Sodium pentosan polysulphate--a novel inhibitor of urinary risk factors and enzymes in experimental urolithiatic rats

Pentosan Polysulfate Affords Pleotropic Protection to Multiple Cells and Tissues

Pentosan polysulfate (PPS), a small semi-synthetic highly sulfated heparan sulfate (HS)-like molecule, shares many of the interactive properties of HS. The aim of this review was to outline the potential of PPS as an interventional therapeutic protective agent in physiological processes affecting pathological tissues. PPS is a multifunctional molecule with diverse therapeutic actions against many disease processes. PPS has been used for decades in the treatment of interstitial cystitis and painful bowel disease, it has tissue-protective properties as a protease inhibitor in cartilage, tendon and IVD, and it has been used as a cell-directive component in bioscaffolds in tissue engineering applications. PPS regulates complement activation, coagulation, fibrinolysis and thrombocytopenia, and it promotes the synthesis of hyaluronan. Nerve growth factor production in osteocytes is inhibited by PPS, reducing bone pain in osteoarthritis and rheumatoid arthritis (OA/RA). PPS also removes fatty compounds from lipid-engorged subchondral blood vessels in OA/RA cartilage, reducing joint pain. PPS regulates cytokine and inflammatory mediator production and is also an anti-tumor agent that promotes the proliferation and differentiation of mesenchymal stem cells and the development of progenitor cell lineages that have proven to be useful in strategies designed to effect repair of the degenerate intervertebral disc (IVD) and OA cartilage. PPS stimulates proteoglycan synthesis by chondrocytes in the presence or absence of interleukin (IL)-1, and stimulates hyaluronan production by synoviocytes. PPS is thus a multifunctional tissue-protective molecule of potential therapeutic application for a diverse range of disease processes.

A rabbit model to tissue engineer the bladder

A rabbit model was used for the evaluation of a collagen-based biomatrix of small intestinal submucosa (SIS, COOK) in comparison to a biochemically reconstructed biomatrix for bladder tissue regeneration. Rabbits underwent partial cystectomy and cystoplasty with SIS patch graft or with a biochemically defined collagen biomatrix. The grafts of the regenerated bladder wall were harvested at different intervals and tissue regeneration was evaluated. The results of the SIS and biochemically defined biomatrix grafts were comparable. At harvesting, we found five bladder stones and encrustation of the biomatrix in 21/56 animals. No stone formation was observed in the control group. The results of the molecularly defined biomatrix are thus far comparable to SIS. Both matrices show good epithelialization and ingrowth of smooth muscle cells. Both biomatrices show considerable encrustation, which appears to disappear in time. The rabbit model is suitable for bladder tissue engineering studies as it is an easy model to use. In this model, besides tissue regeneration, also some of the clinical problems are seen such as encrustation of foreign body material in the bladder. These aspects are subject for further pre-clinical studies in this animal model.

Is there a role for pentosan polysulfate in the prevention of calcium oxalate stones?

The clinical role for pentosan polysulfate (PPS) in the prevention of calcium oxalate urolithiasis is not known. Crystallization and aggregation are important steps in calcium oxalate stone formation, and PPS has been shown to inhibit these steps, both in vitro and in vivo. In addition, PPS has a role in repairing injured urothelium and inhibiting adhesion to epithelial defects. A randomized double-blind placebo-controlled study appears warranted to assess the utility of PPS in the prevention of recurrent calcium oxalate stones.

Evaluation of the effect of triterpenes on urinary risk factors of stone formation in pyridoxine deficient hyperoxaluric rats

Investigations were carried out to evaluate the efficacy of the pentacyclic triterpene, lupeol and its ester, lupeol linoleate, against calcium oxalate urolithiasis in rats. Administration of a pyridoxine deficient diet containing 3% glycollic acid for 21 days led to increased excretion of stone forming constituents such as calcium, oxalate and uric acid. Crystal deposition and subsequent renal tubular damage resulted in increased excretion of the tubular enzymes alkaline phosphatase, lactate dehydrogenase, gamma glutamyl transferase, beta glucuronidase and N-acetyl glucosaminidase along with reduced fibrinolytic enzymes. A reduction in the urinary inhibitory factors magnesium and glycosaminoglycans was also observed. Treatment with lupeol and lupeol linoleate reduced the extent of tubular damage as evidenced from reduced enzymuria and minimized the excretion of stone forming constituents.

Mitigation of free radical toxicity in hyperoxaluric condition by a novel derivative eicosapentaenoate-lipoate

Lipoic acid (LA) and eicosapentaenoic acid (EPA) have been shown to ameliorate the changes associated with hyperoxaluria. This prompted us to study the effect of EPA-LA, a new derivative, in experimental urolithiatic condition. Foreign body implantation method followed by supplementation of ammonium oxalate was adopted to induce stone formation in the bladder. Significant depletion in the antioxidant status was observed in the kidney and bladder of stone-forming animals, associated with increased lipid peroxidation. The present observations provide supporting evidence to the hypothesis that free radicals might be involved in causing toxicity in hyperoxaluric condition. The three drugs, namely LA, EPA and EPA-LA had reversed the above changes, but the effect was more pronounced in EPA-LA-treated stone formers. These features highlight the beneficial effect of EPA-LA wherein the potency of two drugs has been combined. The practical outcome of these findings is that the cellular antioxidant defence can be increased by the supplementation of lipoate and its derivative EPA-LA.

Attenuation of oxalate-induced nephrotoxicity by eicosapentaenoate-lipoate (EPA-LA) derivative in experimental rat model

Hyperoxaluria is one of the major risk factors for the formation of urinary calcium oxalate stones. Calcium oxalate crystals and their deposition have been implicated in inducing renal tubular damage. Lipoic acid (LA) and eicosapentaenoic acid (EPA) have been shown to ameliorate the changes associated with hyperoxaluria. This prompted us to investigate the nephroprotectant role of EPA-LA, a new derivative, in vivo in hyperoxaluric rats. Elevation in the levels of calcium, oxalate and phosphorus, the stone-forming constituents, were observed in calculogenic rats as a manifestation of crystal deposition. Tubular damage to the renal tissue was assessed byassaying the excretion of marker enzymes in the urine. Damage to the tubules was indicated by increased excretion of alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma-glutamyl transferase (gamma-GT), beta-Glucuronidase (beta-GLU) and N-Acetyl beta-D glucosaminidase (NAG). Fibrinolytic activity was found to be reduced. Administration of EPA, LA and EPA-LA reduced the tubular damage and decreased the markers of crystal deposition markedly, which was substantiated by the reduction in weight of bladder stone formed. Our results highlight that EPA-LA is the most effective drug in inhibiting stone formation and mitigating renal damage caused by oxalate toxicity, thus confirming it as a nephroprotectant. Further work in this direction is warranted to establish the therapeutic effectiveness of this new derivative.