Pathophysiological roles of the serum acylcarnitine level and acylcarnitine/free carnitine ratio in patients with cardiovascular diseases.

Introduction: L-carnitine exerts protective effects, such as maintaining mitochondrial functions and decreasing reactive oxygen species, while acylcarnitine (AC) is linked to the development of heart failure and atherosclerosis. Hypothesis: Serum carnitines play important pathophysiological roles in cardiovascular diseases. Methods: Pre-operative biochemical data were obtained from 117 patients (71 men, average age 69.9 years) who underwent surgery for cardiovascular diseases. Measurements included pre-operative biochemical data including estimated glomerular filtration rate (eGFR), physical functions, skeletal muscle mass index (SMI) measured by bioelectrical impedance analysis, anterior thigh muscle thickness (MTh) measured by ultrasound, and routine echocardiography. Carnitine components were measured with the enzyme cycling method. Muscle wasting was diagnosed based on the Asian Working Group for Sarcopenia criteria. Results: Plasma brain natriuretic peptide (BNP) level was correlated with serum free carnitine (FC) and AC level, and the acylcarnitine/free carnitine ratio (AC/FC). AC/FC was elevated with stage of chronic kidney disease. In multivariate analysis, log (eGFR) and log (BNP) were extracted as independent factors to define log (serum AC) (eGFR: ß = 0.258, p = 0.008; BNP: ß = 0.273, p = 0.011), even if corrected for age, sex and body mass index. AC/FC was negatively correlated with hand-grip strength (r = -0.387, p = 0.006), SMI (r = -0.314, p = 0.012), and anterior thigh MTh (r = -0.340, p = 0.014) in men. Conclusions: A significant association between serum AC level and AC/FC, and chronic kidney disease and heart failure exists in patients with cardiovascular diseases who have undergone cardiovascular surgery. Skeletal muscle loss and muscle wasting are also linked to the elevation of serum AC level and AC/FC.

Utility of growth differentiation factor-15 as a predictor of cardiovascular surgery outcomes: Current research and future directions.

In a world increasingly confronted by cardiovascular diseases (CVDs) and an aging population, accurate risk assessment prior to cardiac surgery is critical. Although effective, traditional risk calculators such as the Japan SCORE, Society of Thoracic Surgeons score, and EuroSCORE II may not completely capture contemporary risks, particularly due to emerging factors such as frailty and sarcopenia. These calculators often focus on regional and ethnic specificity and rely heavily on evaluations based on age and underlying diseases. Growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine that has been identified as a potential biomarker for sarcopenia and a tool for future cardiac risk assessment. Preoperative plasma GDF-15 levels have been associated with preoperative, intraoperative, and postoperative factors and short- and long-term mortality rates in patients undergoing cardiac surgery. Increased plasma GDF-15 levels have prognostic significance, having been correlated with the use of cardiopulmonary bypass during surgery, amount of bleeding, postoperative acute kidney injury, and intensive care unit stay duration. Notably, the inclusion of preoperative levels of GDF-15 in risk stratification models enhances their predictive value, especially when compared with those of the N-terminal prohormone of brain natriuretic peptide, which does not lead to reclassification. Thus, this review examines traditional risk assessments for cardiac surgery and the role of the novel biomarker GDF-15. This study acknowledges that the relationship between patient outcomes and elevated GDF-15 levels is not limited to CVDs or cardiac surgery but can be associated with variable diseases, including diabetes and cancer. Moreover, the normal range of GDF-15 is not well defined. Given its promise for improving patient care and outcomes in cardiovascular surgery, future research should explore the potential of GDF-15 as a biomarker for postoperative outcomes and target therapeutic intervention.

Association between serum GDF-15, myostatin, and sarcopenia in cardiovascular surgery patients.

Background: Myostatin is a negative regulator of skeletal muscle mass. On the other hand, growth differentiation factor (GDF)-15 is associated with lower muscle strength and muscle mass. We investigated the relationship between serum GDF-15, myostatin, and sarcopenia in patients receiving cardiovascular surgery through a ROC curve and a multivariate regression analysis. Methods: Skeletal muscle mass index (SMI) by bioelectrical impedance analysis, hand-grip strength, knee extension strength, and walking speed were measured. Preoperative serum GDF-15 and myostatin levels were determined by ELISA. The sarcopenia index could be expressed as: -0.0042 × [myostatin] + 0.0007 × [GDF-15] + 0.0890 × age + 1.4030 × sex - 0.2679 × body mass index (BMI) - 2.1186. A ROC curve was plotted to identify the optimal cutoff level of the sarcopenia index to detect sarcopenia. Results: 120 patients receiving cardiovascular surgery were included in the study. SMI, hand-grip strength, knee extension strength, and walking speed inversely correlated with GDF-15, but positively correlated with myostatin. In the multivariate stepwise regression analysis, SMI was a determinant of myostatin, and both GDF-15 and myostatin were determinants of SMI and muscle thickness, even after adjustment for age, sex, and BMI. A ROC curve showed that the sarcopenia index was a determinant of sarcopenia (cutoff value -1.0634, area under the curve 0.901, sensitivity 96.9%, specificity 70.9%). Conclusion: GDF-15 and myostatin are associated with skeletal muscle volume in patients receiving cardiovascular surgery, but these associations are different. The sarcopenia index calculated from GDF-15 and myostatin levels may be a biomarker of sarcopenia.

Serum and Adipose Dipeptidyl Peptidase 4 in Cardiovascular Surgery Patients: Influence of Dipeptidyl Peptidase 4 Inhibitors.

Dipeptidyl peptidase 4 (DPP-4) is a novel adipokine and may be involved in the association between adipose tissue and metabolic syndrome. We investigated DPP-4 and adiponectin levels in the serum, subcutaneous adipose tissue (SAT), and epicardial adipose tissue (EAT), and their relationship with preoperative factors, as well as comparing the DPP-4 levels in SAT and EAT with and without DPP-4 inhibitors. This study included 40 patients (25 men, age 67.5 ± 13.8 years). The serum adipokine, DPP-4, and adiponectin levels in SAT and EAT were measured using ELISA and Western blotting. The DPP-4 and adiponectin levels were significantly higher in the SAT than in the EAT. The serum DPP-4 and DPP-4 activity levels had no correlation with the DPP-4 levels in the SAT and EAT, but the DPP-4 levels in the SAT and EAT had a positive correlation. The DPP-4 levels in the SAT were positively correlated with atherosclerosis, diabetes mellitus, DPP-4-inhibitor use, and fasting blood glucose. The DPP-4 levels in the EAT showed a negative correlation with eGFR and a positive correlation with atrial fibrillation. The DPP-4 activity in the serum had a lower tendency in the group taking DPP-4 inhibitors than in the group not taking them. DPP-4 inhibitors may suppress angiogenesis and adipose-tissue hypertrophy.

Relationship between the serum GDF-15 concentration and muscle function in female patients receiving aortic valve replacement (TAVR, SAVR): Comparison with healthy elderly female subjects.

Purpose: Sarcopenia is closely associated with postoperative prognosis in patients undergoing cardiovascular surgery. Growth differentiation factor (GDF)-15 is involved in the pathogenesis of cardiovascular disease. We examined the relationship between the serum GDF-15 concentration and muscle function in patients receiving aortic valve replacement and healthy elderly subjects. Methods: Forty-three female patients undergoing aortic valve surgery (79.9 ± 6.4 years; transcatheter aortic valve replacement [TAVR] n = 19, conventional surgical aortic valve replacement [SAVR] n = 24) and 64 healthy elderly female subjects (75.9 ± 6.1 years) were included. Walking speed, grip strength, and skeletal muscle mass index (SMI) by a multifrequency bioelectrical impedance analyzer were measured to determine the presence of sarcopenia. Preoperative serum GDF-15 concentration was measured by enzyme-linked immunosorbent assay. Results: The GDF-15 level was higher in patients receiving aortic valve replacement than in healthy elderly subjects (aortic valve replacement: 1624 ± 1186 pg/mL vs. healthy: 955 ± 368 pg/mL, p < 0.001). Multivariate linear regression analysis showed that the serum GDF-15 level determined grip strength independently of the high-sensitivity C-reactive protein level and eGFR, even after adjusting for age (ß = -0.318, p = 0.025). Sarcopenia was found in 12.5% of healthy elderly subjects, 83.3% of patients with TAVR, and 64.3% of patients with SAVR. The GDF-15 concentration that defined sarcopenia was 1109 pg/mL in subjects including patients receiving aortic valve replacement. Conclusions: The preoperative serum GDF-15 concentration, which was higher in female patients receiving aortic valve replacement than in healthy elderly subjects, may be a serum marker of sarcopenia.

Effect of sarcopenia on hospital stay from post cardiac surgery to discharge.

Background: Cardiovascular surgery in older patients with sarcopenia has high rates of major complications, long hospital stays, readmissions, and discharge transfers. However, the factors that influence the length of hospital stay are unknown. This study aimed was to identify the predictors of the prolonged hospital stay in patients with sarcopenia after cardiovascular surgery. Methods: A total of 192 patients scheduled for cardiac surgery were enrolled in this retrospective observational study. Sarcopenia was diagnosed preoperatively. Clinical data from the preoperative, intraoperative, and perioperative periods were evaluated to determine the factors influencing the length of hospital stay. Results: The sarcopenia and non-sarcopenia groups differed significantly in age; body mass index; renal function; intubation time; transfusion of red blood cells; hospital transfer; and hemoglobin, brain natriuretic peptide, and albumin levels. Sarcopenia was the most significant factor influencing prolonged postoperative hospital stay, as well as prolonged intubation time. In the sarcopenia group, albumin levels and cardiopulmonary bypass time were the significant factors affecting hospital stay. Conclusions: Sarcopenia was the most significant factor associated with prolonged postoperative hospital stay in patients who underwent cardiac surgery. In addition, improving sarcopenia, nutritional status, and shortening cardiopulmonary bypass time appear to shorten the hospital stay in patients with sarcopenia who underwent cardiovascular surgery.

Preoperative Serum GDF-15, Endothelin-1 Levels, and Intraoperative Factors as Short-Term Operative Risks for Patients Undergoing Cardiovascular Surgery.

OBJECTIVES: The Society of Thoracic Surgeons (STS) risk score is widely used for the risk assessment of cardiac surgery. Serum biomarkers such as growth differentiation factor-15 (GDF-15) and endothelin-1 (ET-1) are also used to evaluate risk. We investigated the relationships between preoperative serum GDF-15, ET-1 levels, and intraoperative factors and short-term operative risks including acute kidney injury (AKI) for patients undergoing cardiovascular surgery. METHODS: In total, 145 patients were included in this study (92 males and 53 females, age 68.4 ± 13.2 years). The preoperative STS score was determined, and the serum GDF-15 and ET-1 levels were measured by ELISA. These were related to postoperative risks, including AKI, defined according to the Acute Kidney Injury Network (AKIN) classification criteria. RESULTS: AKI developed in 23% of patients. The GDF-15 and ET-1 levels correlated with the STS score. The STS score and GDF-15 and ET-1 levels all correlated with preoperative eGFR, Alb, Hb, and BNP levels; perioperative data (urine output); ICU stay period; and postoperative admission days. Patients with AKI had longer circulatory pulmonary bypass (CPB) time, and male patients with AKI had higher ET-1 levels than those without AKI. In multivariable logistic regression analysis, the preoperative ET-1 level and CPB time were the independent determinants of AKI, even adjusted by age, sex, and BMI. The preoperative GDF-15 level, CPB time, and RCC transfusion were independent determinants of 30-day mortality plus morbidity. CONCLUSION: Preoperative GDF-15 and ET-1 levels as well as intraoperative factors such as CPB time may be helpful to identify short-term operative risks for patients undergoing cardiovascular surgery.

Low-Intensity Resistance Training with Moderate Blood Flow Restriction Appears Safe and Increases Skeletal Muscle Strength and Size in Cardiovascular Surgery Patients: A Pilot Study.

We examined the safety and the effects of low-intensity resistance training (RT) with moderate blood flow restriction (KAATSU RT) on muscle strength and size in patients early after cardiac surgery. Cardiac patients (age 69.6 ± 12.6 years, n = 21, M = 18) were randomly assigned to the control (n = 10) and the KAATSU RT group (n = 11). All patients had received a standard aerobic cardiac rehabilitation program. The KAATSU RT group additionally executed low-intensity leg extension and leg press exercises with moderate blood flow restriction twice a week for 3 months. RT-intensity and volume were increased gradually. We evaluated the anterior mid-thigh thickness (MTH), skeletal muscle mass index (SMI), handgrip strength, knee extensor strength, and walking speed at baseline, 5-7 days after cardiac surgery, and after 3 months. A physician monitored the electrocardiogram, rate of perceived exertion, and the color of the lower limbs during KAATSU RT. Creatine phosphokinase (CPK) and D-dimer were measured at baseline and after 3 months. There were no side effects during KAATSU RT. CPK and D-dimer were normal after 3 months. MTH, SMI, walking speed, and knee extensor strength increased after 3 months with KAATSU RT compared with baseline. Relatively low vs. high physical functioning patients tended to increase physical function more after 3 months with KAATSU RT. Low-intensity KAATSU RT as an adjuvant to standard cardiac rehabilitation can safely increase skeletal muscle strength and size in cardiovascular surgery patients.

Vascular Endothelial Dysfunction and Autonomic Nervous Hyperactivity among Premenopausal Women with Cold-Sensitivity Constitution (Hiesho).

The cold-sensitivity constitution (CSC), termed "Hiesho" in Japanese, is a woman-specific cold sense of peripheral sites. The etiology of and criteria for CSC are not yet well established. We defined CSC as temperature gradient > 6˚C between body surface and core, and investigated the autonomic nervous activity by measuring heart rate variability and the vascular endothelial function by determining reactive hyperemia index (RHI) in 43 healthy premenopausal women, aged 18-47 years. Twenty five women had CSC during both the follicular and luteal phases of their menstrual cycles (sustained-CSC group), 8 women did not show CSC during both phases (non-CSC group), and the remaining 10 women showed CSC in either menstrual phase (occasional CSC). To identify the pathophysiological bases of CSC, we compared the sympathetic nervous activity and vascular endothelial function between sustained-CSC and non-CSC. We thus found that sympathetic nervous activity was higher among the sustained-CSC group (p = 0.042) during the follicular phase, compared with the non-CSC group, while the RHI was similar in both groups. Furthermore, the sympathetic nervous activity was similar between the sustained-CSC women aged ≥ 40 years (n = 10) and those aged < 40 years (n = 15) during either menstrual phase, whereas the RHI of the women aged < 40 years was lower during the follicular phase (p = 0.045), compared with the women aged ≥ 40 years. In conclusion, CSC is associated with sympathetic nervous hyperactivity in premenopausal women, and vascular endothelial dysfunction is also involved in CSC among younger women.

Phase Angle as an Indicator of Sarcopenia, Malnutrition, and Cachexia in Inpatients with Cardiovascular Diseases.

Malnutrition is associated with sarcopenia, cachexia, and prognosis. We investigated the usefulness of phase angle (PhA) as a marker of sarcopenia, cachexia, and malnutrition in 412 hospitalized patients with cardiovascular disease. We analyzed body composition with bioelectrical impedance analysis, and nutritional status such as controlling nutritional status (CONUT) score. Both skeletal muscle mass index (SMI) and PhA correlated with age, grip strength and knee extension strength (p < 0.0001) in both sexes. The SMI value correlated with CONUT score, Hb, and Alb in males. Phase angle also correlated with CONUT score, Hb, and Alb in males, and more strongly associated with these nutritional aspects. In females, PhA was correlated with Hb and Alb (p < 0.001). In both sexes, sarcopenia incidence was 31.6% and 32.4%; PhA cut-off in patients with sarcopenia was 4.55° and 4.25°; and cachexia incidence was 11.5% and 14.1%, respectively. The PhA cut-off in males with cachexia was 4.15°. Multivariate regression analysis showed that grip strength and brain natriuretic peptide (BNP) were independent determinants of SMI, whereas grip strength, BNP, and Hb were independent determinants of PhA. Thus, PhA appears to be a useful marker for sarcopenia, malnutrition, and cachexia in hospitalized patients with cardiovascular disease.

Association of serum leptin and adiponectin concentrations with echocardiographic parameters and pathophysiological states in patients with cardiovascular disease receiving cardiovascular surgery.

Leptin and adiponectin are important regulators of energy metabolism and body composition. Leptin exerts cardiodepressive effects, whereas adiponectin has cardioprotective effects, but several conflicting findings have been reported. The aim of the present study was to assess the relationship between serum leptin and adiponectin levels and echocardiographic parameters and pathophysiological states in patients with cardiovascular disease (CVD) receiving cardiovascular surgery. A total of 128 patients (79 males, average age 69.6 years) that had surgery for CVD including coronary artery bypass graft (CABG) and valve replacement were recruited in this study. Preoperative serum adiponectin and leptin concentrations were measured by enzyme-linked immunosorbent assay and compared with preoperative echocardiographic findings. Body fat volume and skeletal muscle volume index (SMI) were estimated using bioelectrical impedance analysis. We also measured grip strength and gait speed. Sarcopenia was diagnosed based on the recommendations of the Asian Working Group on Sarcopenia. Positive correlations were found between adiponectin and brain natriuretic peptide (BNP), age, left atrial diameter (LAD), E/e' (early-diastolic left ventricular inflow velocity / early-diastolic mitral annular velocity), and left atrial volume index (LAVI). Negative correlations were observed between adiponectin and body mass index (BMI), estimated glomerular filtration rate (eGFR), triglyceride, hemoglobin, and albumin. Serum leptin was positively correlated with BMI, total cholesterol, triglyceride, albumin, body fat volume, and LV ejection fraction (LVEF), whereas it was negatively correlated with BNP and echocardiographic parameters (LAD, LV mass index (LVMI), and LAVI). Multiple regression analysis showed associations between log (leptin) and log (adiponectin) and echocardiographic parameters after adjusting for age, sex, and BMI. Serum adiponectin was negatively correlated with leptin, but positively correlated with tumor necrosis factor α (TNFα), an inflammatory cytokine. In males, serum leptin level had a positive correlation with skeletal muscle volume and SMI. However, adiponectin had a negative correlation with anterior mid-thigh muscle thickness, skeletal muscle volume and SMI. And, it was an independent predictive factor in males for sarcopenia even after adjusted by age. These results suggest that leptin and adiponectin may play a role in cardiac remodeling in CVD patients receiving cardiovascular surgery. And, adiponectin appears to be a marker of impaired metabolic signaling that is linked to heart failure progression including inflammation, poor nutrition, and muscle wasting in CVD patients receiving cardiovascular surgery.

Growth Differentiation Factor-15 (GDF-15) is a Biomarker of Muscle Wasting and Renal Dysfunction in Preoperative Cardiovascular Surgery Patients.

Frailty and sarcopenia increase the risk of complications and mortality when invasive treatment such as cardiac surgery is performed. Growth differentiation factor-15 (GDF-15) involves various pathophysiological conditions including renal dysfunction, heart failure and cachexia. We investigated the pathophysiological roles of preoperative GDF-15 levels in cardiovascular surgery patients. Preoperative skeletal muscle index (SMI) determined by bioelectrical impedance analysis, hand-grip strength, 4 m gait speed, and anterior thigh muscle thickness (TMth) measured by echocardiography were assessed in 72 patients (average age 69.9 years) who underwent cardiovascular surgery. The preoperative serum GDF-15 concentration was determined by enzyme-linked immunosorbent assay. Circulating GDF-15 level was correlated with age, brain natriuretic peptide, and estimated glomerular filtration rate (eGFR). It was also negatively correlated with SMI, hand-grip strength, and anterior TMth. In multivariate analysis, eGFR and anterior TMth were the independent determinants of GDF-15 concentration even after adjusting for age, sex, and body mass index. Alternatively, the GDF-15 level was an independent determinant of eGFR and anterior TMth. We concluded that preoperative GDF-15 levels reflect muscle wasting as well as renal dysfunction in preoperative cardiovascular surgery patients. GDF-15 may be a novel biomarker for identify high-risk patients with muscle wasting and renal dysfunction before cardiovascular surgery.

Prediction of Acute-phase Complications in Patients with Infectious Endocarditis.

Objective Embolic events are frequent and life-threatening complications of infective endocarditis (IE). Recently, an embolic risk assessment at admission, based on the Embolic Risk (ER) French Calculator, was designed to predict the development of symptomatic emboli associated with IE. This study aimed to validate the ER French Calculator for the prediction of in-hospital events, including embolic events. Methods We retrospectively analyzed the clinical features of 52 consecutive patients with left-sided IE to identify possible predictors of in-hospital events within 30 days of admission. Results New embolic events were seen in 15 patients (29%), cardiac surgery was performed in 22 patients (42%), and 1 patient (2%) died within 30 days of admission. A composite endpoint of embolic complications, cardiac surgery, or death was observed in 28 patients (54%). The cumulative incidence of new embolic events was significantly higher in the high-risk group identified by the ER French Calculator than in the low-risk group (log-rank test; p=0.0004). The incidence of the composite endpoint was higher in the high-risk group than in the low-risk group (log-rank test; p<0.0001). A multivariate Cox proportional hazards model indicated that the high-risk designation on the ER French Calculator predicted embolic events (p=0.0410) and composite events (p=0.0371) independently of other candidate predictors. Conclusion The ER French Calculator may be a useful tool for predicting new in-hospital embolic events and other unfavorable in-hospital events in patients with IE.

Heat induces myogenic transcription factors of myoblast cells via transient receptor potential vanilloid 1 (Trpv1).

Exercise generates heat, blood flow, and metabolic changes, thereby inducing hypertrophy of skeletal muscle cells. However, the mechanism by which heat incudes hypertrophy in response to heat is not well known. Here, we hypothesized that heat would induce differentiation of myoblast cells. We investigated the underlying mechanism by which myoblast cells respond to heat. When mouse myoblast cells were exposed to 42 °C for over 30 min, the phosphorylation level of protein kinase C (PKC) and heat shock factor 1 (Hsf1) increased, and the mRNA and protein expression level of heat shock protein 70 (Hsp70) increased. Inhibitors of transient receptor potential vanilloid 1 (Trpv1), calmodulin, PKC, and Hsf1, and the small interfering RNA-mediated knockdown of Trpv1 diminished those heat responses. Heat exposure increased the phosphorylation levels of thymoma viral proto-oncogene 1 (Akt), mammalian target of rapamycin (mTOR), eukaryotic translation initiation factor 4E binding protein 1 (Eif4ebp1), and ribosomal protein S6 kinase, polypeptide 1 (S6K1). The knockdown of Trpv1 decreased these heat-induced responses. Antagonists of Hsp70 inhibited the phosphorylation level of Akt. Finally, heat increased the protein expression level of skeletal muscle markers such as myocyte enhancer factor 2D, myogenic factor 5, myogenic factor 6, and myogenic differentiation 1. Heat also increased myotube formation. Knockdown of Trpv1 diminished heat-induced increases of those proteins and myotube formation. These results indicate that heat induces myogenic transcription factors of myoblast cells through the Trpv1, calmodulin, PKC, Hsf1, Hsp70, Akt, mTOR, Eif4ebp1, and S6K1 pathway. Moreover, heat increases myotube formation through Trpv1.

Association of serum concentrations of irisin and the adipokines adiponectin and leptin with epicardial fat in cardiovascular surgery patients.

Epicardial fat located adjacent to the heart and coronary arteries is associated with increased cardiovascular risk. Irisin is a myokine produced by skeletal muscle after physical exercise, and originally described as a molecule able to promote the browning of white adipose tissue and energy expenditure. In order to decrease cardiovascular risk, it has been proposed as a promising therapeutic target in obesity and type 2 diabetes. We investigated the relationships between serum concentrations of irisin and the adipokines adiponectin and leptin and body fat including epicardial fat in patients undergoing cardiovascular surgery. We obtained serum samples from 93 patients undergoing cardiovascular surgery (age 69.6 (SD 12.8) years, BMI 24.1 ± 4.8 kg/m2). Computed tomography (CT) and echocardiographic data were obtained from the routine preoperative examination. Subcutaneous fat area (SFA, cm2) and visceral fat area (VFA, cm2) near the umbilicus were automatically measured using the standard fat attenuation range. Epicardial fat area (EFA, cm2) was measured at the position where the heart became a long axis image with respect to the apex of the heart in the coronal section image. Total body fat mass, body fat percentage, and skeletal muscle volume (SMV) were estimated using bioelectrical impedance analysis (BIA). Serum irisin concentration was measured by enzyme-linked immunosorbent assay, and compared with adiponectin and leptin concentrations. The data were also compared with the clinical biochemical data. EFA was strongly correlated with BMI (P = 0.0001), non-HDL-C (P = 0.029), TG (P = 0.004), body fat mass (P = 0.0001), and body fat percentage (P = 0.0001). Serum leptin concentration showed a significant positive correlation with BMI (P = 0.0001) and TG (P = 0.001). Adiponectin, but not irisin, showed a significant negative correlation with BMI (P = 0.006) and TG (P = 0.001). Serum leptin level had a significant positive correlation with EFA, VFA, and SFA. In contrast, the serum adiponectin level was significantly negatively correlated with EFA, VFA, and SFA. The serum irisin level was also negatively correlated with EFA (r = -0.249, P = 0.015), and SFA (r = -0.223, P = 0.039), and tended to correlate with VFA (r = -0.198, P = 0.067). The serum level of adiponectin was negatively correlated with that of leptin (r = -0.296, P = 0.012), but there were no significant correlations between irisin and either adiponectin or leptin. Multivariate linear regression demonstrated that EFA showed a positive association with serum leptin level (ß = 0.438, P = 0.0001) and a negative correlation with serum irisin level (ß = -0.204, P = 0.038) and serum adiponectin level (ß = -0.260, P = 0.015) after adjusting for age, sex, and BMI. The present study provided the first evidence of associations of the serum irisin and adipokines (adiponectin and leptin) concentrations with epicardial fat in cardiovascular surgery patients. Irisin may play a role in preventing excess adiposity including epicardial fat, and consequently cardiovascular risk in patients.

Serum adiponectin and TNFα concentrations are closely associated with epicardial adipose tissue fatty acid profiles in patients undergoing cardiovascular surgery.

BACKGROUND: Epicardial adipose tissue (EAT) releases both adiponectin and TNFα, and these two adipokines play important roles in heart diseases such as coronary arterial disease. The aim of the present study was to clarify whether fatty acid (FA) profiles in EAT are linked to the serum concentration of these adipokines. The relationships between serum adipokine levels and FA profiles in patients undergoing cardiovascular surgery were analyzed. METHODS: Patients (n = 21) undergoing cardiovascular surgery (11 males, 70.4 ± 9.0 years, BMI 26.0 ± 5.1 kg/m2) were included. EAT samples were taken. We measured clinical biochemical data and FA profiles in venous blood and EAT samples using gas chromatography. Serum adiponectin and TNFα concentrations were also measured. RESULTS: The adiponectin and TNFα levels were not correlated with any fatty acid concentration in serum lipids. In contrast, there was a positive correlation between the serum adiponectin level and epicardial level of nervonic acid (C24:1ω9, r = 0.525, P = 0.025). In multiple regression analysis, adiponectin showed a positive association with the epicardial C24:1ω9 concentration after controlling for age and BMI, or TG, non-HDL-C, and BNP. The serum TNFα concentration was negatively correlated with the epicardial C18:3ω3, C12:0 and C18:0 content. In multiple regression analysis, the serum TNFα concentration showed a positive association with the epicardial C18:3ω3 level (ß = - 0.575, P = 0.015). CONCLUSIONS: These results suggest that there is a close relationship between epicardial FA profiles and serum levels of adiponectin and TNFα. Dietary therapy to target FA profiles may be helpful to modulate inflammation.

Heat induces interleukin-6 in skeletal muscle cells via TRPV1/PKC/CREB pathways.

Interleukin-6 (IL-6) is released from skeletal muscle cells and induced by exercise, heat, catecholamine, glucose, lipopolysaccharide, reactive oxygen species, and inflammation. However, the mechanism that induces release of IL-6 from skeletal muscle cells remains unknown. Thermosensitive transient receptor potential (TRP) proteins such as TRPV1-4 play vital roles in cellular functions. In this study we hypothesized that TRPV1 senses heat, transmits a signal into the nucleus, and produces IL-6. The purpose of the present study is to investigate the underlying mechanisms whereby skeletal muscle cells sense and respond to heat. When mouse myoblast cells were exposed to 37-42°C for 2 h, mRNA expression of IL-6 increased in a temperature-dependent manner. Heat also increased IL-6 secretion in myoblast cells. A fura 2 fluorescence dual-wavelength excitation method showed that heat increased intracellular calcium flux in a temperature-dependent manner. Intracellular calcium flux and IL-6 mRNA expression were increased by the TRPV1 agonists capsaicin and N-arachidonoyldopamine and decreased by the TRPV1 antagonists AMG9810 and SB366791 and siRNA-mediated knockdown of TRPV1. TRPV2, 3, and 4 agonists did not change intracellular calcium flux. Western blotting with inhibitors demonstrated that heat increased phosphorylation levels of TRPV1, followed by PKC and cAMP response element-binding protein (CREB). PKC inhibitors, Gö6983 and staurosporine, CREB inhibitors, curcumin and naphthol AS-E, and knockdown of CREB suppressed the heat-induced increases in IL-6. These results indicate that heat increases IL-6 in skeletal muscle cells through the TRPV1, PKC, and CREB signal transduction pathway.NEW & NOTEWORTHY Heat increases the release of interleukin-6 (IL-6) from skeletal muscle cells. IL-6 has been shown to serve immune responses and metabolic functions in muscle. It can be anti-inflammatory as well as proinflammatory. However, the mechanism that induces release of IL-6 from skeletal muscle cells remains unknown. Here we show that heat increases IL-6 in skeletal muscle cells through the transient receptor potential vannilloid 1, PKC, and cAMP response element-binding protein signal transduction pathway.

Diverse contribution of bone marrow-derived late-outgrowth endothelial progenitor cells to vascular repair under pulmonary arterial hypertension and arterial neointimal formation.

AIMS: It is still controversial whether bone marrow (BM)-derived endothelial progenitor cells (EPCs) can contribute to vascular repair and prevent the progression of vascular diseases. We aimed to characterize BM-derived EPC subpopulations and to evaluate their therapeutic efficacies to repair injured vascular endothelium of systemic and pulmonary arteries. METHODS AND RESULTS: BM mononuclear cells of Fisher-344 rats were cultured under endothelial cell-conditions. Early EPCs appeared on days 3-6. Late-outgrowth and very late-outgrowth EPCs (LOCs and VLOCs) were defined as cells forming cobblestone colonies on days 9-14 and 17-21, respectively. Among EPC subpopulations, LOCs showed the highest angiogenic capability with enhanced proliferation potential and secretion of proangiogenic proteins. To investigate the therapeutic effects of these EPCs, Fisher-344 rats underwent wire-mediated endovascular injury in femoral artery (FA) and were concurrently injected intraperitoneally with 60mg/kg monocrotaline (MCT). Injured rats were then treated with six injections of one of three EPCs (1×10(6) per time). After 4weeks, transplanted LOCs, but not early EPCs or VLOCs, significantly attenuated neointimal lesion formation in injured FAs. Some of CD31(+) LOCs directly replaced the injured FA endothelium (replacement ratio: 11.7±7.0%). In contrast, any EPC treatment could neither replace MCT-injured endothelium of pulmonary arterioles nor prevent the progression of pulmonary arterial hypertension (PAH). LOCs modified protectively the expression profile of angiogenic and inflammatory genes in injured FAs, but not in MCT-injured lungs. CONCLUSION: BM-derived LOCs can contribute to vascular repair of injured systemic artery; however, even they cannot rescue injured pulmonary vasculature under MCT-induced PAH.

Angiogenic potential of early and late outgrowth endothelial progenitor cells is dependent on the time of emergence.

BACKGROUND: Recent studies have suggested that late-outgrowth endothelial progenitor cells (EPCs) derived from human peripheral blood mononuclear cells (hPBMNCs) might have higher angiogenic potential than classically-defined early-outgrowth EPCs (EOCs). However, it still remains unclear which of "so-called" EPC subpopulations defined in a variety of ways has the highest angiogenic potential. METHODS AND RESULTS: We classified hPBMNC-derived EPC subpopulations by the time of their emergence in culture. EOCs were defined as attached cells on culture days 3-7. Late-outgrowth EPCs, defined as the cell forming colonies with cobblestone appearance since day 10, were further classified as follows: "moderate"-outgrowth EPCs (MOCs) emerging on days 10-16, "late"-outgrowth EPCs (LOCs) on days 17-23, and "very late"-outgrowth EPCs (VOCs) on days 24-30. Flow cytometry analyses showed the clear differences of hematopoietic/endothelial markers between EOC (CD31(+)VE-cadherin(-)CD34(-)CD14(+)CD45(+)) and LOC (CD31(+)VE-cadherin(+)CD34(+)CD14(-)CD45(-)). We found that LOCs had the highest proliferation and tube formation capabilities in vitro along with the highest expression of angiogenic genes including KDR and eNOS. To investigate the in vivo therapeutic efficacies, each EPC subpopulation was intravenously transplanted into immunocompromised mice (total 4 × 10(5) cells) after unilateral hindlimb ischemia surgery. The LOC-treated mice exhibited significantly-enhanced blood flow recovery (flow ratios of ischemic/non-ischemic leg: 0.99±0.02 [LOC group] versus 0.67 ± 0.07 to 0.78 ± 0.09 [other groups]; P < 0.05) and augmented capillary collateral formation in ischemic leg, which were attributable to their direct engraftment into host angiogenic vessels (approximately 10%) and paracrine effects. CONCLUSION: hPBMNC-derived late-outgrowth EPCs emerging on culture days 17-23 are superior to other EPC subpopulations with regard to therapeutic angiogenic potential.

Deletion of angiotensin-converting enzyme 2 promotes the development of atherosclerosis and arterial neointima formation.

AIMS: Angiotensin-converting enzyme 2 (ACE2) is known as a negative regulator of the renin-angiotensin system. We aimed to determine the roles of ACE2 on the development of vascular diseases. METHODS AND RESULTS: Using two diversely different models of vascular diseases, hyperlipidaemia-induced atherosclerosis in apolipoprotein E knockout (KO) mice and mechanical injury-induced arterial neointimal hyperplasia in C57Bl6 mice, we examined whether ACE2 deficiency could affect formation of the vascular lesions. ACE2 deficiency resulted in significantly larger vascular lesions in both aortic atherosclerotic plaques and arterial neointima formation, compared with ACE2(+) control. These ACE2-deficient vascular lesions exhibited enhanced accumulation of macrophages into the lesions and proliferation of vascular smooth muscle cells (VSMCs), accompanied with increased angiotensin-II (Ang-II) levels and enhanced expression of vascular inflammation-related genes, including vascular cell adhesion molecule (VCAM)-1, monocyte chemoattractant protein (MCP)-1, and matrix metalloproteinase (MMP)9 in aorta/artery tissues. Primary bone marrow macrophages and aortic VSMCs isolated from ACE2 KO mice also displayed enhanced pro-inflammatory responsiveness such as up-regulated gene/protein expression of VCAM-1, MCP-1, and MMP9 to stimulation with tumour necrosis factor-α and Ang-II. The similar phenotype was shown in human macrophages and aortic VSMCs that were transfected with ACE2-specific siRNA. In ACE2-deficient VSMCs, inhibition of c-Jun N-terminal kinase (JNK) by pharmacological blockade with SP600125 or genetic knockdown with JNK-specific siRNA significantly attenuated their pro-inflammatory phenotype. CONCLUSION: ACE2 deficiency promotes the development of vascular diseases associated with Ang-II-mediated vascular inflammation and activation of the JNK signalling, leading to the notion that ACE2 potentially confers protection against vascular diseases.