Mechanical Overload Regulates Osteoblast Proliferation, Differentiation And Mineralization Through Wnt/Β-Catenin Signaling Pathway

Objectives: To study the effect of mechanical overload stimulation on proliferation, differentiation and mineralization of osteoblast and the underlying mechanisms.Methods: MC3T3-E1 cells were divided into overload group and control group. Four-point bending loading device was used to exert mechanical overload stimulation on MC3T3-E1 cells for a certain time. The proliferation of osteoblasts was detected by MTT colorimetric assay. Real-time PCR and Western Blot were used to detect the transcription and expression of osteoblast marker genes and proteins. The specific fluorescent dyes were used to label the actin filament and the nucleus, and the changes of cytoskeleton were observed under laser scanning confocal microscope. The mineralization of osteoblasts was evaluated by the number of calcium nodules formed by alizarin red staining. Results: Compared with the control group, the mechanical overload group significantly inhibited the proliferation of osteoblasts (p <0.05). Real-time PCR and Western Blot showed that the expression of osteoblast differentiation marker gene and protein was inhibited by mechanical overload stimulation. Under laser confocal microscopy, the overload group cell shrinkage deformation was observed, also the microfilament arrangement disorder, the skeleton arrangement loose, the direction difference and the skeleton breakage, but the nucleus does not have obvious change. Alizarin red staining showed that mechanical overload inhibited the formation of calcium nodules in osteoblasts. The expression of β-catenin protein in Wnt signaling pathway was inhibited by overload mechanical stimulation under immunofluorescence microscopy.Conclusion: Mechanical overload stimulation reduces the expression of Runx 2 by affecting the classical Wnt/β-catenin signaling pathway, thus it was inhibited osteoblast proliferation, differentiation and mineralization.

A ATUAÇÃO DA FISIOTERAPIA NA PREVENÇÃO DA SÍNDROME DO ESTRESSE TIBIAL MEDIAL EM CORREDORES

Medial tibial stress syndrome is a common injury due to mechanical overload, especially in athletes, causing local inflammation and bone stress. Street running has become increasingly popular, being one of the most practiced physical activities in recent years. The aim of this research is to identify how the assistance of sports physiotherapy professionals would contribute to the care offered to the runner with regards to the prevention of the syndrome. The methodology present in this study is based on a literature review research. The role of the physiotherapist is essential to prevent medial tibial stress, since this professional will be able to guide the runner during his activity. Once injured, the initial treatment requires resting and caring and a pause in the running activity, so that the physiotherapist can treat the injury, and in this way, the runner progressively tends to return to training and running.

The Regulation of Polyamine Pathway Proteins in Models of Skeletal Muscle Hypertrophy and Atrophy - a potential role for mTORC1

Polyamines have been shown to be absolutely required for protein synthesis and cell growth. The serine/threonine kinase, the mechanistic target of rapamycin complex 1 (mTORC1), also plays a fundamental role in the regulation of protein turnover and cell size, including in skeletal muscle, where mTORC1 is sufficient to increase protein synthesis and muscle fiber size, and is necessary for mechanical overload-induced muscle hypertrophy. Recent evidence suggests that mTORC1 may regulate the polyamine metabolic pathway; however, there is currently no evidence in skeletal muscle. This study examined changes in polyamine pathway proteins during muscle hypertrophy induced by mechanical overload (7 d), with and without the mTORC1 inhibitor, rapamycin, and during muscle atrophy induced by food deprivation (48 h) and denervation (7 d) in mice. Mechanical overload induced an increase in mTORC1 signalling, protein synthesis and muscle mass, and these were associated with rapamycin-sensitive increases in adenosylmethione decarboxylase 1 (Amd1), spermidine synthase (SpdSyn) and c-Myc. Food deprivation decreased mTORC1 signalling, protein synthesis and muscle mass, accompanied by a decrease in spermidine/spermine acetyltransferase 1 (Sat1). Denervation, resulted increased mTORC1 signalling and protein synthesis, and decreased muscle mass, which was associated with an increase in SpdSyn, spermine synthase (SpmSyn) and c-Myc. Combined, these data show that polyamine pathway enzymes are differentially regulated in models of altered mechanical and metabolic stress, and that Amd1 and SpdSyn are, in part, regulated in a mTORC1-dependent manner. Furthermore, these data suggest that polyamines may play a role in the adaptive response to stressors in skeletal muscle.

Epicondylopathia humeri radialis

Background Lateral epicondylitis is a common orthopaedic condition often massively restricting the quality of life of the affected patients. There are a wide variety of treatment options – with varying levels of evidence. Method The following statements and recommendations are based on the current German S2k guideline Epicondylopathia radialis humeri (AWMF registry number: 033 – 2019). All major German specialist societies participated in this guideline, which is based on a systematic review of the literature and a structured consensus-building process. Outcomes Lateral epicondylitis should be diagnosed clinically and can be confirmed by imaging modalities. The Guidelines Commission issues recommendations on clinical and radiological diagnostic workup. The clinical condition results from the accumulated effect of mechanical overload, neurologic irritation and metabolic changes. Differentiating between acute and chronic disorder is helpful. Prognosis of non-surgical regimens is favourable in most cases. Most cases spontaneously resolve within 12 months. In case of unsuccessful attempted non-surgical management for at least six months, surgery may be considered as an alternative, if there is a corresponding structural morphology and clinical manifestation. At present, it is not possible to recommend a specific surgical procedure. Conclusion This paper provides a summary of the guideline with extracts of the recommendations and statements of its authors regarding the pathogenesis, prevention, diagnostic workup as well as non-surgical and surgical management.

Left ventricular unloading and the role of ECpella

The main reason for the emergency implantation of venoarterial extracorporeal membrane oxygenation (VA-ECMO) is the restoration of adequate systemic perfusion, while protecting the failing heart and promoting myocardial recovery are equally important goals. Following initial haemodynamic stabilization and often the urgent revascularization of the culprit lesion, the clinical focus is then directed towards the most efficient strategy for cardioprotection. Frequent echocardiography measurements may help to estimate the degree of unwanted left ventricular (LV) overloading during VA-ECMO. Additionally, the estimation of high LV filling pressures by Doppler echocardiography or their (in-)direct measurement using a dedicated surgical left atrial pressure line and conventional pulmonary artery catheter in a wedge position or a pigtail catheter in the left ventricle can be performed. Mechanical overload of the left ventricle is the major adverse effect and an obvious mechanistic and prognostic challenge of contemporary ECMO care. Many efforts are under way to overcome this phenomenon by LV unloading, which was effectively achieved by the current combined approach using an axial decompression device, while novel technical developments and approaches are tested and urgently anticipated. The aim of this report is to introduce in depth pathophysiological background, current concepts, and future perspectives in LV unloading strategies.

What do we know about hallux valgus pathogenesis?

Objective: This work performs a critical review of the different causes described to explain the etiopathogenesis of hallux valgus. Methods: The authors divide the causal factors into two groups: extrinsic and intrinsic factors. In the first group, footwear and mechanical overload caused by different causes such as ballet, trauma, long walks, obesity, etc., should be considered. In the second group we include a series of factors: constitutional ones, such as heredity, sex and age; anatomical aspects, among which we must highlight the morphology and obliquity of the metatarsocuneiform joint; hypermobility of the first ray; metatarsus primus varus; muscle function; and atavism. Results: Hallux valgus probably has a multifactorial etiology whose triggering factor is unknown at the moment. Conclusion: If we know the etiopathogenesis of a deformity, in this case hallux valgus, we can perform a treatment as early and effective as possible. Level of Evidence V; Therapeutic Studies; Expert Opinion.

Pasta packaging with bio-based barrier to prevent insect infestation

The results of the infestation by maize weevil, Sitophilus zeamais (Coleoptera, Curculionidae) in various packages filled with pasta are presented. Three different types of packaging were used, i.e. two paper tubes (a novel one laminated with bio-based polyethylene and one without lamination) and a commercially available polypropylene pillow pouch packaging. Material properties such as moisture and water resistance and compressive strength were analysed. The results obtained showed that adult maize weevils revealed significant preferences to penetrate the pasta packaging through the already existing holes that were present in the polypropylene packaging, whereas no infestation was observed inside the paper tube packaging. The study showed that the shape and construction, e.g. tube packaging with an innovative bio-polyethylene film, is very effective against insect infestation and mechanical overload.

Caloric restriction mimetics for the treatment of cardiovascular diseases

Caloric restriction mimetics (CRMs) are emerging as potential therapeutic agents for the treatment of cardiovascular diseases. CRMs include natural and synthetic compounds able to inhibit protein acetyltransferases, to interfere with acetyl coenzyme A biosynthesis, or to activate (de)acetyltransferase proteins. These modifications mimic the effects of caloric restriction, which is associated with the activation of autophagy. Previous evidence demonstrated the ability of CRMs to ameliorate cardiac function and reduce cardiac hypertrophy and maladaptive remodelling in animal models of ageing, mechanical overload, chronic myocardial ischaemia, and in genetic and metabolic cardiomyopathies. In addition, CRMs were found to reduce acute ischaemia–reperfusion injury. In many cases, these beneficial effects of CRMs appeared to be mediated by autophagy activation. In the present review, we discuss the relevant literature about the role of different CRMs in animal models of cardiac diseases, emphasizing the molecular mechanisms underlying the beneficial effects of these compounds and their potential future clinical application.