L. Dalle Carbonare

Persistent secondary hyperparathyroidism and vertebral fractures in kidney transplantation: role of calcium-sensing receptor polymorphisms and vitamin D deficiency.

Bone morbidity remains a major problem even after successful renal transplantation. We investigated the role of calcium‐sensing receptor (CaSR) polymorphisms and 25‐hydroxyvitamin D levels on the persistence of secondary hyperparathyroidism (SHPT) and their relationships with vertebral fractures (VFx) in 125 renal allograft recipients transplanted 44 ± 23 months before. All patients underwent evaluation of the main biochemical parameters of calcium metabolism as well as vertebral and femoral bone density. In 87 patients, CaSR polymorphisms (A986S, R990G, and Q1011E) also were assessed. X‐ray images of the lateral spine were obtained in 102 subjects to perform vertebral morphometry. High parathyroid hormone (PTH) and 25‐hydroxyvitamin D lower than 80 nmol/L were found in 54% and 97% of patients, respectively, with 40% of these showing vitamin D levels lower than 30 nmol/L. VFx were detected in 57% of the subjects. After multiple adjustments, 25‐hydroxyvitamin D, age, and hemodialysis duration, but not CaSR polymorphisms, were found to be significant predictors of high PTH, whereas age and time since transplant were positively related with lower 25‐hydroxyvitamin D values. PTH and time since transplant were significantly associated with VFx. Patients with two or more VFx showed serum PTH levels 50% higher than patients without fractures. We therefore conclude that persistent SHPT is a very common feature after renal transplantation and that, unlike CaSR polymorphisms, low 25‐hydroxyvitamin D is involved in its pathogenesis. High PTH levels, in turn, are associated with an increased VFx risk, which confirms the need for strategies aimed at lowering serum PTH in this setting as well.

STEAP mRNA detection in serum of patients with solid tumours

STEAP was identified by the strategy of suppression subtractive hybridizations in Los Angeles prostate cancer xenografts. It is expressed in prostate and other cancers, and not in most normal tissue; it can be used as a marker to evaluate biological samples from individuals suspected of having a disease associated with STEAP dysregulation, such as cancers, and may provide prognostic information useful in defining appropriate therapeutic options. The aim of this study was to test the STEAP mRNA detection in the serum of patients with different malignant tumours by using Real-Time reverse transcription PCR. The results were compared with biological samples obtained by age-matched non-malignant donors. Our data demonstrated that STEAP mRNA is detectable in serum of patients with different solid tumours whereas it is not amplifiable in non-malignant donors. This marker revealed with the molecular method of quantitative PCR in serum, may be useful to discriminate normal and cancer patients.

Presentation, diagnostic features and glucose handling in a monocentric series of insulinomas

Background: New aspects have emerged in the clinical and diagnostic scenarios of insulinoma: current guidelines have lowered the diagnostic insulin threshold to 3 µU/ml in the presence of hypoglycemia (<55 mg/dl); post-prandial hypoglycemia has been reported as the only presenting symptom; preexisting diabetes mellitus (DM) was recognized in some patients. Aim: To evaluate clinical features, diagnostic criteria and glucose metabolic profile in a monocentric series of patients affected by insulinomas including two subgroups: sporadic and multiple endocrine neoplasia type-1 syndrome (MEN-1). Subjects and methods: Clinical, pathological and biochemical data regarding 33 patients were analyzed. Results: following the current guidelines the 72-h fasting test was initially positive in all cases but one. In this case the test, initially negative, became positive after a 2-yr follow-up. Nadir insulin level was ≥3 µU/ml but <6 µU/ml in 3 patients and ≥6 µU/ml in the remaining 30 cases. At presentation, 27 patients (82%) reported only fasting symptoms, 3 (9%) only post-prandial and 3 (9%) both. Seven cases (21%) had previously been affected by type 2 DM or impaired glucose metabolism. Conclusions: In our series the new cut-off of insulin increased the sensitivity of the 72-h fasting test from 87% to 97%. The absence of hypoglycemia during the test cannot definitively rule out the diagnosis and the test should be repeated in every highly suspicious case. Post-prandial hypoglycemia can be the only presenting symptom. DM may be associated with the occurrence of insulinoma. So that a possible diagnosis of insulinoma must not be ignored if previous impaired glucose handling is evident.

Trabecular bone microarchitecture in mild primary hyperparathyroidism.

Primary hyperparathyroidism (PHPT) is a common endocrine disease. High levels of PTH cause demineralization of bone and increased risk of fracture. On the other hand, the effect of PHPT on bone structure is more ambiguous. The aim of this study was to evaluate the effect of PHPT on cancellous bone volume, structure, and microarchitecture. Thirteen transiliac biopsy specimens taken in untreated post-menopausal women aged 65±5 yr with primary hyperparathyroidism were compared with 13 biopsies taken in normal women aged 66±6 yr. None of the patients presented any other disorder affecting bone metabolism. In these samples we evaluated the direct and indirect histomorphometric parameters of bone microarchitecture using an image analysis system consisting of an epifluorescent microscope (Leica DMR) connected to an analogic 3 CCD camera (Sony DXC 390P) and a computer equipped with specific software for histomorphometric analyses. No significant differences between PHPT patients and controls in cancellous bone volume, trabecular thickness, and number were found. Two-dimensional parameters showed a preserved microarchitecture in PHPT patients. On the other hand, indirect parameters of microarchitecture [Marrow Star Volume (MSV) and Trabecular Bone Pattern Factor (TBPf)] showed a significant compromising of microarchitecture in these patients. PHPT patients have similar structural parameters to normal subjects. Concerning microarchitecture, indirect approach by MSV and TBPf shows a significant compromising of connectivity. These results can explain trabecular fragility observed in clinical studies on PHPT.

Risedronate prevents the loss of microarchitecture in glucocorticoid-induced osteoporosis in rats

Osteoporosis is a severe complication of glucocorticoid treatment. Bisphosphonates are a powerful therapeutic option to prevent osteoporotic fractures. The aims of this study were: a) to determine bone alterations induced by therapy with glucocorticoids (GC); b) to establish the efficacy of risedronate (Ris) in the prevention of these effects. We studied 40 female Sprague-Dawley rats randomly divided into 4 groups of treatment, administered 3 times a week sc: 1. Control: vehicle of methylprednisolone (GC) + vehicle of Ris; 2. Ris: Ris 5 μg/kg body weight vehicle of GC; 3. GC: GC 7 mg/kg + vehicle of Ris; 4. GC+Ris: GC 7 mg/kg, Ris 5 μg/kg. Animals were treated for 30 days and then were sacrificed. Densitometry was performed at baseline and at the end of the treatment. Right tibiae were removed for histomorphometric analyses. The GC group showed a 7% decrease in bone density vs controls (p<0.05), while the GC+Ris group was associated with a 3.5% increase in bone density vs controls (p<0.05). In the GC group, histomorphometric evaluations showed reduced bone volume (BV/TV) and thinning of trabeculae (Tb.Th) vs controls (BV/TV: 31±1 vs 35±1%, p<0.05; Tb.Th: 43±2 vs 50±3 μm, p<0.01; Ac.f: 1.8±0.2 vs 1.6±0.3 N/yr). The GC+Ris group had increased BV/TV and Tb.Th, and reduced Ac.f vs the GC group. Ris also maintained trabecular microarchitecture. At the histological level, glucocorticoid-induced osteoporosis was characterized by decreased bone volume, reduced osteoblastic activity, and deterioration of microarchitecture. Ris counteracted these effects both by prolonging osteoblast activity, and by maintaining bone microarchitecture.

Zoledronic acid decreases mRNA six-transmembrane epithelial antigen of prostate protein expression in prostate cancer cells.

Background: Zoledronic acid (Zol) is used successfully to inhibit bone resorption in tumor bone disease of various human cancer. Zol inhibits the mevalonate pathway and other potential targets include the inhibition of tyrosine phosphatase activity, disruption of metalloproteinase, secretion and down-regulation of the catalytic subunit of telomerase (hTERT). The six-transmembrane epithelial antigen of prostate protein (STEAP) is a new marker highly expressed at all phases of prostate cancer. Aim: Here, we analyzed for the first time the effect of Zol on STEAP gene expression in prostate cancer cells. Material and methods: We evaluated the effects of Zol in STEAP gene expression by RT real time PCR in androgen-sensitive (LNCaP) and androgen-non-sensitive (PC3 and DU145) cell lines. To confirm the pro-apoptotic effect of Zol, we also analyzed the caspase-3 gene expression, that resulted up-regulated in cancer cell apoptosis. Results: Zol strongly decreased cell viability and lowered STEAP gene expression in a dose-dependent manner. In addition, this effect was accompanied by an increase of apoptotic index and an up-regulation of caspase-3 gene expression. Conclusion: Zol may affect cancer cells also by targeting the gene expression of STEAP.