sirolimus and Bone-Diseases

Topics: Bone Diseases; Female; Humans; Lymphatic Abnormalities; Pamidronate; Sirolimus; Vincristine

Pancreas-kidney transplant is an effective treatment for patients with insulin-dependent dabetes and chronic renal failure. Reduction in technical failure loss and early acute rejection rates contributed to prolong pancreas graft survival. However, drug toxicity affects negatively both short- and long-term follow-ups.. This article reviews the existing literature and knowledge of the immunosuppressive drugs that are frequently used in pancreas transplant, including calcineurin inhibitors, sirolimus, corticosteroids, and mycophenolate. The article also discusses the short- and long-term adverse effects of these drugs. The article also reports and discusses the most relevant in vitro studies, providing additional information to in vivo findings. Some clinically relevant drug interactions with immunosuppressive drugs are also highlighted. Over- and underimmunosuppression effects will not be addressed.. Immunosuppressive regimen after pancreas transplant is very effective and contributed to pancreas allograft survival. However, they present several side effects that are potentiated when drugs are combined. Modifiable and non-modifiable risk factors can aggravate metabolic and toxicological effects of immunosuppressive drugs. It is important to critically analyze the results of clinical studies and investigate new immunosuppressive drugs and/or novel drug combinations. It is equally important to comprehend and interpret experimental data. Therefore, minimization of side effects, based on safe approaches, can prolong pancreas allograft survival.

Topics: Adrenal Cortex Hormones; Bone Diseases; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Gastrointestinal Diseases; Graft Rejection; Graft Survival; Hematologic Diseases; Humans; Hyperkalemia; Hyperuricemia; Immunosuppressive Agents; Mycophenolic Acid; Nervous System Diseases; Pancreas Transplantation; Pneumonia; Renal Insufficiency, Chronic; Sirolimus

Lytic bone diseases and in particular osteoporosis are common age-related diseases characterized by enhanced bone fragility due to loss of bone density. Increasingly, osteoporosis poses a major global health-care problem due to the growth of the elderly population. Recently, it was found that the gene regulatory transcription factor CCAAT/enhancer binding protein beta (C/EBPbeta) is involved in bone metabolism. C/EBPbeta occurs as different protein isoforms of variable amino terminal length, and regulation of the C/EBPbeta isoform ratio balance was found to represent an important factor in osteoclast differentiation and bone homeostasis. Interestingly, adjustment of the C/EBPbeta isoform ratio by the process of translational control is downstream of the mammalian target of rapamycin kinase (mTOR), a sensor of the nutritional status and a target of immunosuppressive and anticancer drugs. The findings imply that modulating the process of translational control of C/EBPbeta isoform expression could represent a novel therapeutic approach in osteolytic bone diseases, including cancer and infection-induced bone loss.

Topics: Animals; Bone Diseases; CCAAT-Enhancer-Binding Protein-beta; Cell Differentiation; Humans; Osteoclasts; Sirolimus

Understanding of the regulation of bone catabolism has advanced significantly over the past two decades with the identification of key enzymes that regulate osteoclast formation, activation, and survival following their knockout in mice or recognition of mutations in humans. This led to the discovery of specific inhibitors of some of these key enzymes as proof-of-concept lead compounds or potential clinical candidates for the prevention of osteoporosis and other diseases associated with increased bone resorption. Bisphosphonates have been the major therapeutic agents prescribed for the prevention of bone loss in a variety of pathologic conditions for over 30 years. More potent amino bisphosphonates have increased efficacy than earlier drugs, but side effects such as upper gastrointestinal symptoms and the requirement to take them at least 2 h before food have limited patient compliance. This, coupled with the growing knowledge of the pathways regulating osteoclast function, has driven efforts to identify small molecular lead compounds that could be developed into new therapeutic agents with efficacy that matches or supersedes that of bisphosphonates for the prevention of bone loss. In this article, we review briefly the effects of specific inhibitors of bone resorption that have been developed to date and highlight in a variety of models of increased bone resorption the effects of Src kinase inhibitors that have been targeted to bone to limit potential unwanted side effects on other cells.

Topics: Bone and Bones; Bone Diseases; Bone Resorption; Cathepsin K; Cathepsins; Enzyme Inhibitors; Humans; Osteoclasts; Protein-Tyrosine Kinases; Sirolimus; Vacuolar Proton-Translocating ATPases

Renal transplantation is the definitive treatment for many metabolic abnormalities of uremic patients, although it is only partially effective for renal osteodystrophy, which may interact with posttransplant renal osteopathy. Osteopenic-osteoporotic syndrome represents, together with fractures secondary to osteoporosis and osteonecrosis, the bone complication most related to renal transplantation. Several factors contribute to the pathogenesis of posttransplantation osteoporosis, particularly immunosuppressive treatment. In this study, we evaluated the prevalence of factors related to posttransplant renal osteopathy and the clinical impact of immunosuppressive protocols. We studied 24 renal transplant recipients with hypercalcemia. Glomerular filtration rate was >50 mL/min. Mean age, time on dialysis, and time from transplantation were 49.6, 5.4, and 6.9 years, respectively. We evaluated serum and urine calcium and phosphorus, calcitonin, parathormone, bone-specific alkaline phosphatase, osteocalcin, urine deoxypyridinoline, telopeptide of type 1 procollagen, 1,25-(OH)(2) and 25-OH vitamin D, parathyroid ultrasound, and computerized bone mineralometry. The combination of sirolimus and steroids resulted in the most disadvantageous outcomes regarding alkaline phosphatase and mineralometry. Calcineurin inhibitors did not significantly influence bone metabolism markers; mycophenolate mofetil evidenced no effect on bone. According to the literature, steroids account for the abnormalities found in our patients and in severe osteopenia. Several factors may contribute to the development of osteoporosis and fractures in transplantation patients, although they are overcome by the prominent effect of steroids. In patients at high risk of osteoporosis, steroid-free therapy should be considered. Everolimus is indicated for diseases with bone loss. Combined therapy with everolimus and mycophenolic acid without cyclosporine and steroids, seemed to be particularly indicated. Prophylactic treatments should be commenced early. No single marker was useful to diagnose posttransplant renal osteopathy. The definitive diagnosis should be made by bone biopsy during transplantation, and noninvasive procedures, such as densitometry and evaluation of biologic markers, may be useful during follow-up.

Topics: Adult; Alkaline Phosphatase; Animals; Bone Density; Bone Diseases; Calcium; Disease Models, Animal; Female; Fractures, Bone; Humans; Hypercalcemia; Immunosuppressive Agents; Kidney Transplantation; Male; Middle Aged; Osteocalcin; Osteoporosis; Phosphorus; Procollagen; Rats; Sirolimus; Uremia

Osteoporosis, osteopenia, and osteonecrosis are common in renal transplant recipients. In this study, we evaluated relationship between bone mineral density (BMD) and posttransplant duration; creatinine clearance; serum levels of glucose, calcium, phosphorus, alkaline phosphatase, vitamin D (vitD), parathormone, magnesium, C telopeptide, osteocalcin, lipids, and vit D therapy. Eighty five subjects included in this study had a mean age of 36.25 ± 10.5 years. At least at 6-month intervals we measured femoral neck (FN) and lumbar vertebra (LV) by DEXA and biochemical parameters. VitD was prescribed in 57 patients (vitDG). The mean duration of posttransplantation follow-up was 9.82 ± 2.72 months. T scores (TS) of FN and LV were normal in 29.4% and 21.2%; osteopenia in 56.5% and 49.4%; and osteoporosis in 12.1% and 29.4% of patients, respectively. Upon follow-up, TS improved significantly from -1.58 to -1.46 in FN and from -1.88 to -1.70 in LV (P < .05 for both). In patients receiving vitDG, TS improved significantly from -1.74 to -1.61 on FN and from -2.16 to -1.97 on LV (P < .05 for both). Osteocalcin and vitDG levels decreased in all patients (P < .05 for all). Blood urea nitrogen and serum creatinine increased (P < .05). In VitDG cohort, triglyceride levels decreased (P < .05) with unchanged blood glucose values; but among the other patients, triglycerides were unchanged but glucose levels had increased (P < .05). Bone disease including osteopenia or osteoporosis was observed among 70%. During the follow-up period, BMD increased significantly from baseline at 9.82 ± 2.72 months. VitD therapy caused more prominent improvements in BMD and decreases in serum triglycerides as well as mutigated the increase in blood glucose.

Topics: Azathioprine; Bone Density; Bone Diseases; Bone Diseases, Metabolic; Creatinine; Female; Humans; Kidney Transplantation; Lipids; Male; Methylprednisolone; Mycophenolic Acid; Osteonecrosis; Osteoporosis; Sirolimus; Vitamin D