Factors influencing myogenic differentiation of adipose-derived stem cells and their application in muscle regeneration

Skeletal muscle regeneration mainly depends on muscle satellite cells;however,these cells are not sufficient for supporting repair and regeneration in volumetric muscle loss(VML),Duchenne muscular dystrophy,and other muscle injuries or muscle diseases.As such,much work has been conducted in recent years to search for myogenic stem cells.Adipose-derived stem cells(ADSCs)have a wide range of sources,rapid growth,and multi-directional differentiation potential,and have become vital candidates for muscle regeneration.Multiple factors influence the myogenic differentiation capacity of ADSCs.This paper reviews the regulatory aspects and possible factors that have been identified in recent years to affect myogenic differentiation of ADSCs.Based on these factors,gene editing,and perfusion concepts,a method was proposed to achieve maximal differentiation efficiency of ADSCs.This study focused on the application of ADSCs in muscle regeneration and disease.Based on the importance of myogenic differentiation of ADSCs for the repair and regeneration of muscle damage,this study provides a basis for future research surrounding the efficient induction of myogenic differentiation of ADSCs in vitro.

Circular smooth muscle contributes to esophageal shortening during peristalsis

AIM:To study the angle between the circular smooth muscle(CSM) and longitudinal smooth muscle(LSM) fibers in the distal esophagus.METHODS:In order to identify possible mechanisms for greater shortening in the distal compared to proximal esophagus during peristalsis,the angles between the LSM and CSM layers were measured in 9 cadavers.The outer longitudinal layer of the muscularis propria was exposed after stripping the outer serosa.The inner circular layer of the muscularis propria was then revealed after dissection of the esophageal mucosa and the underlying muscularis mucosa.Photographs of each specimen were taken with half of the open esophagus folded back showing both the outer longitudinal and inner circular muscle layers.Angles were measured every one cm for 10 cm proximal to the squamocolumnar junction(SCJ) by two independent investigators.Two human esophagi were obtained from organ transplant donors and the angles between the circular and longitudinal smooth muscle layers were measured using micro-computed tomography(micro CT) and Image J software.RESULTS:All data are presented as mean ± SE.The CSM to LSM angle at the SCJ and 1 cm proximal to SCJ on the autopsy specimens was 69.3 ± 4.62 degrees vs 74.9 ± 3.09 degrees,P = 0.32.The CSM to LSM angle at SCJ were statistically significantly lower than at 2,3,4 and 5 cm proximal to the SCJ,69.3 ± 4.62 degrees vs 82.58 ± 1.34 degrees,84.04 ± 1.64 degrees,84.87 ± 1.04 degrees and 83.72 ± 1.42 degrees,P = 0.013,P = 0.008,P = 0.004,P = 0.009 respectively.The CSM to LSM angle at SCJ was also statistically significantly lower than the angles at 6,7 and 8 cm proximal to the SCJ,69.3 ± 4.62 degrees vs 80.18 ± 2.09 degrees,81.81 ± 1.75 degrees and 80.96 ± 2.04 degrees,P = 0.05,P = 0.02,P = 0.03 respectively.The CSM to LSM angle at 1 cm proximal to SCJ was statistically significantly lower than at 3,4 and 5 cm proximal to the SCJ,74.94 ± 3.09 degrees vs 84.04 ± 1.64 degrees,84.87 ± 1.04 degrees and 83.72 ± 1.42 degrees,P = 0.019,P = 0.008,P = 0.02 respectively.At 10 cm above SCJ the angle was 80.06 ± 2.13 degrees which is close to being perpendicular but less than 90 degrees.The CSM to LSM angles measured on virtual dissection of the esophagus and the stomach on micro CT at the SCJ and 1 cm proximal to the SCJ were 48.39 ± 0.72 degrees and 50.81 ± 1.59 degrees.Rather than the angle of the CSM and LSM being perpendicular in the esophagus we found an acute angulation between these two muscle groups throughout the lower 10 cm of the esophagus.CONCLUSION:The oblique angulation of the CSM may contribute to the significantly greater shortening of distal esophagus when compared to the mid and proximal esophagus during peristalsis.

Amiodarone-induced muscle tremor in an elderly patient:A case report

BACKGROUND Amiodarone is a Class III antiarrhythmic drug,which has been adopted for the treatment of atrial fibrillation and ventricular arrhythmia.However,the use of amiodarone can cause lower limb muscle tremors,which is recognized as a rare side effect of this medication.CASE SUMMARY An 84-year-old female was administrated with amiodarone for paroxysmal supraventricular tachycardia and frequent ventricular tachycardia.The patient developed a bilateral gastrocnemius tremor in the course of medication,and the strength of the patient’s bilateral knee flexor and extensor reached 4/5 and 3/5,respectively.After the use of amiodarone was stopped,and the patient was given a small dose of levetiracetam,the lower limb tremor symptoms were significantly mitigated,along with activity and function.CONCLUSION Attention should be paid to the significance of the side effects of drugs in the elderly,which may be atypical in the elderly.The relevant side effects of drugs may not be as rare as reported due to individual differences and different pharmacokinetics.If the side effects are generated,the medication should be adjusted in time,and the progress of the side effects should be intervened.

Effect of ACTN3 gene polymorphism on the pathogenic phenotype of related diseases and its treatment prospect

Theα-actin-3 protein expressed by ACTN3 gene cod is a troponin binding protein,which is mainly located in the Z disk on skeletal muscle fibers.Due to the homozygous nonsense polymorphism(R577X)of the gene,about 1.5 billion people in the world have lost the expression of this protein.Because the presence ofα-actin-3 protein increases skeletal muscle cells to be compliant,the gene is often referred to as the“speed gene”,and current studies suggest that this gene polymorphism has varying degrees of influence on muscle injury,decreased endurance,hypomyopathy,osteoporosis,endocrine disease,cardiovascular disease.This is a review of the current effects of ACTN3 gene polymorphisms on a variety of diseases,as well as its possible intervention treatment options.

Muscle mass loss and intermuscular lipid accumulation were associated with insulin resistance in patients receiving hemodialysis

Background An accelerated muscle wasting was the pivotal factor for protein-energy wasting in end stage renal disease. However, very few researches have examined the skeletal muscle quantity and quality in clinical patients. This study investigated the muscle morphologic changes by magnetic resonance imaging （MRI） and analyzed the related factors in hemodialysis patients. Methods Fifty-eight patients receiving maintenance hemodialysis （HD） were investigated and 28 healthy adults with gender and age matched were used as controls （Control）. Anthropometry, cytokine factors, and laboratory data were measured. The muscle and intermuscular adipose tissues （IMAT） were analyzed via a Thigh MRI. The bicep samples were observed after HE staining. Homeostatic model assessment of insulin resistance （HOMA-IR） was measured and their association with muscle wasting was analyzed. Results HD patients tended to have a lower protein diet, anthropometry data, and serum albumin, but the C reactive protein and interleukin-6 increased significantly. The MRI showed that HD patients had less muscle mass and a lower muscle/total ratio, but the fat/muscle and IMAT was higher when compared to the Control group. The muscle fiber showed atrophy and fat accumulation in the biceps samples come from the HD patients. Moreover, we found that the HD patients presented with a high level of plasma fasting insulin and increased HOMA-IR which negatively correlated with the muscle/ total ratio, but positively with the fat/muscle ratio. Conclusions Muscle wasting presented early before an obvious malnutrition condition emerged in HD patients. The main morphological change was muscle atrophy along with intermuscular lipid accumulation. Insulin resistance was associated with muscle wasting in dialysis patients.