No abstract

Glycation of LDL occurs chiefly due to the nonenzymatic reaction of glucose and its metabolites with the free amino groups of lysine in which LDL is rich. Higher concentrations of glycated LDL are present in diabetic than in nondiabetic individuals, but even in the latter, there is generally more circulating glycated LDL than oxidatively modified LDL. Probably, oxidation and glycation of LDL are at least partially interdependent, but both prevent LDL receptor-mediated uptake and promote macrophage scavenger receptor uptake. The recognition that LDL glycation is at least as important as oxidation in atherogenesis may lead to improvements in our understanding of its mechanism and how to prevent it.

No abstract

Glycation of apoB (apolipoprotein B) of LDL (low-density lipoprotein) increases its atherogenicity. Concentrations of both serum glyc-apoB (glycated apoB) and SD-LDL (small dense LDL) (syn LDL3; D=1.044-1.063 g/ml) are increased in diabetes and are closely correlated. We studied whether SD-LDL is more susceptible to glycation in vitro than more buoyant LDL in statin- and non-statin-treated Type 2 diabetes mellitus. Serum SD-LDL apoB and glyc-apoB on statins was 20±2 (means±S.D.) and 3.6±0.41 compared with 47±3 and 5.89±0.68 mg/dl in those not receiving statins (P<0.001 and <0.01, respectively). There was a dose-dependent increase in glycation on incubation of LDL subfractions with glucose, which was accompanied by an increase in LPO (lipid peroxide) and electrophoretic mobility and a decrease in free amino groups. SD-LDL was more susceptible to these changes than more buoyant LDL. Both SD-LDL and more buoyant LDL from statin-treated patients were less susceptible to glycation. There were fewer free amino groups on LDL subfractions from statin-treated patients, which may contribute to this resistance. In conclusion, greater susceptibility of SD-LDL to glycation is likely to contribute to the raised levels of circulating glyc-apoB in diabetes. Statins are associated with lower levels of both SD-LDL and glyc-apoB.

No abstract

Small-dense LDL (SD-LDL) has been particularly implicated in atherosclerosis. It has previously been reported that in non-diabetic people SD-LDL is preferentially glycated. The distribution of glycated apolipoprotein B (glyc-apoB) in lipoproteins in metabolic syndrome (MS) and in type 2 diabetes has not previously been studied. Plasma apoB and glyc-apoB were determined in different apoB-containing lipoproteins including buoyant and SD-LDL in MS (n=18) and type 2 diabetes (DM) [n=48; 12 statin-untreated (DM-S) and 36 statin-treated (DM+S)]. Plasma glyc-apoB was 5.6 ± 0.9, 3.5 ± 0.5 and 4.0 ± 0.2 mg/dl in DM-S, DM+S and MS, respectively. The glycated proportion of SD-LDL-apoB was greater than buoyant LDL in all groups. SD-LDL contributed most to plasma glyc-apoB in DM-S, because SD-LDL-apoB was higher in DM-S than in MS and DM+S (p < 0.001). Plasma glyc-apoB correlated with SD-LDL-apoB (r=0.74, p < 0.0001 in diabetes and r=0.53, p < 0.001 in MS), but not with HbA(1c). SD-LDL is preferentially glycated in type 2 diabetes and MS. Its concentration is a stronger determinant of plasma glycapoB than glycaemia. Statin-induced changes in its level may be important in decreasing apoB glycation in diabetes. These findings may explain the small effect of improving glycaemia relative to statin treatment in reducing atherosclerosis risk in type 2 diabetes and the increased risk in MS even before the onset of type 2 diabetes.

No abstract

Chronic kidney disease may lead to subsequent tissue fibrosis. However, many factors can combat injurious stimuli in these tissues aiming to repair, heal, and alleviate any disturbance. Chemokines release, migration of inflammatory cells to the affected site, and activation of fibroblasts for the production of extracellular matrix are commonly observed in this disease. In the last years, many studies have focused on spironolactone (SPL), a mineralocorticoid receptor antagonist, and its pharmacological effects. In the present study, SPL was selected as an anti-inflammatory agent to combat nephrotoxicity and renal fibrosis induced by cisplatin. Mesenchymal stem cells (MSCs) were also selected in addition as a referring agent. Renal fibrosis induced by cisplatin intake significantly increased creatinine, urea, nuclear factor kappa B, insulin-like growth factor-1, fibroblast growth factor-23, and kidney malondialdehyde (MDA) content. Hepatocyte growth factor and renal content of reduced glutathione demonstrated a significant decrease. Histopathological examination of kidney tissues demonstrated marked cellular changes which are correlated with the biochemical results. Oral SPL intake (20 mg/kg/body weight) daily for 4 weeks and MSCs administration (3 × 10 cell/rat) intravenous to the experimental rats resulted in a significant improvement of both the biomarkers studied and the histopathological profile of the renal tissue. Individual administration of spironolactone and MSCs exhibited a marked anti-inflammatory potential and alleviated to a great extent the nephrotoxicity and renal fibrotic pattern induced by cisplatin.