Fructooligosaccharides act on the gut-bone axis to improve bone independent of Tregs and alter osteocytes in young adult C57BL/6 female mice

Targeting the gut-bone axis with probiotics and prebiotics is considered as a promising strategy to reduce the risk of osteoporosis. Gut-derived short chain fatty acids (SCFA) mediate the effects of probiotics on bone via Tregs, but it is not known whether prebiotics act through a similar mechanism. We investigated how 2 different prebiotics, tart cherry (TC) and fructooligosaccharide (FOS), affect bone, and whether Tregs are required for this response. Eight-wk-old C57BL/6 female mice were fed with diets supplemented with 10% w/w TC, FOS, or a control diet (Con; AIN-93M) diet, and they received an isotype control or CD25 Ab to suppress Tregs. The FOS diet increased BMC, density, and trabecular bone volume in the vertebra (~40%) and proximal tibia (~30%) compared to the TC and control diets (Con), irrespective of CD25 treatment. Both prebiotics increased (P < .01) fecal SCFAs, but the response was greater with FOS. To determine how FOS affected bone cells, we examined genes involved in osteoblast and osteoclast differentiation and activity as well as genes expressed by osteocytes. The FOS increased the expression of regulators of osteoblast differentiation (bone morphogenetic protein 2 [Bmp2], Wnt family member 10b [Wnt10b] and Osterix [Osx]) and type 1 collagen). Osteoclasts regulators were unaltered. The FOS also increased the expression of genes associated with osteocytes, including (Phex), matrix extracellular phosphoglycoprotein (Mepe), and dentin matrix acidic phosphoprotein 1 (Dmp-1). However, Sost, the gene that encodes for sclerostin was also increased by FOS as the number and density of osteocytes increased. These findings demonstrate that FOS has a greater effect on the bone mass and structure in young adult female mice than TC and that its influence on osteoblasts and osteocytes is not dependent on Tregs.

Interleukin (IL)-10 Is Important in the Maintenance of Trabecular and Cortical Bone and Protects Against Western Diet-Induced Disruption in Bone Remodeling in Mice

Objectives

The purpose of this study was to investigate if consumption of a western diet (WD) exacerbates the effects of loss of function of IL-10, an anti-inflammatory cytokine, on biomarkers of bone metabolism and microarchitecture.

Methods

Six-week-old male B6.129P2-Il10tm1Cgn/J (IL-10 KO) and C57BL/6 mice (WT) were randomized to treatment in a 2 × 2 factorial with diet (AIN-93 control diet CD vs WD) and strain (IL-10 KO vs WT) as factors. Due to potential influence of high fat on intestinal Ca absorption, a WD diet with added Ca (1.2 g/kg) was used. After 12 wks, whole body dual-energy x-ray absorptiometry scans were performed to assess bone density and body composition, and micro-computed x-ray tomography was used to evaluate trabecular and cortical bone microarchitecture in the femur and lumbar vertebra. Serum biomarkers of bone formation, procollagen 1 intact N-terminal propeptide (P1NP), and resorption, c-terminal telopeptide of type I collagen (CTX-1) were assessed.

Results

Body weight, but not % body fat, was lower (P &lt; 0.05) in IL-10 KO mice relative to WT controls. 12 weeks of WD increased (P &lt; 0.05) body weight and % fat, but the response was not as great in the IL-10 KO mice. Bone mineral density and content were lower in IL-10 KO mice compared to WT, and the WD had no effect on these parameters. The IL-10 KO mice exhibited a decrease in trabecular bone volume, thickness, and number, and an increase in trabecular separation and structure model index compared to WT mice within the femur and vertebrae. The WD had no effect on these trabecular bone parameters. Cortical bone thickness and area were reduced (P &lt; 0.05) and porosity increased in both the femur and vertebra of IL-10 KO mice relative to their WT counterparts. This strain effect was not altered by the WD. IL-10 KO mice exhibited a significantly lower serum PINP and higher CTX-1 compared to the WT mice. Despite the lack of structural changes in bone after 12 wks, the WD increased (P &lt; 0.05) CTX-1 and tended to suppress P1NP (P = 0.051) in the IL-10 KO mice compared to WT.

Conclusions

We conclude that IL-10 plays an important role in bone metabolism and maintaining structural properties and in the absence of IL-10, WD negatively affects both osteoclast and osteoblast activity. Further studies are warranted to determine if structural changes occur with longer exposure to WD.

Funding Sources

Oklahoma Agricultural Experiment Station.

Understanding How Sex Influences the Impact of IL-10 on Bone Microarchitecture and Bone Metabolism Over Time

Objectives

Dietary interventions with pre- and probiotics favorably affect the gut-bone axis, mediated in part by the anti-inflammatory cytokine, interleukin (IL)-10. This study sought to understand how IL-10’s impact on bone metabolism and microarchitecture differs with sex and time.

Methods

Six-week-old B6.129P2-Il10tm1Cgn/J (KO) and C57BL/6 (WT) mice were assigned in a 2 × 2 × 2 factorial design with strain (WT & KO), sex, and time (3 & 6 m) as factors. Mice were fed AIN-93G diet for 3 m followed by AIN-93 M for the study duration. Dual-energy x-ray absorptiometry was used to assess bone mineral content (BMC) and density (BMD). Micro-computed tomography was used to assess femur and lumbar vertebrae trabecular and cortical bone. Serum procollagen 1 intact N-terminal propeptide (P1NP) and C-terminal telopeptide of type I collagen (CTX-1), bone formation and resorption markers respectively, were assessed by ELISA. Data were analyzed using ANOVA; p &lt; 0.05 was considered significant.

Results

Reductions in BMC and BMD (P &lt; 0.05) in KO vs WT and at 3 vs 6 m were observed; a sex effect was found with reductions in BMC in KO females compared to KO males. Femoral trabecular bone volume (BV/TV) was lower (P &lt; 0.05) in KO vs WT, females vs males, and at 6 vs 3 m. Trabecular thickness (TbTh) decreased (P &lt; 0.05) in KO vs WT and increased from 3 to 6 m, while decreases in trabecular number (TbN) were greater (P &lt; 0.05) in KO mice, females, and at 6 m compared to counterparts. Cortical area and thickness were decreased (P &lt; 0.05) in KO vs WT and in females vs males, which was greater at 6 m, while cortical bone porosity was higher in KO vs WT and increased at 6 mo. Vertebral trabecular BV/TV was lower (P &lt; 0.05) in KO vs WT at 3 and 6 m, with KO females showing reduced BV/TV (P &lt; 0.05) from 3 to 6 m. Reduced TbTh and TbN were observed in KO vs WT, and females had increased (P &lt; 0.05) TbTh and trabecular separation and reduced TbN. P1NP showed a time effect (P &lt; 0.05) with reductions in WT females and males at 6 m compared to 3 m KO females (P &lt; 0.05). CTX-1 shows a sex effect (P &lt; 0.05) and a trending strain effect (P = 0.059), with elevated serum CTX-1 in 3 m KO males compared to WT and KO females at 6 m (P &lt; 0.05).

Conclusions

While IL-10 plays an important role in maintaining both trabecular and cortical bone, it may have a more protective effect on the cortical bone of female mice over time.

Funding Sources

Oklahoma Agricultural Experiment Station.

Detection of Tubercular Pleural Effusion by Molecular Technique PCR

Tuberculosis is a common cause of death in developing countries like Bangladesh. About 30% of pulmonary tubercular infected patients developed tubercular pleural effusion. Tubercular pleural effusion was diagnosed by cytological, biochemical and bacteriological methods. But these methods showed low sensitivity. In some cases pleural biopsy showed also negative results. Now a days molecular technique like Polymerase chain reaction (PCR) is promising method for diagnosis of pleural TB. PCR was done in 100 pleural fluid collected from suspected tubercular pleural effusion cases admitted in Mymensingh Medical College Hospital, Mymensingh, Bangladesh from January 2011 to January 2013. Among the 100 samples 3% were culture positive and PCR positive was 6%. Sensitivity and Specificity of PCR considering culture as a gold standard method was 100% and 96.71% respectively in this cross sectional study. Among them Adenosine deaminase (ADA) level is >40IU/L in all PCR positive sample. Where PCR is available, measurement of ADA activity as well as PCR can be done simultaneously.