Low-molecular-weight heparin prevents high glucose- and phorbol ester-induced TGF-beta 1 gene activation

Biomimetic Hydrogels as the Inductive Endochondral Ossification Template for Promoting Bone Regeneration

Repairing critical size bone defects (CSBD) is a major clinical challenge and requires effective intervention by biomaterial scaffolds. Inspired by the fact that the cartilaginous template-based endochondral ossification (ECO) process is crucial to bone healing and development, developing biomimetic biomaterials to promote ECO is recognized as a promising approach for repairing CSBD. With the unique highly hydrated 3D polymeric network, hydrogels can be designed to closely emulate the physiochemical properties of cartilage matrix to facilitate ECO. In this review, the various preparation methods of hydrogels possessing the specific physiochemical properties required for promoting ECO are introduced. The materiobiological impacts of the physicochemical properties of hydrogels, such as mechanical properties, topographical structures and chemical compositions on ECO, and the associated molecular mechanisms related to the BMP, Wnt, TGF-β, HIF-1α, FGF, and RhoA signaling pathways are further summarized. This review provides a detailed coverage on the materiobiological insights required for the design and preparation of hydrogel-based biomaterials to facilitate bone regeneration.

Sulodexide and glycosaminoglycans in the progression of renal disease

Experimental data in cell cultures and animal models suggest that sulodexide and glycosaminoglycans are potentially effective drugs to treat chronic kidney diseases and prevent progression to renal failure. However, no conclusive evidence support the use of them in human renal disease. In acute and chronic glomerulonephritis, only few studies have been performed. Sulodexide has been more intensely investigated in diabetic nephropathy (DN) where the body of data supports its effectiveness as an antialbuminuric agent in early stages. Unfortunately, there is no study in DN patients on the effect of sulodexide on clinical end points.

The protective role of fucosylated chondroitin sulfate, a distinct glycosaminoglycan, in a murine model of streptozotocin-induced diabetic nephropathy

BACKGROUND

Heparanase-1 activation, albuminuria, and a decrease in glomerular heparan sulfate (HS) have been described in diabetic nephropathy (DN). Glycosaminoglycan (GAG)-based drugs have been shown to have renoprotective effects in this setting, although recent trials have questioned their clinical effectiveness. Here, we describe the effects of fucosylated chondroitin sulfate (FCS), a novel GAG extracted from a marine echinoderm, in experimentally induced DN compared to a widely used GAG, enoxaparin (ENX).

METHODS

Diabetes mellitus (DM) was induced by streptozotocin in male Wistar rats divided into three groups: DM (without treatment), FCS (8 mg/kg), and ENX (4 mg/kg), administered subcutaneously. After 12 weeks, we measured blood glucose, blood pressure, albuminuria, and renal function. The kidneys were evaluated for mesangial expansion and collagen content. Immunohistochemical quantifications of macrophages, TGF-β, nestin and immunofluorescence analysis of heparanase-1 and glomerular basement membrane (GBM) HS content was also performed. Gene expression of proteoglycan core proteins and enzymes involved in GAG assembly/degradation were analyzed by TaqMan real-time PCR.

RESULTS

Treatment with GAGs prevented albuminuria and did not affect the glucose level or other functional aspects. The DM group exhibited increased mesangial matrix deposition and tubulointerstitial expansion, and prevention was observed in both GAG groups. TGF-β expression and macrophage infiltration were prevented by the GAG treatments, and podocyte damage was halted. The diabetic milieu resulted in the down-regulation of agrin, perlecan and collagen XVIII mRNAs, along with the expression of enzymes involved in GAG biosynthesis. Treatment with FCS and ENX positively modulated such changes. Heparanase-1 expression was significantly reduced after GAG treatment without affecting the GBM HS content, which was uniformly reduced in all of the diabetic animals.

CONCLUSIONS

Our results demonstrate that the administration of FCS prevented several pathological features of ND in rats. This finding should stimulate further research on GAG treatment for this complication of diabetes.

Heparin for assisted reproduction

BACKGROUND

Heparin as an adjunct in assisted reproduction (peri-implantation heparin) is given at or after egg collection or at embryo transfer during assisted reproduction. Heparin has been advocated to improve embryo implantation and clinical outcomes.  It has been proposed that heparin enhances the intra-uterine environment by improving decidualisation with an associated activation of growth factors and a cytokine expression profile in the endometrium that is favourable to pregnancy.

OBJECTIVES

To investigate whether the administration of heparin around the time of implantation (peri-implantation heparin) improves clinical outcomes in subfertile women undergoing assisted reproduction.

SEARCH METHODS

A comprehensive and exhaustive search strategy was developed in consultation with the Trials Search Co-ordinator of the Cochrane Menstrual Disorders and Subfertility Group (MDSG). The strategy was used in an attempt to identify all relevant studies regardless of language or publication status (published, unpublished, in press, and in progress). Relevant trials were identified from both electronic databases and other resources (last search 6 May 2013).

SELECTION CRITERIA

All randomised controlled trials (RCTs) were included where peri-implantation heparin was given during assisted reproduction. Peri-implantation low molecular weight heparin (LMWH) during IVF/ICSI was given at or after egg collection or at embryo transfer in the included studies. Live birth rate was the primary outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and quality of trials and extracted relevant data. The quality of the evidence was evaluated using GRADE methods.

MAIN RESULTS

Three RCTs (involving 386 women) were included in the review.Peri-implantation LMWH administration during assisted reproduction was associated with a significant improvement in live birth rate compared with placebo or no LMWH (odds ratio (OR) 1.77, 95% confidence interval (CI) 1.07 to 2.90, three studies, 386 women, I(2) = 51%, very low quality evidence with high heterogeneity). There was also a significant improvement in the clinical pregnancy rate with use of LMWH (OR 1.61, 95% CI 1.03 to 2.53, three studies, 386 women, I(2) = 29%, very low quality evidence with low heterogeneity).However these findings should be interpreted with extreme caution as they were dependent upon the choice of statistical method: they were no longer statistically significant when a random-effects model was used.Adverse events were poorly reported in all included studies, with no comparative data available. However, LMWH did cause adverse effects including bruising, ecchymosis, bleeding, thrombocytopenia and allergic reactions. It appeared that these adverse effects were increased if heparin therapy was used over a longer duration.

AUTHORS' CONCLUSIONS

The results of this Cochrane review of three randomised controlled trials with a total of 386 women suggested that peri-implantation LMWH in assisted reproduction treatment (ART) cycles may improve the live birth rate in women undergoing assisted reproduction. However, these results were dependent on small low quality studies with substantial heterogeneity, and were sensitive to the choice of statistical model. There were side effects reported with use of heparin, including bruising and bleeding, and no reliable data on long-term effects. The results do not justify this use of heparin outside well-conducted research trials.These findings need to be further investigated with well-designed, adequately powered, double-blind, randomised, placebo-controlled, multicentre trials. Further investigations could also focus on the effects of the local (uterine) and not systemic application of heparin during ART.

Alteration of endothelial proteoglycan and heparanase gene expression by high glucose, insulin and heparin

Heparan sulfate proteoglycans (HSPGs) contain a core protein with glycosaminoglycans attached. Reduced glycosaminoglycan, in endothelial HSPGs syndecan and perlecan, is associated with diabetic cardiovascular complications but changes in core protein remain controversial. Since heparanase degrades heparan sulfate, we wished to determine if changes in endothelial heparanase mRNA, by high glucose (HG), correlate with changes in syndecan and perlecan core proteins, and to observe effects of heparin or insulin. RNA was isolated from cultured human aortic endothelial cells treated with HG (30mM), insulin (0.01 units/mL), heparin (0.5μg/mL), HG plus heparin and/or insulin for 24h. Real time PCR revealed that HG alone significantly increased heparanase, decreased syndecan with no effect on perlecan mRNA. Heparin or insulin significantly prevented the increase in heparanase but decreased perlecan mRNA while heparin, but not insulin, prevented the decrease in syndecan mRNA in HG treated cells. HG plus heparin and insulin increased heparanase and syndecan mRNA compared to all other treatments and decreased perlecan mRNA compared to control and HG alone. Heparin may protect endothelium from HG injury by reducing heparanase and increasing syndecan while insulin inhibits heparanase expression. Effects with insulin plus heparin suggest interference in transcriptional regulation of heparanase and syndecan genes.

A low-dose combination of valsartan and low molecular weight heparin better improved glomerular permeability than did high-dose monotherapy in rats with diabetic nephropathy

Diabetic nephropathy is the most common and severe renal complication of diabetes mellitus. The present study sought to investigate the renoprotective effects of a combination therapy of valsartan and low molecular weight heparin (LMWH) in rats with diabetic nephropathy induced by uninephrectomy and streptozotocin. The animals were divided into five groups as follows: sham-operated rats, diabetic control rats, diabetic rats treated with 20 mg/kg/day valsartan, diabetic rats treated with 600 IU/kg/day LMWH, diabetic rats treated with a combination of valsartan and LMWH (valsartan 10 mg/kg/day and LMWH 300 IU/kg/day). The treatment regimen was maintained for 8 weeks. Treatment with valsartan, LMWH, or a combination of the two had no significant effect on blood glucose levels. However, the urine protein excretion levels significantly decreased for the three drug treatment groups; the most dramatic decreases were observed in the combination treatment group. Kidney histology was examined using periodic acid-Schiff staining and immunohistochemical staining of extracellular matrix proteins. Results indicated that histopathology improved markedly in the three drug treatment groups; combination therapy had an equal or better effect than monotherapy in terms of decreasing the abnormal thickness of the glomerular basal membrane, the ratio of the area of the mesangial region with respect to the total area of renal glomeruli, and the accumulation of collagen IV and laminin in kidney tissue. In addition, serum levels of transforming growth factor-β1 (TGF-β1) also markedly decreased in the drug treatment groups according to ELISA. However, there were no significant differences between the combination therapy group and monotherapy group. These results suggest that a combination of valsartan and LMWH at half the dose used in monotherapy is better at improving glomerular permeability in rats with diabetic nephropathy.

Inhibitory effects of glycosaminoglycans on basal and stimulated transforming growth factor-β1 expression in mesangial cells: biochemical and structural considerations

A number of glycosaminoglycan (GAG) species related to heparin, dermatan sulfate (DeS) and chondroitin sulfate were tested for their ability to interfere with the physiological expression and/or pathological overexpression of the TGF-β1 gene. The influence of the molecular weight, molecular weight distribution, degree of sulfation and location of the sulfate groups was examined in an attempt to unveil fine relationships between structure and activity. The nature of the polysaccharide plays a major part, heparins proving able to inhibit both basal and stimulated TGF-β1 gene expression, DeSs being essentially inactive and chondroitin sulfates only inhibiting stimulated TGF-β1 gene expression. Within this frame, the particular physical and chemical properties of some GAGs appear to further modulate TGF-β1 gene response. Judging from our investigation, chondroitin sulfates seem the most promising for potential pharmacological applications in disorders characterized by fibrogenic TGF-β1 overexpression.

Regulating the availability of transforming growth factor ß1 in B104 neuroblastoma cells

Transforming growth factor (TGF) beta1 is a key player in early brain development, hence, its availability (i.e., synthesis and release) affects neuronogenesis. TGFbeta1 moves proliferating cells out of the cell cycle and promotes their subsequent migration. The present study tested the hypothesis that neural progenitors self-regulate TGFbeta1. B104 neuroblastoma cells which can grow in the absence of serum or growth factors were used in systematic studies of transcription, translation, release, and activation. These studies relied on quantitative enzyme-linked immunosorbent assays and real-time polymerase chain reactions. TGFbeta1 positively upregulated its own intracellular expression and promoted increased release of TGFbeta1 from cells. The induction of TGFbeta1 was independent of a change in transcription, but it depended on cycloheximide-inhibited translation. Signaling mediated by downstream Smad2/3 through the TGFbeta receptors and intracellular protein transport were also required for release of TGFbeta1 from B104 cells. Thus, TGFbeta1 production and release were mediated through a feed-forward mechanism and were pivotally regulated at the level of translation. These activities appear to be key for the role of TGFbeta1 in the proliferation and migration of young neurons.

Synthesis of novel celluloses derivatives and investigation of their mitogenic activity in the presence and absence of FGF2

Novel cellulose sulfates (CS) with a controlled degree of sulfation (DS(S)) were synthesized through acetosulfation as well as direct sulfation. CS containing carboxyl (CO) or carboxymethyl (CM) groups were prepared by TEMPO oxidation or by carboxymethylation with chloroacetic acid. The derivatization was characterized by nuclear magnetic resonance and Raman spectroscopy. The derivatives were investigated regarding their cytotoxicity and mitogenic activity by modulation of 3T3 fibroblast proliferation with or without exogenous FGF2. All derivatives were non-toxic for 3T3 cells. CS strongly promoted FGF2-induced proliferation, which was positively related to overall DS(S). In the absence of FGF2, minute quantities of CS with intermediate degrees of sulfation exerted stronger mitogenic effects than heparin. No significant promoting effects of CO and CM on cell proliferation were found, though the structure of CO shows similarities to heparin.

Sulodexide ameliorates early but not late kidney disease in models of radiation nephropathy and diabetic nephropathy

BACKGROUND

Sulodexide is a glycosaminoglycan with anticoagulant and antithrombotic activities. Although sulodexide reduced albuminuria in patients with type 1 and type 2 diabetes, long-term effects on chronic renal injury are not established. We investigated sulodexide effects and mechanisms in a rat radiation nephropathy model and in the db/db mouse model of diabetic kidney disease.

METHODS

Sprague-Dawley rats received kidney radiation and were treated as follows: 15 mg/kg/day sulodexide s.c., 6 day/week (SUL) or no treatment (CONT). Subsets of animals were sacrificed after 8 weeks and 12 weeks. Blood pressure, serum creatinine, creatinine clearance (CrCl) and urinary protein excretion were measured every 4 weeks. Sclerosis and plasminogen activator inhibitor-1 (PAI-1) expression were assessed at 8 and 12 weeks, and collagen I, total collagen content and phospho-smad-2 expressions were determined at 12 weeks. Twelve-week-old db/db mice received sulodexide as above or vehicle. Albuminuria and CrCl were assessed at intervals till sacrifice at week 9 with assessment of urinary transforming growth factor-beta (TGF-beta) and glomerular lesions.

RESULTS

Blood pressure, serum creatinine and CrCl were not different in radiation rat CONT vs SUL at any time. Proteinuria was significantly lower in SUL compared to CONT at 4 and 8 weeks but not at 12 weeks. Sclerosis and PAI-1 expression trended lower in SUL vs CONT at 8 weeks. There was no difference between the groups in sclerosis, collagen I mRNA, total collagen content or PAI-1 expression at 12 weeks. Phospho-smad 2 expression was significantly decreased in SUL compared to CONT at 12 weeks. Db/db mice with or without SUL showed no difference in urinary albumin/creatinine ratio, urine TGF-beta or mesangial matrix expansion.

CONCLUSIONS

Our data show that sulodexide can reduce the early, but not late, proteinuria in radiation nephropathy in rats. In addition, sulodexide did not affect urine TGF-beta established albuminuria or mesangial matrix expansion in a chronic model of diabetic kidney disease in mice. Although sulodexide may affect TGF-beta activation in radiation nephropathy, this effect appeared insufficient in this model to inhibit the expressions of PAI-1 and collagen and reduce accumulation of extracellular matrix. These results may explain in part its lack of efficacy in recent clinical trials of chronic kidney disease.

The preventive effects of heparin-superoxide dismutase on carbon tetrachloride-induced acute liver failure and hepatic fibrosis in mice

In this study, the effects of heparin-superoxide dismutase conjugate (heparin-SOD) on carbon tetrachloride (CCl4)-induced acute liver failure and hepatic fibrosis were evaluated. To investigate the effects of heparin-SOD on acute liver failure, heparin-SOD was administered to CCl4-treated mice by intravenous injection. Biochemical indicators, such as glutamic oxaloacetic transaminase/glutamic pyruvic transaminase (GOT/GPT), GSH (glutathione), lactate dehydrogenase (LDH), and malondialdehyde (MDA) were determined 24 h after CCl4 treatment. The development of CCl4-induced acute liver failure altered the redox state with a decreased hepatic GSH and increased formation of lipid peroxidative products, which were partially normalized by treatment with heparin-SOD or heparin + SOD. Compared with other groups, the acute liver injury of heparin-SOD group was significantly lessened (reduced activities of GOT/GPT, MDA, and increased activities of GSH). To investigate the effects of heparin-SOD on hepatic fibrosis, heparin-SOD and CCl4 were co-administered by intraperitoneal injection twice a week for 12 weeks. Histological and hepatic hydroxyproline examination revealed that heparin-SOD could significantly prevent the progression of hepatic fibrosis. Moreover, real-time PCR was used to determine transforming growth factor-beta1 (TGF-beta1), metalloproteinase-2 (MMP-2), fibronectin, and collagen-I expression. Significantly, greater fibrosis and TGF-beta1, MMP-2, fibronectin, and collagen-I expression were found in the liver of CCl4-induced mice at the end of 12th week. Heparin-SOD could markedly attenuate the mRNA expression of TGF-beta1, MMP-2, and collagen-I. Western blots of tissue homogenates revealed that the protein expression of TGF-beta1 was substantially reduce also by heparin-SOD treatment. These results demonstrate that administration of heparin-SOD may be useful in the treatment and prevention of acute liver failure and hepatic fibrosis.

Effect of Sulodexide on Plasma Transforming Growth Factor-β1 in Healthy Volunteers

It is unknown whether the glycosaminoglycan drug sulodexide interferes with transforming growth factorβ1—a member of heparin-binding family and a potent regulator of human biology and diseases. Hence, a 2-week pilot study was performed in 11 healthy men. Sulodexide was initially administered intravenously in a single dose, then—orally for 12 days and—again intravenously on study completion. Initial injection had no effect on activated form of the growth factor measured in plasma after 10 and 120 min; no change was also observed after 120 min from drug ingestion on day 7. On final intravenous administration, the growth factor levels increased by almost 60% after 10 min and remained elevated; the 120-min levels directly correlated with sulodexide dosage. Baseline cytokine levels decreased during the 2-week trial by more than 50%. In conclusion, transforming growth factor-β1 release and likely downregulation of its expression may constitute novel pharmacological effects of sulodexide.

Pleiotropic Effects of Heparin and Heparinoids in Peritoneal Dialysis

Unfractionated heparin, low-molecular-weight heparins, and sulodexide belong to the family of glycosaminoglycans. Recent studies report on properties other than anticoagulant activities of these medications. They include modulation of cell growth and proliferation via actions on numerous growth factors affecting the immune system and matrix molecules production and degradation. Long-term peritoneal dialysis remarkably influences peritoneal cavity homeostasis by mechanisms mediated by growth factors. They initiate progression of pathological processes and further account for morphological and functional alterations of the peritoneal membrane. The best-recognized pathologies in peritoneal cavity under these conditions encompass inflammation, fibrosis, and vasculopathy, often leading to fatal encapsulating peritoneal sclerosis. Intraperitoneal heparin and its derivatives, by their pleiotropic actions, may influence these crucial processes and improve the peritoneal dialysis technique survival in a complex and so far understudied way. These issues, novel medical approaches, and their likely mechanisms have been reviewed.

Influence of hypersulfated and low molecular weight heparins on ischemia/reperfusion: injury and allograft rejection in rat kidneys

The aim of the study was to evaluate the effect of the hypersulfated nonanticoagulant heparin derivative LU 51198 (LU) and of the low molecular weight heparin reviparin (REVI) on ischemia/reperfusion (I/R) injury, acute rejection (AR) and chronic allograft nephropathy (CAN) in rats. Organs were harvested 5 days after 60 min of renal I/R injury. For investigation of AR and CAN we used the allogeneic Fisher-Lewis model. Kidneys were harvested at one respectively 32 weeks after transplantation. Rats were treated with either vehicle, LU or REVI. After I/R injury, treatment with REVI or LU reduced infiltration with MHC II and R73-positive cells, whereas only REVI reduced ED1-positive cells and expression of monocyte chemoattractant protein-1. There was no effect of REVI and LU on acute allograft rejection. Treatment with LU or REVI reduced glomerular infiltration with ED1 and MHCII-positive cells and renal expression of transforming growth factor-beta 32 weeks after transplantation. Only REVI treatment reduced albuminuria, interstitial infiltration and histological signs of CAN. LU, and in a more potent manner REVI, reduce signs of CAN and renal inflammation after I/R injury. Chemically modified heparins without anticoagulatory effects may offer a new treatment option in preventing I/R injury and CAN in human kidney transplantation.

Low molecular weight heparin prevents hepatic fibrogenesis caused by carbon tetrachloride in the rat

BACKGROUND/AIMS

In this study, we investigated the effect of dalteparin sodium, a low molecular weight (LMW)-heparin, on hepatic fibrogenesis caused by chronic carbon tetrachloride (CCl4) administration in the rat.

METHODS

Female Wistar rats were given a single, or repeated intraperitoneal injections of CCl4 (1ml/kg, twice per week) and dalteparin (50IU/kg, daily) for 7 weeks.

RESULTS

Dalteparin did not prevent acute CCl4-induced hepatic necrosis and elevation in serum aminotransferases levels; however, proliferating cell nuclear antigen (PCNA)-positive hepatocytes were dramatically increased 24h after simultaneous administration of CCl4 and dalteparin. Interestingly, serum hepatocyte growth factor (HGF) levels 12h after injection of CCl4 were almost doubled when dalteparin was given simultaneously. Hepatic fibrosis following 7-week CCl4 treatment was markedly ameliorated by daily co-administration of dalteparin. Indeed, dalteparin largely inhibited CCl4-induction of smooth muscle alpha-actin expression, alpha1(I)procollagen and transforming growth factor (TGF)-beta1 mRNA levels in the liver. Further, dalteparin blunted platelet-derived growth factor (PDGF)-induced increases in 5-bromo-2'deoxyuridine (BrdU) uptake in 3-day cultured hepatic stellate cells (HSCs) in a dose-dependent manner.

CONCLUSIONS

Dalteparin enhances hepatic regeneration and minimizes hepatic fibrogenesis caused by chronic CCl4 treatment. The mechanism underlying these effects most likely involves both up-regulation of HGF and inhibition of HSC proliferation.

Enoxaparin reduces H2O2-induced activation of human endothelial cells by a mechanism involving cell adhesion molecules and nuclear transcription factors

There are data that document the anti-inflammatory effect of enoxaparin (EP) and its possible antioxidant potential. This study was designed to search for the antioxidant mechanism(s) of EP directly on endothelial cells exposed to an oxidant stimulus. For this purpose cultured human endothelial cells were exposed to nontoxic concentrations of hydrogen peroxide in the presence or absence of EP, and the adhesion of monocytes, the expression of cell adhesion molecules and transcription factors possibly involved in the process were tested. Adhesion assays, ELISA and Western blot analysis revealed that EP reduced monocyte adhesion, ICAM-1 and P-selectin expression, decreased the nuclear levels of c-Jun and p65 proteins, and diminished the phosphorylation of c-Jun protein, MAPK p38 and JNK. Together, the data demonstrate the antioxidant effect of EP and the involvement of ICAM-1, P-selectin, MAPK p38, JNK and the transcription factors NF-kappaB and AP-1 in the mechanism of action of this drug.

Leptin induces TGF-β synthesis through functional leptin receptor expressed by human peritoneal mesothelial cell

Marked increase in leptin concentration in spent peritoneal dialysate has been reported following continuous ambulatory peritoneal dialysis treatment. The present study was designed to determine whether functional leptin receptor is expressed by human peritoneal mesothelial cells and if so, the possible implication in dialysis. Expression of leptin receptors in cultured mesothelial cells and omental tissue was examined. The effect of leptin on the production of transforming growth factor-beta (TGF-beta) by mesothelial cells in the presence or absence of high glucose was determined using in vitro culture model of human peritoneal mesothelial cells and adipocytes. The signaling mechanism involved in leptin-induced TGF-beta synthesis by mesothelial cells was studied. Both mRNA and protein of the full-length leptin receptor are constitutively expressed in mesothelial cells. The leptin receptor expression in mesothelial cells was upregulated by glucose but not leptin. In adipocytes, glucose increased the mRNA expression and synthesis of leptin. The Janus kinase-signal transducers and activation (JAK-STAT) signal transduction pathway in mesothelial cells was activated by either exogenous or adipocytes-derived leptin. Exogenous leptin induced the release of TGF-beta by mesothelial cells. The TGF-beta synthesis induced by leptin was amplified by glucose through increased leptin receptor expression. Our novel findings reveal that functional leptin receptor is present on human peritoneal mesothelial cells. The leptin-induced TGF-beta synthesis in mesothelial cells is associated with the expression of leptin receptor and the activation of the JAK-STAT signal transduction pathway.

The Role of Glycosaminoglycans and Sulodexide in the Treatment of Diabetic Nephropathy

Diabetic nephropathy occurs in 20-40% of diabetic patients, making it one of the most important causes of end-stage renal disease (ESRD). It has a large impact in terms of associated morbidity and mortality for the individual patient and in terms of costs for healthcare. Several studies have demonstrated that micro- and macroalbuminuria predict cardiovascular morbidity and mortality in patients with diabetes mellitus.Current nephroprotective therapies for diabetic nephropathy include the pursuit of normoglycemia and normotension, and a consensus is emerging that there is a necessity to also achieve as low a level of albuminuria as possible. However, the search for innovative and ancillary approaches to the prevention and treatment of this diabetic complication is warranted since strict metabolic control can be difficult, and sometimes dangerous, to achieve and even diabetic patients responding to ACE inhibitors (ACEIs) or angiotensin II receptor antagonists (angiotensin receptor blockers; ARBs) and metabolic control show progressive renal damage and eventually ESRD. A number of drugs are currently being investigated; glycosaminoglycans are particularly interesting since, in theory, they target the generalized endothelial dysfunction and metabolic defect in matrix and basement membrane synthesis which, according to the Steno hypothesis, are responsible for diabetic nephropathy and macroangiopathy.Treatment with glycosaminoglycans, and with sulodexide in particular, significantly improves albuminuria in type 1 and type 2 diabetic patients with micro- or macroalbuminuria. The albuminuria-lowering effect of sulodexide enhances the effect of ACEI/ARB therapy. Most studies have shown that the effect of sulodexide on albuminuria is sustained, strongly suggesting that favorable chemical and anatomic remodeling is induced by exogenous glycosaminoglycans in renal tisues, as observed in the experimental model.

Activation of valvular interstitial cells is mediated by transforming growth factor-beta1 interactions with matrix molecules

Strategies for the tissue-engineering of living cardiac valve replacements are limited by a lack of appropriate scaffold materials that both permit cell viability and actively contribute to the growth of functional tissues. Components of the extracellular matrix can localize and modify growth factor signals, and by doing so impart instructional stimuli for direction of cell phenotype. Fibronectin, collagen I, and heparin were explored as affinity matrices for sequestering and presenting soluble signaling molecules to control differentiation of valvular interstitial cells (VICs) to myofibroblasts. VIC differentiation is commonly characterized by expression of stress fibers containing alpha smooth muscle actin (alpha-SMA), and transforming growth factor-beta1 (TGF-beta1) is a central mediator of this transition. Both fibronectin and heparin, which are known to possess TGF-beta1 binding interactions, were found to increase VIC alpha-SMA expression (120% and 258% of expression in controls), while VICs cultured on collagen I-modified substrates had diminished alpha-SMA expression (66% of control). Heparin treatment significantly stimulated VIC production of TGF-beta1 at all concentrations tested (50 to 400 mug/ml). Heparin-modified substrates were found to alter cell morphology through increased adsorption of serum proteins, specifically TGF-beta1. In sum, heparin produced alpha-SMA-positive myofibroblasts through both the de novo production of TGF-beta1, and its localization in the pericellular environment. The addition of heparin to fibronectin-modified substrates led to a synergistic increase in VIC alpha-SMA expression, produced by the reciprocal binding of fibronectin, heparin, cell-produced TGF-beta1. The characterization of molecules, both soluble and insoluble, that control VIC activation will be important for the development of tailored 3D culture environments for tissue-engineering applications.

Effects of bemiparin on airway responses to antigen in sensitized Brown-Norway rats

Heparins have demonstrated activity in asthma. The effects of bemiparin, a low molecular weight heparin, were examined on antigen-induced responses in sensitized Brown-Norway rats. Inhaled bemiparin (1 mg/ml) reduced the acute bronchospasm produced by aerosol antigen, prevented airway hyperresponsiveness to 5-hydroxytryptamine postantigen exposure, and reduced the eosinophil count (from 0.205+/-0.062 to 0.054+/-0.016 x 10(6) cells/ml in antigen and antigen+bemiparin groups, respectively; P<0.05), eosinophil peroxidase activity, and proteins in the bronchoalveolar lavage fluid (BALF), as well as the transiently augmented mucin Muc5ac expression. Hyperresponsiveness to adenosine was not affected by bemiparin. In similar experiments, inhaled fondaparinux (1 mg/ml) did not affect the antigen-induced responses, while a low-anticoagulant low molecular weight heparin was effective. In conclusion, bemiparin showed beneficial effects in experimental asthma, probably unrelated to its anticoagulant activity, which extends the previous positive findings obtained with other heparins.

Role of mast cells in the development of renal fibrosis: use of mast cell-deficient rats

BACKGROUND

Recent clinical studies have shown that the number of interstitial mast cells increases in various types of renal disease and correlates well with the magnitude of interstitial fibrosis. The present study was conducted to assess the role of mast cells in renal fibrosis by examining an experimental glomerular disease.

METHODS

A rat model of chronic glomerular disease, puromycin aminonucleoside-nephrosis, was induced in mast cell-deficient (Ws/Ws) and normal (+/+) rats.

RESULTS

The area of interstitial fibrosis was widely distributed at 6 weeks in both groups of rats; however, unexpectedly, the area of interstitial fibrosis was greater in Ws/Ws rats than in +/+ littermates. Biochemical analysis of the hydroxyproline content confirmed the more severe fibrosis in the Ws/Ws rats. The number of mast cells increased in both Ws/Ws and +/+ rats, concomitant with the development of interstitial fibrosis, but was confirmed to be lower in Ws/Ws than in +/+ rats. There were no differences in the numbers of interstitial macrophages and T lymphocytes between the two groups. Reverse transcription-polymerase chain reaction analysis of cytokine expression revealed that the level of mRNA for transforming growth factor-beta (TGF-beta), a potent profibrotic cytokine, was higher in Ws/Ws rats. In addition, heparin, one of the major components of mast cells, inhibited the expression of TGF-beta mRNA in rat fibroblasts in culture.

CONCLUSION

These results suggest that mast cells do not play a major role in the pathogenesis of interstitial fibrosis in puromycin aminonucleoside nephrosis. Rather, they might be protective or ameliorative in this model through the inhibition of TGF-beta production by heparin, and possibly in other models and also in humans.

Heparan sulfate proteoglycans in glomerular inflammation

Heparan sulfate proteoglycans (HSPGs) are glycoproteins consisting of a core protein to which linear heparan sulfate side chains are covalently attached. These heparan sulfate side chains can be modified at different positions by several enzymes, which include N-deacetylases, N- and O-sulfotransferases, and an epimerase. These heparan sulfate modifications give rise to an enormous structural diversity, which corresponds to the variety of biologic functions mediated by heparan sulfate, including its role in inflammation. The HSPGs in the glomerular basement membrane (GBM), perlecan, agrin, and collagen XVIII, play an important role in the charge-selective permeability of the glomerular filter. In addition to these HSPGs, various cell types express HSPGs at their cell surface, which include syndecans, glypicans, CD44, and betaglycan. During inflammation, HSPGs, especially heparan sulfate, in the extracellular matrix (ECM) and at the surface of endothelial cells bind chemokines, which establishes a local concentration gradient recruiting leukocytes. Endothelial and leukocyte cell surface HSPGs also play a role in their direct adhesive interactions via other cell surface adhesion molecules, such as selectins and beta2 integrin. Activated leukocytes and endothelial cells exert heparanase activity, resulting in degradation of heparan sulfate moieties in the ECM, which facilitates leukocyte passage into tissues and the release of heparan sulfate-bound factors. In various renal inflammatory diseases the expression of agrin and GBM-associated heparan sulfate is decreased, while the expression of CD44 is increased. Heparan sulfate or heparin preparations affect inflammatory cell behavior and have promising therapeutic, anti-inflammatory properties by preventing leukocyte adhesion/influx and tissue damage.

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Attenuation of glial scar formation in the injured rat brain by heparin oligosaccharides

Injury to the central nervous system causes glial reactions, which eventually lead to the formation of a glial scar and inhibit axonal regeneration. The present study aimed to reduce the extent of glial scar formation in injured cerebral cortex using heparin hexasaccharide (6-mer) and octasaccharide (8-mer). A single injection of 20 microl of heparin 6-mer or heparin 8-mer (10mg/ml), native heparin (10mg/ml), or saline vehicle was given into the wound cavity just after cryo-injury in the cerebral cortex. In saline-injected control rats, strong chondroitin sulfate-A (CS-A) immunoreactivity using 2H6 antibody was observed around the injured site. Double labeling using an antibody against glial fibrillary acidic protein, a glial marker, further demonstrated that CS-A immunoreactivity was mainly expressed on the reactive astrocytes at the glial scar, indicating that CS-A immunohistochemistry is useful for evaluating glial scar formation. Quantitative morphometrical analysis revealed that the area of CS-A immunoreactivity was significantly decreased by 53% in heparin-6-mer-injected animals and 44% in heparin-8-mer-injected ones 6 days after the injury, but native heparin had no effect on CS-A-immunoreactive areas. Both heparin oligosaccharides also attenuated the intensity of CS-A immunoreactivity in the reactive astrocytes and caused astrocytic cellular processes to be less branched. These results demonstrate that a single injection of heparin oligosaccharides attenuates glial scar formation, indicating that heparin oligosaccharides may be applicable to many fibrotic diseases and restore functional integrity.

From minimal background diabetic retinopathy to profuse sight threatening vitreoretinal haemorrhage: management issues in a case of pregestational diabetes and pregnancy

Deterioration of retinopathy is a recognized complication of pregnancy in Type 1 diabetes. We discuss management issues relating to a case of rapid sight-threatening progression of retinopathy in pregnancy complicated by pregestational diabetes.