Talia Weinstein

Transgenic expression of mammalian heparanase uncovers physiological functions of heparan sulfate in tissue morphogenesis, vascularization, and feeding behavior

We have generated homozygous trans¬genic mice (hpa‐tg) overexpressing human hepara¬nase (endo‐β‐D‐glucuronidase) in all tissues and char¬acterized the involvement of the enzyme in tissue morphogenesis, vascularization, and energy metabo¬lism. Biochemical analysis of heparan sulfate (HS) isolated from newborn mice and adult tissues re¬vealed a profound decrease in the size of HS chains derived from hpa‐tg vs. control mice. Despite this, the mice appeared normal, were fertile, and exhib¬ited a normal life span. A significant increase in the number of implanted embryos was noted in the hpa‐tg vs. control mice. Overexpression of heparanase resulted in increased levels of urinary protein and creatinine, suggesting an effect on kidney func¬tion, reflected also by electron microscopy examina¬tion of the kidney tissue. The hpa‐tg mice exhibited a reduced food consumption and body weight com¬pared with control mice. The effect of heparanase on tissue remodeling and morphogenesis was best dem¬onstrated by the phenotype of the hpa‐tg mammary glands, showing excess branching and widening of ducts associated with enhanced neovascularization and disruption of the epithelial basement membrane. The hpa‐tg mice exhibited an accelerated rate of hair growth, correlated with high expression of heparanase in hair follicle keratinocytes and increased vascularization. Altogether, characterization of the hpa‐tg mice emphasizes the involvement of heparanase and HS in processes such as embryonic implan¬tation, food consumption, tissue remodeling, and vascularization.—Zcharia, E., Metzger, S., ChajekShaul, T., Aingorn, H., Elkin, M., Friedmann, Y., Weinstein, T., Li, J.‐P., Lindahl, U., Vlodavsky, I. Transgenic expression of mammalian heparanase uncovers physiological functions of heparan sulfate in tissue morphogenesis, vascularization, and feeding behavior. FASEB J. 18, 252–263 (2004)

Severe Hyponatremia After Water Intoxication: A Potential Cause of Rhabdomyolysis

A 28-year-old woman, treated for schizophrenia, developed severe hypotonic hyponatremia (serum Na: 109 mEq/L) after several days of compulsive water drinking. The patient was admitted in a coma and required intensive supportive therapy. Rhabdomyolysis quickly followed with high serum creatine phosphokinase levels and myoglobinuria. A high volume alkaline diuresis was initiated. Renal failure or compartment syndrome did not complicate the clinical picture. The mechanisms causing water intoxication and hyponatremia are discussed as are the possible pathogenetic explanations behind acute hyponatremia and rhabdomyolysis.

Non-Occlusive Mesenteric Ischemia in Chronically Dialyzed Patients: A Disease with Multiple Risk Factors

Background: Non-occlusive mesenteric ischemia (NOMI) can be a fatal complication in dialysis patients. Intradialytic hypotension is usually the precipitating factor. The occurrence of 16 cases in 5 years (1998–2002), compared with only 4 in previous years, led us to investigate other risk factors contributing to NOMI. A control group of stable hemodialysis patients was used for comparison. Results: 20 patients were studied: 17 diagnosed surgically, and 3 clinically. The mean age was 70.8 ± 1.8 years, and the male:female ratio 7:13. Nineteen patients were on hemodialysis. Clinically overt atherosclerosis was present in 17 patients. Preceding dialysis-associated hypotension was identified in all patients studied and access thrombosis in 6 patients. In all patients, abdominal pain was the presenting symptom. Initial abdominal examination was unimpressive in 16 patients. The hemoconcentration, leukocytosis and metabolic acidosis were the most prominent laboratory findings. 5/11 abdominal sonograms showed intestinal pathology. 2/3 angiographies were diagnostic. Three patients responded to early fluid challenge and did not require surgery. Pathology was related to the area of the superior mesenteric artery in all 15 patients operated. Twelve (60%) patients died from the event. The 1-year mortality rate was 17/20 patients (85%). Possible contributing factors, other than dialysis-associated hypotension, included: high-dose recombinant human erythropoietin (rhEPO) therapy (179 ± 35 vs. 116 ± 10 U/kg/week in the control group, p < 0.05); metastatic calcifications (abdominal aorta 14/14, aortic valve 11/18; medial calcification of mesenteric arteries in 2/11 pathology specimens); digoxin, and hypoalbuminemia. Conclusions: The increased incidence of NOMI in dialysis patients may be related to overly aggressive rhEPO therapy and the unsuspected presence of mesenteric arterial medial calcifications. Identification of patients at risk, prevention of intradialytic hypotension and a controlled increase in dry weight may help to reduce the incidence of NOMI in chronically dialyzed patients.

Improved Immunogenicity of a Novel Third-Generation Recombinant Hepatitis B Vaccine in Patients with End-Stage Renal Disease

Hepatitis B (HBV) infection remains a significant epidemiological problem in the end-stage renal disease (ESRD) population. Vaccination programs using second-generation vaccines lead to effective seroprotection in only 50–60% of these patients. The purpose of this case series was to describe our experience with a novel third-generation vaccine, Bio-Hep-B®, in ESRD patients who had not developed protective anti-HBs titers following a second-generation HBV vaccination protocol. Twenty-nine ESRD patients who had not responded in the past to a standard second-generation HBV vaccination protocol were included in this series. Each patient received 10 µg of Bio-Hep-B® intramuscularly at 0, 1 and 6 months. A month after completion of the vaccination protocol, anti-HBs antibody levels were measured. Following immunization, 25 of 29 patients (86%) developed seroprotective anti-HBs levels ≧10 mIU/ml. There was a significant difference in the titers of anti-HBs antibodies prior to and following vaccination (p < 0.0001). Statistical analysis of the variables age, gender, diagnosis, dialysis mode, weight, hemoglobin, albumin, and KT/V failed to detect predictors of antibody response. A retrospective analysis of the results of a second-generation vaccination program for the years 1999–2001 in our department showed that 19 of 36 (56.4%) ESRD patients developed seroprotection. In conclusion, the results of this study show that the third-generation HBV vaccine Bio-Hep-B® is highly immunogenic in the population of ESRD patients who did not respond in the past to a second-generation vaccine. This enhanced seroprotection offers hope that the new vaccine will reduce the rate of non-responders and help to eliminate HBV infection from dialysis centers.

Peripheral vascular disease and serum phosphorus in hemodialysis: a nested case-control study.

BACKGROUND Serum phosphorus (P) and the product of serum calcium x serum P (Ca x P), are frequently elevated in end-stage renal disease patients on maintenance hemodialysis (HD). Elevated P and Ca x P have been associated with vascular calcification in dialysis patients. OBJECTIVE [corrected] To examine the role of P and Ca x P as risk factors for incident peripheral vascular disease (PVD) in HD patients with pre-existing CVD. METHODS This nested case-control study is drawn from the 11 incident PVD events reported in the cohort of the Secondary prevention with antioxidants of cardiovascular disease in end-stage renal disease (SPACE): a randomized placebo-controlled trial. PVD was defined clinically and confirmed ultrasonographically. Each individual with a PVD event was matched for SPACE treatment group (vitamin E or placebo), age (in 4-year categories) and gender with two individuals who had no CVD end point during the follow-up period. RESULTS Serum P and Ca x P levels were significantly higher in PVD patients than in controls. In univariate logistic regression analysis, only serum P predicted PVD in this population (OR 2.02, 95% CI 1.07 - 3.81, p = 0.03). In multivariate analysis, adjustment was made for variables dissimilar by PVD status including underlying renal disease, diabetes, smoking, history of angina pectoris, prescription for vitamin D3, erythropoietin, calcium channel blockers and aspirin. In this model, serum P remained the only significant predictor of incident PVD (OR 2.4, 95% CI 1.01 - 5.74, p = 0.04). CONCLUSIONS Findings of the present study are consistent with a role for serum P and Ca x P in the pathogenesis of PVD in HD patients.

General Anesthesia for Surgery Influences Melatonin and Cortisol Levels

The purpose of this study was to investigate the effect of general anesthesia and surgery on melatonin production, and to assess the relationship between melatonin secretion and cortisol levels. Twenty (9 males and 11 females) consecutive otherwise healthy patients aged 27 to 52 years were included in this study. The patients underwent laparoscopic cholecystectomy or laparoscopic hernioplasty. All patients had general anesthesia with the same anesthetic drugs. Serum cortisol levels were measured at several time periods. Urine collections for melatonin were performed from 18:00 to 7:00 the day prior to surgery, on the operation day, and on the first postoperative day. Baseline melatonin metabolites were measured the night prior to surgery, and the level was found to be 1979 ± 1.76 ng. The value decreased to 1802 ± 1.82 ng (NS) on the night of surgery, and it became a significantly higher, reaching 2981 ± 1.55 ng the night after surgery (p = .003). The baseline daytime cortisol level was significantly lower than the baseline night cortisol level (6.87 ± 1.51 μg/dl, 14.89 ± 1.66 micrograms/dl, respectively, p < 0.0001). Surgery induced a significant increase in both day and night cortisol levels. Daytime cortisol levels increased from 6.89 ± 1.51μg/dl to 16.90 ± 1.27μg/dl (p < 0.0001), whereas right levels increased from 14.89 ± 1.66 μg/dl to 29.20 ± 1.24 μg/dl (p <0.0001). The morning after surgery, cortisol levels decreased to 10.16 ± 1.40 μg/dl, lower than the value obtained on the day of surgery (p < 0.0001). As was true of melatonin, cortisol levels did not reach the pre operative level (p < 0.005). The finding of the current study is that melatonin and cortisol levels show an inverse correlation after surgery.

H2 O2 induces DNA repair in mononuclear cells: Evidence for association with cytosolic Ca2+ fluxes

Cellular DNA repair systems are induced whenever DNA is damaged. Reactive oxygen species (ROS) are generated, in vivo, in the tissues as a result of regular cellular metabolism or after exposure to oxidizing agents, such as ultraviolet (UV) irradiation. It has been suggested that ROS mediate DNA damage. The objectives of the study were as follows: (1) to investigate whether hydrogen peroxide (H2O2), the commonly occurring cellular ROS, induces DNA repair as a response to the damage it probably causes; (2) to evaluate whether H2O2-induced DNA repair, if present, is signaled through a Ca2(+)-dependent pathway via the tyrosine kinase signal transduction. H2O2 was found to induce DNA repair in human peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner. The recovery of RNA synthesis, which occurred after DNA repair, confirmed that transcribable DNA was repaired. The inhibition of tyrosine kinase activity by genistein reduced the DNA repair significantly. Furthermore, H2O2 caused a dose-dependent significant rise in cytosolic calcium ((Ca2+)i). H2O2 also induced a small rise in (Ca2+)i of cytosolic Ca2(+)-depleted cells, probably reflecting the release of Ca2+ from internal stores. Genistein inhibited both Ca2+ influx and Ca2+ release from internal stores. In summary, H2O2 induced a DNA repair synthesis that was in part Ca2+ dependent and signaled via tyrosine kinase. The changes in DNA repair paralleled changes in (Ca2+)i. The H2O2-induced (Ca2+)i rise was mostly the result of influx, but to some degree it was also due to the translocation of Ca2+ from internal stores.

TGFβ1-dependent podocyte dysfunction.

Purpose of reviewThe glomerular filtration barrier is a unique structure characterized by a specialized framework of podocytes. Transforming growth factor-&bgr;1 (TGF&bgr;1) upregulation occurs in virtually all chronic kidney diseases and is associated with podocyte injury and proteinuria. This review is aimed at describing the latest advances made in the understanding of TGF&bgr;-induced podocyte injury. Recent findingsDuring the past decade, progress has been made in understanding the biology and mechanisms of TGF&bgr;-induced podocyte injury. Most forms of glomerular diseases, including diabetic nephropathy, are associated with increased TGF&bgr;1 signaling and thus TGF&bgr;1 plays a central role in the pathogenesis of podocytopathy. The mechanism of podocyte injury is complex, involving a number of independent and overlapping cellular and molecular pathways. This review will examine these direct and indirect effects of TGF&bgr;1 on podocyte dysregulation as reflected in their growth, differentiation, and motility. SummaryThese new developments in understanding the podocyte response to injury are critical for establishing better therapeutic interventions that target specific pathways, which otherwise could lead to irreversible injury.

Elevated urine heparanase levels are associated with proteinuria and decreased renal allograft function.

Heparanase is an endo-β-glucuronidase that cleaves heparan sulfate side chains, leading to structural modifications that loosen the extracellular matrix barrier and associated with tumor metastasis, inflammation and angiogenesis. In addition, the highly sulfated heparan sulfate proteoglycans are important constituents of the glomerular basement membrane and its permselective properties. Recent studies suggest a role for heparanase in several experimental and human glomerular diseases associated with proteinuria such as diabetes, minimal change disease, and membranous nephropathy. Here, we quantified blood and urine heparanase levels in renal transplant recipients and patients with chronic kidney disease (CKD), and assessed whether alterations in heparanase levels correlate with proteinuria and renal function. We report that in transplanted patients, urinary heparanase was markedly elevated, inversely associated with estimated glomerular filtration rate (eGFR), suggesting a relationship between heparanase and graft function. In CKD patients, urinary heparanase was markedly elevated and associated with proteinuria, but not with eGFR. In addition, urinary heparanase correlated significantly with plasma heparanase in transplanted patients. Such a systemic spread of heparanase may lead to damage of cells and tissues alongside the kidney.The newly described association between heparanase, proteinuria and decreased renal function is expected to pave the way for new therapeutic options aimed at attenuating chronic renal allograft nephropathy, leading to improved graft survival and patient outcome.

Sonographic features of dialysis-related amyloidosis of the shoulder.

This study evaluated the diagnostic role of ultrasonography in dialysis‐related amyloidosis in shoulders of chronically hemodialyzed patients. Fourteen shoulders of 12 long‐term hemodialysis patients were examined. All patients had been on dialysis for at least 10 years. All patients had varying degrees of pain and limitations of movement in the studied shoulders. Dialysis‐related amyloidosis was the presumed diagnosis in all patients. Any patient with a history of any disease, other than dialysis‐related amyloidosis, capable of producing a pathologic shoulder condition was excluded. The following parameters were studied: supraspinatus and biceps tendon thickness, tendon tears, synovial thickening, and the presence of hypoechoic material around tendons and within bursae. All shoulders had a nonhomogeneous thickening, greater than 7 mm, of the supraspinatus tendon. Seven shoulders (50%) had abnormal thickening of the biceps tendon (4 mm or greater), and two shoulders had abnormal thickening of the subscapularis tendon. Hypoechoic deposits were seen in the subdeltoid bursae and biceps sheaths in five and six shoulders, respectively. Three shoulders showed partial tears of the supraspinatus tendon, one shoulder showed a tear in the biceps tendon, and one shoulder had a tear in the subscapularis tendon. Ultrasonography is an excellent imaging modality in diagnosing the presence of dialysis‐related amyloidosis in symptomatic shoulders of long‐term hemodialysis patients, without having to resort to invasive procedures. The results of previous studies have been confirmed and new ultrasonographic findings described. Of particular interest is the involvement of the subscapularis tendon in dialysis‐related amyloidosis. Repeat ultrasonography can become an important way to follow‐up progression of shoulder dialysis‐related amyloidosis in hemodialyzed patients.