Benzofuran pyran hybrid prevents glucocorticoid induced osteoporosis in mice via modulation of canonical Wnt/β-catenin signaling

AUTHORS

Ashish Kumar Tripathi, Divya Rai, Priyanka Kothari, Pragati Kushwaha, Koneni V. Sashidhara & Ritu Trivedi

ABSTRACT

Glucocorticoid induced osteoporosis (GIOP) is the second most leading cause of osteoporosis. We have identified a compound, a benzofuran pyran hybrid compound 4e that has osteogenic potential and we wanted to assess its efficacy in GIOP in male mice. We assessed the effect of dexamethasone and compound 4e on primary osteoblasts using various cell based and immunofluorescence assays. For in vivo studies we administered methylprednisolone and compound 4e as a prophylactic measure in male Balb/c mice for 28 days and then evaluated the effect on bone microarchitecture by microCT, bone formation by histology along with clinically relevant bone markers. Compound 4e preserved osteoblast differentiation as evident by higher ALP positive cells and mineralization in compound treated groups. Compound 4e also increased the expression of osteogenic genes. This compound guarded β-catenin expression both in vitro and in vivo as confirmed by western blot and immunofluorescence assays. This led to the preservation of bone microarchitecture and cortical thickness at 2.5 mg kg−1 and 5 mg kg−1 doses. Further compound 4e enhanced bone formation rate and regulated osteocyte death. The osteogenic potential of compound 4e was reflected by an increased level of serum marker osteocalcin and decreased levels of SOST and CTX-I. Overall, Compound 4e is able to overcome the catabolic effect of dexamethasone on bone by targeting the canonical WNT/β-catenin signaling as evidenced by both in vitro and in vivo studies.

Combined growth hormone and insulin-like growth factor 1 rescues growth retardation in glucocorticoid-treated mdx mice but does not prevent osteopenia

AUTHORS

Claire L Wood, Rob Van't Hof, Scott Dillon, Volker Straub, Sze C Wong, S Faisal Ahmed, Colin Farquharson

ABSTRACT

Short stature and osteoporosis are common in Duchenne muscular dystrophy (DMD) and its pathophysiology may include an abnormality of the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis, which is further exacerbated by long-term glucocorticoid (GC) treatment. Hence an agent that has anabolic properties and may improve linear growth would be beneficial in this setting and therefore requires further exploration. 5-week old x-linked muscular dystrophy (mdx) mice were used as a model of DMD. They were treated with prednisolone ± GH + IGF-1 for 4-weeks and then compared to comtrol mdx mice to allow the study of both growth and skeletal structure. GC reduced cortical bone area, bone fraction, tissue area and volume and cortical bone volume, as assessed by Micro computed tomography (CT) In addition, GC caused somatic and skeletal growth retardation, but improved grip strength. The addition of GH + IGF-1 therapy rescued the somatic growth retardation and induced additional improvements in grip strength (16.9% increase, p<0.05 compared to control). There was no improvement in bone microarchitecture (assessed by Micro-CT and static histomorphometry) or biomechanical properties (assessed by three-point bending). Serum bone turnover markers (P1NP, αCTX) also remained unaffected. Further work is needed to maximise these gains before proceeding to clinical trials in boys with DMD.

Diosmin, a citrus fruit-derived phlebotonic bioflavonoid protects rats from chronic kidney disease-induced loss of bone mass and strength without deteriorating the renal function

AUTHORS

Shivani Sharma, Konica Porwal, Chirag Kulkarni, Subhashis Pal, Praveer Sihota, Saroj Kumar, Mahesh Chandra Tiwari, Roshan Katekar, Ashish Kumar, Priya Singh, Swati Rajput, Rajdeep Guha, Navin Kumar, Jiaur R. Gayen, and Naibedya Chattopadhyay

ABSTRACT

Kidney Disease Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline has recommended treatment decisions for patients with chronic kidney disease (CKD) with osteoporosis and/or high risk of fracture. Bisphosphonates, the first-line anti-osteoporosis drugs have the concern of worsening kidney functions. Moreover, despite impaired bone formation in CKD patients, teriparatide, the formation-stimulating drug is not recommended. Thus, there is an urgent need for safe and effective treatment of osteoporosis in CKD patients. Here, in CKD rats, we tested the osteoprotective effect of diosmin, a citrus-derived bioflavonoid used as a phlebotonic in chronic venous insufficiency and has a renoprotective effect. CKD was developed by 5/6th nephrectomy and diosmin at the human equivalent dose (100 mg kg−1) did not advance renal failure but reduced blood pressure to the level of sham control. Fibroblast growth factor-23 and parathyroid hormone were increased in CKD and diosmin suppressed both. CKD reduced bone mass and deteriorated the microarchitecture of trabecular bones, and diosmin maintained both to control levels. Bone formation and strength were impaired in the CKD and diosmin maintained these levels to control levels. Nanoindentation of bone showed that diosmin significantly increased tissue hardness over the control. Diosmetin, the metabolic surrogate of diosmin had comparable pharmacokinetic profiles between the control and CKD groups. Furthermore, diosmetin (50 mg kg−1) protected against CKD-induced bone loss. These data suggest that diosmin and its metabolic surrogate, diosmetin protect against CKD-induced osteopenia. Since diosmin has no renal adverse effect and protected bone mass and strength in CKD rats, we propose assessing its anti-osteoporosis effect in CKD patients.

Impact of adolescent intermittent ethanol exposure on interneurons and their surrounding perineuronal nets in adulthood

AUTHORS

Carol A. Dannenhoffer, Alexander Gómez-A, Victoria A. Macht, Rayyanoor Jawad, E. Blake Sutherland, Ryan P. Vetreno, Fulton T. Crews, Charlotte A. Boettiger, Donita L. Robinson

ABSTRACT

Background Binge alcohol exposure during adolescence results in long-lasting alterations in brain and behavior. For example, adolescent intermittent ethanol (AIE) exposure in rodents results in long-term loss of functional connectivity among prefrontal cortex (PFC) and striatal regions as well as a variety of neurochemical, molecular, and epigenetic alterations. Interneurons in the PFC and striatum play critical roles in behavioral flexibility and functional connectivity. For example, parvalbumin (PV) interneurons are known to contribute to neural synchrony, and cholinergic interneurons contribute to strategy selection. Furthermore, extracellular perineuronal nets (PNNs) surround some interneurons, particularly PV+ interneurons, to further regulate cellular plasticity. The effect of AIE exposure on expression of these markers within the PFC is not well understood.

Methods The present study tested the hypothesis that AIE exposure reduces expression of PV+ and ChAT+ interneurons in the adult PFC and striatum and increases related expression of PNNs (marked by binding of Wisteria Floribunda agglutinin lectin; WFA) in adulthood. Male rats were exposed to AIE (5 g/kg/day, 2-days-on/2-days-off, i.g., P25-P54) or water (CON), and brain tissue was harvested in adulthood (> P80). Immunohistochemistry and co-immunofluorescence were used to assess expression of ChAT, PV, and WFA labeling within the adult PFC and striatum following AIE exposure.

Results ChAT and PV interneuron numbers in the striatum and PFC were unchanged after AIE exposure. However, WFA labeling in the PFC of AIE-exposed rats was increased compared to CON rats. Moreover, significantly more PV neurons were surrounded by WFA labeling in AIE-exposed subjects relative to controls in both PFC subregions assessed: the orbitofrontal cortex (CON = 34%; AIE = 40%) and the medial PFC (CON = 10%; AIE = 14%).

Conclusions These findings indicate that while PV interneuron expression in the adult PFC and striatum is unaltered following AIE exposure, PNNs surrounding these neurons (indicated by extracellular WFA binding) are increased. This increase in PNNs may restrict plasticity of the ensheathed neurons, thus contributing to impaired microcircuitry in frontostriatal connectivity and related behavioral impairments.

Bacterial infections exacerbate myeloma bone disease

AUTHORS

Rui Liu, Yuping Zhong, Rui Chen, Shiyi Chen, Yazhu Huang & Huan Liu

ABSTRACT

Multiple myeloma is characterized by osteolytic lesions caused by reduced bone formation and activated bone resorption. An important feature of myeloma is a failure of bone healing after successful treatment. In this work, clinical studies indicated a highly positive correlation between bone marrow bacteria abundance and bone lesion numbers of myeloma patients in complete remission. Coculture experiments demonstrated that marrow Escherichia coli (E. coli) promotes osteoclast differentiation and inhibits osteoblast differentiation. Mechanism studies showed that E. coli lipopolysaccharides (LPS) activated NF-κB p65 signaling and reduced phosphorylated smad1/5/9 binding ability with RUNX2 promoter, leading to decreased RUNX2 expression in osteoblast progenitors. Additionally, LPS enhanced phosphorylated NF-κB p65 binding ability with NFATc1 promoter, leading to increased NFATc1 expression in osteoclast progenitors. In vivo studies revealed E. coli contributes to osteolytic bone lesion, and elimination of E. coli infection assists healing of bone lesion in mouse model of myeloma in complete remission. These findings establish a heretofore unrecognized effect for E. coli in the genesis of myeloma bone disease and suggest a new treatment strategy.

Association between bone mineral metabolism and vascular calcification in end-stage renal disease

AUTHORS

Louise Aaltonen, Niina Koivuviita, Marko Seppänen, Heikki Kröger, Xiaoyu Tong, Eliisa Löyttyniemi & Kaj Metsärinne

ABSTRACT

Background

Development of vascular calcification is accelerated in patients with end-stage renal disease. In addition to traditional risk factors of cardiovascular disease (CVD) abnormal bone and mineral metabolism together with many other factors contribute to the excess cardiovascular burden in patients on dialysis. Aortic calcification score and coronary calcification score are predictive of CVD and mortality. The aim of this study was to evaluate the possible relationship between arterial calcification and bone metabolism.

Methods

Thirty two patients on dialysis were included. All patients underwent a bone biopsy to assess bone histomorphometry and a 18F-NaF PET scan. Fluoride activity was measured in the lumbar spine (L1 – L4) and at the anterior iliac crest. Arterial calcification scores were assessed by computerized tomography for quantification of coronary artery calcification score and lateral lumbar radiography for aortic calcification score.

Results

This study group showed high prevalence of arterial calcification and 59% had verified CVD. Both CAC and AAC were significantly higher in patients with verified CVD. Only 22% had low turnover bone disease. There was a weak association between fluoride activity, which reflects bone turnover, measured in the lumbar spine, and CAC and between PTH and CAC. There was also a weak association between erosion surfaces and AAC. No significant association was found between calcification score and any other parameter measured.

Conclusions

The results in this study highlight the complexity, when evaluating the link between bone remodeling and vascular calcification in patients with multiple comorbidities and extensive atherosclerosis. Several studies suggest an impact of bone turnover on development of arterial calcification and there is some evidence of reduced progression of vascular calcification with improvement in bone status. The present study indicates an association between vascular calcification and bone turnover, even though many parameters of bone turnover failed to show significance. In the presence of multiple other factors contributing to the development of calcification, the impact of bone remodeling might be diminished.

Trial registration

The study is registered in ClinicalTrials.gov protocol registration and result system, ID is NCT02967042. Date of registration is 17/11/2016.