The demethylation pathway in methionine metabolism in the liver, which is linked directly to the creatinine generation system, may be disturbed in diabetic patients on HD. This may be the reason why serum tHcy and creatinine in diabetic patients on HD are lower than in non-diabetic patients on HD. Therefore, it is necessary to consider the possibility of an altered relation between serum tHcy and vessel disease when evaluating the atherogenic risk in diabetic patients on HD.

Atherosclerotic diseases (ASD) are the major cause of mortality and morbidity in patients on hemodialysis (HD). To evaluate the significance and usefulness of atherogenic indices, we examined lipoprotein(a) (Lp(a)), remnant-like particles cholesterol (RLP.C), homocysteine (Hcy), cardiac troponin T (TnT), and ankle-arm blood pressure index (AABI) in 114 patients on HD (male 79, female 35; age 62.1 ± 1.3 years). As a result, serum cardiac TnT and AABI levels in patients with diabetes mellitus (DM) (n = 33) were significantly higher than those in patients without DM (n = 81). In patients with cerebrovascular diseases (CVD), serum levels of both RLP.C and Hcy, and AABI levels were significantly higher than those in patients without CVD. In patients with coronary artery diseases (CAD), serum cardiac TnT and AABI levels were significantly higher than those in patients without CAD. In patients with peripheral vascular diseases (PVD), serum levels of both Hcy and cardiac TnT were significantly higher than those in patients without PVD. Multiple regression analysis did show that the presence of DM, serum Hcy levels and age were independent factors as- sociated with ASD: ASD = –0.348 + 0.426 × DM (scored: 0, absence; 1, presence) + 0.005 × Hcy (nmol/ml) + 0.010 × Age (years) (p < 0.001). In conclusion, the presence of DM and advanced age are major determinants for atherosclerosis. In addition, serum Hcy levels are independent risk factors for atherosclerosis irrespective of the absence of DM.

Insulinlike growth factor (IGF) I and IGF-II are synthesized in osteoblasts and stimulate proliferation, differentiation, and matrix synthesis in these cells. There is some evidence that IGFs act on bone cells not only by paracrine but also by endocrine pathways, suggesting that circulating IGFs may be of importance for the regulation of bone metabolism. On the other hand, the serum IGF-I level is also thought to be a good indicator of the nutritional conditions in hemodialysis patients. The present study was performed to analyze the correlations of circulating levels of IGF-I, IGF-II, IGF-binding protein (IGFBP) 1 and IGFBP-3 with biochemical markers of bone metabolism and parameters of the urea kinetic model which reflect nutritional conditions in hemodialysis patients. We also examined the differences between these relationships in male and female patients on hemodialysis. Sixty-two hemodialysis patients, 36 men (male group) and 26 women (female group), were included in this study. We measured the serum levels of IGF-I, IGF-II, IGFBP-1, and IGFBP-3. The bone mineral content (BMC) of the radius was measured by dual-energy X-ray absorptiometry. We calculated Kt/V, protein catabolic rate, and percent creatinine generation rate (%CGR). We also examined the relationships between serum levels of IGFs and BMC and the parameters of the urea kinetic model. It was found that the serum levels of IGF-I in the hemodialysis patients were almost the same as those in the control group. However, the serum levels of IGF-II, IGFBP-1, and IGFBP-3 in the hemodialysis patients were significantly higher than those in the control group. In the male group, the serum IGF-I levels showed a significant correlation with both serum intact parathyroid hormone levels and BMC, but no significant correlations between these indices were found in the female group. The serum levels of both IGF-I and IGF-II showed significant correlations with %CGR in the male group, but not in the female group. Stepwise multiple regression analysis was performed to clarify the relationship between serum levels of IGFs and BMC or %CGR. It was found that age, hemodialysis duration, serum intact parathyroid hormone levels, and sex were independent factors associated with BMC. The %CGR was associated independently with serum levels of IGF-I, and IGF-II and with the presence of diabetes mellitus. In conclusion, it is thought that serum levels of IGF-I and IGF-II can be used as indices of nutritional conditions in hemodialysis patients. However, the serum IGF-I level cannot be used as a marker of bone metabolism in hemodialysis patients.

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