Victoria Zeghbi Cochenski Borba

Hypoparathyroidism and pseudohypoparathyroidism

The principal function of the parathyroid hormone (PTH) is maintenance of calcium plasmatic levels, withdrawing the calcium from bone tissue, reabsorbing it from the glomerular filtrate, and indirectly increasing its intestinal absorption by stimulating active vitamin D (calcitriol) production. Additionally, the PTH prompts an increase in urinary excretion of phosphorus and bicarbonate, seeking a larger quantity of free calcium available in circulation. Two mechanisms may alter its function, limiting its control on calcium: insufficient PTH production by the parathyroids (hypoparathyroidism), or a resistance against its action in target tissues (pseudohypoparathyroidism). In both cases, there are significantly reduced levels of plasmatic calcium associated with hyperphosphatemia. Clinical cases are characterized by nervous hyperexcitability, with paresthesia, cramps, tetany, hyperreflexia, convulsions, and tetanic crisis. Abnormalities such as cataracts and basal ganglia calcification are also typical of these diseases. Treatment consists of oral calcium supplementation associated with increased doses of vitamin D derivatives.

Bone mineral density and serum levels of 25 OH vitamin D in chronic users of antiepileptic drugs

The aim of this cross sectional study was to evaluate bone mineral density (BMD) and serum levels of 25-hydroxy vitamin D (25OHD) in a group of patients taking antiepileptic drugs (AED) for a seizure disorder. Between May-2001 and January-2003, we evaluated 58 patients (40 women/18 men), 34.4+/-6 years old living in Curitiba or in its metropolitan area, on antiepileptic therapy for 2 to 38 years (10 on monotherapy /48 on multiple drugs regime). The group was matched by age, gender, and bone mass index to 29 healthy subjects (20 women/ 9 men); 34.2+/-5.9 years old. Medical history and physical exam were performed on all subjects with particular information sought about fractures and risks factors for osteoporosis. Blood samples were collected for total serum calcium, albumin, phosphorus, creatinine, total alkaline phosphatase, and liver function tests. BMD of the lumbar spine, femur and forearm was determined by dual energy X-ray absorptiometry (DXA, Hologic QDR 1000). Between February and April-2003, other blood samples were collected to measure 25OHD, intact paratohormone (PTH) and calcium. Unemployment and smoking history were more frequent among patients than among controls (p<0.05). Fifteen patients had a fracture history, all of which occurred during a seizure. The BMD of the lumbar spine (0.975+/-0. 13 g/cm2 vs. 1.058+/-0.1 g/cm2; p<0.03) and of the total femur (0.930+/-0.1 g/cm2 vs. 0.988+/-0.12 g/cm2; p<0.02) was lower in patients than in controls. In 63.5% of patients and in 24.1 % of controls a T-score < -1.0 in at least one site was seen. The AED users had higher total alkaline phosphatase and lower 25OHD (p<0.02). No correlations between BMD and 25OHD were found. The use of phenytoin was correlated with a greater incidence of fractures (RR: 2.38). We conclude that patients on chronic use of AED have alterations in bone metabolism characterized in this study by lower BMD of the lumbar spine and total femur and lower serum concentrations of 25OHD.

Osteoporosis After Transplantation

Transplantation is an established therapy for end-stage diseases of kidney, lung, liver, and heart among others. Osteoporosis and fragility fractures are serious complications of organ transplantation, particularly in the first post-transplant year. Many factors contribute to the pathogenesis of osteoporosis following organ transplantation. This review addresses the mechanisms of bone loss that occurs both in the early and late post-transplant periods, including the contribution of the immunosuppressive agents as well as the specific features to bone loss after kidney, lung, liver, cardiac, and bone marrow transplantation. Prevention and treatment for osteoporosis in the transplant recipient are also discussed.

Skeletal microstructural abnormalities in postmenopausal women with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is associated with osteoporosis and fragility fractures. The objectives of this study were to assess static and dynamic indices of cancellous and cortical bone structure in postmenopausal women with COPD. Twenty women with COPD who had not received chronic oral glucocorticoids underwent bone biopsies after double tetracycline labeling. Biopsies were analyzed by histomorphometry and µCT and compared with age‐matched controls. Distribution of the patients according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) was: Type I (15%), Type II (40%), Type III (30%), and Type IV (15%). Mean (±SD) cancellous bone volume (15.20 ± 5.91 versus 21.34 ± 5.53%, p = .01), trabecular number (1.31  ±  0.26 versus 1.77 ± 0.51/mm, p = .003), and trabecular thickness (141 ± 23 versus 174 ± 36 µm, p = .006) were lower in patients than in controls. Connectivity density was lower in COPD (5.56 ± 2.78 versus 7.94 ± 3.08/mm, p = .04), and correlated negatively with smoking (r = −0.67; p = .0005). Trabecular separation (785 ± 183 versus 614 ± 136 µm, p = .01) and cortical porosity (4.11 ± 1.02 versus 2.32 ± 0.94 voids/mm2; p < .0001) were higher in COPD while cortical width (458 ± 214 versus 762 ± 240 µm; p < .0001) was lower. Dynamic parameters showed significantly lower mineral apposition rate in COPD (0.56 ± 0.16 versus 0.66 ± 0.12 µm/day; p = .01). Patients with more severe disease, GOLD III and IV, presented lower bone formation rate than GOLD I and II (0.028 ± 0.009 versus 0.016 + 0.011 µm3/µm2/day; p = 04). This is the first evaluation of bone microstructure and remodeling in COPD. The skeletal abnormalities seen in cancellous and cortical bone provide an explanation for the high prevalence of vertebral fractures in this disease.

Níveis baixos de 25-hidroxivitamina D (25OHD) em pacientes com doença inflamatória intestinal e sua correlação com a densidade mineral óssea

Patients with inflammatory bowel disease (IBD) are at risk of having vitamin D deficiency (25-OHD) and low bone mineral density (BMD). OBJECTIVES: To measure 25OHD in a young group of IBD patients submitted to a clinical evaluation, routine biochemistry and BMD measurement (lumbar spine and proximal femur). RESULTS: 39 Crohn disease (CD) and 37 ulcerative colitis (UC) patients had lower serum levels of 25OHD compared to the control group (CD p = 0,003; UC p < 0,001), and 48.5% of the UC patients were 25OHD deficient. Lumbar spine BMD was lower in patients than controls (CD p = 0,001; UC p = 0,008). In CD patients, serum levels of 25OHD were significantly correlated with total femur (r = 0,391; p = 0,027) and femoral neck (r = 0,384; p = 0,03) BMD. CONCLUSION: It was found lower levels of 25OHD and BMD in young IBD patients compared to normal controls, suggesting an important role of 25OHD deficiency in the pathogenesis of the IBD bone disease.

Post-transplantation osteoporosis

Osteoporosis is prevalent in transplant recipients and is related to pre- and post-transplantation factors. Low bone density and fractures may antedate transplantation, related to traditional risk factors for osteoporosis, effects of chronic illness, and end-stage organ failure and its therapy, on the skeleton. Bone loss after transplantation is related to adverse effects of immunosuppressive drugs (glucocorticoids and calcineurin inhibitors) on bone remodeling. Newer immunosuppressive medications may permit lower doses of glucocorticoids and may be associated with decreased bone loss and fractures. Bisphosphonates are currently the most effective agents for the prevention and treatment of post-transplantation osteoporosis.

The use of PTH in the treatment of osteoporosis

Anabolic drugs have recently widened therapeutic options in osteoporosis treatment, as they influence processes associated with bone formation to a greater extent and earlier than bone reabsortion. They positively affect a number of skeletal properties besides bone density, as intermittent administration of parathyroid hormone (PTH) results in an increase in the number and activity of osteoblasts leading to an increase in bone mass and improvement in skeletal architecture at both the trabecular and cortical bone. Human recombinant parathyroid hormone (hrPTH 1-84) and human recombinant PTH peptide 1-34 (teriparatide) belong to this group. The objective of this paper is to review PTH actions, benefits and adverse effects, action on biochemical markers, combination therapy with antiresorptive agents, impact of antiresorptive therapy prior to anabolic treatment, sequential treatment, and effect on glucocorticoid-induced osteoporosis.

Bone turnover 18 months after a single intravenous dose of zoledronic acid

Zoledronic acid inhibits bone resorption for up to 12 months. It is not known whether the duration of this antiresorptive effect extends beyond this period of time. The aim of this study was to evaluate the changes in bone turnover at 12 months (T12) and 18 months (T18) after a single injection of 4 mg of zoledronic acid.

Bone density and bone turnover markers in patients with epilepsy on chronic antiepileptic drug therapy

In this comparative, cross-sectional study, we evaluated 55 patients with epilepsy on chronic use of antiepileptic drugs (AED); [(38 females and 17 males, 35 +/- 6 years (25 to 47)] and compared to 24 healthy subjects (17 females/7 males). Laboratorial evaluation of bone and mineral metabolism including measurements of bone specific alkaline phosphatase (BALP) and carboxyterminal telopeptide of type I collagen (CTX-I) were performed. Bone mineral density (BMD) was measured by DXA. BALP and CTX-I levels did not differ significantly between the groups. CTX-I levels were significantly higher in patients who were exposed to phenobarbital (P< 0.01) than those who were not. Patients presented BMD of both sites significantly lower than the controls (0.975 +/- 0.13 vs. 1.058 +/- 0.1 g/cm(2); p= 0.03; 0.930 +/- 0.1 vs. 0.988 +/- 0.12 g/cm(2); p= 0.02, respectively). Total hip BMD (0.890 +/- 0.10 vs. 0.970 +/- 0.08 g/cm(2); p< 0.003) and femoral neck (0.830 +/- 0.09 vs. 0.890 +/- 0.09 g/cm(2); p< 0.03) were significantly lower in patients who had been exposed to phenobarbital, in comparison to the non-phenobarbital users. In conclusion, patients on AED demonstrate reduced BMD. Among the AED, phenobarbital seems to be the main mediator of low BMD and increases in CTX-I.

Sarcopenia in COPD: relationship with COPD severity and prognosis

Objective: To evaluate the prevalence of sarcopenia in COPD patients, as well as to determine whether sarcopenia correlates with the severity and prognosis of COPD. Methods: A cross-sectional study with COPD patients followed at the pulmonary outpatient clinic of our institution. The patients underwent dual-energy X-ray absorptiometry. The diagnosis of sarcopenia was made on the basis of the skeletal muscle index, defined as appendicular lean mass/height2 only for low-weight subjects and adjusted for fat mass in normal/overweight subjects. Disease severity (COPD stage) was evaluated with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. The degree of obstruction and prognosis were determined by the Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity (BODE) index. Results: We recruited 91 patients (50 females), with a mean age of 67.4 ± 8.7 years and a mean BMI of 25.8 ± 6.1 kg/m2. Sarcopenia was observed in 36 (39.6%) of the patients, with no differences related to gender, age, or smoking status. Sarcopenia was not associated with the GOLD stage or with FEV1 (used as an indicator of the degree of obstruction). The BMI, percentage of body fat, and total lean mass were lower in the patients with sarcopenia than in those without (p < 0.001). Sarcopenia was more prevalent among the patients in BODE quartile 3 or 4 than among those in BODE quartile 1 or 2 (p = 0.009). The multivariate analysis showed that the BODE quartile was significantly associated with sarcopenia, regardless of age, gender, smoking status, and GOLD stage. Conclusions: In COPD patients, sarcopenia appears to be associated with unfavorable changes in body composition and with a poor prognosis.