Platelet vitamin D receptor is reduced in osteoporotic patients.

AIM: It is well known that vitamin D plays an important role in maintaining bone homeostasis and in regulating calcium absorption. The active form of vitamin D interacts with its receptor the VDR that is expressed in multiple tissues and it is involved in platelets (PLTs) function. In the present study we evaluate PLTs' VDR expression in osteoporotic as opposed to healthy subjects. METHODS: We enrolled in the study 77 women with postmenopausal osteoporosis, 33 healthy women of childbearing age, 49 healthy men, and 11 healthy women matched with patients for age and postmenopausal period. Thirty-nine patients had had one femoral fracture occurred after the age of fifty and attributable to primary osteoporosis. Bone mineral density, markers of bone metabolism and VDR levels were measured in all the subjects. RESULTS: Our data show that VDR level is lower in patients as respect to controls and is positively correlated with bone density, but not with markers of bone metabolism. We also found a decrease in the phosphorus levels in patients without differences in vitamin D levels and in the dietary calcium intake. CONCLUSION: The lower VDR expression in osteoporotic could indicate a lower ability to respond to vitamin D, and could be the explanation of the increase in the PTH and decrease in the phosphorus levels in patients with respect to controls.

Teriparatide increases the maturation of circulating osteoblast precursors.

UNLABELLED: This study shows that teriparatide promotes the circulating osteoblast (OB) precursor degree of maturation in patients affected by postmenopausal osteoporosis. INTRODUCTION: Anabolic treatment with teriparatide has proven effective for the therapy of postmenopausal osteoporosis and significantly reduces the risk of non-vertebral fragility fractures. The aim of this study was to investigate the effect of teriparatide on circulating OB precursors. METHODS: We evaluated by flow cytometry and real-time PCR the expression of OBs typical markers in peripheral blood mononuclear cells during treatment with teriparatide plus calcium and vitamin D, raloxifene plus calcium and vitamin D or calcium and vitamin D alone at various time points. Serum bone alkaline phosphatase and osteocalcin (OC) were measured as markers of bone turnover. RESULTS: Our results show that circulating OB precursors are more numerous and more immature in patients affected by fragility fractures than in osteoporotic patients without fractures. We also show that teriparatide treatment increases the expression of alkaline phosphatase and of OC in OB precursors; thus, it increases their degree of maturation. CONCLUSIONS: We suggest that teriparatide acts as anabolic agents also by promoting the maturation of OB precursors.

Alendronate reduces osteoclast precursors in osteoporosis.

UNLABELLED: This study evaluates the effect of alendronate on osteoclastogenesis, cytokine production, and bone resorption in postmenopausal women. We suggest that it acts on mature bone resorbing osteoclasts after 3 months of treatment, whereas, after 1 year, it diminishes their formation by reducing their precursors and serum RANKL. INTRODUCTION: Osteoclasts are the target cells of bisphosphonates, though the most drug-sensitive steps of their formation and activity have not been determined. The present study evaluates the effect of alendronate on osteoclastogenesis, cytokine production, and bone resorption in postmenopausal women. METHODS: The study was conducted on 35 osteoporotic women; 15 were pretreated with alendronate 70 mg/week, whereas, 20 were treated with calcium 1 g/day and vitamin D 800 IU/day. After 3 months, 30 received alendonate 70/mg, vitamin D 2800 IU/week, and calcium 1 g/day for 12 months (combined therapy), whereas, the other five patients remained on calcium 1 g/day and vitamin D 800 IU/day. The following parameters were assessed before and after therapy: changes in bone resorption markers, circulating osteoclast precursors, formation of osteoclasts in peripheral blood mononuclear cell cultures, their viability, and variations in cytokines production. RESULTS: After 3 months of alendronate, there was no significant reduction in the number of osteoclast precursors, osteoclast formation and viability, and cytokine levels, whereas, there was a significant reduction of bone resorption markers. One year of the combined therapy, on the other hand, reduced osteoclast precursors, osteoclast formation, and serum RANKL, whereas, calcium plus vitamin D alone had no effect. CONCLUSIONS: We suggest that alendronate mainly acts on mature bone resorbing osteoclasts in the short term, whereas, its long-term administration diminishes their formation by reducing their precursors and serum RANKL.

HDL cholesterol and bone mineral density in normal-weight postmenopausal women: is there any possible association?

AIM: Epidemiological investigation of the association between lipid profile, atherosclerosis and bone mass has produced conflicting RESULTS: The present paper reports the assessment of the lipid profile, bone mineral density (BMD) and turnover in a cohort of Italian women. METHODS: In this cross sectional study we enrolled 173 women in menopause (101 osteoporotic and 72 normal). In each subject the authors evaluated BMD, bone turnover, lipid profile (total cholesterol, high density lipoprotein [HDL], low density lipoprotein [LDL] and triglycerides), and risk factors for osteoporosis, cardiovascular diseases and eating habits using a questionnaire. RESULTS: HDL was significantly higher in osteoporotic patients than in controls and the risk of osteoporosis was significantly higher in women with higher level of HDL. The authors suggest that the level of HDL could be used as screening for postmenopausal osteoporosis: the cut-off points recommended are HDL >61 mg/dL to detect women with a high risk (sensitivity 74%) and <45 mg/dL to detect those with a low risk (specificity 83%). CONCLUSION: This study provides evidences of the relation between HDL, but not total cholesterol or LDL levels with BMD in a cohort of normal-weight women and equally distributed cardiovascular risks. It also suggests that a proatherogenic lipid profile is associated with higher bone mineral density, and that HDL can be used in deciding whether a patient's BMD should be measured.

Acute adrenal crisis and hypercalcemia in a patient assuming high liquorice doses.

Two months after monolateral adrenalectomy, a 47-year-old woman stopped taking corticosteroid replacement therapy in the first 15 days of therapy. She was admitted to the Department of Internal Medicine because of hypertension, severe hypercalcemia, uncompensated metabolic alkalosis and clinical symptoms of acute adrenal insufficiency. The presence of hypokalemia and hypernatremia precluded a diagnosis of hypocortisolism, therefore no corticosteroids were given during the time required to investigate the cause of hypercalcemia, which resulted negative. Administration of intravenous saline infusion produced no improvement in her clinical condition. Despite electrolyte alterations, hydrocortison (100 mg i.v.) and zoledronate (4 mg i.v.) were also administered, leading to a rapid and marked improvement in her clinical picture within a few hours, with normalization of the calcemia and the other electrolytic disturbances. After her neurological condition had fully normalized, the patient admitted she had been assuming large amounts of liquorice as a laxative for many years; this compound very likely compensated the adrenal insufficiency by inhibiting 11 b steroid-dehydrogenase and disguised the clinical presentation at the time of admission. This case report confirms that, though rare, hypercalcemia may be a finding in acute adrenal insufficiency and can be rapidly corrected by corticosteroid administration. Furthermore, excessive liquorice intake can induce a clinical picture resembling that of primary hyperaldosteronism. In patients with adrenal insufficiency, it can, at least in part, disguise its metabolic effects and delay diagnosis and treatment.

[Fractures and chronic renal insufficiency]. / La patologia fratturativa nei diversi gradi di insufficienza renale cronica.

Chronic renal insufficiency (CRI) causes important modifications in the metabolism of phosphorus and calcium, to which frequently resulting in serious disorders of the skeleton, including demineralization, reduction of the bone resistance and a higher risk of fractures. Renal osteodystrophy is the term used to describe these disorders; they are generally heterogeneous and are classified according to the state of bone turnover into secondary hyperparathyroidism, adynamic bone, and osteomalacia. The incidence of hip fractures in the patients with CRI is higher than in the general population. Hip fractures are an important cause of morbidity and mortality. The evaluation of the fracture risk in the patients with different degrees of CRI is problematic, in particular because of the difficulty in identifying fractures, especially vertebral ones. The instrumental index that best expresses the fracture risk in the general population is bone mineral density (BMD); however, the relationship between low BMD and CRI is disputed. Bone disorders in patients with CRI have in fact a multifactorial pathogenesis and low BMD is not the only risk factor for fractures. Besides densitometric evaluation, also that vertebral morphometric evaluation would be desirable in patients with CRI. The fracture risk increases progressively with the severity of chronic renal disease and it is especially high in patients with renal insufficiency in more advanced-stages CRI (creatinine clearance<15-20 mL/min). However, not only in patients with severe CRI undergoing dialysis, but also in those with milder renal disease is the risk of bone fractures high.