Heparan Sulfate(HS)/Heparan Sulfate Proteoglycan(HSPG) and Bikunin are Up-regulated During Calcium Oxalate Nephrolithiasis in Rat Kidney.

Abstract

Summary: We reported that expression of both HSPG and of bikunin are increased in calcium oxalate (CaOx) nephrolithic rat kidneys (lida et al., J. Am. Soc. Nephrol. 1999, Urol. Res.1997). However, these findings were obtained from separate experiments. The present study evaluates whether levels of HSPG and bikunin expression differ in the rat kidney during calcium oxalate nephrolithiasis. Twenty-four male Wistar rats weighing 200-250 g were assigned to one of four groups (n=6 each group) and administered with 0.5% ethylene glycol daily and 0.5 pg of 1 a-OH-D3 every other day to induce CaOx nephrolithiasis. Animals were sacrificed 1 or 2 weeks later and both kidneys were excised. The cortex was separated from the medulla and papillary tips in the right kidney, then stored in liquid nitrogen for quantitative competitive-reverse transcription-polymerase chain reaction (QC-RT-PCR). The left kidney was fixed in 10% buffered formalin for histochemical studies. We assessed the variable gene expression of both HSPG and bikunin by QC-RT-PCR. Immunohistochemical analyses of left kidney tissue samples determined the localization of HSPG and bikunin. Normal rats serving as controls (n=6 each) were also sacrificed and processed in the same manner as the experimental groups. QC-RT-PCR confirmed that HSPG and bikunin mRNA expression is significantly increased in nephrolithic kidneys (p<0.05; MannWhitney test), and that medulla and papillary tips tended to express more mRNA of both. Immunohistochemical studies revealed that the production of HS and bikunin was increased in both the distal and proximal tubules of nephrolithic kidneys. These findings suggest that the increased expression of both HSPG and bikunin play an important role during calcium oxalate stone formation. In addition, this phenomenon might be associated with the progression of urothelial damage.

Characterization of glycosaminoglycans in tubular epithelial cells: Calcium oxalate and oxalate ions effects

“…Up-regulation of heparan sulfate proteoglycan in rat kidney [22] and increased expression of heparan sulfate core protein mRNA in both proximal and distal tubules [43] has been reported in nephrolithiasis. Although this is the first paper to describe that calcium oxalate crystals and oxalate ions have different effects upon the glycosamnoglycan synthesis in different cell lines and that keep resemblance to proximal (LLC-PK1) and distal (MDCK) tubular epithelial cells.…”

“…On the other hand, increased expression of syndecan-1, a cell surface heparan sulfate proteoglycan, has been demonstrated in rat kidney during calcium oxalate nephrolithiasis [22]. The increased expression of syndecan-1 and heparan sulfate in a cell line derived from MDCK cells led to a decrease in calcium oxalate attachment to these cells [23], suggesting a preventive role for this proteoglycan in calcium oxalate nephrolithiasis.…”

Development of a method for urine bikunin/urinary trypsin inhibitor (UTI) quantitation and structural characterization: Application to type 1 and type 2 diabetes

“…In relation to this, it is known that several organs beside the liver, including the kidney, synthetize bikunin . Moreover, both “in vivo” and “in vitro” studies demonstrated that bikunin expression is up‐regulated during inflammatory conditions in rat kidney and in porcine renal tubular epithelial cells .…”

A Retrospective Analysis of the Cartilage and Intervertebral Disc Kunitz Protease Inhibitory Proteins Identifies These as Members of The Inter-α-Trypsin Inhibitor Superfamily with potential roles in the protection of the articulatory surface

“…ITI HC proteins accumulate in tumours and are implicated in their pathogenesis (88,89). Renal epithelial cells produce bikunin when stimulated by nephrotoxic agents such as oxalate (90), HA also inhibits calcium oxalate crystallization in-vitro (91). Urinary trypsin inhibitor (UTI) has a regulatory effect on local vascular tone by regulation of Ca2+ influx suppressing smooth muscle contraction (92) and also prevents lipopolysaccharide-induced increases in cytosolic free Ca2+ in human neutrophils and human umbilical vein endothelial cells (93).…”