Lija Joseph

Transforming Growth Factor β Receptor Endoglin Is Expressed in Cardiac Fibroblasts and Modulates Profibrogenic Actions of Angiotensin II

Angiotensin II (Ang II) is a powerful mediator of adverse cardiac remodeling and fibrosis. However, the mechanisms of Ang II–induced myocardial fibrosis remain to be clarified. We postulated that Ang II alters transforming growth factor &bgr; (TGF-&bgr;) receptor expression, specifically that of endoglin, and thereby modulates cardiac fibroblast (CF) collagen metabolism. Experiments were conducted using CF from adult Sprague Dawley rats to determine the expression of TGF-&bgr;1 receptors including endoglin, and the role of Ang II type 1 (AT1) and type 2 (AT2) receptors, and MAPK p42/44 in this process. The functional role of endoglin in modulating Ang II effects on matrix metalloproteinase-1 (MMP-1) and type I collagen expression was also analyzed. Endoglin gene and protein expression were consistently identified in quiescent CFs. Ang II increased the expression of endoglin mRNA and protein in a concentration and time-dependent manner, with no effect on TGF-&bgr; receptors I and II expression. This effect was AT1 receptor mediated, because AT1 receptor antagonists valsartan, candesartan, and losartan inhibited Ang II–induced endoglin expression, whereas the AT2 receptor antagonist PD123319 had no effect. MAPKp42/44 inhibition attenuated Ang II–induced endoglin expression. Ang II–induced decrease in MMP-1 protein expression and increase in type I collagen protein expression were both blocked by a specific endoglin antibody. Hence, our results indicate that endoglin is upregulated in CFs by Ang II via the AT1 receptor and modulates profibrotic effects of Ang II. These findings provide novel insights into Ang II–induced cardiac remodeling.

Myeloma of the central nervous system: association with high-risk chromosomal abnormalities, plasmablastic morphology and extramedullary manifestations.

Summary.  Involvement of the central nervous system (CNS) by multiple myeloma, as defined by the detection of malignant plasma cells in the cerebrospinal fluid in the presence of suggestive symptoms, is considered extremely rare. We report on the characteristics of 18 such patients diagnosed and treated at the University of Arkansas over the last 10 years for an overall incidence of approximately 1%. Their evaluation revealed association of CNS involvement with unfavourable cytogenetic abnormalities (especially translocations and deletion of the chromosome 13), high tumour mass, plasmablastic morphology, additional extramedullary myeloma manifestations and circulating plasma cells. The presence of these features should alert clinicians to the possibility of CNS involvement. The outcome of these patients was extremely poor despite the use of aggressive local and systemic treatment including autologous stem cell transplants. Given this universally poor prognosis, the application of allogeneic transplants should be studied in this clinical setting.

Renal pathologic spectrum in an autopsy series of patients with plasma cell dyscrasia

CONTEXT Renal dysfunction in plasma cell dyscrasias is common. It is the second most common cause of death in patients with myeloma. OBJECTIVE We evaluated 77 sequential autopsies performed on patients dying from complications of plasma cell dyscrasias during an 11-year period at the University of Arkansas for Medical Sciences. These consisted of 15% of all the autopsies performed during this time. DESIGN The kidneys were evaluated by light microscopy using hematoxylin-eosin-stained sections as well as Congo red and thioflavin T stains when amyloidosis was in the differential diagnosis. Immunofluorescence was performed on selected cases. RESULTS The most common lesion identified was cast nephropathy (30%). Other findings included acute tubulopathy, AL-amyloidosis, light chain deposition disease, tubulointerstitial nephritis associated with monotypic light chain deposits, thrombotic microangiopathy, renal infarction, fungal infection, and plasma cell tumor nodules. Autolysis, an expected finding in autopsy evaluations, was significant in 25 cases. CONCLUSIONS Renal lesions are heterogeneous in these patients. In some cases, combined pathologic lesions were noted. Myeloma cast nephropathy predominated among all the renal lesions noted.

Association between a glutathione S‐transferase A1 promoter polymorphism and survival after breast cancer treatment

Glutathione S‐transferase (GST) enzymes detoxify chemotherapeutic drugs, and several studies have reported differences in survival for cancer patients who have variant genotypes for GSTP1, GSTM1 or GSTT1 enzymes. A recently described polymorphism alters hepatic expression of GSTA1, a GST with high activity in glutathione conjugation of metabolites of cyclophosphamide (CP). To consider the possible influence of the reduced‐expression GSTA1*B allele on cancer patient survival, we have conducted a pilot study of breast cancer patients treated with CP‐containing combination chemotherapy. GSTA1 genotype was determined by polymerase chain reaction and restriction fragment length polymorphism. Kaplan‐Meier methods and Cox proportional hazards models were used to evaluate survival in relation to genotype. Among 245 subjects, 35% were GSTA1*A/*A, 49% GSTA1*A/*B and 16% GSTA1*B/*B; the genotype distribution did not differ by ethnic group, age or stage at diagnosis. Among patients who had 0 or 1 GSTA1*B allele, the proportion surviving at 5 years was 0.66 (95% CI = 0.59–0.72), whereas for GSTA1*B/*B subjects the proportion was higher, 0.86 (95% CI = 0.67–0.95). Significantly reduced hazard of death was observed for GSTA1*B/*B subjects during the first 5 years after diagnosis, hazard ratio (HR) = 0.3, 95% CI = 0.1–0.8. The association varied with time, with no survival difference observed for subjects who survived beyond 5 years. These results, although based on a small study population, describe an apparent difference in survival after treatment for breast cancer according to GSTA1 genotype. Further studies should consider the possible association between the novel GSTA1*B variant and outcomes of cancer therapy.

Effects of Fenofibrate on Cardiac Remodeling in Aldosterone-Induced Hypertension

Hypertension and cardiac remodeling are associated with myocardial fibrosis, left ventricular (LV) hypertrophy, and diastolic heart failure. Fenofibrate suppresses aldosterone-mediated increases in myocyte matrix metalloproteinase activity and extracellular signal–regulated kinase phosphorylation. It is unknown whether the peroxisome proliferator–activated receptor-α agonist, fenofibrate, improves cardiac remodeling in a model of aldosterone-induced hypertension and LV hypertrophy. Twelve-week-old uninephrectomized FVB mice received 1% NaCl drinking water. Miniosmotic pumps delivered saline or aldosterone for 4 weeks. Mice were either untreated (n=14) or treated with fenofibrate 100 mg/kg per day (n=12) for 1 week before and 4 weeks after surgery. Aldosterone increased systolic blood pressure in untreated mice versus saline-untreated mice (134±3 versus 91±3 mm Hg; P<0.01). This was unaffected by fenofibrate (131±3 mm Hg). Aldosterone increased LV end-diastolic and end-systolic dimensions, which were significantly attenuated by fenofibrate (3.8±0.1 versus 3.5±0.1 mm, and 1.5±0.1 versus 1.15±0.1 mm, respectively). Fenofibrate also decreased aldosterone-induced LV hypertrophy (LV weight/body weight, 4.1±0.2 versus 4.6±0.1 mg/g) and improved percent LV fractional shortening (67±7% versus 60±2%). Additionally, fenofibrate ameliorated the increased matrix metalloproteinase-2/tissue inhibitors of metalloproteinase-2 ratio and fibrosis seen in aldosterone-untreated hearts (P<0.05 for both). Furthermore, in aldosterone-untreated hearts, fenofibrate decreased transforming growth factor-β, collagen type III (P<0.05 for both), and collagen type I (P<0.01) protein expression. Conversely fenofibrate increased peroxisome proliferator–activated receptor-α, peroxisome proliferator–activated receptor-γ coactivator-1α expression, and acetyl coenzyme A carboxylase phosphorylation (P<0.05 for all) in aldosterone-infused hearts; uncoupling protein-3 and medium-chain acyl coenzyme A dehydrogenase protein expression decreased with fenofibrate (P<0.05 and P<0.01, respectively, versus aldosterone-infused), suggesting that improved myocardial remodeling is independent of fatty acid oxidation. Thus, fenofibrate improved aldosterone-induced LV hypertrophy independently of an effect on blood pressure with decreased fibrosis and altered extracellular matrix.

Flow-Induced Arterial Remodeling Relates to Endothelial Function in the Human Forearm

Background— Chronic changes in blood flow stimulate arterial remodeling, which contributes to the maintenance of vascular homeostasis. Experimental studies suggest that remodeling represents a response to local changes in endothelial shear stress and is nitric oxide–dependent. Methods and Results— To investigate determinants of outward arterial remodeling in humans, we measured ulnar artery flow, diameter, and flow-mediated dilation before and after removal of the adjacent radial artery in 53 patients who were undergoing coronary bypass surgery (age 60±11 years; 13% female). Removal of the radial artery increased ulnar artery blood flow by 35% (P=0.009) and increased ulnar artery diameter by 9% (P<0.001) 4 to 8 weeks after surgery. At 1 week, ulnar artery shear stress was increased by 58% (P<0.001), but it was no longer different from baseline at longer-term follow-up. The contralateral ulnar artery was unaffected, which suggests that these findings were not attributable to the systemic effects of medications or the postoperative state. Extent of outward remodeling correlated with the increase in blood flow (r=0.50, P=0.001) and with flow-mediated dilation at baseline (r=0.50, P=0.001). Remodeling correlated inversely with baseline endothelial expression of P-selectin in the radial artery (r=−0.76, P=0.004, n=14). Conclusions— A sustained increase in blood flow in the ulnar artery induced outward arterial remodeling despite the presence of risk factors and coronary artery disease. The remodeling response was related to endothelial phenotype, as reflected by flow-mediated dilation and expression of P-selectin. These findings provide evidence that the endothelium plays an important role in the regulation of vascular structure in humans.

Influence of mast cells on outcome after heterotopic cardiac transplantation in rats

Correlative data suggest that mast cells adversely affect cardiac transplantation. This study uses a mast cell‐deficient rat model to directly address the role of mast cells in cardiac allotransplantation. Standardized cardiac heterotopic transplantation with cyclosporine immunosuppression was performed in mast cell‐deficient and mast cell‐competent rats. Rejection, ischemia, fibrosis, fibrin deposition, numbers of T‐cell receptor α/β positive cells, expression of transforming growth factor‐β (TGF‐β), and of endothelin‐1 (ET‐1) and its receptors ETA and ETB were assessed. Differences in baseline cardiac gene expression were quantified by real‐time PCR in a separate group of untransplanted animals. Baseline cardiac gene expression levels of all investigated growth factors, cytokines, ET‐1, ETA, and ETB were similar in mast cell‐deficient and mast cell‐competent rats. Surprisingly, upon heterotopic transplantation, donor heart survival was significantly reduced in mast cell‐deficient rats. Moreover, in mast cell‐deficient donor hearts rejection was more severe, although nonsignificant, and extracellular matrix associated TGF‐β immunoreactivity was significantly lower than in mast cell‐competent donor hearts. Fibrin immunoreactive area, on the other hand, was only increased in mast cell‐deficient donor hearts, but not in mast cell‐competent donor hearts. Histopathological changes in all donor hearts were accompanied by increased immunoreactivity for ET‐1. In conclusion, this study shows that mast cells play a protective role after cardiac transplantation.

Cardiac nonamyloidotic immunoglobulin deposition disease

Cardiac nonamyloidotic immunoglobulin (Ig) deposition disease (CIDD) is a rare disorder characterized by Ig deposition in the myocardium associated with plasma cell dyscrasias. A retrospective review of cardiac biopsies performed at two different institutions identified eight patients with CIDD. All patients had plasma cell dyscrasias with monoclonal gammopathy. Three had IgG λ, two had IgG κ, one had IgD κ and one each had free κ and free λ light chain. Four patients had concurrent amyloidosis involving other organs. One had amyloidosis of kidney alone, one had amyloidosis of kidney and abdominal fat pad and two others had amyloidosis of bone marrow vasculature. Three patients had dialysis-dependent renal insufficiency. None of the patients had symptoms of heart failure. Six patients had echocardiographically demonstrable concentric left ventricular hypertrophy with diastolic dysfunction. Two patients had significant cardiac arrhythmias requiring medical intervention. On endomyocardial biopsy, all eight had normal appearing myocardium on light microscopy with negative Congo Red and Thioflavin T stains. On immunofluorescent staining of the cardiac biopsies, all eight stained positive for interstitial Ig deposition. Electron microscopy (EM) confirmed the presence of granular deposits of Igs in the myocardium in five of the eight patients. EM studies were not available in one patient and two others had normal EM studies. In conclusion, CIDD should be considered in the spectrum of cardiovascular pathology in patients with plasma cell dyscrasias. They often, but not always, have left ventricular hypertrophy. These patients may be at risk for developing arrhythmias as well as diastolic dysfunction. Unless immunofluorescent and EM studies are performed routinely in biopsy material, this entity may be missed in the absence of amyloidosis. Concurrent amyloidosis in other organs sheds a unique perspective into the role of local microenvironment in the pathogenesis of systemic Ig deposition disease and amyloidosis.

Expression of syndecan-1 is a sensitive marker for cutaneous plasmacytoma.

Background:  Cutaneous plasmacytoma is a well‐recognized, yet infrequent, occurrence in multiple myeloma (MM). There are limitations in the morphologic assessment, and as such, the diagnosis presents some difficulty, particularly with the plasmablastic type.

Hyperhomocysteinemia and Cardiovascular Disease: New Mechanisms Beyond Atherosclerosis

The association of hyperhomocysteinemia (Hhe) with cardiovascular disease (CVD) has been explored in detail over the last four decades since initial reports in the 1960s. Although several epidemiological studies have shown an association, convincing mechanistic studies are still lacking. However, recent prospective studies demonstrate a strong association of Hhe with coronary disease. Several pathogenic mechanisms have been studied in Hhe and indicate alterations in the various components of vascular disease, namely endothelial cells, vascular smooth muscle cells, platelets, and the coagulation/fibrinolytic systems. Increased oxidative stress, hypomethylation, and protein homocysteinylation have been proposed as potential molecular mechanisms in Hhe-induced CVD. In addition, recent studies indicate a novel link between Hhe and CVD, that is, direct effects on coronary arteriolar and myocardial remodeling resulting in cardiac dysfunction.