BACKGROUND Despite current therapies, diffuse cutaneous systemic sclerosis (scleroderma) often has a devastating outcome. We compared myeloablative CD34+ selected autologous hematopoietic stem-cell transplantation with immunosuppression by means of 12 monthly infusions of cyclophosphamide in patients with scleroderma. METHODS We randomly assigned adults (18 to 69 years of age) with severe scleroderma to undergo myeloablative autologous stem-cell transplantation (36 participants) or to receive cyclophosphamide (39 participants). The primary end point was a global rank composite score comparing participants with each other on the basis of a hierarchy of disease features assessed at 54 months: death, event-free survival (survival without respiratory, renal, or cardiac failure), forced vital capacity, the score on the Disability Index of the Health Assessment Questionnaire, and the modified Rodnan skin score. RESULTS In the intention-to-treat population, global rank composite scores at 54 months showed the superiority of transplantation (67% of 1404 pairwise comparisons favored transplantation and 33% favored cyclophosphamide, P = 0.01). In the per-protocol population (participants who received a transplant or completed ≥9 doses of cyclophosphamide), the rate of event-free survival at 54 months was 79% in the transplantation group and 50% in the cyclophosphamide group (P = 0.02). At 72 months, Kaplan–Meier estimates of event-free survival (74% vs. 47%) and overall survival (86% vs. 51%) also favored transplantation (P = 0.03 and 0.02, respectively). A total of 9% of the participants in the transplantation group had initiated disease-modifying antirheumatic drugs (DMARDs) by 54 months, as compared with 44% of those in the cyclophosphamide group (P = 0.001). Treatment-related mortality in the transplantation group was 3% at 54 months and 6% at 72 months, as compared with 0% in the cyclophosphamide group. CONCLUSIONS Myeloablative autologous hematopoietic stem-cell transplantation achieved long-term benefits in patients with scleroderma, including improved event-free and overall survival, at a cost of increased expected toxicity. Rates of treatment-related death and post-transplantation use of DMARDs were lower than those in previous reports of nonmyeloablative transplantation. (Funded by the National Institute of Allergy and Infectious Diseases and the National Institutes of Health; ClinicalTrials.gov number, NCT00114530.)
Abstract-Patients with chronic renal failure develop a "uremic" cardiomyopathy characterized by diastolic dysfunction, cardiac hypertrophy, and systemic oxidant stress. Patients with chronic renal failure are also known to have increases in the circulating concentrations of the cardiotonic steroid marinobufagenin (MBG). On this background, we hypothesized that elevations in circulating MBG may be involved in the cardiomyopathy. First, we observed that administration of MBG (10 g/kg per day) for 4 weeks caused comparable increases in plasma MBG as partial nephrectomy at 4 weeks. MBG infusion caused increases in conscious blood pressure, cardiac weight, and the time constant for left ventricular relaxation similar to partial nephrectomy. Decreases in the expression of the cardiac sarcoplasmic reticulum ATPase, cardiac fibrosis, and systemic oxidant stress were observed with both MBG infusion and partial nephrectomy. Next, rats were actively immunized against a MBG-BSA conjugate or BSA control, and partial nephrectomy was subsequently performed. Immunization against MBG attenuated the cardiac hypertrophy, impairment of diastolic function, cardiac fibrosis, and systemic oxidant stress seen with partial nephrectomy without a significant effect on conscious blood pressure. These data suggest that the increased concentrations of MBG are important in the cardiac disease and oxidant stress state seen with renal failure.
Abstract-We have observed recently that experimental renal failure in the rat is accompanied by increases in circulating concentrations of the cardiotonic steroid, marinobufagenin (MBG), and substantial cardiac fibrosis. We performed the following studies to examine whether MBG might directly stimulate cardiac fibroblast collagen production. In vivo studies were performed using the 5/6th nephrectomy model of experimental renal failure (PNx), MBG infusion (MBG), PNx after immunization against MBG, and concomitant PNx and adrenalectomy. Physiological measurements with a Millar catheter and immunohistochemistry were performed. In vitro studies were then pursued with cultured isolated cardiac fibroblasts. We observed that PNx and MBG increased MBG levels, blood pressure, heart size, impaired diastolic function, and caused cardiac fibrosis. PNx after immunization against MBG and concomitant PNx and adrenalectomy had similar blood pressure as PNx but less cardiac hypertrophy, diastolic dysfunction, and cardiac fibrosis. MBG induced increases in procollagen-1 expression by cultured cardiac fibroblasts at 1 nM concentration. These increases in procollagen expression were accompanied by increases in collagen translation and increases in procollagen-1 mRNA without any demonstrable increase in procollagen-1 protein stability. The stimulation of fibroblasts with MBG could be prevented by administration of inhibitors of tyrosine phosphorylation, Src activation, epidermal growth factor receptor transactivation, and N-acetyl cysteine. Based on these findings, we propose that MBG directly induces increases in collagen expression by fibroblasts, and we suggest that this may be important in the cardiac fibrosis seen with experimental renal failure. (Hypertension. 2007;49:215-224.)
The cardiotonic steroid marinobufagenin (MBG) has been implicated in the pathogenesis of experimental uremic cardiomyopathy, which is characterized by progressive cardiac fibrosis. We examined whether the transcription factor Friend leukemia integration-1 (Fli-1) might be involved in this process. Fli-1-knockdown mice demonstrated greater cardiac collagen-1 expression and fibrosis compared with wild-type mice; both developed increased cardiac collagen expression and fibrosis after 5/6 nephrectomy. There was a strong inverse relationship between the expressions of Fli-1 and procollagen in primary culture of rat cardiac and human dermal fibroblasts as well as a cell line derived from renal fibroblasts and MBG-induced decreases in nuclear Fli-1 as well as increases in procollagen-1 expression in these cells. Transfection of a Fli-1 expression vector prevented increased procollagen-1 expression from MBG. MBG exposure induced a rapid translocation of the δ-isoform of protein kinase C (PKCδ) to the nucleus. This translocation was prevented by pharmacological inhibition of phospholipase C, and MBG-induced increases in procollagen-1 expression were prevented with a PKCδ- but not a PKCα-specific inhibitor. Finally, immunoprecipitation studies strongly suggest that MBG induced phosphorylation of Fli-1. We feel these data support a causal relationship with MBG-induced translocation of PKCδ, which results in phosphorylation of as well as decreases in nuclear Fli-1 expression, which, in turn, leads to increases in collagen production. Should these findings be confirmed, we speculate that this pathway may represent a therapeutic target for uremic cardiomyopathy as well as other conditions associated with excessive fibrosis.
The vascular endothelium is an important functional unit in the regulation of the vascular and perivascular environment. Various chemical and physical stimuli mediate an endothelial-dependent vasoconstriction through the release of endothelial soluble factors, such as the recently recognized endothelium-derived vasoconstrictor peptide called endothelin. The presence of circulating endothelin and the effect of cold exposure on plasma endothelin levels were investigated in patients with scleroderma and in healthy control subjects. Radioimmunoassay demonstrated a mean f SD plasma level of 10.7 f 7.3 pg/ml in the patients (n = 19) and 3.7 f 2 in the control subjects (n = 16) (P < 0.005). These levels were also assessed in 5 control subjects and 5 scleroderma patients before and after 30 minutes of total body cooling (to 15OC). The endothelin level did not change significantly in either group; however, 2 scleroderma patients showed a significant increase after cooling. The effects of endothelin on fibroblast proliferation and collagen synthesis were evaluated in order to assess the impact of released endothelin on the interstitium. A significant mitogenic effect and a collagen synthesisenhancing effect, which were dose-dependent, were seen. The strong, characteristically prolonged, vasoconstrictor activity coupled with the profibrotic effect demonstrated here make it likely that disturbances in the From the Medical College of Ohio, Toledo.
Functional and structural vascular lesions have been observed in the organs involved in scleroderma. The etiology of these vascular changes is poorly understood. The ability to isolate, characterize, and maintain endothelial cells in vitro provides a target cell population to study endothelial damage in scleroderma. The present report describes the effect of scleroderma serum on endothelial, smooth muscle, and fibroblast cell types. Sera from patients with scleroderma (31/52) and Raynaud's syndrome (11/19) contain cytotoxic activity, specific for endothelial cells, which is nondialyzable, heat-stable, and elutes with albumin on gel-filtration chromatography.
Von Willebrand factor activity and factor VIII/von Willebrand factor (fVIII/vWf) antigen concentrations were evaluated in 17 patients with scleroderma, nine patients with Raynaud's phenomenon, and eight control volunteers. Higher circulating levels of both activities were seen: von Willebrand factor, 374% +/- 40% (percent of control values) in scleroderma patients, 502% +/- 104% in patients with Raynaud's phenomenon and 102% +/- 6% in control subjects (p less than 0.005, scleroderma versus control): fVIII/vWf antigen, 255% +/- 24% in scleroderma patients; 271% +/- 46% in patients with Raynaud's phenomenon, and 99% +/- 4% in control subjects (p less than 0.005, scleroderma versus control). Because endothelial cells synthesize and secrete both substances, the role of endothelial injury in vitro was investigated. Wound injury induced a 344% +/- 33% increase in von Willebrand factor and a 115% +/- 5% increases in fVIII/vWf antigen; cold injury induced 644% +/- 66% and 150% +/- 10% increases, and cytotoxic endothelial injury induced 1055% +/- 83% and 185% +/- 20% increases. In five patients with scleroderma, cold exposure led to a further increase in both activities. The observed increase of both activities in scleroderma and Raynaud's phenomenon may reflect in-vivo endothelial injury and regeneration in these related conditions.
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