Improved blood pressure and flow-mediated dilatation via increased plasma adropin and nitrate/nitrite induced by high-intensity interval training in patients with type 2 diabetes.

NEW FINDINGS: What is the central question of this study? Exercise training increases adropin and nitrite/nitrate (NOx) plasma levels in middle-aged and older healthy people. We hypothesized that high-intensity interval training may improve blood pressure and flow-mediated dilatation through the effects of adropin and NOx in patients of this age with type 2 diabetes. What is the main finding and its importance? High-intensity interval training may be more effective than moderate-intensity continuous training in improving endothelial function, blood pressure and flow-mediated dilatation through its effects on adropin and NOx in patients with type 2 diabetes. ABSTRACT: Adropin is a newly identified bioactive protein that is important in energy hemostasis and vascular endothelial function. Lower levels of adropin in patients with type 2 diabetes are related to coronary atherosclerosis, characterized by impaired flow-mediated dilatation (FMD). The purpose of the present study was to investigate FMD and plasma levels of adropin and nitrite/nitrate (NOx) in patients with type 2 diabetes at baseline and follow-up after 12 weeks of high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT). Sixty-six persons with type 2 diabetes were divided into HIIT, MICT, and control groups. The HIIT group intervention was 12 intervals (1.5 min) at 85-90% maximal heart rate (HRmax ) separated by 2 min at 55-60% HRmax in three sessions per week for 12 weeks. MICT training consisted of 42 min of cycling at 70% HRmax . Before and after the intervention, FMD was recorded with high-resolution Doppler ultrasound. Plasma levels of adropin and NOx were measured by enzyme-linked immunosorbent assay. After training FMD was significantly higher in the MICT and HIIT groups compared to the control group (P < 0.05). Plasma levels of adropin and NOx were higher in both exercise groups, but the increase was greater in the HIIT group (P < 0.01). Peak oxygen consumption was increased after exercise training in both groups compared to the control group (P < 0.01). Percentage FMD showed a positive correlation with plasma levels of adropin and NOx (both P < 0.01), and a negative correlation with diastolic blood pressure (r = -0.530, P = 0.035) and systolic blood pressure (r = -0.606, P = 0.013) in the HIIT group. The results indicate that HIIT improved FMD whilst increasing adropin, NOx and peak oxygen consumption. Increased plasma levels of adropin may contribute, in part, to blood pressure reduction by increasing nitric oxide production.

Synergistic effect of high-intensity interval training and stem cell transplantation with amniotic membrane scaffold on repair and rehabilitation after volumetric muscle loss injury.

Despite the high regenerative capacity of skeletal muscle, volumetric muscle loss (VML) is an irrecoverable injury. One therapeutic approach is the implantation of engineered biologic scaffolds enriched with stem cells. The objective of this study is to investigate the synergistic effect of high-intensity interval training (HIIT) and stem cell transplantation with an amniotic membrane scaffold on innervation, vascularization and muscle function after VML injury. A VML injury was surgically created in the tibialis anterior (TA) muscle in rats. The animals were randomly assigned to three groups: untreated negative control group (untreated), decellularized human amniotic membrane bio-scaffold group (dHAM) and dHAM seeded with adipose-derived stem cells, which differentiate into skeletal muscle cells (dHAM-ADSCs). Then, each group was divided into sedentary and HIIT subgroups. The exercise training protocol consisted of treadmill running for 8 weeks. The animals underwent in vivo functional muscle tests to evaluate maximal isometric contractile force. Regenerated TA muscles were harvested for molecular analyses and explanted tissues were analyzed with histological methods. The main finding was that HIIT promoted muscle regeneration, innervation and vascularization in regenerated areas in HIIT treatment subgroups, especially in the dHAM-ADSC subgroup. In parallel with innervation, maximal isometric force also increased in vivo. HIIT upregulated neurotrophic factor gene expression in skeletal muscle. The amniotic membrane bio-scaffold seeded with differentiated ADSC, in conjunction with exercise training, improved vascular perfusion and innervation and enhanced the functional and morphological healing process after VML injury. The implications of these findings are of potential importance for future efforts to develop engineered biological scaffolds and for the use of interval training programs in rehabilitation after VML injury.

Improved carotid intima-media thickness-induced high-intensity interval training associated with decreased serum levels of Dkk-1 and sclerostin in type 2 diabetes.

AIMS: Carotid intima-media thickness (cIMT) is a validated surrogate marker of atherosclerosis. Dickkopf-1 (Dkk-1) and sclerostin modulate wingless signaling, which is involved in atherosclerosis. The purpose of this study was to investigate whether 12 weeks of high-intensity interval training (HIIT) would improve cIMT and serum Dkk-1 and sclerostin levels in patients with type 2 diabetes. METHODS: Seventy-four sedentary patients with type 2 diabetes were randomly divided into HIIT and control groups. The HIIT group intervention was 6 intervals (4 min) at 85%-90% HRmax separated by 3 min at 45%-50% HRmax in 3 sessions/week for 12 weeks. Before and after the intervention, cIMT, artery diameter and wall/lm ratio were recorded with high-resolution ultrasound. Serum sclerostin and Dkk-1 were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: cIMT decreased significantly in the HIIT group (0.83 ±â€¯0.17 baseline, 0.71 ±â€¯0.14 follow-up) compared to the control group (0.84 ±â€¯0.20 baseline, 0.85 ±â€¯0.19 follow-up) (P < .05). Dkk-1 and sclerostin decreased significantly after 12 weeks of HIIT (P < .01). In addition, VO2peak was increased in the HIIT group than the control group (by 6.2 mL/kg/min) (P < .05). There was a positive correlation between percent changes in cIMT and percent changes in Dkk-1 and sclerostin (both P < .01). Additionally, there were a negative correlation between percent changes VO2peak and cIMT (r = - 0.740, P = .003), Dkk-1 (r = - 0.844, P < .001) and sclerostin (r = - 0.575, P = .001) in HIIT group. CONCLUSION: Our results indicate that HIIT decreases cIMT, serum levels of Dkk-1 and sclerostin and improves VO2peak in patients with type 2 diabetes.

Improved brachial artery shear patterns and increased flow-mediated dilatation after low-volume high-intensity interval training in type 2 diabetes.

NEW FINDINGS: What is the central question of this study? Can low-volume high-intensity interval training and continuous moderate-intensity exercise modulate oscillatory and retrograde shear, blood flow and flow-mediated arterial dilatation in patients with type 2 diabetes? What is the main finding and its importance? Low-volume high-intensity interval training, by increasing anterograde shear and decreasing retrograde shear and oscillatory index, can increase nitric oxide production and consequently result in increased flow-mediated dilatation and outward arterial remodelling in patients with type 2 diabetes. ABSTRACT: Atherosclerosis in patients with type 2 diabetes is characterized by endothelial dysfunction associated with impaired flow-mediated dilatation (FMD) and increases retrograde and oscillatory shear. The present study investigated endothelium-dependent vasodilatation and shear rate in patients with type 2 diabetes at baseline and follow-up after 12 weeks of low-volume high-intensity interval training (LV-HIIT) or continuous moderate-intensity training (CMIT). Seventy-five sedentary patients with type 2 diabetes and untreated pre- or stage I hypertension were randomly divided into LV-HIIT, CMIT and control groups. The LV-HIIT group intervention was 12 intervals of 1.5 min at 85-90% maximal heart rate (HRmax ) and 2 min at 55-60% HRmax . The CMIT group intervention was 42 min of exercise at 70% HRmax for three sessions per week during 12 weeks. High-resolution Doppler ultrasound was used to measure FMD, arterial diameter, anterograde and retrograde blood flow, and shear rate patterns. Brachial artery FMD increased significantly in the LV-HIIT group (3.83 ± 1.13 baseline, 7.39 ± 3.6% follow-up), whereas there was no significant increase in the CMIT group (3.45 ± 0.97 baseline, 4.81 ± 2.36% follow-up) compared to the control group (3.16 ± 0.78 baseline, 4.04 ± 1.28% follow-up) (P < 0.05). Retrograde shear in the LV-HIIT group decreased significantly (P < 0.05), and no significant decrease in retrograde shear was seen in the CMIT group. Anterograde shear after LV-HIIT increased significantly (P < 0.05) but was unchanged in the CMIT group. However, oscillatory shear index in both exercise groups decreased significantly (P = 0.029). Nitrite/nitrate (NOx) level increased in both exercise groups, but the increase was greater in the LV-HIIT group (P < 0.001). The results indicate that by increasing NOx, HIIT decreases the oscillatory shear-induced improvement in FMD and outward artery remodelling in patients with type 2 diabetes.

High-intensity interval training lowers blood pressure and improves apelin and NOx plasma levels in older treated hypertensive individuals.

Hypertension is the major risk factor for cardiovascular diseases and is one of the primary causes of morbidity and mortality worldwide. Apelin levels and NO bioavailability are impaired in older hypertensive patients. Exercise is an effective intervention for treating hypertension. Our purpose was to evaluate the effect of high-intensity interval training on blood pressure, apelin, and NOx plasma levels in older treated hypertensive individuals. Thirty treated hypertensive subjects (61.70 ± 5.78 years, 17 males, 13 females) were randomly divided into 6 weeks of high-intensity interval training (n = 15) and control (n = 15). The exercise training was conducted for three 35-min sessions a week (1.5-min interval at 85-90% of heart rate reserve [HRR] and 2 min active phase at 50-55% of HRR). Assessment of plasma apelin, nitrite/nitrate (NOx), and endothelin-1 (ET-1) was performed before and after the intervention. At the end of the study, apelin, and NOx plasma levels increased significantly in the high-intensity interval training (HIIT) group (P = 0.021, P = 0.003, respectively). Conversely, ET-1 plasma levels significantly decreased in the training group after the intervention (P = 0.015). Moreover, there was a positive correlation between the change of plasma apelin and change of plasma NOx (r = 0. 771, P = 0.0008). In addition, there was a negative correlation between the change of plasma ET-1, change of plasma apelin (r = - 0.595, P = 0.019), and variation of NOx (r = - 0.572, P = 0.025). This study indicates that, by increasing of apelin and NOx plasma levels, HIIT may be effective in reducing blood pressure.