Generalized morphoea and primary biliary cirrhosis: a rare association and improvement with oxypentifylline

Generalized morphea and primary biliary cirrhosis coexisting in a male patient

We present further evidence that generalized morphea (GM) and primary biliary cirrhosis (PBC) may be associated. As far as we know, only six cases with this association have been previously reported in the published work, all of which were observed in women. We describe the case of a 62-year-old man diagnosed with M2-antibody-positive PBC who developed multiple generalized indurated plaques on the trunk and extremities 3 years later. Clinical history, laboratory data and histopathological examination were consistent with the diagnosis of GM. The coexistence in a male of these two entities that predominantly affect females reinforces the hypothesis that a pathogenic link exists between GM and PBC. Consequently, PBC should be looked for in all patients with GM.

Does transformation of microvascular endothelial cells into myofibroblasts play a key role in the etiology and pathology of fibrotic disease?

Fibrosis is a major cause of human death and disability. It has been hypothesized widely that activation of resident tissue fibroblasts is responsible for the increase in matrix protein synthesis present in fibrotic tissue. More recent studies in vitro of the physiology of human dermal microvascular endothelial cells and their transformation into spindle-shaped cells by proinflammatory cytokines may provide a new explanation for the increase in myofibroblasts in fibrotic diseases. In cell culture human dermal microvascular endothelial cells transform reversibly into 2 distinct cell phenotypes observed in the endothelium in vivo: an epithelioid phenotype present in a homeostatic microvasculature and a more spindle-shaped phenotype present in an inflammed and a reactive microvasculature. When epithelioid endothelial cell cultures are exposed to proinflammatory cytokines typically increased in fibrosis in vivo (e.g. TNF-alpha and IL-beta) for sustained periods, epithelioid dermal microvascular endothelial cells transform into a spindle-shaped morphology. Many of the transformed cells are identified as myofibroblast-like cells by electron microscopy (cytoplasmic microfilaments with attachment plaques), matrix protein synthesis (type I collagen, alpha smooth muscle actin, calponin) and by RT-PCR analysis of matrix protein mRNA. Following injury to an endothelial cell culture a similar (but reversible) transformation into myofibroblast-like cells also is induced. Drugs known to slow the clinical progression to fibrosis in vivo (e.g. phosphodiesterase inhibitors, antibodies to inflammatory cytokines) are the the same drug types capable of inhibiting endothelial cell tranformation in vitro. The in vivo and in vitro observations made on blood vessel physiology and pathology following sustained inflammation support a hypothesis that endothelial cell transformation into myofibroblast-like cells may begin to explain the increase in matrix proteins and myofibroblasts pathognomonic of fibrotic disease. The experimental and clinical evidence leading to and supporting this hypothesis is presented and discussed in this report.

Inhibition of DNA repair by Pentoxifylline and related methylxanthine derivatives

The methylxanthine drug Pentoxifylline is reviewed for new properties which have emerged only relatively recently and for which clinical applications can be expected. After a summary on the established systemic effects of Pentoxifylline on the microcirculation and reduction of tumour anoxia, the role of the drug in the treatment of vasoocclusive disorders, cerebral ischemia, infectious diseases, septic shock and acute respiratory distress, the review focuses on another level of drug action which is based on in vitro observations in a variety of cell lines. Pentoxifylline and the related drug Caffeine are known radiosensitizers especially in p53 mutant cells. The explanation that the drug abrogates the G2 block and shortens repair in G2 by promoting early entry into mitosis is not anymore tenable because enhancement of radiotoxicity requires presence of the drug during irradiation and fails when the drug is added after irradiation at the G2 maximum. Repair assays by measurement of recovery ratios and by delayed plating experiments indeed strongly suggested a role in repair which is now confirmed for Pentoxifylline by constant field gel electrophoresis (CFGE) measurements and for Pentoxifylline and for Caffeine by use of a variety of repair mutants. The picture now emerging shows that Caffeine and Pentoxifylline inhibit homologous recombination by targeting members of the PIK kinase family (ATM and ATR) which facilitate repair in G2. Pentoxifylline induced repair inhibition between irradiation dose fractions to counter interfraction repair has been successfully applied in a model for stereotactic surgery. Another realistic avenue of application of Pentoxifylline in tumour therapy comes from experiments which show that repair events in G2 can be targeted directly by addition of cytotoxic drugs and Pentoxifylline at the G2 maximum. Under these conditions massive dose enhancement factors of up to 80 have been observed suggesting that it may be possible to realise dramatic improvements to tumour growth control in the clinic.

Pentoxifylline and skin inflammation

Cyclic nucleotide phosphodiesterase inhibitors, such as pentoxifylline, have been shown to beneficially influence a large number of inflammatory skin diseases. The biological effects of pentoxifylline on the production of proinflammatory cytokines, leukocyte-endothelial cell adhesion, chemokines and leukocyte-keratinocyte adhesion in skin inflammation are discussed.

Localized scleroderma

Localized scleroderma can be divided into three main subtypes: morphea, linear scleroderma, and generalized morphea. Plaque morphea usually has a good prognosis. Variants of morphea, including guttate morphea and atrophoderma of Pasini and Pierini, are seen. Linear scleroderma, whether involving an extremity or the face, is often associated with serological abnormalities. Cosmetic and functional prognosis may be poor. Therapy is usually ineffective. Generalized morphea may be difficult to differentiate from systemic scleroderma. However, progression to systemic scleroderma is uncommon.

Pentoxifylline inhibits T-cell adherence to keratinocytes

In many inflammatory dermatoses leukocyte function-associated antigen-1/intercellular adhesion molecule-1 mediated T-cell/keratinocyte adhesion is considered to play an important role. Pentoxifylline (PTX), a methylxanthine derivative widely used for the symptomatic treatment of various vascular disorders, was recently found to have anti-inflammatory effects. PTX can suppress tumor necrosis factor-alpha production and function, and inhibits leukocyte-endothelial cell adherence. The aim of the present study was to investigate whether PTX also interferes with T-cell/keratinocyte binding. Peripheral blood T cells were activated with phorbol myristate acetate and co-incubated with interferon-gamma- or tumor necrosis factor-alpha-stimulated keratinocytes (SVK 14 cells) in the presence or absence of PTX. Using an enzyme-linked immuno cell adhesion assay PTX was found to inhibit T-cell/keratinocyte adhesion in a dose-dependent manner. A similar inhibition was found when PTX was replaced by isobutylmethylxanthine, another methylxanthine derivative, or by a combination of two cyclic adenosine monophosphate analogues. No major effect on T-cell/keratinocyte adherence was observed when PTX was present during the pre-incubation of keratinocyte monolayers with tumor necrosis factor-alpha or interferon-gamma prior to the adhesion assay. In keratinocyte monolayers the interferon-gamma or tumor necrosis factor-alpha induced intercellular adhesion molecule-1 expression could not be inhibited by PTX. However, when PTX was added to short-term organ cultures of normal human skin biopsies, the lipopolysaccharide- and tumor necrosis factor-alpha-induced keratinocyte intercellular adhesion molecule-1 expression was blocked completely. The interferon-gamma-induced ICAM-1 expression was not blocked by PTX. The results presented herein suggest that impaired T-cell/keratinocyte binding may be one of the mechanisms by which PTX exerts a beneficial effect in certain inflammatory dermatoses.

Pentoxifylline

Pentoxifylline (oxpentifylline) is a methylxanthine derivative with potent hemorrheologic properties. In the United States it is marketed for the treatment of intermittent claudication. Human and animal studies have shown that pentoxifylline therapy results in a variety of physiological changes at the cellular level, which may be important in treating a diverse group of human afflictions. Immune modulation includes increased leukocyte deformability and chemotaxis, decreased endothelial leukocyte adhesion, decreased neutrophil degranulation and release of superoxides, decreased production of monocyte-derived tumor necrosis factor, decreased leukocyte responsiveness to interleukin 1 and tumor necrosis factor, inhibition of T and B lymphocyte activation, and decreased natural killer cell activity. Hypercoagulable states improve through decreased platelet aggregation and adhesion, increased plasminogen activator, increased plasmin, increased antithrombin III, decreased fibrinogen, decreased alpha 2-antiplasmin, decreased alpha 1-antitrypsin, and decreased alpha 2-macroglobulin. Wound healing and connective tissue disorders may respond to an increase in fibroblast collagenases and decreased collagen, fibronectin, and glycosaminoglycan production. Fibroblast responsiveness to tumor necrosis factor is also diminished. Potential medical uses of pentoxifylline are reviewed.