Differential effects of cholecalciferol and calcitriol on muscle proteolysis and oxidative stress in angiotensin II-induced C2C12 myotube atrophy.

Renin-angiotensin system activation contributes to skeletal muscle atrophy in aging individuals with chronic diseases. We aimed to explore the effects of cholecalciferol (VD) and calcitriol (1,25VD) on signaling of muscle proteolysis and oxidative stress in myotubes challenged with angiotensin II (AII). The mouse C2C12 myotubes were assigned to vehicle, AII, AII + VD, AII + 1,25VD, and AII + losartan groups.

TGF-β1 stimulation and VDR-dependent activation modulate calcitriol action on skeletal muscle fibroblasts and Smad signalling-associated fibrogenesis.

Fibroblasts play a pivotal role in fibrogenesis after skeletal muscle injury. Excess fibrous formation can disrupt contractile functions and delay functional recovery. Although vitamin D receptor (VDR) is expressed explicitly in regenerating muscle compared with uninjured muscle, how calcitriol [1α,25(OH)D] directly regulates skeletal muscle primary fibroblast proliferation, the transition to myofibroblasts, and Smad signalling-associated fibrogenesis is currently unknown.

Autophagy-lysosomal signaling responses to heat stress in tenotomy-induced rat skeletal muscle atrophy.

Aims: The autophagy-lysosomal system plays a crucial role in maintaining muscle proteostasis. Excessive stimulation of the autophagic machinery is a major contributor to muscle atrophy induced by tendon transection. Hyperthermia is known to attenuate muscle protein loss during disuse conditions; however, little is known regarding the response of the autophagy pathway to heat stress following tenotomy-induced muscle atrophy.

Regulation of vitamin D system in skeletal muscle and resident myogenic stem cell during development, maturation, and ageing.

Skeletal muscle exhibits enormous plasticity throughout life, however, less is known regarding how the stages of growth regulate its local vitamin D system. Herein, we investigated serum 25(OH)D and Ca levels along with the vitamin D system in skeletal muscle and resident myogenic stem cells of male C57BL/6 mice during development, maturation, and ageing. Compared with development, significant increases in vitamin D receptor (VDR) protein expression in mature and aged muscles were associated with increased serum 25(OH)D and centronucleated fibres, respectively.

Heat stress ameliorates tenotomy-induced inflammation in muscle-specific response via regulation of macrophage subtypes.

During disuse-induced muscle atrophy, macrophages play a significant role in inflammatory responses that occur with muscle degeneration and repair. Heat treatment has been shown to alleviate muscle atrophy; however, the effect of heat on inflammatory responses following tenotomy has not been evaluated. This study examined the effects of heat stress on proinflammatory (M1-like) and anti-inflammatory (M2-like) macrophage populations.

Differential effects of heat stress on fibre capillarisation in tenotomised soleus and plantaris muscles.

Purpose: Capillary regression is commonly observed in response to disuse muscle atrophy. Heat stress is known to alleviate muscle atrophy, while effect of heat exposure on capillary adaptation following disuse atrophy is not defined. Here, we examined the effect of heat treatment on capillarisation and the associated signalling in slow-oxidative soleus and fast-glycolytic plantaris muscles following Achilles tendon ablation (tenotomy).

Effect of 20-Hydroxyecdysone on Proteolytic Regulation in Skeletal Muscle Atrophy.

Background/aim: 20-Hydroxyecdystone (20E) is an ecdysteroid hormone which controls molting and reproduction in arthropods. 20E also produces a variety of effects in vertebrates, including enhancing protein synthesis and skeletal muscle regeneration. The effect of 20E on disuse muscle atrophy has not been reported to date.

Effects of intramuscular administration of 1α,25(OH)2D3 during skeletal muscle regeneration on regenerative capacity, muscular fibrosis, and angiogenesis.

The recent discovery of the vitamin D receptor (VDR) in regenerating muscle raises the question regarding the action of vitamin D3 on skeletal muscle regeneration. To investigate the action of vitamin D3 on this process, the tibialis anterior muscle of male C57BL/6 mice (10 wk of age) was injected with 1.2% BaCl2 to induce extensive muscle injury.

Heat stress promotes extracellular matrix remodelling via TGF-β1 and MMP-2/TIMP-2 modulation in tenotomised soleus and plantaris muscles.

Purpose: Heat stress has been shown to reduce muscle atrophy and enhance muscle regeneration. However, the role of heat stress on extracellular matrix (ECM) remodelling remains poorly understood. Here, we examined the effect of heat exposure on intramuscular fibrosis and its associated signalling in soleus and plantaris muscles after tenotomy.

Effect of caffeine on bladder function in patients with overactive bladder symptoms.

Objectives: To evaluate the effect of caffeine at the dose of 4.5 mg/kg on bladder function in overactive bladder (OAB) adults.

Materials And Methods: Nine women and three men aged 21-40 years with OAB symptoms were included.