Combined Effects of Botulinum Toxin Injection and Hind Limb Unloading on Bone and Muscle

Bone receives mechanical stimulation from two primary sources, muscle contractions and external gravitational loading; but the relative contribution of each source to skeletal health is not fully understood. Understanding the most effective loading for maintaining bone health has important clinical implications for prescribing physical activity for the treatment or prevention of osteoporosis. Therefore, we investigated the relative effects of muscle paralysis and reduced gravitational loading on changes in muscle mass, bone mineral density, and microarchitecture. Adult female C57Bl/6J mice (n = 10/group) underwent one of the following: unilateral botulinum toxin (BTX) injection of the hind limb, hind limb unloading (HLU), both unilateral BTX injection and HLU, or no intervention. BTX and HLU each led to significant muscle and bone loss. The effect of BTX was diminished when combined with HLU, though generally the leg that received the combined intervention (HLU+BTX) had the most detrimental changes in bone and muscle. We found an indirect effect of BTX affecting the uninjected (contralateral) leg that led to significant decreases in bone mineral density and deficits in muscle mass and bone architecture relative to the untreated controls; the magnitude of this indirect BTX effect was comparable to the direct effect of BTX treatment and HLU. Thus, while it was difficult to definitively conclude whether muscle force or external gravitational loading contributes more to bone maintenance, it appears that BTX-induced muscle paralysis is more detrimental to muscle and bone than HLU.National Institutes of Health (U.S.) (H R21 AR057522)United States. National Aeronautics and Space Administration (NNX10AE39G)National Space Biomedical Research Institute (NASA NCC 9-58)United States. National Aeronautics and Space Administration (NASA-Jenkins predoctoral fellowship)Northrop Grumman Corporation (Aerospace Systems PhD Training Fellowship

Modulation of the immune response by nematode secreted acetylcholinesterase revealed by heterologous expression in Trypanosoma musculi

Nematode parasites secrete molecules which regulate the mammalian immune system, but their genetic intractability is a major impediment to identifying and characterising the biological effects of these molecules. We describe here a novel system for heterologous expression of helminth secreted proteins in the natural parasite of mice, Trypanosoma musculi, which can be used to analyse putative immunomodulatory functions. Trypanosomes were engineered to express a secreted acetylcholinesterase from Nippostrongylus brasiliensis. Infection of mice with transgenic parasites expressing acetylcholinesterase resulted in truncated infection, with trypanosomes cleared early from the circulation. Analysis of cellular phenotypes indicated that exposure to acetylcholinesterase in vivo promoted classical activation of macrophages (M1), with elevated production of nitric oxide and lowered arginase activity. This most likely occurred due to the altered cytokine environment, as splenocytes from mice infected with T. musculi expressing acetylcholinesterase showed enhanced production of IFNγ and TNFα, with diminished IL-4, IL-13 and IL-5. These results suggest that one of the functions of nematode secreted acetylcholinesterase may be to alter the cytokine environment in order to inhibit development of M2 macrophages which are deleterious to parasite survival. Transgenic T. musculi represents a valuable new vehicle to screen for novel immunoregulatory proteins by extracellular delivery in vivo to the murine host

Sequential High-Impact Loading and Zoledronic Acid Before Hindlimb Unloading Protects Against Decrements in Bone Microarchitecture and Strength

The purpose of our investigation was to evaluate the efficacy of prophylactic interventions consisting of impact loading (free-fall landing) and/or a bisphosphonate (zoledronic acid), to counter disuse-induced bone loss of adult male rats (6 months old) subjected to 28 days of hindlimb unloading. Furthermore, we aimed to define the effects of these treatments on mechanical strength properties and bone turnover. We hypothesized that monotherapy would mitigate adverse alterations in bone mass, microarchitecture, and strength, while the combined sequential treatment would completely prevent them. Animals were assigned to one of six groups (n=12 each): baseline control (BC, euthanized on study day 0), cage control (CC), hindlimb unloading (HU), zoledronic acid treatment plus hindlimb unloading (ZA+HU), impact loading treatment plus hindlimb unloading (IL+HU), and impact loading and zoledronic acid treatments plus hindlimb unloading (IL+ZA+HU). IL animals were dropped 25 times (five drops from 30 cm followed by 20 drops from 60 cm) three times per week for the first five weeks of the study. ZA (60 μg/kg body weight) was administered on day 36, immediately following IL and just prior to HU. HU began on day 37 and persisted for four weeks. At the distal femur metaphysis (DFM) and femoral neck (FN), HU caused declines in cancellous bone volume fraction (BV/TV, -25%) and total volumetric bone mineral density (vBMD, -14%), respectively, compared to CC. Mechanical strength and bone turnover were also impaired due to unloading. Individually, IL and ZA attenuated HU-induced changes in mass, microarchitecture, and strength, but when given sequentially, IL+ZA fully rescued them. While HU caused an uncoupling of bone remodeling, ZA treatment successfully reduced bone degradation without affecting bone formation. Treatment with IL followed by ZA resulted in enhanced DFM BV/TV (+20%) and trabecular thickness (Tb.Th, +5%). Also, FN ultimate force was highest with combination treatment. While IL and ZA alone attenuated the deleterious effects of disuse on bone quality, when the two were administered in sequence adult male rats were fully protected against HU-induced alterations in bone mass, microarchitecture, strength, and turnover

Predicting response to physiotherapy treatment for musculoskeletal shoulder pain : A systematic review

© 2013 Chester et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: People suffering from musculoskeletal shoulder pain are frequently referred to physiotherapy. Physiotherapy generally involves a multimodal approach to management that may include; exercise, manual therapy and techniques to reduce pain. At present it is not possible to predict which patients will respond positively to physiotherapy treatment. The purpose of this systematic review was to identify which prognostic factors are associated with the outcome of physiotherapy in the management of musculoskeletal shoulder pain. Methods. A comprehensive search was undertaken of Ovid Medline, EMBASE, CINAHL and AMED (from inception to January 2013). Prospective studies of participants with shoulder pain receiving physiotherapy which investigated the association between baseline prognostic factors and change in pain and function over time were included. Study selection, data extraction and appraisal of study quality were undertaken by two independent assessors. Quality criteria were selected from previously published guidelines to form a checklist of 24 items. The study protocol was prospectively registered onto the International Prospective Register of Systematic Reviews. Results: A total of 5023 titles were retrieved and screened for eligibility, 154 articles were assessed as full text and 16 met the inclusion criteria: 11 cohort studies, 3 randomised controlled trials and 2 controlled trials. Results were presented for the 9 studies meeting 13 or more of the 24 quality criteria. Clinical and statistical heterogeneity resulted in qualitative synthesis rather than meta-analysis. Three studies demonstrated that high functional disability at baseline was associated with poor functional outcome (p ≤ 0.05). Four studies demonstrated a significant association (p ≤ 0.05) between longer duration of shoulder pain and poorer outcome. Three studies, demonstrated a significant association (p ≤ 0.05) between increasing age and poorer function; three studies demonstrated no association (p > 0.05). Conclusion: Associations between prognostic factors and outcome were often inconsistent between studies. This may be due to clinical heterogeneity or type II errors. Only two baseline prognostic factors demonstrated a consistent association with outcome in two or more studies; duration of shoulder pain and baseline function. Prior to developing a predictive model for the outcome of physiotherapy treatment for shoulder pain, a large adequately powered prospective cohort study is required in which a broad range of prognostic factors are incorporated.Peer reviewe