Effects of enzyme replacement therapy in adult patients with Fabry disease on cardiac structure and function: a retrospective cohort study of the Fabry Munster Study (FaMuS) data.

OBJECTIVE: Fabry disease (FD) is an X-linked inborn error of glycosphingolipid catabolism caused by deficient lysosomal α-galactosidase A activity. Progressive accumulation of globotriaosylceramide and related glycosphingolipids in vascular endothelial lysosomes of the heart, kidneys and brain is responsible for the main disease manifestations. The aim of our study was to assess short-term and long-term effects of enzyme replacement therapy (ERT) on cardiac mass and function. DESIGN: Retrospective cohort study. SETTING: Hospital outpatient clinic. PARTICIPANTS: 40 FD patients (21 men, 19 women) receiving agalsidase ß-ERT. OUTCOME MEASURES: The focus at baseline and follow-up examinations was on structural, functional (Doppler-echocardiography) as well as electrical changes (ECG) and blood pressure. RESULTS: In the Early Group, systolic and diastolic blood pressures significantly decreased. Left-ventricular (LV) also decreased; however, wall thickness and LV mass index showed no further increase. VE as an indicator for diastolic function significantly improved (64±21 vs 75±27 cm/s, p=0.038). There were no significant changes of ECG parameters. There were few relevant changes in the Late Group, albeit systolic blood pressure significantly decreased and QRS duration significantly increased. In conclusion, echocardiographic left-ventricular mass index, interventricular septum thickness, left-ventricular posterior wall, left-ventricular end-diastolic dimension) and diastolic function parameters are valuable for follow-up and guidance of therapy. CONCLUSIONS: The primary positive impact of ERT appears to be an early effect after the start of therapy, and early initiation of ERT should be recommended.

Signaling by the matrix proteoglycan decorin controls inflammation and cancer through PDCD4 and MicroRNA-21.

The mechanisms linking immune responses and inflammation with tumor development are not well understood. Here, we show that the soluble form of the extracellular matrix proteoglycan decorin controls inflammation and tumor growth through PDCD4 (programmed cell death 4) and miR-21 (microRNA-21) by two mechanisms. First, decorin acted as an endogenous ligand of Toll-like receptors 2 and 4 and stimulated production of proinflammatory molecules, including PDCD4, in macrophages. Second, decorin prevented translational repression of PDCD4 by decreasing the activity of transforming growth factor-ß1 and the abundance of oncogenic miR-21, a translational inhibitor of PDCD4. Moreover, increased PDCD4 abundance led to decreased release of the anti-inflammatory cytokine interleukin-10, thereby making the cytokine profile more proinflammatory. This pathway operates in both pathogen-mediated and sterile inflammation, as shown here for sepsis and growth retardation of established tumor xenografts, respectively. Decorin was an early response gene evoked by septic inflammation, and protein concentrations of decorin were increased in the plasma of septic patients and mice. In cancer, decorin reduced the abundance of anti-inflammatory molecules and increased that of proinflammatory molecules, thereby shifting the immune response to a proinflammatory state associated with reduced tumor growth. Thus, by stimulating proinflammatory PDCD4 and decreasing the abundance of miR-21, decorin signaling boosts inflammatory activity in sepsis and suppresses tumor growth.

Perforating vein fistula is superior to forearm fistula in elderly haemodialysis patients with diabetes and arterial hypertension.

BACKGROUND: Access-related problems are one of the major causes of morbidity in elderly patients with chronic kidney disease. The aim of this study was to assess potential risks and benefits in elderly patients comparing forearm arteriovenous fistula (AVF) and perforating vein AVF below the elbow for primary vascular access. METHODS: A retrospective comparison of elderly patients (65.7 ± 9.3 years, 70.4% male patients, 36.2% late referral) undergoing primary vascular access surgery using forearm AVF (n = 50) and perforating vein AVF (n = 55) was performed over a 2-year period, including a multivariate analysis of potential risk factors and benefits of primary patency (PP = intervention-free access survival) and secondary patency (SP = access survival until abandonment). RESULTS: Patency rates after 24 months were significantly higher in patients with perforating vein AVF (PP + SP: 78.2%) compared to forearm AVF (PP: 62%, SP: 56%, P = 0.04). Presence of diabetes mellitus in patients with forearm AVF was associated with a decreased PP [odds ratio (OR): 3.6, 95% confidence interval (CI): 0.9-13.8] and SP (OR: 4.8, 95% CI: 1.3-17.9), and arterial hypertension was associated with a lower PP (OR: 6.7, 95% CI: 0.8-53.9), whereas the presence of hyperparathyroidism was associated with higher PP and SP (OR: 0.2, 95% CI: 0.1-0.7). In contrast, PP and SP in patients with perforating vein AVF were not influenced by comorbidities. CONCLUSIONS: Perforating vein AVF is superior to forearm AVF in elderly patients with diabetes and arterial hypertension due to the proximal fistula location, probably caused by an improved artery distensibility during fistula maturation.

The proteoglycan biglycan regulates expression of the B cell chemoattractant CXCL13 and aggravates murine lupus nephritis.

CXCL13 is a key B cell chemoattractant and marker of disease activity in patients with SLE; however, the mechanism of its induction has not been identified yet. Here, we have shown that the proteoglycan biglycan triggers CXCL13 expression via TLR2/4 in macrophages and dendritic cells. In vivo, levels of biglycan were markedly elevated in the plasma and kidneys of human SLE patients and lupus-prone (MRL/lpr) mice. Overexpression of soluble biglycan in MRL/lpr mice raised plasma and renal levels of CXCL13 and caused accumulation of B cells with an enhanced B1/B cell ratio in the kidney, worsening of organ damage, and albuminuria. Importantly, biglycan also triggered CXCL13 expression and B cell infiltration in the healthy kidney. Conversely, biglycan deficiency improved systemic and renal outcome in lupus-prone mice, with lower levels of autoantibodies, less enlargement of the spleen and lymph nodes, and reduction in renal damage and albuminuria. This correlated with a marked decline in circulating and renal CXCL13 and a reduction in the number of B cells in the kidney. Collectively, our results describe what we believe to be a novel mechanism for the regulation of CXCL13 by biglycan, a host-derived ligand for TLR2/4. Blocking biglycan-TLR2/4 interactions might be a promising strategy for the management of SLE and other B cell-mediated inflammatory disease entities.

Dialysis and transplantation in Fabry disease: indications for enzyme replacement therapy.

ESRD is a major cause of morbidity and premature mortality in Fabry disease, particularly in classically affected males. The decline of renal function in Fabry nephropathy is adversely affected by male gender, advanced chronic kidney disease (CKD), and severe proteinuria. The diagnosis of Fabry nephropathy may be missed if not specifically addressed in progressive CKD and patients have been first identified in screening programs of dialysis patients. Fabry patients have worse 3-year survival rates on dialysis as compared with nondiabetic controls. The 5-year survival rate of transplanted Fabry patients is also lower than that of controls. However, because Fabry nephropathy does not recur in the allograft and transplanted Fabry patients appear to have better overall outcomes than those maintained on dialysis, kidney transplantation should be recommended as a first choice in renal replacement therapy (RRT) for Fabry disease. Appropriately designed and powered studies are not available to answer the question whether enzyme replacement therapy (ERT) influences outcomes, the course of cardiomyopathy, events, or survival in Fabry patients on RRT. The authors are not aware of compelling indications for ERT in RRT patients because progression of cardiomyopathy was documented during ERT. Whether the excess mortality risk of Fabry patients on RRT can be prevented by ERT is unknown. Despite observational reports of symptomatic improvement, the available evidence supporting ERT for such patients is not compelling enough. To clarify this issue, studies are needed to test the effectiveness of agalsidases in preventing cardiac and cerebrovascular complications in Fabry patients with ESRD.

Proteoglycans: from structural compounds to signaling molecules.

Our knowledge of proteoglycan biology has significantly expanded over the past decade with the discovery of a host of new members of this multifunctional family leading to their present classification into three major categories: (1) small leucine-rich proteoglycans, 2) modular proteoglycans, and 3) cell-surface proteoglycans. In addition to being structural proteins, proteoglycans play a major role in signal transduction with regulatory functions in various cellular processes. Being mostly extracellular, they are upstream of many signaling cascades and are capable of affecting intracellular phosphorylation events and modulating distinct pathways, including those driven by bone morphogenetic protein/transforming growth factor superfamily members, receptor tyrosine kinases, the insulin-like growth factor-I receptor, and Toll-like receptors. Mechanistic insights into the molecular and cellular functions of proteoglycans have revealed both the sophistication of these regulatory proteins and the challenges that remain in uncovering the entirety of their biological functions. This review aims to summarize the multiple functions of proteoglycans with special emphasis on their intricate composition and the newly described signaling events in which these molecules play a key role.

The matricellular functions of small leucine-rich proteoglycans (SLRPs).

The small leucine-rich proteoglycans (SLRPs) are biologically active components of the extracellular matrix (ECM), consisting of a protein core with leucine rich-repeat (LRR) motifs covalently linked to glycosaminoglycan (GAG) side chains. The diversity in composition resulting from the various combinations of protein cores substituted with one or more GAG chains along with their pericellular localization enables SLRPs to interact with a host of different cell surface receptors, cytokines, growth factors, and other ECM components, leading to modulation of cellular functions. SLRPs are capable of binding to: (i) different types of collagens, thereby regulating fibril assembly, organization, and degradation; (ii) Toll-like receptors (TLRs), complement C1q, and tumor necrosis factor-alpha (TNFalpha), regulating innate immunity and inflammation; (iii) epidermal growth factor receptor (EGF-R), insulin-like growth factor receptor (IGF-IR), and c-Met, influencing cellular proliferation, survival, adhesion, migration, tumor growth and metastasis as well as synthesis of other ECM components; (iv) low-density lipoprotein receptor-related protein (LRP-1) and TGF-beta, modulating cytokine activity and fibrogenesis; and (v) growth factors such as bone morphogenic protein (BMP-4) and Wnt-I-induced secreted protein-1 (WISP-1), controlling cell proliferation and differentiation. Thus, the ability of SLRPs, as ECM components, to directly or indirectly regulate cell-matrix crosstalk, resulting in the modulation of various biological processes, aptly qualifies these compounds as matricellular proteins.

Enzyme replacement therapy for Fabry disease: a systematic review of available evidence.

Fabry disease is a progressive and life-threatening glycolipid storage disorder affecting both males and females. The primary driver of the disease is the accumulation of glycolipids (globotriaosylceramide [GL-3]) in a variety of cell types, including vascular endothelial cells, a range of renal cell types, cardiomyocytes and neurons, which is caused by deficient activity of the lysosomal enzyme, alpha-galactosidase. The disease typically presents during childhood or adolescence. First manifestations reflect involvement of small nerve fibres of the peripheral and autonomic nervous systems. With age, severe complications involving the kidneys, heart and brain cause considerable morbidity and premature death. Outside the US, enzyme replacement therapy (ERT) with agalsidase alfa 0.2 mg/kg every other week (EOW) and agalsidase beta 1.0 mg/kg EOW is available for the treatment of patients with Fabry disease, while agalsidase beta 1.0 mg/kg EOW is the only approved drug in the US. To analyse the evidence for ERT, a systematic review of the literature was performed to identify prospectively designed randomized, controlled trials (RCTs) and open-label studies on the efficacy of agalsidase alfa and agalsidase beta. MEDLINE and EMBASE databases were searched; inclusion criteria for the systematic review were prospectively designed clinical studies evaluating ERT with quantifiable endpoints: double-blind and open-label studies were eligible. Exclusion criteria were review articles, case reports, case studies, letters to the editor and articles based on registry data (Fabry Outcome Survey or Fabry Registry). In addition, any studies with a retrospective design or data based on post hoc analyses were excluded. The evidence was reviewed with respect to the clinical benefits of ERT at the level of the end organ. A total of 9 RCTs and 23 open-label studies were identified for inclusion. The efficacy of ERT in Fabry disease has been measured against a variety of endpoints, the majority of which were subclinical parameters rather than clinical outcomes. Plasma levels of GL-3 together with accumulation in the kidney, heart and skin were the most commonly studied endpoints, followed by renal endpoints of proteinuria and glomerular filtration rate, whereas cardiac and neurological endpoints were not commonly studied. To date, only one RCT with ERT defined hard clinical outcomes in the form of cardiac, renal or cerebrovascular events, or death as its primary endpoint. The currently available data from prospective RCTs and open-label studies in patients with Fabry disease are more robust for ERT at a dose of 1 mg/kg EOW than a dose of 0.2 mg/kg EOW, although the beneficial effects of ERT with either dose or preparation are variable.

Biglycan, a danger signal that activates the NLRP3 inflammasome via toll-like and P2X receptors.

The role of endogenous inducers of inflammation is poorly understood. To produce the proinflammatory master cytokine interleukin (IL)-1beta, macrophages need double stimulation with ligands to both Toll-like receptors (TLRs) for IL-1beta gene transcription and nucleotide-binding oligomerization domain-like receptors for activation of the inflammasome. It is particularly intriguing to define how this complex regulation is mediated in the absence of an infectious trigger. Biglycan, a ubiquitous leucine-rich repeat proteoglycan of the extracellular matrix, interacts with TLR2/4 on macrophages. The objective of this study was to define the role of biglycan in the synthesis and activation of IL-1beta. Here we show that in macrophages, soluble biglycan induces the NLRP3/ASC inflammasome, activating caspase-1 and releasing mature IL-1beta without the need for additional costimulatory factors. This is brought about by the interaction of biglycan with TLR2/4 and purinergic P2X(4)/P2X(7) receptors, which induces receptor cooperativity. Furthermore, reactive oxygen species formation is involved in biglycan-mediated activation of the inflammasome. By signaling through TLR2/4, biglycan stimulates the expression of NLRP3 and pro-IL-1beta mRNA. Both in a model of non-infectious inflammatory renal injury (unilateral ureteral obstruction) and in lipopolysaccharide-induced sepsis, biglycan-deficient mice displayed lower levels of active caspase-1 and mature IL-1beta in the kidney, lung, and circulation. Our results provide evidence for direct activation of the NLRP3 inflammasome by biglycan and describe a fundamental paradigm of how tissue stress or injury is monitored by innate immune receptors detecting the release of the extracellular matrix components and turning such a signal into a robust inflammatory response.

Predictors for contrast media-induced nephropathy and long-term survival: prospectively assessed data from the randomized controlled Dialysis-Versus-Diuresis (DVD) trial.

BACKGROUND: Among the numerous studies concerning contrast media-induced nephropathy (CIN), there was no prospective trial that provided data on the long-term outcomes. OBJECTIVES: To prospectively assess predictors of CIN and long-term outcomes of affected patients. METHODS: Four hundred twelve consecutive patients with serum creatinine levels of 115 micromol/L to 309 micromol/L (1.3 mg/dL to 3.5 mg/dL) undergoing elective coronary angiography were included. Patients were randomly assigned to periprocedural hydration alone, hydration plus one-time hemodialysis or hydration plus N-acetylcysteine. RESULTS: Multivariate logistic regression identified the following as predictors of CIN within 72 h (equivalent to an increase in creatinine 44.2 micromol/L [0.5 mg/dL] or more) : prophylactic postprocedural hemodialysis (OR 2.86, 95% CI 1.07 to 7.69), use of angiotensin-converting enzyme inhibitors (OR 6.16, 95% CI 2.01 to 18.93), baseline glomerular filtration rate (OR 0.94, 95% CI 0.90 to 0.98) and the amount of contrast media given (OR 1.01, 95% CI 1.00 to 1.01). With regard to long-term outcome (mean follow-up 649 days), multivariate Cox regression models found elevated creatinine levels at 30 days (hazard rate ratio [HRR] 5.48, 95% CI 2.85 to 10.53), but not CIN within 72 h (HRR 1.12, 95% CI 0.63 to 2.02), to be associated with increased mortality. In addition, independent predictors for death during follow-up included left ventricular ejection fraction lower than 35% (HRR 4.01, 95% CI 2.22 to 7.26), serum phosphate (HRR 1.64, 95% CI 1.10 to 2.43) and hemoglobin (HRR 0.80, 95% CI 0.67 to 0.96). CONCLUSION: From the present prospective trial, performance of postprocedural hemodialysis, use of angiotensin-converting enzyme inhibitors, reduced baseline glomerular filtration rate and amount of contrast media were independent predictors of CIN within 72 h after catheterization. Assessing renal function after 30 days, rather than within 72 h, seemed to be more predictive for patients' long-term survival.

Decorin-mediated regulation of fibrillin-1 in the kidney involves the insulin-like growth factor-I receptor and Mammalian target of rapamycin.

Decorin, a small leucine-rich proteoglycan, affects the synthesis of the elastic fiber component fibrillin-1 in the kidney via hitherto unknown mechanisms. Here, we show that decorin binds to and induces phosphorylation of insulin-like growth factor-I (IGF-I) receptor in renal fibroblasts. Inhibition of the IGF-I receptor tyrosine kinase and its downstream target phosphoinositide-3 kinase prevented decorin-mediated synthesis of fibrillin-1. Furthermore, decorin induced phosphorylation of phosphoinositide-dependent kinase 1, protein kinase B/Akt, mammalian target of rapamycin (mTOR), and p70 S6 kinase. Accordingly, the enhanced synthesis of fibrillin-1 was blocked by rapamycin, an inhibitor of mTOR. Notably, IGF-I, which signals through the same pathway, also stimulated fibrillin-1 synthesis. Systemic administration of rapamycin to mice subjected to unilateral ureteral obstruction, a model of renal fibrosis and increased fibrillin-1 synthesis, markedly reduced the number of interstitial fibroblasts and fibrillin-1 deposition. In streptozotocin-induced diabetes, IGF-I receptor was up-regulated in the kidneys from decorin-null mice. However, this could not compensate for the decorin deficiency, resulting ultimately in decreased fibrillin-1 content. This study provides evidence for the involvement of decorin and the IGF-I receptor/mTOR/p70 S6 kinase signaling pathway in the translational regulation of fibrillin-1.

Rheumatologic aspects of lysosomal storage diseases.

Lysosomal storage diseases are rare metabolic disorders, some of which can now be treated using enzyme replacement therapies. Because the time point of treatment initiation significantly influences the outcome in Gaucher disease, Fabry disease, and mucopolysaccharidosis type I, early diagnosis is of utmost importance. All three disorders can present with musculoskeletal symptoms in early stages, therefore, the rheumatologist may be the first to be contacted by these patients. Here, we present three characteristic lysosomal storage disease cases to increase awareness in the rheumatological community of the typical symptom constellations associated with these rare but treatable disorders.

[Management of acute renal failure in intensive care patients]. / Management des akuten Nierenversagens beim Intensivpatienten.

Crucial for the management of acute renal failure is the differentiation in a prerenal, renal and postrenal form. Prerenal acute renal failure, i.e., hypovolemia, and postrenal acute renal failure, i.e., urinary obstruction, can be treated specifically, and generally, these forms of acute renal failure resolve quickly. By contrast, for intrinsic acute renal failure with acute tubular necrosis, there is no specific therapy and supportive care is necessary until renal function resumes. Prevention of intrinsic acute renal failure is important, i.e., avoidance of nephrotoxic substances, maintenance of adequate hydration and perfusion, cure of septic foci. However, in intensive care patients the development of acute renal failure often cannot be prevented. With the incidence of acute renal failure, the prognosis of intensive care patients deteriorates significantly. Temporary extracorporeal detoxification is often necessary, until eventually, there is a restitution of renal function. The prognosis of acute renal failure in intensive care patients is poor, if there is preexisting renal disease or the cause of the acute renal failure cannot be eliminated.

The matrix component biglycan is proinflammatory and signals through Toll-like receptors 4 and 2 in macrophages.

Biglycan, a small leucine-rich proteoglycan, is a ubiquitous ECM component; however, its biological role has not been elucidated in detail. Here we show that biglycan acts in macrophages as an endogenous ligand of TLR4 and TLR2, which mediate innate immunity, leading to rapid activation of p38, ERK, and NF-kappaB and thereby stimulating the expression of TNF-alpha and macrophage inflammatory protein-2 (MIP-2). In agreement, the stimulatory effects of biglycan are significantly reduced in TLR4-mutant (TLR4-M), TLR2-/-, and myeloid differentiation factor 88-/- (MyD88-/-) macrophages and completely abolished in TLR2-/-/TLR4-M macrophages. Biglycan-null mice have a considerable survival benefit in LPS- or zymosan-induced sepsis due to lower levels of circulating TNF-alpha and reduced infiltration of mononuclear cells in the lung, which cause less end-organ damage. Importantly, when stimulated by LPS-induced proinflammatory factors, macrophages themselves are able to synthesize biglycan. Thus, biglycan, upon release from the ECM or from macrophages, can boost inflammation by signaling through TLR4 and TLR2, thereby enhancing the synthesis of TNF-alpha and MIP-2. Our results provide evidence for what is, to our knowledge, a novel role of the matrix component biglycan as a signaling molecule and a crucial proinflammatory factor. These findings are potentially relevant for the development of new strategies in the treatment of sepsis.

Diabetic nephropathy, percutaneous coronary interventions, and blockade of the renin-angiotensin system.

Since recent studies demonstrated an impaired outcome after percutaneous coronary interventions (PCI) in patients with chronic renal failure but did not address the aetiology of renal failure, we now analysed the outcome of patients with diabetic nephropathy in 721 consecutive patients undergoing PCI. Diabetic nephropathy was present in 37 patients (5.1%), and diabetes alone in 126 patients (17.5%); 178 patients (24.7%) suffered from renal insufficiency of other causes; the other 380 patients (52.7%) were used as controls. Although angiographic success rates were similar in the subgroups (94-97%), 30-day and long-term mortality after 4 years was significantly higher in patients with diabetic nephropathy (8.1 and 27%, respectively) than in diabetics (1.6 and 8.7%, respectively), patients with renal insufficiency (3.9 and 16.8%, respectively), or controls (2.4 and 5.0%, respectively, each p<0.001, log-rank test). Treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers was associated with a marked decrease in 2-year mortality in patients with diabetic nephropathy (19.4 vs. 33.3%, respectively, p=0.02, log-rank test).

Nitric oxide upregulates induction of PDGF receptor-alpha expression in rat renal mesangial cells and in anti-Thy-1 glomerulonephritis.

PDGF and nitric oxide (NO) have been shown to participate in the progression of several forms of glomerulonephritis. A potential influence of NO on PDGF-mediated signaling cascades was therefore examined. Treatment of rat mesangial cells (MC) with the NO donors diethylenetriamine NO (DETA-NO) or spermine-NONOate resulted in a time- and dose-dependent upregulation of PDGF receptor alpha (PDGFRalpha) but not PDGFRbeta mRNA levels. Administration of DETA-NO also induced PDGFRalpha protein expression that was paralleled also by an enhanced receptor phosphorylation. Further experiments using 3-(5-hydroxymethyl-2-furyl)-1-benzylindazole (YC-1), an activator of the soluble guanylyl cyclase (sGC), the membrane-soluble cyclic GMP (cGMP) analog 8-Bromo-PET-cGMP, and the inhibitors of sGC ODQ and NS2028 suggest that elevated cGMP levels are responsible for the effects of NO. Importantly, NO-dependent autophosphorylation of PDGFRalpha drastically augmented PDGF-AA-evoked phosphorylation of PKB/Akt, a classical downstream target of PDGFRalpha signaling. Furthermore, in a rat model of anti-Thy-1 glomerulonephritis, expression and phosphorylation of PDGFRalpha but not PDGFRbeta expression was markedly reduced in nephritic animals that were treated with the inducible NO synthase inhibitor L-N6(1-iminoethyl)lysine(dihydrochloride) (L-NIL) compared with non-L-NIL-treated nephritic rats as demonstrated by Western blotting and immunohistochemistry. Taken together, the data suggest that NO modulates PDGFRalpha-triggered signaling in a cGMP-dependent manner by induction of PDGFRalpha expression in MC and in a rat model of mesangioproliferative glomerulonephritis. The mechanistic details of this regulation have to be elucidated in further experiments.

Essential contribution of tumor-derived perlecan to epidermal tumor growth and angiogenesis.

As a major heparan sulfate proteoglycan (PG) in basement membranes, perlecan has been linked to tumor invasion, metastasis, and angiogenesis. Here we produced epidermal tumors in immunocompromised rats by injection of mouse RT101 tumor cells. Tumor sections stained with species-specific perlecan antibodies, together with immunoelectron microscopy, showed that perlecan distributed around blood vessels was of both host and tumor cell origin. Tumor-derived perlecan was also distributed throughout the tumor matrix. Blood vessels stained with rat-specific PECAM-1 antibody showed their host origin. RT101 cells also expressed two other basement membrane heparan sulfate PGs, agrin and type XVIII collagen. Antisense targeting of perlecan inhibited tumor cell growth in vitro, while exogenous recombinant perlecan, but not heparin, restored the growth of antisense perlecan-expressing cells, suggesting that perlecan core protein, rather than heparan sulfate chains from perlecan, agrin, or type XVIII collagen, regulates tumor cell growth. However, perlecan core protein requirement was not related to fibroblast growth factor-7 binding because RT101 cells were unresponsive to and lacked receptors for this growth factor. In vivo, antisense perlecan-transfected cells generated no tumors, whereas untransfected and vector-transfected cells formed tumors with obvious neovascularization, suggesting that tumor perlecan rather than host perlecan controls tumor growth and angiogenesis.

Nephrin expression is increased in anti-Thy1.1-induced glomerulonephritis in rats.

Nephrin is an important constituent of the glomerular filtration barrier and alteration of its expression is associated with severe proteinuria. In this study we show that injection of an anti-Thy1.1 antibody in rats not only induces a mesangioproliferative glomerulonephritis associated with increased proteinuria, but also leads to a sustained increase of nephrin mRNA and protein expression in renal glomeruli over a time period of 29 days. In contrast, podocin and CD2AP, two proteins shown to interact with nephrin in the slit diaphragm, are acutely downregulated at days 3-7 and, thereafter, recovered again to normal levels after 29 days. Interestingly, immunofluorescence staining of kidney sections at day 10 of the disease shows a highly heterogeneous pattern, in that some podocytes show complete absence of nephrin, whereas others show highly accumulated staining for nephrin compared to control sections, which in total results in an increased level of nephrin per glomerulus. In summary, our data show that in the course of mesangioproliferative glomerulonephritis in rats, an upregulation of nephrin expression occurs with a concomitant transient downregulation of podocin and CD2AP which may account for a highly dysregulated filtration barrier and increased proteinuria.