents and ameliorates the symptoms of dermal sclerosis in a mouse model of scleroderma

Systemic sclerosis (SSc) is a connective tissue disorder with an unknown etiology. There are currently no effective therapies for SSc. (In this study, working with a bleomycin(BLM)-induced scleroderma model mice, we performed two transfections of human hepatocyte growth factor (HGF) cDNA into the skeletal muscle and showed that this treatment not only helped to prevent the dermal sclerosis simultaneously injected BLM but also improved the symptoms of dermal sclerosis induced by BLM 4 weeks previously.) RT-PCR, ELISA and an immunohistochemical analysis revealed that both mRNA and protein of human HGF as well as murine HGF were enhanced in the skin, lung, muscle and the serum after two transfections of human HGF cDNA. These analyses also revealed that this treatment significantly reduced both the expression of the TGF-beta1 mRNA and the production of TGF-beta1 on macrophage-like cells that infiltrated the dermis and the fibroblastic cells in BLM-induced scleroderma. Furthermore, HGF-gene transfection both prevented and ameliorated the symptoms of not only dermal sclerosis but also of lung fibrosis induced by a subcutaneous BLM injection. These results indicated that gene therapy by the transfection of the human HGF cDNA may thus be a useful therapy for SSc and lung fibrosis involved with SSc.

A nuclear target for interleukin-1alpha: interaction with the growth suppressor necdin modulates proliferation and collagen expression

There is growing evidence for the intracellular role of cytokines and growth factors, but the pathways by which these activities occur remain largely obscure. Previous work from our laboratory identified the constitutive, aberrant expression of the 31-kDa IL-1 alpha precursor (pre-IL-1 alpha) in the nuclei of fibroblasts from the lesional skin of patients with systemic sclerosis (SSc). We established that pre-IL-1 alpha expression was associated with increased fibroblast proliferation and collagen production. Further investigation has led to the identification of a mechanism by which nuclear expression of pre-IL-1 alpha affects fibroblast growth and matrix production. By using a yeast two-hybrid method, we found that pre-IL-1 alpha binds necdin, a nuclear protein with growth suppressor activity. We mapped the region of pre-IL-1 alpha responsible for necdin binding and found it to be localized near the N terminus, a region that is present on pre-IL-1 alpha, but not the mature 17-kDa cytokine. Expression studies demonstrated that pre-IL-1 alpha associates with necdin in the nuclei of mammalian cell lines and regulates cell growth and collagen expression. Our results provide the first evidence, to our knowledge, of a nuclear target for pre-IL-1 alpha. Based on these findings, we propose that the constitutively up-regulated expression of pre-IL-1 alpha in the nuclei of SSc fibroblasts up-regulates proliferation and matrix production of SSc fibroblasts through binding necdin, and by counteracting its effects on cell growth and collagen production.

Deficient Smad7 expression: a putative molecular defect in scleroderma

Scleroderma is a chronic systemic disease that leads to fibrosis of affected organs. Transforming growth factor (TGF) beta has been implicated in the pathogenesis of scleroderma. Smad proteins are signaling transducers downstream from TGF-beta receptors. Three families of Smads have been identified: (i) receptor-regulated Smad2 and -3 (R-Smads); (ii) common partner Smad4 (Co-Smad); and (iii) inhibitory Smad6 and -7 (I-Smads, part of a negative feedback loop). We have investigated the signaling components for the TGF-beta pathway and TGF-beta activity in scleroderma lesions in vivo and in scleroderma fibroblasts in vitro. Basal level and TGF-beta-inducible expression of Smad7 are selectively decreased, whereas Smad3 expression is increased both in scleroderma skin and in explanted scleroderma fibroblasts in culture. TGF-beta signaling events, including phosphorylation of Smad2 and -3, and transcription of the PAI-1 gene are increased in scleroderma fibroblasts, relative to normal fibroblasts. In vitro adenoviral gene transfer with Smad7 restores normal TGF-beta signaling in scleroderma fibroblasts. These results suggest that alterations in the Smad pathway, including marked Smad7 deficiency and Smad3 up-regulation, may be responsible for TGF-beta hyperresponsiveness observed in scleroderma.

Clinical and laboratory features of scleroderma patients with pulmonary hypertension

OBJECTIVE

Pulmonary hypertension (PH) is a frequent cause of death in patients with systemic sclerosis (SSc). In this study, we examined the occurrence of PH and investigated the clinical and laboratory features of SSc patients with PH.

METHODS

A cross-sectional study of 125 Japanese patients with SSc was conducted using Doppler echocardiography, other multiple cardiopulmonary tests, and laboratory examination.

RESULTS

PH (systolic pressure >40 mmHg) was diagnosed in 20 patients (16%) by Doppler echocardiography. In the six patients who had secondary pulmonary hypertension (SPH), PH was due to severe pulmonary fibrosis; 14 patients had isolated pulmonary hypertension (IPH). An elevated erythrocyte sedimentation rate (ESR) and increased immunoglobulin G (IgG) were found in a significantly greater proportion of the patients with PH than in those without PH. The incidence of pitting scars/ulcers was significantly greater in the patients with SPH than in those without PH.

CONCLUSION

Elevated ESR and increased IgG were common features of scleroderma patients with PH, and scleroderma patients with SPH were inclined to have pitting scars/ulcers.

Increased phosphorylation of transcription factor Sp1 in scleroderma fibroblasts: association with increased expression of the type I collagen gene

OBJECTIVE

To determine the potential roles of transcription factors Sp1 and Sp3 in the increased expression of the human alpha2(I) collagen gene in scleroderma fibroblasts.

METHODS

Dermal fibroblasts from 7 patients with diffuse systemic sclerosis (SSc; scleroderma) of recent onset and from 7 healthy individuals were studied. The levels of expression of alpha2(I) procollagen, Sp1, and Sp3 messenger RNA (mRNA), with or without stimulation by transforming growth factor beta (TGFbeta) or oncostatin M (OSM), were evaluated by Northern blot analysis, and the respective protein levels were determined by immunoblotting. The DNA binding activity of nuclear proteins recognizing the cis-acting elements in the human alpha2(I) collagen promoter was examined by gel mobility shift assays. The levels of Sp1 phosphorylation were investigated by immunoprecipitation using an antiphosphoserine-specific antibody.

RESULTS

SSc fibroblasts showed basal alpha2(I) collagen mRNA levels that were approximately 3 times higher than those in normal fibroblasts. TGFbeta or OSM increased human alpha2(I) collagen mRNA expression in normal dermal fibroblasts, but these cytokines failed to increase alpha2(I) collagen mRNA levels in SSc fibroblasts. There were no significant differences in the levels of expression of Sp1 or Sp3 between SSc and normal fibroblasts. However, increased Sp1 phosphorylation was detected in SSc fibroblasts compared with normal fibroblasts. Mithramycin, a specific inhibitor of Sp1 binding, abolished the increased expression of the alpha2(I) collagen gene in SSc fibroblasts, in a dose-dependent manner.

CONCLUSION

These results demonstrate the involvement of Sp1 in the up-regulation of expression of the alpha2(I) collagen gene in SSc fibroblasts.

Endothelial injury in internal organs of University of California at Davis line 200 (UCD 200) chickens, an animal model for systemic sclerosis (Scleroderma)

Systemic sclerosis (SSc) is a multisystem disorder characterized by mononuclear cell infiltration and fibrosis. Using skin samples from human SSc and UCD 200 chickens, which spontaneously develop a hereditary disease closely resembling human SSc, we have shown previously that endothelial cell apoptosis is a primary event in the pathogenesis of SSc. The aim of the present study was to investigate the initial disease stage in visceral organs of UCD 200 chickens with special emphasis on endothelial apoptosis, mononuclear cell infiltration and collagen deposition using tissue samples from oesophagus, lung, heart, kidney and liver. Apoptotic endothelial cells were detected by terminal deoxynucleotidyl transferase-mediated FITC-dUTP nick end labeling (TUNEL), mononuclear cell infiltrates were stained with hematoxylin and eosin, and increased collagen deposition was demonstrated by Goldner staining. Apoptotic endothelial cells were detected in oesophagus, lung and kidney of UCD 200 chickens at the initial stage of the disease. No apoptotic endothelial cells were found in heart or liver of UCD 200 or in visceral organs of healthy normal UCD 058 control chickens. Oesophagus of UCD 200 chickens, which was the most affected internal organ, showed mononuclear cell infiltrations and increased deposition of collagen. Perivascular inflammatory infiltrates and collagen deposition appeared later than endothelial cell apoptosis. These data support the hypothesis that endothelial cell apoptosis initiates the disease process, followed by mononuclear cell infiltration and fibrosis.

Treatment of patients with systemic sclerosis with extracorporeal photochemotherapy (photopheresis)

BACKGROUND

Effective treatment modalities for systemic sclerosis, a life-threatening and disabling disease, are still lacking. Possible efficacy of photopheresis has been reported in several studies. Because of the complexity of the treatment, placebo-controlled trials are difficult to perform.

OBJECTIVE

We investigated the effect of photopheresis on clinical parameters (skin score and internal organ functions), immunologic parameters, and quality of life.

METHODS

Nineteen patients with progressive systemic sclerosis of less than 5 years' duration were randomized into 2 groups. One group (group A) received photopheresis for 1 year, the other group (group B) received no treatment at all. After 1 year the groups switched (crossover design). Photopheresis was performed on 2 consecutive days every 4 weeks; the psoralens were administered parenterally. The main outcome parameter was the skin score after 1 year of treatment compared with that of the control group.

RESULTS

The average skin score improved with 5.4% (standard error [SE], 20. 8%) in group A and deteriorated with 4.5% (SE, 13.8%) in group B (not significant; P =.71). Before crossover, the average increase in skin score was 5.3% (means of entire group). No change was observed in other clinical parameters. Approximately 1 year after crossover, the skin score reversed to what would have been expected with an average increase of 5.3% per year. There was also no effect on immunologic parameters. Quality of life did not change during treatment.

CONCLUSION

We were not able to show that photopheresis, performed as described above, is an effective treatment in systemic sclerosis. The difference in average skin score was statistically and clinically insignificant. Despite the small sample size, we concluded that the magnitude of the observed changes is too small to justify photopheresis as a regular treatment.

Intracellular IL-1 Receptor Antagonist Is Elevated in Human Dermal Fibroblasts That Overexpress Intracellular Precursor IL-1α

Cultured dermal fibroblasts from systemic sclerosis patients express higher levels of intracellular IL-1α than fibroblasts from healthy controls. In this study, we found that systemic sclerosis dermal fibroblasts also express higher levels of the intracellular isoform of IL-1 receptor antagonist (icIL-1Ra) than normal fibroblasts after stimulation with IL-1β or TNF-α. A possible relationship between elevated precursor IL-1α (preIL-1α) and elevated icIL-1Ra was investigated by transducing normal dermal fibroblasts to overexpress preIL-1α, preIL-1β, or icIL-1Ra. Fibroblasts that overexpressed icIL-1Ra did not have elevated levels of IL-1α. On the other hand, fibroblasts that overexpressed preIL-1α had at least 4-fold higher basal levels of icIL-1Ra than control fibroblasts and 4-fold higher levels of icIL-1Ra after induction with IL-1β or TNF-α. Fibroblasts overexpressing preIL-1β did not exhibit elevated icIL-1Ra. The differences in icIL-1Ra protein levels were reflected in differences in mRNA. In contrast, IL-1-stimulated levels of MCP-1 and IL-6 were not different in control and preIL-1α-transduced fibroblasts. Addition of neutralizing anti-IL-1α Abs to fibroblast cultures did not diminish basal or stimulated levels of icIL-1Ra in the preIL-1α-transduced cells, supporting an intracellular site of action of preIL-1α. This is the first report of an association between intracellular levels of these IL-1 family members. We hypothesize that intracellular preIL-1α participates in the regulation of icIL-1Ra.

Expression of TGF-beta 1, -beta 2 and -beta 3 in localized and systemic scleroderma

Scleroderma is a generalized or localized disorder which leads to fibrosis of the affected organs. TGF-beta has been implicated as a causal agent in its pathogenesis. In mammals, TGF-beta comprises a family of three members, beta 1, beta 2 and beta 3. Since cutaneous wound healing is thought to result either in formation of a scar or in scar-free tissue regeneration, depending on the relative amounts of the beta 3 isoform, the expression of all three isoforms was studied in skin biopsies of patients with either localized or systemic scleroderma. mRNA for all three isoforms was detected in inflammatory skin areas of both disease forms, but never in sclerotic or healthy skin. Immunohistochemical analysis confirmed expression of beta1 and beta 2 proteins in inflammatory skin of patients, whereas beta 3 protein appeared to be present in the subepidermal area and also found throughout the dermis of patients and healthy dermis as well.

Fibroblast expression of collagen integrin receptors alpha1beta1 and alpha2beta1 is not changed in systemic scleroderma

The skin of patients with systemic scleroderma (SSc) is characterized by excessive extracellular matrix deposition in the dermis. As collagens represent the major structural component, we used fluorescence-activated cell sorter analysis to study the levels of collagen receptors expressed at the surface of fibroblasts derived from involved skin areas. In contrast to previous reports, no differences in the expression of alpha1, alpha2 or beta1 integrin subunits, which constitute the major collagen receptors on fibroblasts, were detected on SSc fibroblasts as compared with normal control fibroblasts. Variation of cell culture conditions, e. g. passage number (from 2 to 10), seeding density, cell cycle or serum concentration, did not change this result. These observations indicate that any abnormal response of SSc fibroblasts to their matrix environment is not controlled at the level of receptor expression.

Distribution and antigen specificity of anti-U1RNP antibodies in patients with systemic sclerosis

Systemic sclerosis (SSc) is a generalized connective tissue disease which is characterized by the presence of several autoantibodies. To determine the prevalence and antigen specificity of anti-U1RNP antibodies (anti-U1RNP) in patients with SSc, serum samples from 223 patients with SSc, 117 patients with systemic lupus erythematosus (SLE), 18 patients with mixed connective tissue disease (MCTD) and 40 healthy control subjects were examined by indirect immunofluorescent analysis (IIF), double immunodiffusion, and immunoblotting using nuclear extract of HeLa cells. Eighteen of the 223 (8%) serum samples from patients with SSc were shown to be positive for anti-U1RNP. The frequency of anti-U1RNP positivity in limited cutaneous SSc (14%) was significantly higher than that in those with diffuse cutaneous SSc (3%). Anti-Sm antibodies were detected in patients with SLE positive for anti-U1RNP, but not in those with SSc positive for anti-U1RNP or those with MCTD. Immunoblotting demonstrated that anti-70-kD antibodies were detected more often in patients with SSc positive for anti-U1RNP and in those with MCTD than in those with SLE. Furthermore, anti-U1RNP was closely correlated with pulmonary fibrosis and joint involvement in patients with SSc. These results suggest that anti-70-kD antibodies are useful in the classification of patients with anti-U1RNP.

Systemic sclerosis stimulates angiogenesis in the chick embryo chorioallantoic membrane

Skin biopsies from patients with systemic sclerosis (SSc) were investigated for their angiogenic activity by using the chick embryo chorioallantoic membrane (CAM) assay. Ten samples of SSc and 10 of normal skin from age- and sex-matched subjects were grafted onto the CAM, and the angiogenic response in pathological and control implants was assessed on histological sections by a planimetric point-count method 4 days after grafting. The vascular counts in the area underlying the SSc were significantly higher than those of normal skin and a dense mononuclear cell infiltrate was detectable around the blood vessels in pathological specimens. These results suggest that SSc may promote angiogenesis, perhaps leading to the release of several angiogenic factors. Moreover, the role played in the angiogenic response by the inflammatory cells forming the cellular infiltrate is suggested by this study.

Humoral and cellular immune response to elastin in patients with systemic sclerosis

The humoral immune response against elastin and collagen was studied in parallel with the delayed type hypersensitivity (DTH) reaction to elastin and the percentage of lymphocyte subpopulations in peripheral blood in 20 patients with systemic sclerosis (SSc). An increase of anti-elastin antibodies of all subclasses was found with a significant prevalence of IgE and IgA antibodies. The profile of anti-collagen type I and type IV antibodies showed an increase of IgE isotypes. In 25% of the patients (5 out of 20) positive DTH reactions to elastin were observed as compared to the negative skin reactions in all control individuals. At the same time a significant hyporeactivity to common bacterial and mould antigens was found in 40% of the patients (versus 16% in the control group) which could be an explanation for the low incidence of positive anti-elastin DTH reaction. The DTH hyporeactivity in SSc cases was in contrast with the increased percentage of CD4 T cells (58.4 vs. 42.0) and increased CD4/CD8 ratio (2.5 vs. 1.5) in the peripheral blood of the patients. This finding together with the increased IgE antibodies to elastin and collagen type I and type IV might suggest a possible shift of the immune balance towards the Th2 type of immune response. This is in line with the increased CD8+CD57+ cells which correlated with the highest number of other parameters studied - disease duration, total skin score, IgE anti-elastin antibodies, IgG anti-collagen type I antibodies, CD4/CD8 ratio and CD19 B cells. The results of this study demonstrated the existence of both humoral and cell-mediated immune response against elastin in SSc patients. However, we could not define whether this was an essential part of pathogenetic mechanisms or a secondary phenomenon reflecting the extent of the damage of connective tissue.

Pathogenesis and evolution of plexiform lesions in pulmonary hypertension associated with scleroderma and human immunodeficiency virus infection

Patients with primary pulmonary hypertension develop vascular lesions characterized by proliferated blood channels, the so-called plexiform lesions. These lesions are often associated with concentric intimal obliteration of pulmonary vessels. We report that the lungs of three patients with scleroderma-associated pulmonary hypertension showed a predominance of obliterative-concentric lesions, with relatively few plexiform or combined lesions. In contrast, plexiform lesions predominated in the lungs obtained from three patients with human immunodeficiency virus (HIV)-associated pulmonary hypertension; pure obliterative-concentric lesions were infrequent. Both plexiform and concentric obliterative lesions stained strongly positive for the endothelial cell marker factor VIII-related antigen. Muscle-specific actin immunostaining highlighted the smooth muscle cells of the tunica media of plexiform vessels, but not the luminal layers of the concentric-obliterative lesions. Proliferating cells, as determined by immunostaining with the MIB-1 antibody, were only detected in the plexiform vascular lesions. We postulate that concentric-obliterative lesions and plexiform lesions are temporally and etiologically related. A scaffolding of proliferating endothelial cells could be the common denominator of both lesions. Our hypothesis that there exists a chronological continuum, proceeding from early, proliferative plexiform lesions to late, nonproliferative concentric-obliterative lesions in primary and secondary pulmonary hypertension, may lead to better targeted treatment strategies and disease classification.

Increased capillary permeability in systemic sclerosis: help or hindrance?

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Role of Borrelia burgdorferi in the pathogenesis of morphea/scleroderma and lichen sclerosus et atrophicus: a PCR study of thirty-five cases

Morphea (localized scleroderma), and lichen sclerosus et atrophicus (LSA) share common features with acrodermatitis chronica atrophicans (ACA), a known chronic form of borreliosis. These include similar histologic findings such as diffuse dermal fibrosis. These observations have led several investigators to consider the possibility of Borrelia burgdorferi (Bb) as a common etiologic factor among all of these diseases. The aim of this study is to investigate the role of Bb in the pathogenesis of morphea and LSA, by assaying for its presence in lesional skin biopsies from patients with these diseases. We utilized the nested polymerase chain reaction (PCR) technique to selectively amplify a longer segment of a Bb-specific somatic gene, on DNA from paraffin-embedded, formalin-fixed tissues. The results revealed no Bb-specific DNA sequence in 28 specimens of morphea/scleroderma and 7 of LSA with varying stages of disease. Furthermore, confirmatory Southern blot of the PCR product, resulted in similar findings. These data seriously question the role played by this spirochete in the pathogenesis of morphea and LSA, at least in the southeastern part of the USA.

Differential regulation of transcription and transcript stability of pro-alpha 1(I) collagen and fibronectin in activated fibroblasts derived from patients with systemic scleroderma

Activated fibroblasts were derived from the skin of patients with systemic scleroderma (SSc), used as a model for fibrosis. Such cells are characterized by increased production of collagens and other matrix constituents. Increased collagen and fibronectin production has been correlated with similarly elevated mRNA steady-state levels. In the present study we analysed the contribution of transcriptional activity and post-transcriptional transcript stability to the increases in pro-alpha 1(I) collagen and fibronectin mRNA steady-state levels in activated (scleroderma) fibroblasts. Fibroblasts, when cultured in close contact with a three-dimensional collagenous matrix, down-regulate collagen synthesis. Culture of skin fibroblasts from two patients with SSc in three-dimensional collagen lattices, however, showed 4-fold elevated pro-alpha 1(I) collagen mRNA levels over fibroblasts from healthy donors. Transcription of the COL1A1 gene in SSc fibroblasts was induced 2-3-fold over that in controls in both monolayer and lattice cultures, accounting in part for the elevated steady-state level. A 50% decrease in transcription rate in lattice compared with monolayer culture occurred, as in control cells. In contrast, whereas control cells in lattices responded with decreased (50%) pro-alpha 1(I) collagen mRNA stability, in SSc cells these transcripts were found to be more stable (half-life of 5 h compared with 2 h in control cells). Fibronectin steady-state mRNA levels, in contrast, were not significantly regulated by the three-dimensional environment. In SSc fibroblasts, fibronectin mRNA levels were induced 1.5-4.9-fold over controls. In part, this increase appears to be due to elevated transcription, and an increase in fibronectin transcript stability was also detected. We therefore conclude that activated fibroblasts such as those derived from scleroderma patients utilize transcriptional and posttranscriptional mechanisms to maintain increased collagen and fibronectin production, which contribute to the pathogenesis of the disease.

The safety and efficacy of low-dose tissue plasminogen activator in the treatment of systemic sclerosis

The safety and efficacy of low-dose (10 mg) recombinant human tissue plasminogen activator (rhtPA: Activase: Genentech) was studied in 14 systemic sclerosis (SSc) patients. The patients were enrolled in a double blind, placebo-controlled crossover trial. Patients who met the inclusion criteria were enrolled in the study, given placebo or rhtPA, and then crossed over at 3 months. Assessment criteria included the Rodnan skin score; a daily patient diary to record side-effects, frequency, and severity of Raynaud's episodes and activity; and pulmonary function tests. Ten mg of rhtPA (Genentech) was administered over a 4 hour period using a myocardial infarction protocol. None of the patients experienced side-effects from the treatment protocol. No differences in the frequency or severity of Raynaud's episodes were noted during the two arms of the study. However, when the mean change of the Rodnan skin score in the placebo arm was compared to the rhtPA arm of the protocol, a significant difference was observed (0.8 vs. -5.4, p < 0.001). Three patients had moderate improvement and seven showed mild improvement. Mild deterioration or no change in study parameters was noted in 4 patients. This study has demonstrated that the administration of low-dose rhtPA is safe and is accompanied by modest improvement in symptoms of a subset of scleroderma patients.

Increased frequency of in vivo hprt gene-mutated T cells in the peripheral blood of patients with systemic sclerosis

OBJECTIVE

Activated T lymphocytes are involved in the pathogenesis of scleroderma (systemic sclerosis, SSc); such cells rapidly divide in vivo and are thus theoretically subject to random mutation more frequently than resting cells. To study whether SSc is associated with rapidly expanding T cell clones the frequency was determined of in vivo mutated T cells (MF) at the hypoxanthine guanine phosphoribosyl transferase (hprt) gene in the peripheral blood from patients with SSc. Specific clinical or serological associations were also investigated.

METHODS

Peripheral blood lymphocytes from 16 healthy individuals and 20 patients with SSc were cultured using an hprt clonal assay; mutated and wild T cell clones were established to assess individual values of T cell MF. T cell clones were further expanded in vitro and their phenotype was determined by standard immunofluorescence technique. Enzyme-linked immunosorbent assays were used for simultaneous measurements of plasma levels of soluble Interleukin-2 receptors (s-IL-2R) and Intercellular adhesion molecule-1 (s-ICAM-1).

RESULT

Mean (SD) value of T cell MF in patients with SSc was 2.5-fold higher than the normal mean (SD) value [10.6 (6.6) x 10(-6) v [4.4 (2.8) x 10(-6), p = 0.0007]. Eleven of 20 patients with SSc (55%) had T cell MF values greater than two SD above the normal mean value. The majority (84%) of mutated T cells had a helper/inducer, memory phenotype while 12% were cytotoxic/suppressor T cells. There was no association between T cell MF and the extent of skin involvement or the duration of Raynaud's phenomenon. High individual T cell MF values were not related to a possible concurrent immune overactivity as assessed by plasma levels of s-IL-2R and s-ICAM-1. Patients with long standing skin disease, however, had almost double T cell MF values than patients with early skin disease [(13.6 (7.4)) x 10(-6) v (7.5 (4.3)) x 10(-6), p = 0.03], suggesting that increased T cell MF in SSc may reflect an ongoing process of chronic in vivo T cell proliferation and/or prolonged survival.

CONCLUSION

Increased in vivo T cell mutation in patients with SSc suggests that excessive division and/or survival of T cell clones contribute to the pathology in SSc; this approach can be used in further investigations to identify the stimulus that is triggering T cell activation in this disease.

Long-term thymopentin treatment in systemic scleroderma

A study was carried out to investigate whether thymopentin treatment is capable of inducing changes in the immunological status of patients with systemic scleroderma and to compare any such changes with modifications in clinical condition. Nine patients were given thymopentin, 1 ml in 10 ml saline solution, by slow intravenous infusion 3-times weekly for 5 weeks (cycle). The cycles were repeated at 3-month intervals. Treatment duration ranged from 1 to 5 years. Blood samples were drawn at the beginning and at the end of each cycle and the patients' lymphocytic sub-populations were examined. A control group of 9 comparable healthy subjects were similarly tested. Data analysis showed that a statistically significant decrease of CD16+ and CD25+ lymphocytes compared to pretreatment was already apparent at the end of the first thymopentin treatment cycle. An improvement was found in the clinical condition of 7 of the 9 patients at the end of the follow-up period with a significant correction of unbalanced lymphocytic subsets.