Southwestern Internal Medicine Conference: The Many Faces of Scleroderma

Inflammatory myopathy associated with mixed connective tissue disease and scleroderma renal crisis

Mixed connective tissue disease is a rheumatological syndrome with neuromuscular manifestations that may include inflammatory myopathy and carpal tunnel syndrome. We report a patient who presented with an inflammatory myopathy and bilateral carpal tunnel syndrome prior to the diagnosis of a connective tissue disorder. Early in the course of treatment, a syndrome of acute renal failure developed. Knowledge of this syndrome, scleroderma renal crisis, and its possible relation to corticosteroid treatment is important to clinicians involved in the management of patients with inflammatory myopathies.

Differential expression of nitric oxide by dermal microvascular endothelial cells from patients with scleroderma

Vascular abnormalities in scleroderma are fundamental to the pathogenesis of this disease. The objective of this study was to characterize dermal microvascular endothelial cells (DMEC) isolated from scleroderma patients with respect to growth and expression of the constitutive form of endothelial nitric oxide synthase (eNOS). DMEC from patients with both systemic sclerosis (SSc) and localized scleroderma (Loc Scl) contained small intact microvascular structures in contrast to single cell isolations obtained from control skin. Immunoaffinity selection on anti-PECAM-1 beads yielded pure populations of DMEC expressing normal markers. While the morphology and initial growth of SSc DMEC closely paralleled control cells, the growth of SSc DMEC decreased with time in culture (doubling time of 3 days vs. 5 days). Expression of ecNOS mRNA was reduced in both Loc Scl and SSc as shown by semi-quantitative RT-PCR (p < 0.001). Western blots showed variable but generally lower ecNOS protein levels and decreased levels of nitrogen oxides in media were found from both SSc and Loc Scl relative to control cells. The results indicate an intrinsic defect in the mechanism of nitric oxide production in DMEC isolated from scleroderma patients and suggest its possible involvement in the pathophysiology of scleroderma.

Endothelial cell responses to hypoxic stress

1. Changes in the environmental oxygen tension to which cells are exposed in vivo result in physiological and sometimes pathological consequences that are associated with differential expression of specific genes. 2. Low oxygen tension (hypoxia) affects endothelial cellular physiology in vivo and in vitro in a number of ways, including the transcriptionally regulated expression of vasoactive substances and matrix proteins involved in modulating vascular tone or remodelling the vasculature and surrounding tissue. 3. Hypoxia results in the transcriptional induction of genes encoding vasoconstrictors and smooth muscle mitogens (PDGF-B, endothelin-1, VEGF, thrombospondin-1) and genes encoding matrix or remodelling molecules (collagenase IV (MMP-9), thrombospondin-1) and reciprocal transcriptional inhibition of vasodilatory or anti-mitogenic effectors (eNOS). 4. Oxygen appears to signal through a novel haem-containing sensor and signals initiated by this sensor alter the levels and DNA-binding activity of transcription factors such as activating protein (AP)-1, nuclear factor-kappa B and hypoxia-inducible transcription factor-1. 5. The genes encoding vasoactive factors regulated by oxygen tension are themselves also regulated by the vasoactive agent nitric oxide (NO). 6. Nitric oxide and oxygen transduce similar signals (i.e. their absence results in identical patterns of gene expression in endothelial cells and other cell types). 7. Thus, NO can feedback on and modulate signals induced by hypoxia and vice versa. For example, NO, which can act directly on smooth muscle cells as a vasodilator, can also facilitate vasodilation indirectly by reversing the production of vasoconstrictors induced by hypoxia. 8. Short-term exposure of endothelial cells to low oxygen tension results in the elaboration of predominantly vasoconstricting effectors, while longer-term and more severe hypoxic exposure generates factors that can induce smooth muscle proliferation and remodelling. 9. Thus, the endothelial cell response to hypoxic stress can result in two different consequences in the surrounding tissues, depending on the duration of the exposure: short-term exposure causes physiological and reversible modulation of vascular tone and blood flow; chronic hypoxic stress results in irreversible remodelling of the vasculature and surrounding tissues, with smooth muscle proliferation and fibrosis. 10. This dichotomy of responses to hypoxia may explain, in part, both the acute and chronic pathophysiological sequelae of diseases characterized by regional hypoxia, including atherosclerosis, pulmonary hypertension, sickle cell disease and systemic sclerosis (scleroderma).

Study of apoptosis in human lymphocytes by toxic substances implicated in toxic oil syndrome

Toxic Oil Syndrome is a multisystemic disease that occurred in epidemic proportions in Spain in 1981 caused by the ingestion of rapeseed oil denatured with aniline. Several data implicate T cells in the pathogenesis of the disease. We evaluated the mechanisms of cytotoxicity in human lymphocytes of TOS-related products: aniline, 3-(N-phenylamino)-1,2-propanediol and its mono- and di-oleyl esters and eosinophilia myalgia-related product such as 3-(phenylamino)-L-alanine, which is chemically similar to 3-(N-phenylamino)-1,2-propanediol, and has been found in manufactured L-tryptophan. Our results show that only di-oleyl ester of 3-(N-phenylamino)-1,2-propanediol induces apoptosis in human lymphocytes, in a concentration and time-dependent way, confirmed by morphology, expression of phosphatidylserine in membrane and analysis of DNA degradation.

Scleroderma renal crisis is still a life-threatening syndrome

Scleroderma renal crisis (SRC) was known as a rare and catastrophic syndrome responsible for acute renal failure (ARF) in a context of widespread microvascular disease occurring in progressive systemic sclerosis (PSS). Following pathogenetic hypoteses, angiotensin converting enzyme (ACE) inhibitors, plasma infusions (PI), and plasma-exchange (PE) have been employed in SRC with favorable results. Our purpose was to verify whether these therapies have consistently changed the fatal prognosis of SRC, even in our experience. In the last 10 years, SRC was diagnosed in eight patients (all eight with histologic data). The first five cases were treated with steroids, antihypertensive-cocktail, and PI: all five died, two within 48 hours, three after 10, 15, and 300 days, respectively. Three other patients were treated with ACE inhibitors, PI, and PE: all three died after 1, 9, and 12 months of HD. Clinical-histological correlations showed a strong relationship between the extent of glomerular involvement and the degree of renal failure, while arterial lesions seem to be more related to the past history of PSS, independently from the previous existence of hypertension. We conclude that "true" SRC diagnosed by restrictive criteria is still a rare life-threatening syndrome, and, unfortunately, no clear predictive biochemical or clinical signs could be identified; vascular renal involvement correlates to the duration of PSS independently of previous clinical evidence of renal failure or hypertension; a glomerular pattern similar to that reported for hemolytic-uremic syndrome (HUS)/thrombotic thrombocytopenic purpura (TTP) syndrome is directly related to the degree of acute renal involvement; SRC may occur even in the absence of hypertension, mainly if cardiomyopathy is present: in our experience. ACE inhibitors and plasma therapies have changed the short-time prognosis of SRC, but they may be unable to provide recovery from dialysis and do not avoid further evolution of extrarenal PSS exiting in late death.

Renal dysfunctions in glomerulonephropathy with rapidly declined renal failure

Eight patients aged between 5 and 26 years developed rapid deterioration of renal function and became oliguric/anuric with duration ranging from 1 to 21 days. The initial functional assessment revealed severe degree of glomerular, tubular, and vascular dysfunctions. The magnitude of renal dysfunction was quantified and expressed in terms of a clinical score. The degree of glomerular and tubular dysfunctions were inversely proportional to the renal plasma flow and peritubular capillary blood flow (PTCB), respectively. Similar findings have been observed in a variety of severe glomerulonephropathies. In this aspect, it is likely that the reduction of peritubular capillary blood flow and tubulointerstitial disease are interrelated. Further evidence to support the primary role of reduction of PTCB in inducing tubulointerstitial disease is provided by the following: (a) Reduction of PTCB is documented in mesangial proliferative nephrosis with steroid resistance prior to the detection of tubulointerstitial disease. (b) Ischemic insult can induce tubulointerstitial disease in experimental setting of renal artery occlusion in animal, (c) Improved tubular function can be achieved following the increase in PTCB with the enhanced renal perfusion therapy.

Raynaud's disease: pathophysiology, diagnosis, and treatment

Raynaud's disease is a common vasospastic disorder affecting the digits of both hands. Women are most commonly affected. This disorder occurs in two forms: Raynaud's disease and Raynaud's phenomenon. Raynaud's phenomenon is associated with a secondary etiology, most commonly scleroderma. Symptoms may precede the onset of connective tissue disease by a number of years. The pathophysiology, differential diagnosis, recommendations for referral, and treatment of Raynaud's disease are presented. A protocol for use by the nurse practitioner in the primary care setting is provided.