FGF21 promotes myocardial angiogenesis and mediates the cardioprotective effects of exercise in myocardial infarction mice

The mechanism by which aerobic exercise promotes cardiac function after myocardial infarction (MI) is still not fully understand. In this study, we investigated the role of fibroblast growth factor 21 (FGF21) in exercise protecting the cardiac function of MI mice. In vivo, MI was induced by left anterior descending coronary artery ligation in wild-type and fgf21 knockout mice on the C57BL/6 background. One week after MI, the mice underwent aerobic exercise for 4 wk. In vitro, human umbilical vein endothelial cells (HUVECs) were treated with H2O2, recombinant human FGF21 (rhFGF21), fibroblast growth factor receptor 1 (FGFR1) inhibitor (PD166866), and phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002) to explore the potential mechanisms. Scratch wound healing and tubule formation analysis were used to detect the migration and tubule formation ability of HUVECs. Our results showed that aerobic exercise significantly promoted angiogenesis and cardiac function through enhancing the expression of FGF21 and activating FGFR1/PI3K/AKT/VEGF pathway. But such changes in cardiac from aerobic exercise were attenuated by fgf21 knockout mice. 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) enhanced angiogenesis and cell migration through FGF21/FGFR1/PI3K/AKT/VEGF signaling pathway. Under the intervention of H2O2, rhFGF21 also played the role of promoting angiogenesis and cell migration through the same mechanism. In conclusion, our results showed that FGF21 promoted the aerobic exercise-induced angiogenesis and improved cardiac function via FGFR1/PI3K/AKT/VEGF signal in MI mice.NEW & NOTEWORTHY FGF21 activated FGFR1/PI3K/AKT/VEGF signaling pathway mediated angiogenesis in MI mice. FGF21 deficiency attenuated aerobic exercise-induced cardiac angiogenesis in MI mice. FGF21/FGFR1/PI3K/AKT/VEGF signal played an important role in aerobic exercise to promote myocardial angiogenesis and improved cardiac function.

ELABELA-APJ-Akt/YAP Signaling Axis: A Novel Mechanism of Aerobic Exercise in Cardioprotection of Myocardial Infarction Rats

PURPOSE

The aim of this study was to investigate the function and mechanisms of ELABELA (ELA) in the aerobic exercise-induced antiapoptosis and angiogenesis of ischemic heart.

METHODS

The myocardial infarction (MI) model of Sprague-Dawley rat was established by the ligation of the left anterior descending coronary artery. MI rats underwent 5 wk of Fc-ELA-21 subcutaneous injection and aerobic exercise training using a motorized rodent treadmill. Heart function was evaluated by hemodynamic measures. Cardiac pathological remodeling was evaluated by Masson's staining and the calculation of left ventricular weight index. Cell proliferation, angiogenesis, and Yes-associated protein (YAP) translocation were observed by immunofluorescence staining. Cell apoptosis was analyzed by TUNEL. Cell culture and treatment were used to elucidate the molecular mechanism of ELA. Protein expression was detected by Western blotting. Angiogenesis was observed by tubule formation test. One-way or two-way ANOVA and Student's t -test were used for statistical analysis.

RESULTS

Aerobic exercise stimulated the endogenous ELA expression. Exercise and Fc-ELA-21 intervention significantly activated APJ-Akt-mTOR-P70S6K signaling pathway, kept more cardiomyocytes alive, and increased angiogenesis, so as to inhibit the cardiac pathological remodeling and improved the heart function of MI rats. Fc-ELA-32 also had the cellular and functional cardioprotective activities in vivo . In vitro , ELA-14 peptide regulated the phosphorylation and nucleoplasmic translocation of YAP and activated the APJ-Akt signaling pathway so as to increase the proliferation of H9C2 cells. Moreover, the antiapoptosis and the tubule formation of HUVECs were also enhanced by ELA-14, whereas the inhibition of Akt activity weakened such effects.

CONCLUSIONS

ELA is a potential therapeutic member that plays a key role through APJ-Akt/YAP signaling axis in aerobic exercise-induced cardioprotection of MI rats.

FNDC5/Irisin Inhibits the Inflammatory Response and Mediates the Aerobic Exercise-Induced Improvement of Liver Injury after Myocardial Infarction

Myocardial infarction (MI) causes peripheral organ injury, in addition to cardiac dysfunction, including in the liver, which is known as cardiac hepatopathy. Aerobic exercise (AE) can effectively improve liver injury, although the mechanism and targets are currently not well established. Irisin, mainly produced by cleavage of the fibronectin type III domain-containing protein 5 (FNDC5), is a responsible for the beneficial effects of exercise training. In this study, we detected the effect of AE on MI-induced liver injury and explored the role of irisin alongside the benefits of AE. Wildtype and Fndc5 knockout mice were used to establish an MI model and subjected to AE intervention. Primary mouse hepatocytes were treated with lipopolysaccharide (LPS), rhirisin, and a phosphoinositide 3-kinase (PI3K) inhibitor. The results showed that AE significantly promoted M2 polarization of macrophages and improved MI-induced inflammation, upregulated endogenous irisin protein expression and activated the PI3K/ protein kinase B (Akt) signaling pathway in the liver of MI mice, while knockout of Fndc5 attenuated the beneficial effects of AE. Exogenous rhirisin significantly inhibited the LPS-induced inflammatory response, which was attenuated by the PI3K inhibitor. These results suggest that AE could effectively activate the FNDC5/irisin-PI3K/Akt signaling pathway, promote the polarization of M2 macrophages, and inhibit the inflammatory response of the liver after MI.

Irisin and ALCAT1 mediated aerobic exercise-alleviated oxidative stress and apoptosis in skeletal muscle of mice with myocardial infarction

Skeletal muscle in patients with heart failure (HF) exhibits altered structure, function and metabolism. Myocardial infarction (MI) is the most common cause of HF. Oxidative stress and cell apoptosis are involved in the pathophysiology of MI/HF-induced skeletal muscle atrophy. It is well recognized that aerobic exercise (AE) could prevent skeletal muscle atrophy after MI, but the underlying mechanism and molecular targets are still not fully clarified. In this study, Fndc5^-/- and Alcat1^-/- mice were used to establish the MI model and subjected to six weeks of moderate-intensity AE. C2C12 cells were treated with H₂O₂ and recombinant human Irisin (rhIrisin), or transduced with a lentiviral vector to mediate the overexpression of ALCAT1 (LV-Alcat1). Results showed that MI reduced Irisin expression and antioxidant capacity of skeletal muscle, increased ALCAT1 expression, induced protein degradation and cell apoptosis, which were partly reversed by AE; Knockout of Fndc5 further aggravated MI-induced oxidative stress and cell apoptosis in skeletal muscle, and partly weakened the beneficial effects of AE. In contrast, knockout of Alcat1 reduced MI-induced oxidative stress and cell apoptosis and strengthened the beneficial effects of AE. rhIrisin and AICAR intervention inhibited ALCAT1 expression, oxidative stress and cell apoptosis, which induced by H₂O₂ or LV-Alcat1 in C2C12 cells. These findings reveal that AE could alleviate the levels of oxidative stress and apoptosis in skeletal muscle following MI, partly via up-regulating Irisin and inhibiting ALCAT1 expression.

The role of exercise in rehabilitation of discharged COVID-19 patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mainly caused pneumonia and pulmonary fibrosis through upper respiratory tract infection, which resulted in acute respiratory distress syndrome (ARDS) and multiorgan damage of cardiovascular, nervous, digestive, and genitourinary systems. Although the virus test turned negative after the patient recovered, the damage to multiorgan caused by SARS-CoV-2 may irreversible. Therefore, the health status of the recovered patients has gradually become the focus of people's attention. Whether coronavirus disease 2019 (COVID-19) patients can receive exercise rehabilitation training after discharge? and what's the basis? We try to analyze and answer these questions, will provide some ideas about the patients to develop a reasonable and effective exercise rehabilitation program.

Exercise Training Enhances Myocardial Mitophagy and Improves Cardiac Function via Irisin/FNDC5-PINK1/Parkin Pathway in MI Mice

Myocardial infarction is the major cause of death in cardiovascular disease. In vitro and in vivo models are used to find the exercise mode which has the most significant effect on myocardial irisin/FNDC5 expression and illuminate the cardioprotective role and mechanisms of exercise-activated myocardial irisin/FNDC5-PINK1/Parkin-mediated mitophagy in myocardial infarction. The results indicated that expression of irisin/FNDC5 in myocardium could be up-regulated by different types of exercise and skeletal muscle electrical stimulation, which then promotes mitophagy and improves cardiac function and the effect of resistance exercise. Resistance exercise can improve cardiac function by activating the irisin/FNDC5-PINK1/Parkin-LC3/P62 pathway, regulating mitophagy and inhibiting oxidative stress. OPA1 may play an important role in the improvement of cardiac function and mitophagy pathway in myocardial infarction mice by irisin-mediated resistance exercise. Resistance exercise is expected to become an effective therapeutic way to promote myocardial infarction rehabilitation.

Up-regulation of Thioredoxin 1 by aerobic exercise training attenuates endoplasmic reticulum stress and cardiomyocyte apoptosis following myocardial infarction

Exercise training (ET) has been reported to reduce oxidative stress and endoplasmic reticulum (ER) stress in the heart following myocardial infarction (MI). Thioredoxin 1 (Trx1) plays a protective role in the infarcted heart. However, whether Trx1 regulates ER stress of the infarcted heart and participates in ET-induced cardiac protective effects are still not well known. In this work, H9c2 cells were treated with hydrogen peroxide (H₂O₂) and recombinant human Trx1 protein (TXN), meanwhile, adult male C57B6L mice were used to establish the MI model, and subjected to a six-week aerobic exercise training (AET) with or without the injection of Trx1 inhibitor, PX-12. Results showed that H₂O₂ significantly increased reactive oxygen species (ROS) level and the expression of TXNIP, CHOP and cleaved caspase12, induced cell apoptosis; TXN intervention reduced ROS level and the expression of CHOP and cleaved caspase12, and inhibited cell apoptosis in H₂O₂-treated H9c2 cells. Furthermore, AET up-regulated endogenous Trx1 protein expression and down-regulated TXNIP expression, restored ROS level and the expression of ER stress-related proteins, inhibited cell apoptosis as well as improved cardiac fibrosis and heart function in mice after MI. PX-12 partly inhibited the AET-induced beneficial effects in the infarcted heart. This study demonstrates that Trx1 attenuates ER stress-induced cell apoptosis, and AET reduces MI-induced ROS overproduction, ER stress and cell apoptosis partly through up-regulating of Trx1 expression in mice with MI.

Satb1 promotes Schwann cell viability and migration via activation of PI3K/AKT pathway

OBJECTIVE

Satb1 regulates chromatin structure and gene expression, and is aberrantly expressed in many tumors. However, there is still no report about Satb1 functions in peripheral nerve injury until now. In this study, we explored the regulatory effect of Satb1 on Schwann cells.

MATERIALS AND METHODS

MTT assay, transwell assay, and flow cytometry assay were respectively used to determine Schwann cell viability, migration, and apoptosis. The mRNA and phosphorylation levels of Satb1 and SHIP1 were assessed by RT-PCR and Western blotting analysis, respectively. The correlation between Satb1 and SHIP1 was examined by ChIP assay. The expressions of PI3K/AKT pathway related factors were detected by Western blotting.

RESULTS

In the present study, we found that knock-out of Satb1 significantly inhibited cell viability and migration, and promoted Schwann cells apoptosis. Conversely, over-expression of Satb1 promoted cell viability, migration, and inhibited apoptosis. Satb1 inhibited SHIP1 expression by recruiting HDAC1. Furthermore, results showed that Satb1 activated the PI3K/AKT signaling pathway by inhibiting the expression of SHIP1. SHIP1 showed significant reversal effects on the regulatory roles of Satb1 in Schwann cells. Over-expression of Satb1 and SHIP1 inhibited cell viability, migration, and promoted apoptosis.

CONCLUSIONS

Our study demonstrated that the Satb1 knock-out could inhibit the activation of PI3K/AKT pathway by up-regulating SHIP1, thus inhibiting cell viability and migration, and promoting Schwann cell apoptosis.

Mating compatibility between Bactrocera invadens and Bactrocera dorsalis (Diptera: Tephritidae)

The invasive fruit fly, Bactrocera invadens Drew, Tsuruta & White, is a highly polyphagous fruit pest that occurs predominantly in Africa yet has its origins in the Indian subcontinent. It is extremely morphologically and genetically similar to the Oriental fruit fly, Bactrocera dorsalis (Hendel); as such the specific relationship between these two species is unresolved. We assessed prezygotic compatibility between B. dorsalis and B. invadens using standardized field cage mating tests, which have proven effectiveness in tephritid cryptic species studies. These tests were followed by an assessment of postzygotic compatibility by examining egg viability, larval and pupal survival, and sex ratios of offspring produced from parental and subsequent F1 crosses to examine for hybrid breakdown as predicted under a two-species hypothesis. B. dorsalis was sourced from two countries (Pakistan and China), and each population was compared with B. invadens from its type locality of Kenya. B. invadens mated randomly with B. dorsalis from both localities, and there were generally high levels of hybrid viability and survival resulting from parental and F1 crosses. Furthermore, all but one hybrid cross resulted in equal sex ratios, with the single deviation in favor of males and contrary to expectations under Haldane's rule. These data support the hypothesis that B. dorsalis and B. invadens represent the same biological species, an outcome that poses significant implications for pest management and international trade for sub-Saharan Africa.

Mapping shape quantitative trait loci using a radius-centroid-contour model

As the consequence of complex interactions between different parts of an organ, shape can be used as a predictor of structural-functional relationships implicated in changing environments. Despite such importance, however, it is no surprise that little is known about the genetic detail involved in shape variation, because no approach is currently available for mapping quantitative trait loci (QTLs) that control shape. Here, we address this problem by developing a statistical model that integrates the principle of shape analysis into a mixture-model-based likelihood formulated for QTL mapping. One state-of-the-art approach for shape analysis is to identify and analyze the polar coordinates of anatomical landmarks on a shape measured in terms of radii from the centroid to the contour at regular intervals. A procrustes analysis is used to align shapes to filter out position, scale and rotation effects on shape variation. To the end, the accurate and quantitative representation of a shape is produced with aligned radius-centroid-contour (RCC) curves, that is, a function of radial angle at the centroid. The high dimensionality of the RCC data, crucial for a comprehensive description of the geometric feature of a shape, is reduced by principal component (PC) analysis, and the resulting PC axes are treated as phenotypic traits, allowing specific QTLs for global and local shape variability to be mapped, respectively. The usefulness and utilization of the new model for shape mapping in practice are validated by analyzing a mapping data collected from a natural population of poplar, Populus szechuanica var tibetica, and identifying several QTLs for leaf shape in this species. The model provides a powerful tool to compute which genes determine biological shape in plants, animals and humans.

Newly defined clinical features and treatment experience of seventh day syndrome following living donor liver transplantation

AIM

The aim of this study was to describe a unique Seventh-Day Syndrome (7DS) in our liver transplantation center.

METHODS

We performed a retrospective analysis of 244 cases of adult living donor liver transplantations (LDLT) performed in our liver transplantation center from January 1995 to January 2009.

RESULTS

Since 2005, we identified 8 cases of 7DS. Previously reported features for 7DS include a rapid deterioration of liver function followed by renal failure and a sudden peak in liver enzyme levels around day 7. In addition, the following attributes have been observed in our patients: (1) all recipients were males while the donors included both genders; (2) most patients showed increased levels of irritability; (3) color Doppler revealed reduced blood flow or bidirectional blood flow in the portal vein; (4) coagulation necrosis was observed with disruption of lobular architecture and increased expression of death receptor Fas in all examined patients; (5) after onset, a steroid pulse with or without OKT3 therapy showed minimal effect; (6) a abrupt increase in liver enzymes was noted 1-2 days after intravenous (IV) methylprednisolone was switched to oral immunosuppressants; and (7) extension of IV methylprednisolone treatment delayed the occurrence from 8 to 11 days postoperatively.

CONCLUSIONS

7DS is a distinct entity associated with early graft dysfunction, which is associated with a high rate of mortality and need for retransplantation. Coagulation necrosis and Fas receptor activation may be implicated in the occurrence of 7DS. Our study supported the hypothesis that 7DS may be associated with an undefined immune response. Our experience extending IV methylprednisolone treatment seeking to delay occurrence and reduce mortality provided a possible therapeutic approach for 7DS.

Superiority of visipaque (iodixanol)-controlled density gradient over Ficoll-400 in adult porcine islet purification

OBJECTIVE

Sufficient and favorable biological functions of islets are major problems hindering xenotransplantation. The aim of the present study was to evaluate the effects on harvesting, purity, viability, and function of using improved Visipaque (iodixanol) and Ficoll-400 for adult porcine islet purification.

METHODS

Twelve adult porcine pancreata were randomly divided into an Iodixanol-University of Wisconsin (UW) group and a Ficoll-400-UW group according to the purification method. Porcine pancreata were isolated by collagenase digestion. After isolation and purification, the islet yield and purity were evaluated by dithizone staining, and islet function assessed by in vitro insulin release assays and in vivo islet xenotransplantation.

RESULTS

There were no marked differences in the islet yield before purification (5254.67 +/- 189.44 IEQ/g vs 5092.67 +/- 178.94 IEQ/g, P > .05). After purification, there were significantly more islets harvested in Iodixanol-UW group than in the Ficoll-400-UW group: 4222.00 +/- 228.84 IEQ/g vs 3036.83 +/- 79.60 IEQ/g (P < .05). Islets from the two groups showed satisfactory insulin secretory ability. There were no significant differences in islet survival times between the two groups in diabetic rats: 8.2 +/- 1.619 days vs 6.9 +/- 1.197 days (P > .05).

CONCLUSION

The improved iodixanol-UW density gradient method was superior to Ficoll-400 method to improve the number, viability, and insulin secret of purified adult porcine islets although the benefits did not improve in vivo survival.

Defining new pathogens and nonculturable infectious agents associated with inflammatory bowel disease

The causes of inflammatory bowel disease remain uncertain, but increasing evidence supports roles for two pathogenic processes: genetic susceptibility in the host and an aberrant host response to enteric bacteria. Here, we review studies showing that the pathogenesis of inflammatory bowel disease involves both bacterial agents and genetic susceptibilities. We discuss the roles of known and novel commensal intestinal bacteria in the pathogenesis of inflammatory bowel disease and the various recombinant approaches used to identify these pathogens.

Transcranial Doppler characteristics in persistent vegetative status, locked-in syndrome and brain death

AIM

Comparison of the transcranial Doppler (TCD) characteristics of cerebral circulation in persistent vegetative status (PVS), locked-in syndrome and brain death patients.

METHODS

Using TCD ultrasound to detect the flow velocity and waveform patterns of middle cerebral artery (MCA) and basilar artery (BA) in patients with PVS, locked-in syndrome and brain death.

RESULTS

The mean velocities of middle cerebral artery (Vmca) and basilar artery (Vba) were 30.0 cm/s and 24.3 cm/s in PVS patients respectively, which decreased 45.0% and 14.4% in comparing with normal value. For patients with locked-in syndrome, Vmca and Vba were 49.7 cm/s and 9.8 cm/s, which decreased 5.0% and 61.7% than the normal value respectively. These results showed that the decrease of anterior circulation was predominant in PVS, and the decrease of posterior circulation was predominant in locked-in syndrome. A unique diastolic reverse flow, short peak systolic wave or undetectable flow signal in middle cerebral artery were predominant in brain death patients, which was completely different from that of either PVS or locked-in syndrome.

CONCLUSION

TCD was a valuable tool in distinguishing PVS, locked-in syndrome and brain death patients according to the differences in velocities and patterns of anterior and posterior cerebral arteries.

Expression of HIS50 Ag: a rat homologue of mouse heat-stable antigen and human CD24 on B lymphoid cells in the rat

Recently, a cDNA encoding a newly identified rat antigen (HIS50 Ag) that binds to monoclonal antibody (mAb) HIS50 was cloned and shown to be homologous to cDNA encoding murine heat-stable antigen (HSA) and human CD24. Here we show that, like CD24 and HSA, at least part of HIS50 Ag is inserted into the plasma membrane by a glycosylphosphatidylinosito: (GPI)-lipid linkage and we describe its expression in rat haemolymphopoietic tissues. HIS50 Ag expression was almost exclusively confined to B lymphoid cells, the vast majority of T lymphoid cells, erythroid and myeloid cells were HIS50+. Cell suspension analysis indicated that in bone marrow (BM) almost all Thy-1+ cells, HIS24+ cells [HIS24 recognizes the B-cell form of leucocyte common antigen (LCA)], terminal deoxynucleotidyl transferase-positive (TdT+) cells and (c + s)kappa cells expressed HIS50 Ag, and all (c + s)mu 1 cells. A presumably early population of B lymphoid cells, expressing HIS24 Ag without HIS50 Ag, TdT or immunoglobulin HIS24+HIS50+ TdT Ig+), constituted 1.6% of BM nucleated cells. In blood, one-fifth of mononuclear cells were HIS50+, and about 85% of these expressed mu and/or kappa chains. In spleen, flow cytometry analysis and immunohistology demonstrated heterogeneous expression of HIS50 Ag: immunoglobulin M (IgM)bright cells (as found largely in red pulp and marginal zone) were HIS50bright, while IgMdull cells expressed low or undetectable levels of HIS50 Ag. Germinal centre B cells expressed high levels of HIS50 Ag. Germinal centres of lymph nodes and tonsil of man also bound HIS50. We conclude that HIS50 Ag expression in the haemolymphopoietic system of rat is virtually restricted to the B lineage.