Blood Flow Restriction Enhances Post–Resistance Exercise Angiogenic Gene Expression

Abstract

Purpose The objective of this study is to evaluate the effects of blood flow restriction (BFR) on muscle oxygenation during low-intensity resistance exercise as well as postexercise expression of molecules related to physiological angiogenesis. Methods Using a randomized cross-over design, six apparently healthy young adults (22 ± 1 yr) performed 120 unilateral knee extensions at 40% of 1 repetition maximum with and without BFR (CNTRL). Near-infrared spectroscopy was used to measure oxygenation of the vastus lateralis during exercise. Serum and muscle expression of Post–Resistance vascular endothelial growth factor (VEGF) were determined preexercise, 4 h postexercise, and 24 h postexercise. Transcript (mRNA) expression of VEGF and other angiogenic genes was also determined. Results BFR increased muscle hemoglobin (Hb) concentrations during exercise (14.4 ± 1.6 vs. 0.9 ± 1.6, P = 0.002), driven largely by an increase in deoxygenated Hb (11.0 ± 2.5 vs. 0.5 ± 1.1, P = 0.030). BFR also increased (P < 0.05) transcript expression of VEGF, VEGF-R2, hypoxia-inducible factor 1 alpha, inducible nitric oxide synthase (NOS), and neuronal NOS. The most dramatic change in response to BFR was an increase in VEGF mRNA at 4 h postexercise (4.1 ± 0.6 vs. 0.6 ± 0.2-fold change, P = 0.028). Compared with control, transcript expression of endothelial NOS, serum VEGF, or muscle protein expression of VEGF was not altered in response to BFR (P > 0.05). Conclusion Acute BFR increases postexercise expression of mRNA related to skeletal muscle angiogenesis, plausibly in response to changes in muscle Hb concentrations.

Exercise with Blood Flow Restriction: An Updated Evidence-Based Approach for Enhanced Muscular Development

“…While expression of hypoxia-inducible factor-1α is known to increase in response to hypoxia [31], some evidence suggests that it is expressed to a similar degree following low-load resistance exercise either with or without BFR [32]. However, conflicting results have been observed in another study, where hypoxia-inducible factor-1α was increased by a significantly larger amount at 4 hr following a bout of low-load BFR exercise than the equivalent unrestricted exercise [33]. While it is possible that a degree of hypoxia results from the addition of BFR during exercise, it is difficult at this point to reconcile whether tissue hypoxia does in fact drive downstream responses to a BFR stimulus.…”

Exercise and Blood Flow Restriction

“…The hypoxic intramuscular condition promoted via BFR may stimulate increases in capillarization with implications for subsequent improvements in localized muscular endurance performance. Larkin et al (47) used the unilateral knee extension with or without the addition of BFR to examine the postexercise serum levels of vascular endothelial growth factor (VEGF)-a key growth factor that upregulates angiogenesis or capillary formation. In addition to protein expression of VEGF, mRNA transcripts indicative of angiogenesis were also examined, including: VEGF and its primary receptor (VEGF--R2), hypoxia--inducible factor 1 alpha (HIF--1a), and isoforms of nitric oxide synthase (NOS).…”

“…In addition to protein expression of VEGF, mRNA transcripts indicative of angiogenesis were also examined, including: VEGF and its primary receptor (VEGF--R2), hypoxia--inducible factor 1 alpha (HIF--1a), and isoforms of nitric oxide synthase (NOS). Larkin et al (47) tested subjects on 2 occasions (separated by 3 weeks) in a randomized crossover design; each exercise bout consisted of 10 sets of 12 repetitions of unilateral knee extensions with the dominant limb, at 40% of 1RM, and with 1--minute rest intervals between sets. For the BFR condition, an external cuff was placed around the proximal thigh and inflated to 220 mm Hg (cuff width not specified).…”

Blood flow-restricted strength training displays high functional and biological efficacy in women: a within-subject comparison with high-load strength training

“…Such information would arguably provide hallmark information on cell-signaling events. Of the few studies that have looked into the subject, all have assessed a scarce number of genes (12,32,33,39), with only one study having compared BFR to HST directly (33). Furthermore, no study has investigated effects of BFR on muscle fiber composition, which should be of particular interest given the hypothesized fiber-type specificity of BFR protocols, potentially leading to reduced stress of type 2 fiber (8), potentially skewing the expected transition of glycolytic 2X fibers into aerobic 2A fibers (1,17,63).…”