Comparison of clinical, biochemical and histomorphometric analysis of bone biopsies in dialysis patients with and without fractures.

Chronic kidney disease-mineral bone disorders (CKD-MBD) are associated with increased risk of fracture. Studies report about 3% of fractures in CKD patients, and these occur earlier than in the general population, namely 16 and 13 years earlier for men and women, respectively. Better understanding of the pathophysiology of fractures would probably contribute to new therapeutic approaches. This study aimed to evaluate report of long bone fractures from a bone biopsies bank from patients on hemodialysis and compare clinical and biochemical characteristics, as well as the results of the histomorphometric analysis of trabecular and cortical bone of these patients with a control group (without fractures), paired for age, gender, and time on hemodialysis. Bone proteins (SOST, DMP1 and MEPE) were evaluated by immunohistochemistry. Seventeen patients with fracture and controls were studied. Fracture prevalence was 0.82/1000 patients/year. Serum phosphorus levels were significantly lower in the fracture group. Histomorphometric analysis revealed that all the patients had high turnover disease, and the fracture group had smaller volume and trabecular thickness, greater osteoid surface, smaller eroded surface, smaller mineralizing surface, formation rate and longer mineralization lag time when compared to controls; the DMP1 expression in the cortical bone was smaller and the SOST in the trabecular bone was higher in fractured patients. As conclusion, we found low prevalence of fractures. Both groups had high turnover disease, but the fractured ones presented more impaired bone microarchitecture, as well as lower formation and greater mineralization defect. Bone proteins expression correlated with parameters involved in bone remodeling.

Perinatal salt restriction: a new pathway to programming adiposity indices in adult female Wistar rats.

Low birth weight has been associated with increased obesity in adulthood. It has been shown that dietary salt restriction during intrauterine life induces low birth weight and insulin resistance in adult Wistar rats. The present study had a two-fold objective: to evaluate the effects that low salt intake during pregnancy and lactation has on the amount and distribution of adipose tissue; and to determine whether the phenotypic changes in fat mass in this model are associated with alterations in the activity of the renin-angiotensin system. Maternal salt restriction was found to reduce birth weight in male and female offspring. In adulthood, the female offspring of dams fed the low-salt diet presented higher adiposity indices than those seen in the offspring of dams fed a normal-salt diet. This was attributed to the fact that adipose tissue mass (retroperitoneal but not gonadal, mesenteric or inguinal) was greater in those rats than in the offspring of dams fed a normal diet. The adult offspring of dams fed the low-salt diet, compared to those dams fed a normal-salt diet, presented the following: plasma leptin levels higher in males and lower in females; plasma renin activity higher in males but not in females; and no differences in body weight, mean arterial blood pressure or serum angiotensin-converting enzyme activity. Therefore, low salt intake during pregnancy might lead to the programming of obesity in adult female offspring.