Potential role for S100A4 in the disruption of the blood-brain barrier in collagen-induced arthritic mice, an animal model of rheumatoid arthritis.

Rheumatoid arthritis (RA) is an autoimmune disease associated with chronic inflammation of the joints. RA has been shown to increase the morbidity of and mortality due to cardiovascular and cerebrovascular diseases. We recently reported that cerebrovascular permeability was increased in mice with collagen-induced arthritis (CIA), an animal model of RA. S100A4, a member of the S100 family, is up-regulated in synovial fluid and plasma from RA patients. This study was aimed at evaluating a role of S100A4 in the mediation of blood-brain barrier (BBB) dysfunction in CIA mice. CIA was induced by immunization with type II collagen in mice. Cerebrovascular permeability was assessed by measurement of sodium fluorescein (Na-F) levels in the brains of control and CIA mice. Serum S100A4 concentrations in control and CIA mice were measured by enzyme-linked immunosorbent assays (ELISA). Accumulation of Na-F in the brain and serum levels of S100A4 were increased in CIA mice. Increased S100A4 levels in the serum are closely correlated with hyperpermeability of the cerebrovascular endothelium to Na-F. We investigated whether S100A4 induces BBB dysfunction using mouse brain capillary endothelial cells (MBECs). S100A4 decreased the transendothelial electrical resistance and increased Na-F permeability in the MBECs. S100A4 reduced the expression of occludin, a tight junction protein, and stimulated p53 expression in MBECs. These findings suggest that S100A4 increases paracellular permeability of MBECs by decreasing expression levels of occludin, at least in part, via p53. The present study highlights a potential role for S100A4 in BBB dysfunction underlying cerebrovascular diseases in patients with RA.

High water intake ameliorates tubulointerstitial injury in rats with subtotal nephrectomy: possible role of TGF-beta.

BACKGROUND: It has been shown that tubulointerstitial injury correlates well with a decline of renal function. In this study, we investigated the effect of high water intake (HWI) on functional and structural parameters in rats with subtotal nephrectomy. METHODS: Two weeks after the ablative procedure, rats were divided into two groups. One group received the treatment with HWI (3% sucrose added to drinking water) for eight weeks. Functional parameters were compared with sham-operated control (CONT) or nephrectomized rats without treatment (NX). Remnant kidneys were then assessed histologically for evidence of interstitial fibrosis and glomerulosclerosis. RESULTS: Creatinine clearance was significantly improved in HWI rats compared with NX rats. Simultaneously, urinary protein was also significantly reduced in HWI rats. HWI predominantly ameliorated interstitial lesions and, to a lesser extent, glomerular lesions. Northern blot analysis demonstrated that transforming growth factor-beta (TGF-beta) mRNA expression was significantly suppressed in HWI rats. In situ hybridization revealed that HWI suppressed TGF-beta mRNA expression mainly in the outer medulla. Fibronectin mRNA was also reduced by the HWI treatment. The changes in TGF-beta and fibronectin mRNA were in parallel with Na+/myo-inositol cotransporter (SMIT) mRNA, which is regulated by extracellular osmolarity. Immunohistochemistry demonstrated that protein expression of TGF-beta and fibronectin coincided with the mRNA expression. CONCLUSION: These results suggest that HWI reduces TGF-beta mRNA expression in medullary interstitium and ameliorates tubulointerstitial injury in rats with reduced renal mass.

N-acetylcysteine improves cytotoxic activity of cirrhotic rat liver-associated mononuclear cells.

Liver cirrhosis, which is associated with decreased plasma and hepatic glutathione (GSH), has been reported to cause the suppression of NK activity in peripheral blood mononuclear cells. Since low GSH levels in lymphocytes are known to alter lymphocyte function, we examined the correlation between intracellular GSH levels and the cytotoxic activity of liver-associated mononuclear cells (liver MNC). We show here that rat liver contains a highly active population of NK cells (CD3- NKR-P1 + cells) that kill Yac-1 in vitro and that the cytotoxic activity of this NK population is directly proportional to liver MNC GSH. This proportionality is independent of the methods used to alter GSH level. Thus, in vitro treatment of liver MNC with buthionine sulfoximine to lower GSH levels lowers the cytotoxic activity. MNC from cirrhotic liver, in which implanted tumor cells grow faster, have both low GSH levels and low cytotoxicity, and supplementation of cirrhotic liver MNC with N-acetylcysteine raises GSH levels and increases cytotoxicity. These findings suggest a physiologic mechanism, i.e. decreased GSH, may be causally associated with the increased incidence of hepatoma in cirrhotic individuals and the increased growth of hepatoma cells in cirrhotic animals. Thus, we suggest that the GSH is important to the optimal functioning of the hepatic immunity that protects against hepatoma development.

Inhibition of myo-inositol transport causes acute renal failure with selective medullary injury in the rat.

Myo-inositol is a major compatible osmolyte in the renal medulla that is accumulated under hypertonic conditions via the Na+/myo-inositol cotransporter (SMIT). We have recently reported that SMIT is predominantly present in the thick ascending limb of Henle (TAL) and is strongly induced by acute NaCl loading, suggesting an important role of myo-inositol in this nephron segment. In the present study, we sought to examine in vivo effects of inhibition of myo-inositol transport using a transport inhibitor, 2-O, C-methylene-myo-inositol (MMI). Intraperitoneal injection of MMI caused acute renal failure in the rats. Serum creatinine and urea nitrogen were significantly increased 12 hours after MMI injection. Morphologic study revealed that the tubular cells were extensively injured in the outer medulla. A considerable number of the tubular cells were injured in the cortex as well. Immunohistochemical study for Tamm-Horsfall protein (THP), which was used for identification of the TAL cells, showed that THP-positive cells were predominantly injured. The tubular injury apparently appeared to worsen when high concentration of NaCl was injected with MMI. Administration of myo-inositol prevented acute renal failure and improved the tubular injury after MMI injection. Furthermore, supplementation of betaine, another osmolyte in the TAL cells, partially prevented the toxic effects of MMI. These results suggest that myo-inositol play a crucial role in the TAL regarding osmoregulation of the cells.

Effects of aminoguanidine on serum advanced glycation endproducts, urinary albilmin excretion, mesangial expansion, and glomerular basement membrane thickening in Otsuka Long-Evans Tokushima fatty rats.

This study evaluated the effects of treatment with an inhibitor of advanced glycation endproducts, aminoguanidine, on the development of albuminuria, mesangial expansion and glomerular basement membrane (GBM) thickening in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which we found to be an excellent model of non insulin-dependent diabetes mellitus (NIDDM), for its very close similarity to human NIDDM. OLETF rats were randomized into a non-treatment diabetic group (D-group, n = 5) and an aminoguanidine-treated group (AG-group, n = 5). The AG-group was given 100 mg/dl aminoguanidine HCl in free drinking water. Treatment was started at 16 weeks of age. We measured body weight, plasma glucose, total cholesterol, triglycerides and the urinary albumin excretion (UAE) rate before and after treatment at regular intervals. At 56 weeks of age, we measured serum advanced glycation endproducts (AGE), mesangial expansion and glomerular basement membrane. There were no significant differences in pre-treatment body weight, plasma glucose and UAE between the D-group and the AG-group. Likewise, after treatment there were no significant differences in body weight, plasma glucose, total cholesterol, triglycerides and immunoreactive insulin. Significant differences were, however, noted in serum AGE (63.2 +/- 3.5 and 51.8 +/- 3.0 U AGE/ml, P < 0.05), UAE (203.6 +/- 37.7 and 89.8 +/- 18.6 mg/day, P < 0.05), fractional mesangial volume (21.3 +/- 1.7 and 16.7 +/- 0.8%, P < 0.05) and GBM thickness (453 +/- 17 and 366 +/- 50 nm, P < 0.05) between the D-group and the AG-group. Our results suggest that aminoguanidine inhibits the AGE formation and the development of diabetic nephropathy in OLETF rats.

Expression of Na+/myo-inositol cotransporter mRNA in normal and hypertonic stress rat eyes.

We studied the localization of Na+/myo-inositol cotransporter (SMIT) mRNA in normal and hypertonic stress rat eyes by in situ hybridization histochemistry using cRNA probes. SMIT mRNA signals were observed in the iris-ciliary body, the lens epithelial cells, and the ganglion cell layer and the inner nuclear layer of the retina. There was a rapid increase on SMIT mRNA in the retina of hypertonic stress rats compared with control rats. These findings suggest that Na+/myo-inositol cotransporter gene expression is osmotically regulated in vivo to protect retinal neuronal function against hypertonic stress.

Amino acids and glucose differentially increased extracellular 5-hydroxyindoleacetic acid in the rat brain.

To reveal the role of serotonergic neurons in the regulation of feeding, the levels of 5-hydroxyindoleacetic acid (5-HIAA), a metabolite of serotonin, in the striatum and the hypothalamus were continuously monitored by an in vivo microdialysis technique. Intake of 20% casein diet did not induce significant changes in the 5-HIAA level in these regions. When rats were fed on 5% casein diet (83.5% carbohydrate diet) for 2 h, the level of 5-HIAA in the striatum gradually increased and reached a maximum (226 +/- 44% of basal level, M +/- SEM, n = 7) at 4 h after stopping the diet. In the medial hypothalamus, its level also increased to 183 +/- 19% (n = 10) at 2 h after starting the diet. On the other hand, a 60% casein diet increased the level of 5-HIAA in the lateral hypothalamus to 138 +/- 19% (n = 10) at 2 h after starting the diet. The intravenous infusion of each of these nutrients, glucose, amino acid mixture or lipid, produced more rapid elevation of the 5-HIAA level than oral intake of the diets. When rats were infused with glucose, its level in the striatum continued to be elevated. In the medial hypothalamus, glucose infusion increased 5-HIAA to the maximum (189 +/- 38%, n = 7) at 4 h after starting infusion. In contrast, serotonergic neurons in the lateral hypothalamus seemed to respond only to infusion of the amino acid mixture, and the level of 5-HIAA reached 163 +/- 14% (n = 5) of the basal level at 1 h after starting the infusion. These results suggest that rapid elevation of glucose or amino acids may independently stimulate serotonin metabolism in these brain areas, participating in the feedback regulation of nutrient intake.

[Choreito and Shakuyakukanzoto: their effects on facilitating the voiding of stones in the urinary tract].

We treated 30 patients having 37 urinary calculi in all, with " Choreito " (5 g/day) and " Shakuyakukanzoto " (5 g/day) to study whether these medicines hastened spontaneous calculus excretion. Within 2 months, 91% of the small calculi (5 X 5 mm and smaller), and 33% of the medium-sized (6 X 10 mm and below) were excreted. These results were similar to those obtained with conventional conservative treatment, and suggest that this therapy will be useful.