Enzymatic and Non-enzymatic Collagen Cross-Links and Fracture Occurrence in Type 1 Diabetes Patients.

Increased fracture risk in type 1 diabetes (T1D) patients is not fully captured by bone mineral density (BMD) by DXA. Advanced glycation end-products (AGEs) have been implicated in the increased fracture risk in T1D, yet recent publications question this. To test the hypothesis that enzymatic collagen cross-links rather than AGEs correlate with fracture incidence in T1D, we analyzed iliac crest biopsies from sex-matched, fracturing T1D patients (N = 5; T1DFx), 6 non-fracturing T1D patients (T1DNoFx), and 6 healthy subjects, by Raman microspectroscopy as a function of tissue age (based on double fluorescent labels), in intracortical and trabecular bone, to determine pyridinoline (Pyd), ε-N-Carboxymethyl-L-lysine, and pentosidine (PEN)). There were no differences in the clinical characteristics between the T1DFx and T1DNoFx groups. At trabecular forming surfaces, T1DFx patients had higher PEN and Pyd content compared to T1DNoFx ones. Previous studies have shown that elevated PEN does not necessarily correlate with fracture incidence in postmenopausal, long-term T1D patients. On the other hand, the elevated Pyd content in the T1DFx patients would be consistent with published studies showing a significant correlation between elevated trivalent enzymatic collagen cross-links and fracture occurrence independent of BMD. Collagen fibers with high Pyd content are more brittle. Thus, a plausible suggestion is that it is the enzymatic collagen cross-links that either by themselves or in combination with the adverse effects of increased AGE accumulation that result in fragility fracture in T1D.

Bone-targeting liposome formulation of Salvianic acid A accelerates the healing of delayed fracture Union in Mice.

Delayed fracture union is a significant clinical challenge in orthopedic practice. There are few non-surgical therapeutic options for this pathology. To address this challenge, we have developed a bone-targeting liposome (BTL) formulation of salvianic acid A (SAA), a potent bone anabolic agent, for improved treatment of delayed fracture union. Using pyrophosphorylated cholesterol as the targeting ligand, the liposome formulation (SAA-BTL) has demonstrated strong affinity to hydroxyapatite in vitro, and to bones in vivo. Locally administered SAA-BTL was found to significantly improve fracture callus formation and micro-architecture with accelerated mineralization rate in callus when compared to the dose equivalent SAA, non-targeting SAA liposome (SAA-NTL) or no treatment on a prednisone-induced delayed fracture union mouse model. Biomechanical analyses further validated the potent therapeutic efficacy of SAA-BTL. These results support SAA-BTL formulation, as a promising therapeutic candidate, to be further developed into an effective and safe clinical treatment for delayed bone fracture union.

Effect of Macroanatomic Bone Type and Estrogen Loss on Osteocyte Lacunar Properties in Healthy Adult Women.

This is the first study to examine clinical human bone specimens by three-dimensional imaging to characterize osteocyte lacunar properties as a function of macroanatomic bone type and estrogen loss. We applied laboratory-based instrumentation [3D X-ray microscope (3DXRM), MicroXCT-200; Carl Zeiss/Xradia, Inc.] that reaches the same resolution as synchrotron microscopy. We used serial transiliac bone biopsy specimens to examine the effect of macroanatomic bone type and estrogen status on osteocyte lacunar properties. These properties include lacunar size (volume, axes lengths of the ellipsoidal lacunar voids), distribution (density, average near-neighbor lacunar distance), and shape factors (sphericity ratio, average eigenvalues, degree of equancy, elongation, and flatness) in both cortical and trabecular bone tissue. The lacunar properties (volume, surface area, density, near-neighbor distance, etc.) and the shape factors (E1, L1, L2, degree of equancy, degree of elongation) were different between cortical and trabecular bone regardless of estrogen status. In cortical bone and trabecular nodes, the lacunar void volume and surface area were either smaller or tended to be smaller in postmenopausal as compared to premenopausal women. The void volume-to-bone volume ratio of cortical bone showed declining trends with estrogen loss. While there were differences between trabecular and cortical bone tissue, the lacunar void sphericity ratio for trabecular struts shows decreasing trends in postmenopausal women. These data suggest that using 3DXRM can provide new insight into osteocyte lacunar properties in transiliac bone biopsies from patients with various skeletal disease/conditions and pharmaceutical treatments.

Investigation of physico-chemical properties and microbial community during poultry manure co-composting process.

Co-composting of poultry manure and rubber wood sawdust was performed with the ratio of 2:1 (V/V) for a period of 60 days. An investigation was carried out to study the extracellular enzymatic activities and structural degradation utilizing Fourier transform infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TG/DTA) and scanning electron microscopy (SEM). The microbial succession was also determined by using denaturing gel gradient electrophoresis (DGGE). The compost was able to reach its highest temperature of 71°C at day 3 and stabilized between 30 and 40°C for 8 weeks. CMCase, FPase and ß-glucosidase acted synergistically in order to degrade the cellulosic substrate. The xylanase activities increased gradually during the composting and reached the peak value of 11.637 U/g on day 35, followed by a sharp decline. Both LiP and MnP activities reached their peak values on day 35 with 0.431 and 0.132 U/g respectively. The FT-IR spectra revealed an increase in aromaticity and a decrease in aliphatic compounds such as carbohydrates as decomposition proceeded. TGA/DTG data exhibited significant changes in weight loss in compost samples, indicating degradation of organic matter. SEM micrographs showed higher amounts of parenchyma exposed on the surface of rubber wood sawdust at day 60, showing significant degradation. DGGE and 16S rDNA analyses showed that Burkholderia sp., Pandoraea sp., and Pseudomonas sp. were present throughout the composting process. Ornithinibacillus sp. and Castellaniella ginsengisoli were only found in the initial stage of the composting, while different strains of Burkholderia sp. also occurred in the later stage of composting.

Utility of Film Array Meningoencephalitis Panel in Children With Acute Encephalitis Syndrome: A Single Centre Experience from South India.

OBJECTIVE: To describe the utility of film array meningoencephalitis (FAME) panel in the management of children with acute encephalitis syndrome (AES). METHODS: A retrospective audit was conducted between January 2017 to July 2022. We included children aged < 18 years with a diagnosis of AES for whom a CSF analysis study including FAME panel testing performed within 48 hours of admission was available. Electronic medical records were reviewed for details including demographic profile, clinical presentation, investigations and outcome. RESULTS: Out of 157 CSF samples sent for FAME panel testing, 49 were positive (31.4%.) Viral pathogens were identified in 42 (Enterovirus: 31, Human herpes virus 6: 9, Varicella zoster virus: 1, and Cytomegalovirus: 1) Bacterial pathogens were identified in 6 (Streptococcus pneumoniae: 2, Streptococcus agalactiae: 2, Hemophilus influenzae: 1, and Escherischia coli: 1). Fungal etiology (Cryptococcus neoformans) was detected in one child. Antibiotics could be stopped within 72 hours of initiation in 42 children in whom a viral etiology was established. Acyclovir could be stopped in 21 out of 32 children within 72 hours after the FAME panel testing. FAME panel was presumed to be false positive in 4 children. CONCLUSION: Etiology of AES could be established in nearly a third of children with AES using the rapid diagnostic FAME panel testing in CSF and it was found to be effective in reducing empirical antibiotic/antiviral therapy.

Pharmacokinetic interaction between etravirine or darunavir/ritonavir and artemether/lumefantrine in healthy volunteers: a two-panel, two-way, two-period, randomized trial.

OBJECTIVES: Etravirine is a substrate and inducer of cytochrome P450 (CYP) 3A and a substrate and inhibitor of CYP2C9 and CYPC2C19. Darunavir/ritonavir is a substrate and inhibitor of CYP3A. Artemether and lumefantrine are primarily metabolized by CYP3A; artemether is also metabolized to a lesser extent by CYP2B6, CYP2C9 and CYP2C19. Artemether has an active metabolite, dihydroartemisinin. The objective was to investigate pharmacokinetic interactions between darunavir/ritonavir or etravirine and arthemether/lumefrantrine. METHODS: This single-centre, randomized, two-way, two-period cross-over study included 33 healthy volunteers. In panel 1, 17 healthy volunteers received two treatments (A and B) in random order, with a washout period of 4 weeks between treatments: treatment A: artemether/lumefantrine 80/480 mg alone, in a 3-day course; treatment B: etravirine 200 mg twice a day (bid) for 21 days with artemether/lumefantrine 80/480 mg from day 8 (a 3-day treatment course). In panel 2, another 16 healthy volunteers received two treatments, similar to those in panel 1 but instead of etravirine, darunavir/ritonavir 600/100 mg bid was given. RESULTS: Overall, 28 of the 33 volunteers completed the study. Co-administration of etravirine reduced the area under the plasma concentration-time curve (AUC) of artemether [by 38%; 90% confidence interval (CI) 0.48-0.80], dihydroartemisinin (by 15%; 90% CI 0.75-0.97) and lumefantrine (by 13%; 90% CI 0.77-0.98) at steady state. Co-administration of darunavir/ritonavir reduced the AUC of artemether (by 16%; 90% CI 0.69-1.02) and dihydroartemisinin (by 18%; 90% CI 0.74-0.91) but increased lumefantrine (2.75-fold; 90% CI 2.46-3.08) at steady state. Co-administration of artemether/lumefantrine had no effect on etravirine, darunavir or ritonavir AUC. No drug-related serious adverse events were reported during the study. CONCLUSIONS: Co-administration of etravirine with artemether/lumefantrine may lower the antimalarial activity of artemether and should therefore be used with caution. Darunavir/ritonavir can be co-administered with artemether/lumefantrine without dose adjustment but should be used with caution.

Dexamethasone prodrug treatment prevents nephritis in lupus-prone (NZB × NZW)F1 mice without causing systemic side effects.

OBJECTIVE: To evaluate the potentially improved therapeutic efficacy and safety of nephrotropic macromolecular prodrugs of glucocorticoids (GCs) for the treatment of lupus nephritis. METHODS: Lupus-prone female (NZB × NZW)F1 mice received monthly injections of N-(2-hydroxypropyl) methacrylamide copolymer-based dexamethasone prodrug (P-Dex) or daily injections of dexamethasone phosphate sodium (Dex; overall dose equivalent to that of P-Dex) for 2 months. During treatment, the mice were monitored for albuminuria, mean arterial pressure, and serum autoantibody levels. Nephritis, renal immune complex levels, and macrophage infiltration were evaluated histologically. Bone quality was analyzed using peripheral dual x-ray absorptiometry and micro-computed tomography. The in vivo distribution of P-Dex was investigated using optical imaging, immunohistochemistry, and fluorescence-activated cell sorting (FACS). The antiinflammatory effect of P-Dex was validated using lipopolysaccharide-activated human proximal tubule epithelial (HK-2) cells. RESULTS: Monthly P-Dex injections completely abolished albuminuria in the (NZB × NZW)F1 mice; this approach was significantly more efficacious than daily Dex treatment. P-Dex treatment did not reduce serum levels of anti-double-stranded DNA antibodies or renal immune complexes but did decrease macrophage infiltration, which is a marker of chronic inflammation. Immunohistochemical and FACS analyses revealed that P-Dex was primarily sequestered by proximal tubule epithelial cells, and that it could attenuate the inflammatory response in HK-2 cell culture. In contrast to Dex treatment, P-Dex treatment did not lead to any significant deterioration of bone quality or reduction in the level of total serum IgG. CONCLUSION: Macromolecularization of GCs renders them nephrotropic. Protracted retention, subcellular processing, and activation of GC prodrugs by kidney cells would potentiate nephritis resolution, with a reduced risk of systemic toxicities.

Bone intrinsic material and compositional properties in postmenopausal women diagnosed with long-term Type-1 diabetes.

The incidence of diabetes mellitus and the associated complications are growing worldwide, affecting the patients' quality of life and exerting a considerable burden on health systems. Yet, the increase in fracture risk in type 1 diabetes (T1D) patients is not fully captured by bone mineral density (BMD), leading to the hypothesis that alterations in bone quality are responsible for the increased risk. Material/compositional properties are important aspects of bone quality, yet information on human bone material/compositional properties in T1D is rather sparse. The purpose of the present study is to measure both the intrinsic material behaviour by nanoindentation, and material compositional properties by Raman spectroscopy as a function of tissue age and microanatomical location (cement lines) in bone tissue from iliac crest biopsies from postmenopausal women diagnosed with long-term T1D (N = 8), and appropriate sex-, age-, BMD- and clinically-matched controls (postmenopausal women; N = 5). The results suggest elevation of advanced glycation endproducts (AGE) content in the T1D and show significant differences in mineral maturity / crystallinity (MMC) and glycosaminoglycan (GAG) content between the T1D and control groups. Furthermore, both hardness and modulus by nanoindentation are greater in T1D. These data suggest a significant deterioration of material strength properties (toughness) and compositional properties in T1D compared with controls.

Intrinsic material properties of trabecular bone by nanoindentation testing of biopsies taken from healthy women before and after menopause.

Postmenopausal osteoporosis in women is characterized by an increase in bone fragility and risk of fracture. In addition to transmenopausal decline in three-dimensional trabecular bone architecture, changes in intrinsic material properties (local stiffness, damping, and hardness) may contribute to increased bone fragility. In this study, nanoindentation was used to quantify transmenopausal changes in the intrinsic properties of trabecular bone. Paired transilial biopsy specimens were used from a previously reported study in which bone biopsies were obtained from women prior to menopause (premenopausal, age 49.0 ± 1.9) and at 12 months past the last menstrual period (postmenopausal, age 54.6 ± 2.2). Elastic and viscoelastic material properties of the trabecular bone were measured using quasi-static and dynamic nanoindentation techniques, respectively. Paired Student's t tests (n = 15) were performed to assess the significance of the measured intrinsic properties. Trabecular bone microarchitecture is compromised in postmenopausal women, and although this loss is associated with a trend toward reduction in some intrinsic properties (storage modulus), we found no statistically significant changes in bone intrinsic properties between healthy pre- and postmenopausal biopsies in the quasi-static results and frequency-averaged dynamic results.

Evaluation of functional groups on amino acids in cyclic tetrapeptides in histone deacetylase inhibition.

The naturally occurring cyclic tetrapeptide, chlamydocin, originally isolated from fungus Diheterospora chlamydosphoria, consists of α-aminoisobutyric acid, L-phenylalanine, D-proline and an unusual amino acid (S)-2-amino-8-((S)-oxiran-2-yl)-8-oxooctanoic acid (Aoe) and inhibits the histone deacetylases (HDACs), a class of regulatory enzymes. The epoxyketone moiety of Aoe is the key functional group for inhibition. The cyclic tetrapeptide scaffold is supposed to play important role for effective binding to the surface of enzymes. In place of the epoxyketone group, hydroxamic acid and sulfhydryl group have been applied to design inhibitor ligands to zinc atom in catalytic site of HDACs. In the research for more potent HDAC inhibitors, we replaced the epoxyketone moiety of Aoe with different functional groups and synthesized a series of chlamydocin analogs as HDAC inhibitors. Among the functional groups, methoxymethylketone moiety showed as potent inhibition as the hydroxamic acid. On the contrary, we confirmed that borate, trifruoromethylketone, and 2-aminoanilide are almost inactive in HDAC inhibition.

Preliminary investigation of 48V-labeled VO(acac)2 for cancer imaging: An initial proof-of-concept study.

In this preliminary study, a procedure for synthesizing novel PET radiotracer vanadium-48-labeled-vanadyl acetylacetonate was developed, including radioisotope production via cyclotron, separation of 48V, chelation as 48VO(acac)2, and assessment through in vitro cellular studies. We employed the beam-stop setup in a cyclotron as the target holder to irradiate titanium foils in the reaction of natTi (p,n)48V. The radioisotope production rate was 4.84 ± 0.67 µCi/µA-h. Overall radiochemical yield was 12.86 ± 0.51% with gamma-ray spectroscopy showing no detectable contaminant peaks. HPLC of 48VO(acac)2 showed a retention time (1:48) corresponding closely to that (1:50) of commercial VO(acac)2, verifying the successful synthesis of 48VO(acac)2. In vitro cellular studies demonstrated radiotracer uptake and saturation around 0.48 nM. These studies pave the way for improving methodologies and in vivo experiments, including imaging studies, in future investigations.

A pilot study on the nanoscale properties of bone tissue near lacunae in fracturing women.

The goal of this study is to investigate the causes of osteoporosis-related skeletal fragility in postmenopausal women. We hypothesize that bone fragility in these individuals is largely due to mineral, and/or intrinsic material properties in the osteocyte lacunar/peri-lacunar regions of bone tissue. Innovative measurements with nanoscale resolution, including scanning electron microscope (SEM), an atomic force microscope that is integrated with infrared spectroscopy (AFM-IR), and nanoindentation, were used to characterize osteocyte lacunar and peri-lacunar properties in bone biopsies from fracturing (Cases) and matched (Age, BMD), non-fracturing (Controls) postmenopausal healthy women. In the peri-lacunar space, the nanoindentation results show that the modulus and hardness of the Controls are lower than the Cases. The AFM-IR results conclusively show that the mineral matrix, maturity (peak) (except in outer/far regions in Controls) were greater in Controls than in Cases. Furthermore, these results indicate that while mineral-to-matrix area ratio tend to be greater, the mineral maturity and crystallinity peak ratio "near" lacunae is greater than at regions "far" or more distance from lacunae in the Controls only. Due to the heterogeneity of bone structure, additional measurements are needed to provide more convincing evidence of altered lacunar characteristics and changes in the peri-lacunar bone as mechanisms related to postmenopausal women and fragility. Such findings would motivate new osteocyte-targeted treatments to reduce fragility fracture risks in these groups.

Intrinsic material properties of cortical bone.

The G171V mutation (high bone mass, HBM) is autosomal dominant and is responsible for high bone mass in humans. Transgenic HBM mice in which the human LRP5 G171V gene is inserted also show a similar phenotype with greater bone mass and biomechanical performance than wild-type mice, as determined by whole bone testing. Whole bone mechanics, however, depend jointly on bone mass, architecture, and intrinsic bone tissue mechanical properties. To determine whether the HBM mutation affects tissue-level biomechanical performance, we performed nano-indentation testing of unembedded cortical bone from HBM mice and their nontransgenic (NTG) littermates. Femora from 17-week-old mice (female, 8 mice/genotype) were subjected to nano-indentation using a Triboscope (Hysitron, Minneapolis, MN, USA). For each femoral specimen, approximately 10 indentations were made on the midshaft anterior surface with a target force of either 3 or 9 mN at a constant loading rate of 400 mN/s. The load-displacement data from each test were used to calculate indentation modulus and hardness for bone tissue. The intrinsic material property that reflected the bone modulus was greater (48%) in the HBM as compared to the NTG mice. Our results of intrinsic properties are consistent with the published structural and material properties of the midshaft femur in HBM and NTG mice. The greater intrinsic modulus in HBM reflects greater bone mineral content as compared to NTG (wild-type, WT) mice. This study suggests that the greater intrinsic property of cortical bone is derived from the greater bone mineral content and BMD, resulting in greater bone strength in HBM as compared to NTG (WT) mice.

Addition of fructooligosaccharides and dried plum to soy-based diets reverses bone loss in the ovariectomized rat.

Dietary bioactive components that play a role in improving skeletal health have received considerable attention in complementary and alternative medicine practices as a result of their increased efficacy to combat chronic diseases. The objectives of this study were to evaluate the additive or synergistic effects of dried plum and fructooligosaccharides (FOS) and to determine whether dried plum and FOS or their combination in a soy protein-based diet can restore bone mass in ovarian hormone deficient rats. For this purpose, 72 3-month-old female Sprague-Dawley rats were divided into six groups (n = 12) and either ovariectomized (Ovx, five groups) or sham-operated (sham, one group). The rats were maintained on a semipurified standard diet for 45 days after surgery to establish bone loss. Thereafter, the rats were placed on one of the following dietary treatments for 60 days: casein-based diet (Sham and Ovx), soy-based diet (Ovx + soy) or soy-based diet with dried plum (Ovx + soy + plum), FOS (Ovx + soy + FOS) and combination of dried plum and FOS (Ovx + soy + plum + FOS). Soy protein in combination with the test compounds significantly improved whole-body bone mineral density (BMD). All test compounds in combination with soy protein significantly increased femoral BMD but the combination of soy protein, dried plum and FOS had the most pronounced effect in increasing lumbar BMD. Similarly, all of the test compounds increased ultimate load, indicating improved biomechanical properties. The positive effects of these test compounds on bone may be due to their ability to modulate bone resorption and formation, as shown by suppressed urinary deoxypyridinoline excretion and enhanced alkaline phosphatase activity.

Biotin immunoassay interference: A UK-based prevalence study.

BACKGROUND: Biotin interference in biotin-streptavidin-based immunoassays is increasingly reported due to individuals taking biotin-containing supplements and patients prescribed biotin. The reported prevalence of serum biotin above the lowest threshold (≥10 µg/L) for interference in Roche Diagnostics immunoassay tests is 0.8% in Australia and 7.4% in the USA. There are, however, no such data in UK populations. In a service evaluation, we therefore studied the prevalence of biotin interference in routine serum samples received in our laboratory. METHODS: Biotin was measured in 524 anonymized surplus serum samples in which at least one immunoassay test had been requested. RESULTS: The median (95% confidence intervals) for serum biotin was 0.27 µg/L (0.07-0.93 µg/L). Serum biotin was <10 µg/L in all samples, <5 µg/L in 522 (99.6%) and <1 µg/L in 513 (98.1%) samples. In four samples, serum biotin was ≥2.5 µg/L (0.8%). CONCLUSIONS: These data indicate that the probability of biotin immunoassay interference in our patient population is extremely low, with the exception of assays reporting the lowest interference thresholds (e.g. Ortho Troponin I assay [threshold ≥2.5 µg/L]).

Osteocyte Wnt/ß-catenin pathway activation upon mechanical loading is altered in ovariectomized mice.

Estrogen levels decline in both sexes with age, but more dramatically in females. Activation of the Wnt/ß-catenin signaling pathway is central to the regulation of bone mass accrual and maintenance and in response to mechanical loading. Using the ovariectomized mouse model we examined the effect of estrogen loss on the osteocyte's ability to activate the Wnt/ß-catenin pathway following mechanical loading. Female TOPGAL mice underwent ovariectomy (OVX) (n = 10) or sham surgery (n = 10) at 16 weeks of age. Four weeks post-surgery, a single loading session (global strain of 2200 µÎµ for 100 cycles at 2 Hz) was performed on the right forearm with the left as a non-loaded control. Mice (n = 5) were sacrificed at 1 or 24 hr post-load. Ulnae were stained for ß-catenin activation, femurs were used for µCT and 3-pt bending/biomechanical testing, and tibiae were used for histology analysis and to determine osteocyte lacunar size using SEM and high resolution micro-XCT. A 2.2-fold increase in ß-catenin signaling activation was observed 24 hr post-load in the Sham group but did not occur in the OVX group. The OVX group versus control had significant losses (p < 0.05) in trabecular BMD (-8%), BV/TV (-35%) and thickness (-23%), along with cortical thickness (-6%) and periosteal perimeter (-4%). The OVX group had significantly higher trabecular bone osteoclast numbers (63%), OCS/BS (77%) and N.OC/BPm (94%) and a significant decrease in osteoblast number (53%), OBS/BS (37%) and N.OB/BPm (40%) compared to the sham group (p < 0.05). Cortical bone lacunar number/lacunar volume and bone biomechanical properties did not change between groups. Given that the ulna is a cortical bone loading model and the lack of changes in osteocyte lacunar number/volume in cortical bone, which would alter strains experienced by osteocytes, these data suggest the absence of estrogen resulted in intrinsic changes in the ability of the osteocyte to respond to mechanical load, rather than changes in the biomechanical and architectural properties of bone.

Altered collagen chemical compositional structure in osteopenic women with past fractures: A case-control Raman spectroscopic study.

Incidences of low-trauma fractures among osteopenic women may be related to changes in bone quality. In this blinded, prospective-controlled study, compositional and heterogeneity contributors of bone quality to fracture risk were examined. We hypothesize that Raman spectroscopy can differentiate between osteopenic women with one or more fractures (cases) from women without fractures (controls). This study involved the Raman spectroscopic analysis of cortical and cancellous bone composition using iliac crest biopsies obtained from 59-cases and 59-controls, matched for age (62.0 ± 7.5 and 61.7 ± 7.3 years, respectively, p = 0.38) and hip bone mineral density (BMD, 0.827 ± 0.083 and 0.823 ± 0.072 g/cm3, respectively, p = 0.57). Based on aggregate univariate case-control and odds ratio based logistic regression analyses, we discovered two Raman ratiometric parameters that were predictive of past fracture risk. Specifically, 1244/1268 and 1044/959 cm-1 ratios, were identified as the most differential aspects of bone quality in cortical cases with odds ratios of 0.617 (0.406-0.938 95% CI, p = 0.024) and 1.656 (1.083-2.534 95% CI, p = 0.020), respectively. Both 1244/1268 and 1044/959 cm-1 ratios exhibited moderate sensitivity (59.3-64.4%) but low specificity (49.2-52.5%). These results suggest that the organization of mineralized collagen fibrils were significantly altered in cortical cases compared to controls. In contrast, compositional and heterogeneity parameters related to mineral/matrix ratios, B-type carbonate substitutions, and mineral crystallinity, were not significantly different between cases and controls. In conclusion, a key outcome of this study is the significant odds ratios obtained for two Raman parameters (1244/1268 and 1044/959 cm-1 ratios), which from a diagnostic perspective, may assist in the screening of osteopenic women with suspected low-trauma fractures. One important implication of these findings includes considering the possibility that changes in the organization of collagen compositional structure plays a far greater role in postmenopausal women with osteopenic fractures.

Effects of glucocorticoid treatment on bone strength.

Glucocorticoids (GCs) are prescribed for the treatment of several diseases, but their long-term use causes osteoporosis. Current research suggests that GCs suppress the canonical Wnt/beta pathway, resulting in decreased expression of critical bone proteins. This study examined how bone structure and strength of high bone mass (HBM) mice and low density lipoprotein receptor-related protein 5 (LRP5) knockout (KO+/-) mice are affected by GC treatment in comparison to wild-type (WT) mice, and if changes were specific to either trabecular or cortical bone. Mice were treated with either prednisone or placebo. The femurs and L4 vertebral bodies were analyzed by micro-CT for structure and mechanically tested to determine strength and apparent material strength properties. Differences in all measured variables corresponding to GC treatment and genotype were tested using two-way ANOVA. GC treatment caused decreased structural strength parameters, weakened apparent material strength properties, and disruption of bone structure in HBM, but not LRP5+/- or WT, mice. Despite treatment-related loss, trabecular bone structure and strength remained elevated as compared to LRP5+/- and WT mice. In HBM femurs, both cortical and trabecular structure, but not strength parameters, were negatively affected by treatment. In HBM vertebral bodies, both structural and strength parameters were negatively affected by treatment.

Cigarette smoke-induced effects on bone marrow B-cell subsets and CD4+:CD8+ T-cell ratios are reversed by smoking cessation: influence of bone mass on immune cell response to and recovery from smoke exposure.

Cigarette smoking adversely affects the immune system, and is a risk factor for developing osteoporosis. How smoking contributes to osteoporosis is unclear, but since lymphocytes help maintain bone homeostasis and lymphocyte depletion results in bone loss, one potential mechanism for how smoke exposure promotes osteoporosis is by reducing bone marrow lymphocytes. Since the risk for developing osteoporosis is reportedly greater in smokers with polymorphisms in LRP5, a gene involved in canonical Wnt signaling that regulates bone metabolism, smoking-induced effects on lymphocytes may be influenced by Lrp5 functionality. To test these possibilities, we examined how the duration and cessation of cigarette smoke exposure affects lymphocyte distribution and function in normal mice and mice predisposed to low or high bone mass due to disruption or mutation of Lrp5. We find that, independent of genotype, mice exposed to cigarette smoke for 3-12 weeks showed a significant reduction in bone marrow B220(+)CD43(-) B cells and splenic transitional T1 B cells, and exhibited a splenic CD4(+):CD8(+) T-cell ratio that was skewed toward CD8(+) T cells. Smoke exposure had little or no effect on other lymphocyte subsets or on lymphocyte function ex vivo. Interestingly, these differences were no longer apparent after 6 weeks without smoke exposure, except in mice with high bone mass where bone marrow B220(+)CD43(-) B cells failed to fully recover. These data provide the first evidence that smoke exposure reduces bone marrow B cells, providing a plausible mechanism for how smoking contributes to osteoporosis.

Trabecular bone score and transilial bone trabecular histomorphometry in type 1 diabetes and healthy controls.

Patients with type 1 Diabetes Mellitus (T1DM) have an increased risk of fracture. Little is known about the microarchitecture of trabecular bone in T1DM, which may account for some of the increased risk. We report here a secondary analysis comparing Trabecular Bone Score (TBS) derived from DXA to 2-D histomorphometric and 3-D micro-computerized tomography (CT) variables obtained from iliac biopsies in 83 subjects (29 T1DM and 54 controls). The transilial bone biopsy specimens were fixed, embedded and scanned using a desktop micro-CT at 16 µm resolution. They were then sectioned and quantitative histomorphometry was performed. TBS of the anterior/posterior (AP) spine was obtained by re-analysis of AP lumbar spine DXA images. Overall, there were no differences in TBS, histomorphometry or micro-CT measurements between T1DM and controls. There was a significant association between TBS and 2-D BV/TV using multivariable linear regression after adjusting for group, age and gender. For every 1 unit increase in 2-D BV/TV, TBS increases by 0.0036 units after adjusting for group, gender and age. In conclusion, T1DM does not result in abnormal TBS, histomorphometric or micro-CT variables in young T1DM patients in the absence of diabetic complications. TBS is a good surrogate measure for trabecular microarchitecture.