Exercise intervention under hypoxic condition as a new therapeutic paradigm for type 2 diabetes mellitus:A narrative review

This review aims to summarize the health benefits of exposure to hypoxic conditions during exercise in patients with type 2 diabetes mellitus(T2 DM).Exposure to hypoxic conditions during exercise training positively changes the physiological response in healthy subjects.Exposure to hypoxic conditions during exercise could markedly increase skeletal muscle glucose uptake compared to that in normoxic conditions.Furthermore,post-exercise insulin sensitivity of T2 DM patients increases more when exercising under hypoxic than under normoxic conditions.Regular exercise under short-term hypoxic conditions can improve blood glucose control at lower workloads than in normoxic conditions.Additionally,exercise training under short-term hypoxic conditions can maximize weight loss in overweight and obese patients.Previous studies on healthy subjects have reported that regular exercise under hypoxic conditions had a more positive effect on vascular health than exercising under normoxic conditions.However,currently,evidence indicating that exposure to hypoxic conditions could positively affect T2 DM patients in the long-term is lacking.Therefore,further evaluations of the beneficial effects of exercise under hypoxic conditions on the human body,considering different cycle lengths,duration of exposures,sessions per day,and the number of days,are necessary.In this review,we conclude that there is evidence that exercise under hypoxic conditions can yield health benefits,which is potentially valuable in terms of clinical care as a new intervention for T2 DM patients.

Effect of Korean Magnolia obovata Extract on Platelet-Derived Growth Factor-Induced Vascular Smooth Muscle Cells

Objective:To investigate the effects of Korean Magnolia obovata crude extract(KME)on plateletderived growth factor(PDGF)-BB-induced proliferation and migration of vascular smooth muscle cells(VSMCs).Methods:KME composition was analyzed by high-performance liquid chromatography(HPLC).VSMCs were isolated from the aorta of a Sprague-Dawley rat,incubated in serum free-Dulbecco's modified Eagle's medium in the presence or absence of KME(10,30,100,and 300(xg/mL),then further treated with PDGF-BB(10 ng/mL).VSMC proliferation was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and VSMC migration was determined using the Boyden chamber and scratch wound healing assays.Western blot analysis was used to detect phosphorylation of extracellular signal-regulated protein kinases 1 and 2(p-ERK1/2),protein kinase B(p-Akt),and stress-activated protein kinase/c-Jun NH2-terminal kinase(p-SAPK/JNK).The antimigration and proliferation effects of KME were tested using aortic sprout outgrowth.Results:The HPLC analysis identified honokiol(0.45 mg/g)and magnolol(0.34 mg/g)as the major components of KME.KME(30,100,and 300μg/m L)significantly decreased the proliferation and migration of PDGF-BB-stimulated(10 ng/mL)VSMCs and the PDGF-BB-induced phosphorylation of EKR1/2,Akt,and SAPK/JNK(P<0.05).Furthermore,PDGF-BBinduced VSMCs treated with 300μg/m L of KME showed reduction in aortic sprout outgrowth.Conclusion:KME could inhibit abnormal proliferation and migration of VSMCs by down-regulating the phosphorylation of EKR1/2 and Akt.Thus,KME might be a functional food for preventing vascular disorders.