Immunoglobulins from scleroderma patients inhibit the muscarinic receptor activation in internal anal sphincter smooth muscle cells

Bioengineered human IAS reconstructs with functional and molecular properties similar to intact IAS

Because of its critical importance in rectoanal incontinence, we determined the feasibility to reconstruct internal anal sphincter (IAS) from human IAS smooth muscle cells (SMCs) with functional and molecular attributes similar to the intact sphincter. The reconstructs were developed using SMCs from the circular smooth muscle layer of the human IAS, grown in smooth muscle differentiation media under sterile conditions in Sylgard-coated tissue culture plates with central Sylgard posts. The basal tone in the reconstructs and its changes were recorded following 0 Ca(2+), KCl, bethanechol, isoproterenol, protein kinase C (PKC) activator phorbol 12,13-dibutyrate, and Rho kinase (ROCK) and PKC inhibitors Y-27632 and Gö-6850, respectively. Western blot (WB), immunofluorescence (IF), and immunocytochemical (IC) analyses were also performed. The reconstructs developed spontaneous tone (0.68 ± 0.26 mN). Bethanechol (a muscarinic agonist) and K(+) depolarization produced contraction, whereas isoproterenol (β-adrenoceptor agonist) and Y-27632 produced a concentration-dependent decrease in the tone. Maximal decrease in basal tone with Y-27632 and Gö-6850 (each 10(-5) M) was 80.45 ± 3.29 and 17.76 ± 3.50%, respectively. WB data with the IAS constructs' SMCs revealed higher levels of RhoA/ROCK, protein kinase C-potentiated inhibitor or inhibitory phosphoprotein for myosin phosphatase (CPI-17), phospho-CPI-17, MYPT1, and 20-kDa myosin light chain vs. rectal smooth muscle. WB, IF, and IC studies of original SMCs and redispersed from the reconstructs for the relative distribution of different signal transduction proteins confirmed the feasibility of reconstruction of IAS with functional properties similar to intact IAS and demonstrated the development of myogenic tone with critical dependence on RhoA/ROCK. We conclude that it is feasible to bioengineer IAS constructs using human IAS SMCs that behave like intact IAS.

Gastrointestinal manifestations of scleroderma: recent progress in evaluation, pathogenesis, and management

Gastrointestinal (GI) involvement is frequent in scleroderma (systemic sclerosis [SSc]) and is the most frequent internal complication of the disease. Patients with GI involvement have impaired quality of life, and their prognosis may be one of severe impairment. Unfortunately, GI involvement is often noticed when severe complications have already occurred, is irreversible, and is difficult to manage. The past 2 to 3 years have been rich in exciting studies that we hope will help identify, prevent, treat, and monitor disease progression. Recent studies on the pathophysiology of GI tract disease could lead to advances in the treatment of GI tract involvement. The importance of treating gastroesophageal reflux (GER) has been reinforced by studies showing GER damage in almost all SSc patients, and the fact that GER damage is reversible if early treatment with proton pump inhibitors is introduced. Moreover, recent data showing a link between GER and interstitial lung disease in SSc underscore the importance of aggressive GER treatment in SSc patients. A novel lung pattern possibly related to GER also has been described. New, exciting data on gastric vascular antral ectasia have been published. Finally, malnutrition in SSc patients has been highlighted, and anorectal involvement has been emphasized.

Gastrointestinal manifestations of scleroderma: recent progress in evaluation, pathogenesis, and management

Gastrointestinal (GI) involvement is frequent in scleroderma (systemic sclerosis [SSc]) and is the most frequent internal complication of the disease. Patients with GI involvement have impaired quality of life, and their prognosis may be one of severe impairment. Unfortunately, GI involvement is often noticed when severe complications have already occurred, is irreversible, and is difficult to manage. The past 2 to 3 years have been rich in exciting studies that we hope will help identify, prevent, treat, and monitor disease progression. Recent studies on the pathophysiology of GI tract disease could lead to advances in the treatment of GI tract involvement. The importance of treating gastroesophageal reflux (GER) has been reinforced by studies showing GER damage in almost all SSc patients, and the fact that GER damage is reversible if early treatment with proton pump inhibitors is introduced. Moreover, recent data showing a link between GER and interstitial lung disease in SSc underscore the importance of aggressive GER treatment in SSc patients. A novel lung pattern possibly related to GER also has been described. New, exciting data on gastric vascular antral ectasia have been published. Finally, malnutrition in SSc patients has been highlighted, and anorectal involvement has been emphasized.

RhoA/ROCK pathway is the major molecular determinant of basal tone in intact human internal anal sphincter

The knowledge of molecular control mechanisms underlying the basal tone in the intact human internal anal sphincter (IAS) is critical for the pathophysiology and rational therapy for a number of debilitating rectoanal motility disorders. We determined the role of RhoA/ROCK and PKC pathways by comparing the effects of ROCK- and PKC-selective inhibitors Y 27632 and Gö 6850 (10(-8) to 10(-4) M), respectively, on the basal tone in the IAS vs. the rectal smooth muscle (RSM). Western blot studies were performed to determine the levels of RhoA/ROCK II, PKC-α, MYPT1, CPI-17, and MLC(20) in the unphosphorylated and phosphorylated forms, in the IAS vs. RSM. Confocal microscopic studies validated the membrane distribution of ROCK II. Finally, to confirm a direct relationship, we examined the enzymatic activities and changes in the basal IAS tone and p-MYPT1, p-CPI-17, and p-MLC(20), before and after Y 27632 and Gö 6850. Data show higher levels of RhoA/ROCK II and related downstream signal transduction proteins in the IAS vs. RSM. In addition, data show a significant correlation between the active RhoA/ROCK levels, ROCK enzymatic activity, downstream proteins, and basal IAS tone, before and after ROCK inhibitor. From these data we conclude 1) RhoA/ROCK and downstream signaling are constitutively active in the IAS, and this pathway (in contrast with PKC) is the critical determinant of the basal tone in intact human IAS; and 2) RhoA and ROCK are potential therapeutic targets for a number of rectoanal motility disorders for which currently there is no satisfactory treatment.

Pharmacotherapy of systemic sclerosis

IMPORTANCE OF THE FIELD

Systemic sclerosis (SSc) is an uncommon autoimmune disease with variable degrees of fibroproliferation in blood vessels and certain organs of the body. There is currently no cure. The purpose of this article is to review the current literature regarding pathogenesis and treatment of complications of SSc.

AREAS COVERED IN THIS REVIEW

All available articles regarding research related to SSc pathogenesis and treatment listed in the PubMed database were searched; relevant articles were then reviewed and used as sources of information for this review.

WHAT THE READER WILL GAIN

This review attempts to highlight for the reader some current thought regarding mechanisms of SSc pathogenesis and how autoimmunity relates to vascular changes and fibrogenesis of the disease, as well as providing a review of results of completed clinical trials and current ongoing clinical trials that address organ-specific or global therapies for this disease. This can aid physicians who provide medical care for patients with SSc.

TAKE HOME MESSAGE

SSc is a complex autoimmune disease, the pathogenesis of which, although not completely understood, is under active study; new insights into pathogenesis are continually being discovered. Although there is no effective disease-modifying treatment for patients with SSc, quality of life, morbidity and mortality can be improved by using targeted therapy directed at affecting the consequences of damage to lungs, blood vessels, kidneys and the gastrointestinal tract. Innovative approaches to treating SSc are under intense investigation.