Are the metabolic benefits of resistance training in type 2 diabetes linked to improvements in adipose tissue microvascular blood flow?

Abstract

The microcirculation in adipose tissue is markedly impaired in type 2 diabetes (T2D). Resistance training (RT) often increases muscle mass and promotes a favorable metabolic profile in people with T2D, even in the absence of fat loss. Whether the metabolic benefits of RT in T2D are linked to improvements in adipose tissue microvascular blood flow is unknown. Eighteen sedentary people with T2D (7 women/11 men, 52 ± 7 yr) completed 6 wk of RT. Before and after RT, overnight-fasted participants had blood sampled for clinical chemistries (glucose, insulin, lipids, HbA1c, and proinflammatory markers) and underwent an oral glucose challenge (OGC; 50 g glucose × 2 h) and a DEXA scan to assess body composition. Adipose tissue microvascular blood volume and flow were assessed at rest and 1 h post-OGC using contrast-enhanced ultrasound. RT significantly reduced fasting blood glucose ( P = 0.006), HbA1c ( P = 0.007), 2-h glucose area under the time curve post-OGC ( P = 0.014), and homeostatic model assessment of insulin resistance ( P = 0.005). This was accompanied by a small reduction in total body fat ( P = 0.002), trunk fat ( P = 0.023), and fasting triglyceride levels ( P = 0.029). Lean mass ( P = 0.003), circulating TNF-α ( P = 0.006), and soluble VCAM-1 ( P < 0.001) increased post-RT. There were no significant changes in adipose tissue microvascular blood volume or flow following RT; however those who did have a higher baseline microvascular blood flow post-RT also had lower fasting triglyceride levels ( r = −0.476, P = 0.045). The anthropometric, glycemic, and insulin-sensitizing benefits of 6 wk of RT in people with T2D are not associated with an improvement in adipose tissue microvascular responses; however, there may be an adipose tissue microvascular-linked benefit to fasting triglyceride levels.

Impact of Short-Term Continuous and Interval Exercise Training on Endothelial Function and Glucose Metabolism in Prediabetes

“…Herein, CONT and INT exercise increased plasma VCAM, and the elevations in VCAM after training correlated with attenuated rises in fasting FMD. These data agree with recent work in people with type 2 diabetes showing that 6 weeks of resistance exercise raised circulating TNF-α and VCAM in parallel with no improvement in FMD [29]. Further work is warranted to understand the physiologic importance of this vascular inflammation as it relates training adaptation and cardiometabolic health.…”

Physical Activity and Health: The Benefits of Physical Activity in the Prevention of Diabetes Mellitus and Cardiovascular Disorders

“…High-intensity resistance exercises (75% to 85% 1RM) were efficient in reducing fat mass and increasing lean mass in elderly diabetics of both sexes, with no difference between them (Lee, Kim, Kim, 2017). A 6-week protocol of moderate to high-intensity resistance exercises (65% to 85% 1RM) was effective in reducing the fat mass percentage and increasing lean mass in middle-aged diabetic men and women (Hu, Russell, Remash, et al 2018).…”

Molecular and pathophysiological relationship between obesity and chronic inflammation in the manifestation of metabolic dysfunctions and their inflammation‑mediating treatment options (Review)

“…This evidence may support the hypothesis that AT TNF-α, which is not secreted in the systemic circulation may act in an autocrine or paracrine manner. Therefore, the anti-TNF-α agents may not reach the AT microcirculation, which is markedly impaired in T2DM ( 347 , 349 , 350 ). Thus, anti-TNF-α therapy may fail to improve insulin sensitivity in such cases.…”