V. Turchetti

Long-term treatment with calcitriol in postmenopausal osteoporosis

In order to assess the long-term effects of calcitriol treatment in postmenopausal osteoporotic patients, 1.0 micrograms/d of calcitriol was administered in two divided doses for 1 to 8 years to 270 women with symptomatic, histologically proven postmenopausal osteoporosis. No calcium supplementation was given. Clinically, the treatment resulted in substantial relief from pain, with improvement of ambulancy. Intestinal calcium absorption, which was lower than normal at baseline, increased significantly and remained higher than the baseline value as long as calcitriol was administered. Urinary calcium absorption also increased, but hypercalcemia occurred, exceptionally and transiently, in only a few patients. Urinary hydroxyproline excretion did not increase, indicating that hypercalciuria was not of resorptive origin. Total-body density, determined by dual-photon total-body absorptiometry in 56 patients, showed an increase after 18 to 24 months of therapy in most cases. The occurrence of nontraumatic, clinically relevant fractures decreased noticeably as compared with the period preceding calcitriol treatment. No change occurred in renal function, and no renal stones developed. Calcitriol was an effective and safe treatment of postmenopausal osteoporosis.

Effect of a long-term treatment with 1,25-dihydroxyvitamin D3 on osteocalcin in postmenopausal osteoporosis

SummarySerum bone Gla-protein (BGP or osteocalcin) was measured in 25 women with histologically confirmed postmenopausal osteoporosis before and during long-term treatment with 1 μg/day of 1,25-dihydroxyvitamin D3(1,25(OH)2D3).Basal serum BGP was significantly lower in osteoporotic women (3.8±1.4 ng/ml) than in agematched controls (6.8±2.0 ng/ml). During 1,25(OH)2D3 therapy serum BGP increased so that the mean of the values observed on treatment (4.8±1.5) was significantly higher than the mean basal value.It is known that BGP synthesis is stimulated by 1,25 (OH)2D3 and that serum BGP is a specific marker of bone formation; therefore, it is possible that the low basal levels of osteocalcin we observed were related to the low serum 1,25(OH)2D concentrations reported in osteoporotic women and that the increase in BGP levels observed under 1,25(OH)2D3 treatment was a consequence of osteoblast stimulation.

25-Hydroxycholecalciferol as an antagonist of adverse corticosteroid effects on phosphate and calcium metabolism in man

The present study was performed in 30 patients who needed steroid therapy: courses of triamcinolone or DTM 8–15 given orally lasted 30 days. In 15 of these patients glucoactive corticosteroids were administered in combination with 5 μg/day of 25OH-vitamin D3 (250HD3). 47Calcium oral test and 99mTc-MDP kinetics, as an index of bone turnover, were performed at the beginning of the therapy and after 30 days. At the end of treatment a significant improvement of intestinal radiocalcium transport together with a decrease in bone turnover in the group of patients treated with 250HD3 was observed. As it concerns plasma calcium level, inorganic phosphate, the urinary excretion of calcium, phosphate and hydroxyproline no significant difference between the two groups examined were noticed. These results indicate that the adverse effects of glucoactive corticosteroids on intestinal calcium transport and bone turnover may be counteracted by the combined administration of physiological doses of 250HD3.

Action of pentoxifylline on cytosolic calcium and on the erythrocytic morphology during ageing

Cytosolic calcium is an important parameter of cell functionality and its concentration is determined by homeostatic mechanisms which are ATP dependent. When an energetic depletion occurs, as in the case of ischaemia, uncontrolled accumulation of ion in the cytosol, with a reduction of membrane deformability, and the modification of the physiologic shape of erythrocyte can be noted. Pentoxifylline has a rheological effect acting on energetic metabolism of red cells. Our objective was to verifY the action of pentoxifylline on calcium concentration and on the erythrocytic morphology of cell ageing. We used as ageing model the conservation of blood in vitro: 3 blood samples (from 6 taken by 8 normal subjects), have been incubated with pentoxifylline (1.4XIO-4M). We dosed cytosolic calcium and evaluated cell morphology in 2 samples (with and without pentoxifylline) in basal conditions, after 4 and after 8 hours of conservation at 37°C. Dosage of intraerythrocytic calcium was made with FURA2-AM (Calbiochem) according to the David-Dufilho method. Erythrocytic morphology was evaluated with an optical microscope following the Zipursky method. Results showed a reduction of the increase of cytosolic calcium and a major conservation of the erythrocytic physiologic morphology in samples incubated with pentoxifylline after 4 and 8 hours in comparison with control samples. These observations confirm that pentoxifylline delays uncontrolled accumulation of calcium which, in ageing, causes cell suffering and keeps its morphologic physiology for a longer time.

Impact of Hemorheological and Endothelial Factors on Microcirculation

Previous studies showed that endothelial alterations caused by physical stress worsened the hemorheological parameters mainly in patients affected by ischemic vascular diseases: major vascular alterations have been found in patients with very high endothelial dysfunction indexes: these indexes are given by the various substances produced by the endothelium, but it is very difficult to have a value which clearly identifies the real state of the endothelial alteration. The function of the NO, an endogenous vasodilator whose synthesis is catalyzed by NOs, can be determined by the Citrulline/Arginine ratio, which represents the level of activity of the enzyme. A very good index of the endothelial dysfunction is asymmetric dimethylarginine (ADMA), a powerful endogenous inhibitor of NOs; in fact several studies have demonstrated a strong relationship between ischemic vascular disease and high levels of plasmatic ADMA. Our recent studies on heart failure and on ischemic cerebrovascular diseases evaluate endothelial dysfunctions and hemorheological parameters.

High levels of human chromogranin A in umbilical cord plasma and amniotic fluid at parturition

Objective: The human placenta is a neuroendocrine organ that produces several hypothalanmic and pituitary hormones that are secreted during pregnancy and parturition into maternal and fetal circulation and amniotic fluid. Human chromogranin A (CgA) is a glycoprotein mainly localized to the adrenal medulla and released in response to several stressful events. During pregnancy, intrauterine tissues express and synthesize CgA mRNA and peptide and secret it into the biologic fluids of pregnancy, so we investigated whether maternal, umbilical, and amniotic human CgA levels are affected by the stress of parturition. Methods: We measured pregnancy CgA levels in maternal and umbilical cord plasma and in amniotic fluid at term (39-40 weeks), by enzyme-linked immunosorbent assay at elective cesarean (n = 16), after spontaneous vaginal delivery (n = 12), and longitudinally throughout labor and 2 hours postpartum. Results: CgA levels were highest in umbilical cord blood (P < .001). Umbilical cord plasma and amniotic fluid CgA levels were significantly higher at spontaneous vaginal delivery than at cesarean (P < .001), and the levels were not changed in maternal plasma according to cervical dilatation and postpartum. Conclusions: The present findings showed that the stress of parturition increased CgA levels in umbilical cord plasma and amniotic fluid and was probably of fetal origin. Whatever the mode of delivery, CgA levels in infants were much more elevated than in mothers, providing evidence for an unusual and sustained high level of sympathoadrenal stimulation in full-term neonates.

Total body and regional analysis by dual-photon absorptiometry in osteogenesis imperfecta.

No extensive studies have been reported concerning the quantitation of bone mineral content in osteogenesis imperfecta. Osteogenesis imperfecta is a heterogeneous inherited disorder with multiple clinical and biochemical subtypes.’ Schematically bone fragility with a history of multiple fractures characterizes the clinical picture: blue sclerae, joint laxity, growth retardation, presenile hearing loss and abnormal dentition represent additional clinical features?’ X-ray examinations show variable degrees of osteopenia along with evidence of fractures or bone deformities. Using quantitative computed tomography of the lumbar spine in patients with osteogenesis imperfecta types I, 111, and IV, it was demonstrated that the bone disease is heterogenous even among family members and that bone mineral content during young adulthood averages about 70% of normal and subsequently falls more rapidly than in normal subjects: Dual-photon absorptiometry with 153 Gadolinium was first developed for measurements of bone mineral content of the lumbar spine and proximal femur.’*6 In comparison with single-photon absorptiometry, which is confined to compact bone of peripheral skeleton, the chief advantage of the dual-photon technique is the lack of the requirement to surround the measured bone in a constant thickness of soft-tissue. This method provided opportunities to quantify mineral content of trabecular bone of the axial skeleton: methodological difficulties concerning visualization of disk space, abnormalities due to partial vertebral compression or osteophytes can otherwise invalidate a correct scan.’ Nevertheless, quantitative measurements of bone mineral of the entire skeleton is clinically useful in metabolic bone disease. Total bone calcium estimation by neutron activation analysis is not currently practicable because of radiation safety and high costs. Recently dual-photon absorptiometry allowed measurements of bone mineral of the entire skeleton and its major anatomical the results were highly significant in that they correlated with the actual weight of skeletons and with total body calcium evaluated by neutron activation analysis.’o Toward a better understanding of the degree of osteopenia of osteogenesis imper-

Serum osteocalcin radioimmunoassay in bone diseases

SummaryOsteocalcin (or bone Gla protein, BGP) is a non-collagenous vitamin K-dependent protein accounting for 1–2% of the total bone proteins. It represents a specific index of osteoblastic activity and directly reflects the bone turnover. Serum levels of osteocalcin were measured by a radioimmunoassay method. In 40 postmenopausal women with osteoporosis, mean serum BGP levels were lower than the normal range (3.69 ± 1.35 ng/ml), whereas they significantly increased in 7 patients with osteomalacia (10.48 ± 3.05 ng/ml), in 12 patients with secondary hyperparathyroidism (11.1 ±0 4.9 ng/ml) and in 41 patients with Paget’s disease (12.09 ± 6.5 ng/ml). Four patients with primary hyperparathyroidism showed very high BGP levels (64.0 ± 32.3 ng/ml), which strikingly fell after the surgical removal of a parathyroid adenoma. These results confirm that the quantitation of serum osteocalcin is a specific and sensitive method in the diagnosis of bone disease, represents a useful index of bone turnover and is particularly helpful in the follow-up of patients with treated bone disease.