Number Of Muscle Fibers Research Articles

The spatiotemporal matching pattern of Ezrin/Periaxin involved in myoblast differentiation and fusion and Charcot-Marie-Tooth disease-associated muscle atrophy

BackgroundClinically, Charcot-Marie-Tooth disease (CMT)-associated muscle atrophy still lacks effective treatment. Deletion and mutation of L-periaxin can be involved in CMT type 4F (CMT4F) by destroying the myelin sheath form, which may be related to the inhibitory role of Ezrin in the self-association of L-periaxin. However, it is still unknown whether L-periaxin and Ezrin are independently or interactively involved in the process of muscle atrophy by affecting the function of muscle satellite cells.MethodA gastrocnemius muscle atrophy model was prepared to mimic CMT4F and its associated muscle atrophy by mechanical clamping of the peroneal nerve. Differentiating C2C12 myoblast cells were treated with adenovirus-mediated overexpression or knockdown of Ezrin. Then, overexpression of L-periaxin and NFATc1/c2 or knockdown of L-periaxin and NFATc3/c4 mediated by adenovirus vectors were used to confirm their role in Ezrin-mediated myoblast differentiation, myotube formation and gastrocnemius muscle repair in a peroneal nerve injury model. RNA-seq, real-time PCR, immunofluorescence staining and Western blot were used in the above observation.ResultsFor the first time, instantaneous L-periaxin expression was highest on the 6th day, while Ezrin expression peaked on the 4th day during myoblast differentiation/fusion in vitro. In vivo transduction of adenovirus vectors carrying Ezrin, but not Periaxin, into the gastrocnemius muscle in a peroneal nerve injury model increased the numbers of muscle myosin heavy chain (MyHC) I and II type myofibers, reducing muscle atrophy and fibrosis. Local muscle injection of overexpressed Ezrin combined with incubation of knockdown L-periaxin within the injured peroneal nerve or injection of knockdown L-periaxin into peroneal nerve-injured gastrocnemius muscle not only increased the number of muscle fibers but also recovered their size to a relatively normal level in vivo. Overexpression of Ezrin promoted myoblast differentiation/fusion, inducing increased MyHC-I+ and MyHC-II + muscle fiber specialization, and the specific effects could be enhanced by the addition of adenovirus vectors for knockdown of L-periaxin by shRNA. Overexpression of L-periaxin did not alter the inhibitory effects on myoblast differentiation and fusion mediated by knockdown of Ezrin by shRNA in vitro but decreased myotube length and size. Mechanistically, overexpressing Ezrin did not alter protein kinase A gamma catalytic subunit (PKA-γ cat), protein kinase A I alpha regulatory subunit (PKA reg Iα) or PKA reg Iβ levels but increased PKA-α cat and PKA reg II α levels, leading to a decreased ratio of PKA reg I/II. The PKA inhibitor H-89 remarkably abolished the effects of overexpressing-Ezrin on increased myoblast differentiation/fusion. In contrast, knockdown of Ezrin by shRNA significantly delayed myoblast differentiation/fusion accompanied by an increased PKA reg I/II ratio, and the inhibitory effects could be eliminated by the PKA reg activator N6-Bz-cAMP. Meanwhile, overexpressing Ezrin enhanced type I muscle fiber specialization, accompanied by an increase in NFATc2/c3 levels and a decrease in NFATc1 levels. Furthermore, overexpressing NFATc2 or knocking down NFATc3 reversed the inhibitory effects of Ezrin knockdown on myoblast differentiation/fusion.ConclusionsThe spatiotemporal pattern of Ezrin/Periaxin expression was involved in the control of myoblast differentiation/fusion, myotube length and size, and myofiber specialization, which was related to the activated PKA-NFAT-MEF2C signaling pathway, providing a novel L-Periaxin/Ezrin joint strategy for the treatment of muscle atrophy induced by nerve injury, especially in CMT4F.

TNF-α contributes to sarcopenia through caspase-8/caspase-3/GSDME-mediated pyroptosis

Sarcopenia has become a leading cause of disability and mortality in the elderly. It has been reported that programmed cell death (PCD) is associated with the development of sarcopenia that is characterized by reduction of muscle fiber size and number. TNF-α is also validated to play a prominent role in sarcopenia through its complex signaling pathways including cell death signaling. However, it is still unclear whether TNF-α contributes to sarcopenia by mediating pyroptosis, one type of PCD. Here, we first established naturally aged mice with sarcopenia model and confirmed an inflammatory state represented by TNF-α in aged mice. Evidence of GSDME-mediated pyroptosis and activation of apoptotic caspase-8/-3 were also found in skeletal muscle cells of aged mice with sarcopenia. We demonstrated that TNF-α triggered GSDME-mediated pyroptosis in myotubes through activating caspase-8 and caspase-3 by using caspase-8 and caspase-3 inhibitors. Comparing the activation of caspase-8 and GSDME expression between TNF Complex IIa and TNF Complex IIb, TNF-α was found to be more inclined to assemble TNF Complex IIb in activating caspase-8 and triggering pyroptosis. Moreover, pyroptotic myotubes were validated to result in decreased expression of MHC1 and finally loss of myotubes by knockdown of GSDME. Our work reveals a novel mechanism that TNF-ɑ/caspase-8/caspase-3/GSDME signaling-mediated pyroptosis contributes to the development of sarcopenia. Caspase-3/GSDME signaling-mediated pyroptosis may be a promising therapeutic target for sarcopenia.

Proteome network analysis of skeletal muscle in lignan-enriched nutmeg extract-fed aged mice

Sarcopenia, characterized by reduced muscle mass and fiber number leading to muscular atrophy, has been associated with serious socioeconomic challenges among the elderly in developed countries. Therefore, preventing sarcopenia could be a promising strategy for achieving a healthy aging society. Nutmeg (Myristica fragrans) has been used as a spice to increase flavor and prevent putrefaction of food. Nutmeg contains various bioactive components that improve muscle activity. To determine the potential effect of lignan-enriched nutmeg extract (LNX) on sarcopenia, LNX (100 mg/kg body weight)-fed aged mice were subjected to forced exercise. Herein, aged (22-month-old) mice fed LNX for three weeks exhibited a shortened and thickened soleus muscle. The ratio of the soleus muscle mass (%) to body weight was significantly increased in LNX-fed aged mice. The relative increase in muscle mass in LNX-fed aged mice improved exercise activities, including rotarod, swimming, and grip strength test results. Proteome profiles of the soleus muscle of LNX-fed mice were used to analyze protein–protein interaction network. Several myosin heavy chain isoforms were found to interact with actin, ACTA1, which functions as a hub protein. Furthermore, the expression of myogenic proteins, such as MYH1, MYH4, and ACTA1, was dose-dependently increased in vivo. In result, our functional proteomic analysis revealed that feeding LNX restored muscle proteins in aged mice.

Ultrastructural features of the body wall of the helminth Heterakis dispar (Schrank, 1790) (Nematoda, Heterakidae)

The structure of the body wall (cuticle, hypoderm, and muscle layer) of the nematode Heterakis dispar (Schrank, 1790) from the family Heterakidae was studied using light and electron microscopy methods and compared with other species of the same family. The cuticle of the adult nematode H. dispar consists of 8 layers: 1 - an outer membrane layer or epicuticle; 2, 3 - outer and inner cortical layers; 4, 5 - outer and inner homogeneous or middle layers; 6, 7 - outer and inner fibrous or fibrillar layers; 8 - basement membrane. The cortical, homogeneous and fibrillary layers constitute 12.4, 45.3 and 42.3% of the all cuticle, respectively. The homogeneous layer of the cuticle in the lateral ridges in both male and female and near the bursa of the male is several times as thick as other parts of the helminth cuticle. Unlike other species of the family, males of H. dispar possess 3 different forms of cuticular structure in different parts of the body. In the basal layer of the cuticle, sustaining structures consisting of dense fibrils and microtubules were found, which were not previously noted in other species of the family. It is likely that they provide strength to the body wall of the helminth. In the hypodermis of the nematode, dorsal, ventral, and 2 lateral ridges are traced, the lateral ridges being twice as large as others. Ultrastructural features of the excretory channels and nerve cords located in the hypodermal ridges, were also revealed. The nervous system of the helminth is orthogonal. The ventral nerve cord is wider than the dorsal one. Muscle layer is of the polymyar type, number of muscle cells arranged in groups varies from 17 to 26, depending on the sex and body part of the helminth.

The Effects of Resistance Exercise on the Cardiorespiratory Tissue of Rats with Parkinson's Disease.

Parkinson's Disease (PD) affects the cardiorespiratory system, causing an increase in the left ventricular mass in the heart and respiratory muscle weakness in relation to healthy individuals. The objective of this study was to investigate the effects of progressive resistive physical exercise on the vertical ladder on the histomorphometry of cardiac tissue and respiratory muscles in rats with PD. Seventy male Wistar rats, aged 40 days old, were divided into Parkinson's (PD) and Sham (SH) groups; they were also subdivided into groups that performed progressive resistive physical exercise on the vertical ladder Before Surgery (ExBS), After Surgery (ExAS), and Before and After Surgery (ExBAS). The physical training was carried out before and/or after PD induction. Exercise was performed five times a week for 25 min/day for four or eight weeks. PD induction was conducted via electrolytic stimulation of the Substantia nigra of the animals' brains, adopting the following stereotaxic table coordinates: -4.9; lateral medium equal to 1.7, and dorsoventral equal to 8.1. For the morphometric analysis of the heart, the following variables were calculated: relative weight and diameter and thickness of the left ventricle. The diaphragm and the myocardial, intercostal, and abdominal muscles were stained with Hematoxylin and Eosin (HE). The histomorphometric analysis was performed using the ImageJ software to assess the cross-sectional area of muscles and the number of muscle fibers. Progressive resistance exercise promoted the hypertrophy of respiratory muscles and the left ventricle in animals with PD.

Long-Term Effects of a Short Juvenile Feeding Period with Diets Enriched with the Microalgae Nannochloropsis gaditana on the Subsequent Body and Muscle Growth of Gilthead Seabream, Sparus aurata L.

Currently, microalgae are used in fish diets, but their long-term growth effect is unknown. In this experiment, juvenile seabream specimens were fed with microalgae-enriched diets for three months, and then transferred to a microalgae-free diet for 10 months to assess long-term effects up to commercial size (≈27 cm and ≈300 g). The juvenile diets contained Nannochloropsis gaditana at 2.5 or 5% inclusion levels, either raw (R2.5 and R5 groups) or cellulose-hydrolyzed (H2.5 and H5 groups). The body length and weight were measured in 75 fish group-1 at commercial stage. The size, number, and fibrillar density of white muscle fibers and the white muscle transverse area were measured in nine fish group-1 at commercial stage. The results showed the highest body weight in H5 at commercial stage. The white muscle transverse area and the white fibres hyperplasia and density also showed the highest values in H5, followed by H2.5. In contrast, the highest hypertrophy was observed in C and R2.5, being associated with the lowest muscle growth in both groups. These results showed a microalgae concentration-dependent effect in hydrolyzed diets as well as an advantageous effect of the hydrolyzed versus raw diets on the long-term growth of Sparus aurata.

Muscle fiber plasticity, stress physiology, and muscle transcriptome determine the inter-individual difference of swimming performance in the large yellow croaker (Larimichthys crocea)

Swimming performance is extremely important to critical activities of fishes, such as foraging, anti-predator, and migration. As one of primary stock enhancement fish species in China, it is imperative to study on swimming performance of the large yellow croaker (Larimichthys crocea). In the present study, the swimming performance of juvenile large yellow croaker was investigated, including the behavior, muscle morphology, stress physiology, and genetic mechanisms underlying the individual difference. Juveniles of the croaker were individually subjected to the critical swimming speed (Ucrit) test, and thereby divided into fast (36.47 cm/s) and slow (18.65 cm/s) groups. The juveniles in the fast group had significantly higher tail beat frequency, smaller muscle fiber diameter and more muscle fiber number, as well as lower plasma cortisol and corticotropin releasing hormone (CRH) levels than those in the slow group. Meanwhile, expression levels of hsp70 and pcna in the brain were significantly higher in the fast group than in the slow group, however no significant difference was observed in syt1a expression. Furthermore, the key genes and pathways involved in the swimming performance were assessed by mapping the white skeletal muscle transcriptome. We found that a total of 157 transcripts was differentially expressed between the fast and slow groups, enriched in oxidative phosphorylation, glycosaminoglycan biosynthesis, nicotinate and nicotinamide metabolism, cellular senescence, and cardiac muscle contraction pathways. A multitude of mitochondrial NADH dehydrogenase subunits and solute carrier family genes were especially related. In conclusion, we for the first time found that fish swimming performance directly links to muscle fiber plasticity, stress physiology, and molecular base divergence in the large yellow croaker. The present results lay a foundation for ethological-character-based selective breeding for the large yellow croaker in the regards of swimming performance.

Особенности строения поверхностной грудной мышцы на 14-е сутки эмбриогенеза у кур пород брама и орловская ситцевая

The micromorphological organization of the superficial pectoral muscle in 14-day-old embryos of Brama chickens (meat direction of productivity) and Orlovskaya sitcevaya (egg direction of productivity) is shown. According to most of the studied indicators characterizing the structure of muscle tissue, such as the thickness (diameter) of muscle fibers, their bundles, perimisium, as well as the total area of muscle tissue, Brama is ahead of the Orlovskaya sitcevaya. The exception is the thickness of the endomysium and the number of muscle fibers in the field of view of the microscope in the superficial pectoral muscle. The study of myogenesis in chickens of meat and egg productivity allows us to form the concept of structural features of the muscles of individual breeds and crosses in separate stages of the development of the organism. The information obtained can be used by breeders in breeding poultry and in assessing the productive qualities of poultry while improving production technologies.

Comparison of growth performance and related gene expression of muscle and fat from Landrace, Yorkshire, and Duroc and Woori black pigs

The purpose of this study was to compare marbling score, meat quality, juiciness, sarcomere length, and skeletal muscle satellite cell (SMSC) growth and related gene expression between Woori black pig (WB) and the Landrace, Yorkshire, and Duroc (LYD) crossbreed at different body weights (b.w.). WB was developed to improve meat quality and growth efficiency by crossbreeding Duroc with Korean native black pig. A total of 24 pigs were sacrificed when their b.w. reached about 50, 75, 100, and 120 kg. SMSC were isolated from the femoris muscles, and muscle and adipose tissues were sampled from the middle and the subcutaneous part of the femoris of hind legs, respectively. Expression levels of genes including Myoblast determination protein 1 (MyoD), Paired box gene 3 (Pax3), Myosin heavy chain (MyHC), and Myogenin, which are responsible for the growth and development of SMSC, were higher in LYD than the WB. Muscle growth inhibitor myostatin (MSTN), however, was expressed more in WB compared to LYD (p < 0.01). Numbers of SMSC extracted from femoris muscle of LYD at 50, 75, 100, and 120 kg b.w. were 8.5 ± 0.223, 8.6 ± 0.245, 7.2 ± 0.249, and 10.9 ± 0.795, and those from WB were 6.2 ± 0.32, 6.2 ± 0.374, 5.3 ± 0.423, and 17.1 ± 0.315, respectively. Expression of adipogenic genes in adipose tissue including CCAAT/enhancer-binding protein (CEBP)-β, peroxisome proliferator activated receptor (PPAR)-γ, and fatty acid synthase (FASN), were greater in WB when compared with LYD (p < 0.01). Results from the current study suggest that different muscle cell numbers between 2 different breeds might be affected by related gene expression and this warrants further investigation on other growth factors regulating animal growth and development.

Effect of in ovo creatine monohydrate on hatchability, post-hatch performance, breast muscle yield and fiber size in chicks from young breeder flocks

Younger broiler breeder flocks produce smaller eggs containing smaller yolks, with potentially lower energy reserves for the developing chick. Creatine is a naturally occurring energy source and is abundant in metabolically active tissues; providing this to chicks in ovo should provide additional energy to improve hatchability and post-hatch growth. Thus, post-hatch performance of male and female chicks hatched from younger breeder flocks supplemented with creatine monohydrate (CrM) in ovo was investigated. Four hundred eggs from Ross 308 breeder hens aged 27 to 29 wk were collected and at d 14 assigned to a treatment group and received 1) no injection, 2) 0.75% saline injection, or 3) 8.16 mg creatine monohydrate in 0.75% saline. At hatch 72 birds (24/treatment) were euthanized and BW, breast muscle, heart and liver weight were obtained, and breast muscle tissue was placed in 10% buffered formalin. Birds were then placed in raised metal pens (24 pens; 10-11 birds/pen; 8 replicates/treatment) and grown to d 42 with BW and pen feed intake measured once a week. At d 42, ninty-six birds were euthanized (2 male and 2 female/pen) and the process occurred as at hatch. Body composition was obtained for 48 birds (2/pen; 1 male,1 female) with a dual energy X-ray absorptiometry (DXA) scanner. Breast muscle tissue was processed for histological analysis and breast muscle fiber parameters were analyzed by ImageJ. While not statistically significant, the CrM treatment group saw an improved hatch rate (CrM: 93.5%, Saline: 88.6%, Control: 88.8%) and reduced early post hatch mortality. Chicks given in ovo CrM had significantly increased creatine concentrations in both liver and heart tissue at hatch compared to those in the saline and control groups. BW, BW gain, and final body composition parameters were not statistically different between treatments and in ovo CrM did not affect breast muscle fiber number or area. The creatine injection likely improved the energy status of the growing embryo resulting in the improved hatch rate but leaving little reserves for post-hatch growth.

The role of ACTN3 R/X and ACE I/D in the development of endurance in athletes

Annotation. Endurance – one of the most important sports components, which allows you to overcome the workload for a given time without significant losses in strength and speed. It is most manifested in such sports as swimming, skiing, marathon, cycling, gymnastics. Since the endurance development is mostly influenced not only by epigenomic factors, but also by the genotype of the athlete, so the purpose of this review article is to study the effects of ACTN3 and ACE genes on this physical component. In order to do so, we used basic databases to process information that is known to date on the effects of these genes and their variations. The search was conducted up to and including January 2022 in accordance with PRISMA recommendations. Genes under our study affects endurance in different ways, for example, ACTN3 R577X polymorphism increases the number of slow muscle fibers, and the presence of wild allele “I” of the ACE gene slows down the bradykinin decomposition which mitigates the workload impact on the cardiovascular system, thereby facilitating its adaptation, although there is evidence of an increased risk of injury. The purpose of the review results is to help each athlete in selection of training tactics, which could help him in sports achievements.

Histomorfologi Dan Histomorfometri Otot Ayam Hutan Hijau (Gallus Varius) Asal Pulau Alor

Green jungle fowl is one of the endemic animals in Indonesia. One of the distribution areas of green jungle fowl in East Nusa Tenggara is the island of Alor. Until now there has been no research conducted to determine the histological structure of the green jungle fowl so that this study was conducted with the aim of knowing the histological structure and muscle histomorphometry of the green jungle fowl. The research samples were pectoralis and bicep femoris muscles taken from three green jungle fowl in Kalabahi, Alor Regency. Muscle tissue was fixed using 10% formalin, histological preparations were made and stained with hematoxylin and eosin (HE). The results showed that the muscle histomorphology in the transverse section showed that the skeletal muscle of the green jungle fowl was composed of muscle fibers in a polygonal shape with many nuclei at the edges and connective tissue. No intramuscular fat cells were found. In the longitudinal section, it consists of muscle fibers with a light dark line pattern, the cell nucleus is elongated at the edges and connective tissue. The results of muscle histomorphometry, namely the diameter of the muscle fibers, the diameter of the fasciculus and the thickness of the connective tissue in the bicep femoris muscle area were higher than the pectoralis muscle area. The number of muscle fibers in each fasciculus in the bicep pectoralis muscle area is more than in the bicep femoris muscle area. Muscle histomorphometry is influenced by species, breed/race, age, diet, activity level and anatomical location.

Active immunotherapy reduces NOTCH3 deposition in brain capillaries in a CADASIL mouse model

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic form of familial small vessel disease; no preventive or curative therapy is available. CADASIL is caused by mutations in the NOTCH3 gene, resulting in a mutated NOTCH3 receptor, with aggregation of the NOTCH3 extracellular domain (ECD) around vascular smooth muscle cells. In this study, we have developed a novel active immunization therapy specifically targeting CADASIL‐like aggregated NOTCH3 ECD. Immunizing CADASIL TgN3R182C150 mice with aggregates composed of CADASIL‐R133C mutated and wild‐type EGF1–5 repeats for a total of 4 months resulted in a marked reduction (38–48%) in NOTCH3 deposition around brain capillaries, increased microglia activation and lowered serum levels of NOTCH3 ECD. Active immunization did not impact body weight, general behavior, the number and integrity of vascular smooth muscle cells in the retina, neuronal survival, or inflammation or the renal system, suggesting that the therapy is tolerable. This is the first therapeutic study reporting a successful reduction of NOTCH3 accumulation in a CADASIL mouse model supporting further development towards clinical application for the benefit of CADASIL patients.

The effects of irisin on the rat thoracic aorta: a histological study.

Irisin, a polypeptide hormone that is released from skeletal muscle in response to exercise, has been found to improve endothelial functions, protect against endothelial injuries and change blood pressure, which also affected blood vessels. The aim of this study was to assess the histological changes of the rat thoracic aorta in response to irisin injection. Twenty-four rats were used. They were divided into two groups: the control group without irisin injection and the irisin-injected group subdivided into three subgroups treated with different irisin concentrations (20, 40 and 160 nM, respectively) twice a week for 4 weeks. The control group and irisin-treated subgroups consisted of 6 rats each. After 4 weeks all rats were sacrificed, and the descending thoracic aorta was treated for histological evaluation. Sections were stained with haematoxylin and eosin and orcein stains. Morphometric measurement included: intima-media thickness, number of elastic lamellae and number of smooth muscle cells' nuclei. Histological study showed that intraperitoneal injection of different concentrations of irisin (20, 40 and 160 nM) in rats increased intima-media thickness, the number of smooth muscle cell's nuclei and the number of elastic lamellae in media layer of the thoracic aorta in a dose-dependent manner. Irisin significantly affected the morphology of the wall of the rat thoracic aorta indicating a role of irisin in influencing the growth factors of the thoracic aorta walls and activating smooth muscle cells in the thoracic aorta layers.

A potential role of autophagy-mediated vascular senescence in the pathophysiology of HFpEF.

Heart failure with preserved ejection fraction (HFpEF) is one of the most complex and most prevalent cardiometabolic diseases in aging population. Age, obesity, diabetes, and hypertension are the main comorbidities of HFpEF. Microvascular dysfunction and vascular remodeling play a major role in its development. Among the many mechanisms involved in this process, vascular stiffening has been described as one the most prevalent during HFpEF, leading to ventricular-vascular uncoupling and mismatches in aged HFpEF patients. Aged blood vessels display an increased number of senescent endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). This is consistent with the fact that EC and cardiomyocyte cell senescence has been reported during HFpEF. Autophagy plays a major role in VSMCs physiology, regulating phenotypic switch between contractile and synthetic phenotypes. It has also been described that autophagy can regulate arterial stiffening and EC and VSMC senescence. Many studies now support the notion that targeting autophagy would help with the treatment of many cardiovascular and metabolic diseases. In this review, we discuss the mechanisms involved in autophagy-mediated vascular senescence and whether this could be a driver in the development and progression of HFpEF.

The Effects of Nintendo Wii Fit on Postural Balance Control Training in the Geriatric Population: A Review.

Elderly populations who engage in consistent, moderate-intensity exercise are more physically active and have better health than elders who have a sedentary lifestyle. Ageing causes the quality and number of muscle fibres to decline, leaving them with less endurance and ability to effectively work in synchronization and less strength and stamina to support weight or keep a sound body system. Medical practitioners often use the word "balance" across many therapeutic disciplines. Balance is commonly used in conjunction with other ideas like stability and postural control. The capacity of the physiological systems to keep the centre of mass within the base of support during static and dynamic postures and to govern physical alignment in an upright position is known as "balance." Impaired balance has a wide range of effects that can harm physical functionality. Falls in the elderly can result in hip fractures and significant morbidity and mortality. Balance dysfunction is one of the primary reasons behind decreased mobility and postural control in the elderly. It mainly affects the ability to walk and to maintain balance control in everyday life. Virtual reality (VR) can be defined as an interaction model between humans and computers that allows conventional computer-based training. It is a novel and expanding technology combining various characteristics like interactivity, independence, and rehabilitation training. These technologies replicate a seemingly natural environment. A fun and engaging aspect of VR technology is the Wii Fit games. These are enjoyable versions of the fundamental exercise and are widely used. A physiotherapy intervention programme can be structured using Wii Fit games to perform balance exercises. These games are widely used for balance training in the geriatric population.

Single-cell transcriptomic characterization reveals the landscape of airway remodeling and inflammation in a cynomolgus monkey model of asthma.

Monkey disease models, which are comparable to humans in terms of genetic, anatomical, and physiological characteristics, are important for understanding disease mechanisms and evaluating the efficiency of biological treatments. Here, we established an A.suum-induced model of asthma in cynomolgus monkeys to profile airway inflammation and remodeling in the lungs by single-cell RNA sequencing (scRNA-seq). The asthma model results in airway hyperresponsiveness and remodeling, demonstrated by pulmonary function test and histological characterization. scRNA-seq reveals that the model elevates the numbers of stromal, epithelial and mesenchymal cells (MCs). Particularly, the model increases the numbers of endothelial cells (ECs), fibroblasts (Fibs) and smooth muscle cells (SMCs) in the lungs, with upregulated gene expression associated with cell functions enriched in cell migration and angiogenesis in ECs and Fibs, and VEGF-driven cell proliferation, apoptotic process and complement activation in SMCs. Interestingly, we discover a novel Fib subtype that mediates type I inflammation in the asthmatic lungs. Moreover, MCs in the asthmatic lungs are found to regulate airway remodeling and immunological responses, with elevated gene expression enriched in cell migration, proliferation, angiogenesis and innate immunological responses. Not only the numbers of epithelial cells in the asthmatic lungs change at the time of lung tissue collection, but also their gene expressions are significantly altered, with an enrichment in the biological processes of IL-17 signaling pathway and apoptosis in the majority of subtypes of epithelial cells. Moreover, the ubiquitin process and DNA repair are more prevalent in ciliated epithelial cells. Last, cell-to-cell interaction analysis reveals a complex network among stromal cells, MCs and macrophages that contribute to the development of asthma and airway remodeling. Our findings provide a critical resource for understanding the principle underlying airway remodeling and inflammation in a monkey model of asthma, as well as valuable hints for the future treatment of asthma, especially the airway remodeling-characterized refractory asthma.

Larger interface area at the human myotendinous junction in type 1 compared with type 2 muscle fibers.

The myotendinous junction (MTJ) is structurally specialized to transmit force. The highly folded muscle membrane at the MTJ increases the contact area between muscle and tendon and potentially the load tolerance of the MTJ. Muscles with a high content of type II fibers are more often subject to strain injury compared with muscles with type I fibers. It is hypothesized that this is explained by a smaller interface area of MTJ in type II compared with type I muscle fibers. The aim was to investigate by confocal microscopy whether there is difference in the surface area at the MTJ between type I and II muscle fibers. Individual muscle fibers with an intact MTJ were isolated by microscopic dissection in samples from human semitendinosus, and they were labeled with antibodies against collagen XXII (indicating MTJ) and type I myosin (MHCI). Using a spinning disc confocal microscope, the MTJ from each fiber was scanned and subsequently reconstructed to a 3D-model. The interface area between muscle and tendon was calculated in type I and II fibers from these reconstructions. The MTJ was analyzed in 314 muscle fibers. Type I muscle fibers had a 22% larger MTJ interface area compared with type II fibers (p < 0.05), also when the area was normalized to fiber diameter. By the new method, it was possible to analyze the structure of the MTJ from a large number of human muscle fibers. The finding that the interface area between muscle and tendon is higher in type I compared with type II fibers suggests that type II fibers are less resistant to strain and therefore more susceptible to injury.

GPX4 Alleviates Diabetes Mellitus-Induced Erectile Dysfunction by Inhibiting Ferroptosis.

Pharmacological therapy of diabetes mellitus-induced erectile dysfunction (DMED) is intractable owig to the poor response to phosphodiesterase type 5 inhibitors (PDE5i). The surge in the number of diabetic patients makes it extremely urgent to find a novel therapy for DMED. Ferroptosis is a recently discovered form of cell death evoked by lipid peroxidation and is related to several diabetic complications. GPX4, an important phospholipid hydroperoxidase, can alleviate ferroptosis and maintain redox balance via reducing lipid peroxides. However, whether GPX4 can be a prospective target of DMED needs to be determined. Fifty rats were randomly divided into control group, DMED group, DMED + negative control group (DMED + NC group), DMED + low-dose group (1 × 106 infectious units), and DMED + high-dose group (2 × 106 infectious units). Erectile function was assessed 4 weeks after intracavernous injection of GPX4 or negative control lentivirus. The penile shafts were collected for subsequent molecular biological and histological analysis. The results demonstrated that erectile function of the rats in DMED and DMED + NC groups was extremely impaired and was improved in a dose-dependent manner with GPX4 lentivirus (GPX4-LV) injection. Additionally, upregulation of the ACSL4-LPCAT3-LOX pathway, iron overload, oxidative stress, fibrosis, and decreased endothelial and smooth muscle cell numbers were observed in the corpus cavernosum of DMED group. Meanwhile, the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway was inhibited, and the Ras homolog gene family member A (RhoA)/Rho-associated protein kinase (ROCK) pathway was promoted in DMED rats. The above histologic alterations and related molecular changes were alleviated after GPX4-LV injection. The results revealed that GPX4 improved erectile function by modulating ferroptosis during DMED progression. This finding is of paramount significance in deciphering the molecular mechanism of hyperglycemia-induced ferroptosis, thereby providing a prospective target for preventing the development of DMED.

An efficient strategy to recellularization of a rat aorta scaffold: an optimized decellularization, detergent removal, and Apelin-13 immobilization

BackgroundTissue engineering of native vessels is an alternative approach for patients with vascular disease who lack sufficient saphenous vein or other suitable conduits for autologous vascular graft. Moreover, the harvest of vessels prolongs the surgical procedure and it may lead to the morbidity of donor site in elder patients: therefore, it seems that the use of tissue-engineered vessels would be an attractive and less invasive substitute for autologous vascular grafts. Apelin-13 plays a pivotal role in cell proliferation, survival, and attachment; therefore, covalent attachment of apelin-13 to the acellular scaffolds might be a favorable approach for improving recellularization efficacy.MethodsIn the present study, the decellularization process was performed using various detergents. Afterward, the efficacy of decellularization procedure was evaluated using multiple approaches including assessment of DNA, hydroxyproline, and GAG content as well as Masson’s trichrome and orcein staining used for collagen and elastin determination. Subsequently, the scaffold was bioconjugated with apelin-13 using the EDC-NHS linker and acellular scaffolds were recellularized using fibroblasts, endothelial cells, and smooth muscle cells. SEM images and characterization methods were also used to evaluate the effect of apelin-13 attachment to the acellular scaffold on tissue recellularization. We also developed a novel strategy to eliminate the remnant detergents from the scaffold and increase cell viability by incubating acellular scaffolds with Bio-Beads SM-2 resin. Testometric tensile testing machine was also used for the assessment of mechanical properties and uniaxial tensile strength of decellularized and recellularized vessels compared to that of native tissues.ResultsOur results proposed 16-h perfusion of 0.25% sodium dodecyl sulfate (SDS) + 0.5% Triton X-100 combination to the vessel as an optimal decellularization protocol in terms of cell elimination as well as extracellular matrix preservation. Furthermore, the results demonstrated considerable elevation of cell adhesion and proliferation in scaffolds bioconjugated with apelin-13. The immunohistochemical (IHC) staining of CD31, α-SMA, and vimentin markers suggested placement of seeded cells in the suitable sites and considerable elevation of cell attachment within the scaffolds bioconjugated with apelin-13 compared to the non-bioconjugated, and decellularized groups. Moreover, the quantitative analysis of IHC staining of CD31, α-SMA, and vimentin markers suggested considerable elevation in the number of endothelial, smooth muscle, and fibroblast cells in the recellularized scaffolds bioconjugated with apelin-13 group (1.4% ± 0.02, 6.66% ± 0.23, and 9.87% ± 0.13%, respectively) compared to the non-bioconjugated scaffolds (0.03% ± 0.01, 0.28% ± 0.01, and 1.2% ± 0.09%, respectively) and decellularized groups (0.03% ± 0.007, 0.05% ± 0.01, and 0.13% ±0.005%, respectively). Although the maximum strain to the rupture was reduced in tissues decellularized using 0.5% SDS and CHAPS compared to that of native ones (116% ± 6.79, 139.1% ± 3.24, and 164% ± 8.54%, respectively), ultimate stress was decreased in all decellularized and recellularized groups. Besides, our results indicated that cell viability on the 1st, 3rd, and 7th day was 100.79% ± 0.7, 100.34% ± 0.08, and 111.24% ± 1.7% for the decellularized rat aorta conjugated with apelin-13, which was incubated for 48-h with Bio-Beads SM-2, and 73.37% ± 7.99, 47.6% ± 11.69, and 27.3% ± 7.89% for decellularized rat aorta scaffolds conjugated with apelin-13 and washed 48-h by PBS, respectively. These findings reveal that the incubation of the scaffold with Bio-Beads SM-2 is a novel and promising approach for increasing cell viability and growth within the scaffold.ConclusionsIn conclusion, our results provide a platform in which xenograft vessels are decellularized properly in a short time, and the recellularization process is significantly improved after the bioconjugation of the acellular scaffold with apelin-13 in terms of cell adhesion and viability within the scaffold.Graphical