Antiresorptive versus anabolic therapy in managing osteoporosis in people with type 1 and type 2 diabetes

Diabetes is characterized by hyperglycemia, but the two main types, type 1 diabetes (T1D) and type 2 diabetes (T2D), have distinct pathophysiology and epidemiological profiles. Individuals with T1D and T2D have an increased risk of fractures, particularly of the hip, upper arm, ankle, and nonvertebral sites. The risk of fractures is higher in T1D compared to T2D. The diagnosis of osteoporosis in individuals with T1D and T2D follows similar criteria as in the general population, but treatment thresholds may differ. Antiresorptive therapies, the first-line treatment for osteoporosis, are effective in individuals with T2D. Observational studies and post hoc analyses of previous trials have indicated that antiresorptive drugs, such as bisphosphonates and selective estrogen receptor modulators, are equally effective in reducing fracture risk and increasing bone mineral density (BMD) in individuals with and without T2D. Denosumab has shown similar effects on vertebral fracture risk but increases the risk of nonvertebral fractures. Considering the low bone turnover observed in T1D and T2D, anabolic therapies, which promote bone formation and resorption, have emerged as a potential treatment option for bone fragility in this population. Data from observational studies and post hoc analyses of previous trials also showed similar results in increasing BMD and reducing the risk of fractures in people with or without T2D. However, no evidence suggests that anabolic therapy has greater efficacy than antiresorptive drugs. In conclusion, there is an increased risk of fractures in T1D and T2D. Reductions in BMD cannot solely explain the relationship between T1D and T2D and fractures. Bone microarchitecture and other factors play a role. Antiresorptive and anabolic therapies have shown efficacy in reducing fracture risk in individuals with T2D, but the evidence is more robust for antiresorptive drugs. Evidence in T1D is scant. Further research is needed to fully understand the underlying mechanisms and optimize management strategies for bone fragility in T1D and T2D. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research

Combined use of mitochondrial and nuclear genetic markers further reveal immature marine turtle hybrids along the South Western Atlantic

Marine turtle hybridization is usually sporadic and involves reports of only a few individuals; however, Brazilian populations have high hybridization rates. Here we investigated the presence of hybrids in morphologically identified immature hawksbills (Eretmochelys imbricate) along the South Western Atlantic (SWA). We sequenced one mitochondrial (D-Loop) and three nuclear DNA (RAG1, RAG2, and CMOS) markers to better understand the patterns and characteristics of hybrids. We identified 22 hybrids (n = 270), 11 of them at the extreme South of the SWA. Uruguay had the highest hybrid frequency in the SWA (similar to 37.5%) followed by southern Brazil with 30%. These are common areas for loggerheads (Caretta caretta) but uncommon for hawksbills, and these hybrids may be adopting the behavior of loggerheads. By analyzing nuclear markers, we can infer that 50% of the sampled hybrids are first generation (F1) and 36% are the result of backcrosses between hybrids and pure E. imbricate (> F1). We also report for the first time immature E. imbricate x Lepidochelys olivacea hybrids at the Brazilian coast. Considering the high frequency of hybrids in the SWA, continuous monitoring should be performed to assess the fitness, genetic integrity, and extent of changes in the gene pools of involved populations

Chromosome variations and diversity of Epidendrum ibaguense Lindl. (Orchidaceae) on the Tepequém's Tepuy, Roraima, Brazil.

Made available in DSpace on 2017-12-05T23:31:39Z (GMT). No. of bitstreams: 1 chromosomevariationsanddiversityofepidendrumibaguenselindlorchidaceaeonthetepequmstepuyroraimabrazil.pdf: 583762 bytes, checksum: 1d08b2188cdca009a1e2d757f9966a18 (MD5) Previous issue date: 2017-12-05bitstream/item/168231/1/chromosome-variations-and-diversity-of-epidendrum-ibaguense-lindl-orchidaceae-on-the-tepequms-tepuy-roraima-brazil.pd

The effects of type 1 diabetes and diabetic peripheral neuropathy on the musculoskeletal system : a case–control study

Fracture risk is increased in type 1 diabetes (T1D). Diabetic neuropathy might contribute to this increased risk directly through effects on bone turnover and indirectly through effects on balance, muscle strength, and gait. We compared patients with T1D with (T1DN+, n = 20) and without (T1DN−, n = 20) distal symmetric sensorimotor polyneuropathy and controls (n = 20). We assessed areal bone mineral density (aBMD) and appendicular muscle mass by dual-energy X-ray absorptiometry, microarchitecture by high-resolution peripheral quantitative tomography at the standard ultra-distal site and at an exploratory 14% bone length site at the tibia and radius, bone turnover markers, and muscle strength, gait, and balance by Short Physical Performance Battery (SPPB). At the standard ultra-distal site, tibial cortical porosity was 56% higher in T1DN+ compared with T1DN− (p = .009) and correlated positively with the severity of neuropathy (Toronto Clinical Neuropathy Score; r = 0.347, p = .028) and negatively with nerve conduction amplitude and velocity (r = −0.386, p = .015 and r = −0.358, p = .025, respectively). Similar negative correlations were also observed at the radius (r = −0.484, p = .006 and r = −0.446, p = .012, respectively). At the exploratory 14% offset site (less distal), we found higher trabecular volumetric BMD (tibia 25%, p = .024; radius 46%, p = .017), trabecular bone volume (tibia 25%, p = .023; radius 46%, p = .017), and trabecular number (tibia 22%, p = .014; radius 30%, p = .010) in T1DN– compared with controls. Both CTX and PINP were lower in participants with TD1 compared with controls. No difference was found in aBMD and appendicular muscle mass. T1DN+ had worse performance in the SPPB compared with T1DN– and control. In summary, neuropathy was associated with cortical porosity and worse performance in physical tests. Our findings suggest that bone structure does not fully explain the rate of fractures in T1D. We conclude that the increase in the risk of fractures in T1D is multifactorial with both skeletal and non-skeletal contributions

Kidney segmentation in 3D CT images using B-Spline Explicit Active Surfaces

In this manuscript, we propose to adapt the B-Spline Explicit Active Surfaces (BEAS) framework for semi-automatic kidney segmentation in computed tomography (CT) images. To study the best energy functional for kidney CT extraction, three different localized region-based energies were implemented within the BEAS framework, namely localized Chan-Vese, localized Yezzi, and signed localized Yezzi energies. Moreover, a novel gradient-based regularization term is proposed. The method was applied on 18 kidneys from 9 CT datasets, with different image properties. Several energy combinations were contrasted using surface-based comparison against ground truth meshes, assessing their accuracy and robustness against surface initialization. Overall, the hybrid energy functional combining the localized signed Yezzi energy with gradient-based regularization simultaneously showed the highest accuracy and the lowest sensitivity to the initialization. Volumetric analysis demonstrated the feasibility of the method from a clinical point of view, with similar reproducibility to manual observers.The authors acknowledge FCT - Fundação para a Ciência e a Tecnologia, Portugal, and the European Social Found, European Union, for funding support through the Programa Operacional Capital Humano (POCH) in the scope of the PhD grants SFRH/BD/93443/2013 (S. Queirós) and SFRH/BD/95438/2013 (P. Morais).info:eu-repo/semantics/publishedVersio

Bone turnover markers: basic biology to clinical applications

Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and interpretation of these markers, which include commonly used bone formation markers (bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide); and commonly used resorption markers (serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen, and tartrate-resistant acid phosphatase type 5b). BTMs are usually measured by enzyme-linked immunosorbent assay or automated immunoassay. Sources contributing to BTM variability include uncontrollable factors (eg, age, gender, ethnicity) and controllable factors, particularly relating to collection conditions (eg, fasting/feeding state, and timing relative to circadian rhythms, menstrual cycling, and exercise). Pregnancy, season, drugs, and recent fracture(s) can also affect BTMs. BTMs correlate with other methods of assessing bone turnover, such as bone biopsies and radiotracer kinetics, and can usefully contribute to diagnosis and management of several diseases such as osteoporosis, osteomalacia, Paget’s disease, fibrous dysplasia, hypophosphatasia, primary hyperparathyroidism, and chronic kidney disease–mineral bone disorder

Fat, adipokines, bone structure and bone regulatory factors associations in obesity

Context Obese (OB) adults (BMI ≥ 30) have a higher bone mineral density (BMD) and more favourable bone microarchitecture than normal-weight (NW) adults (BMI 18.5–24.9). Objective The objective of this study was to identify which fat compartments have the strongest association with bone density and bone turnover and whether biochemical factors (adipokines, hormones and bone regulators) are likely to be important mediators of the effect of obesity on bone. Design This was a cross-sectional, observational, matched case-control study. Setting Participants were recruited from the local community. Participants Two hundred healthy men and women aged 25–40 or 55–75 were recruited in individually matched OB and NW pairs. Body composition, BMD and bone microarchitecture were determined by dual-energy X-ray absorptiometry (DXA), computed tomography (CT) and high-resolution peripheral CT (HR-pQCT). Bone turnover and potential regulators such as C-terminal cross-linking telopeptide (CTX), type 1 procollagen N-terminal peptide (PINP), sclerostin, periostin, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), insulin-like growth factor 1 (IGF1), adiponectin, leptin and insulin were assessed. Main outcome Planned exploratory analysis of the relationships between fat compartments, areal and volumetric BMD, bone microarchitecture, bone turnover markers and bone regulators. Results Compared with NW, OB had lower CTX, PINP, adiponectin, IGF1, and 25OHD and higher leptin, PTH and insulin (all P < 0.05). CTX and subcutaneous adipose tissue (SAT) were the bone marker and fat compartment most consistently associated with areal and volumetric BMD. In regression models, SAT was negatively associated with CTX (P < 0.001). When leptin was added to the model, SAT was no longer associated with CTX, but leptin (P < 0.05) was negatively associated with CTX. Conclusions SAT is associated with lower bone resorption and properties favourable for bone strength in obesity. Leptin may be an important mediator of the effects of SAT on the skeleton