Department of Kinesiology, Towson University, Towson, Maryland, United States.
Department of Kinesiology, University of Georgia, Athens, Georgia, United States.
J Appl Physiol (1985). 2024 Oct 1;137(4):864-872. doi: 10.1152/japplphysiol.00203.2024. Epub 2024 Aug 15.
The near-infrared spectroscopy (NIRS) vascular occlusion test (VOT) assesses microvascular reperfusion. Two strategies have been used to quantify reperfusion following reactive hyperemia, but it is unclear whether both yield similar results when comparing biological sex. This study aimed to determine whether sex differences in NIRS-based microvascular reperfusion are similarly apparent using the 10-s reactive hyperemia slope of the tissue saturation index (StO) signal (slope 2) and the halftime to maximal reperfusion (T ½). Healthy, recreationally active males ( = 31) and females ( = 31) between 18 and 82 years took part in this study. A NIRS VOT was performed on the tibialis anterior muscle, and reperfusion was quantified using slope 2 (% s) and T ½ (s). Adipose tissue thickness (ATT) was higher in females ( = 0.009), which was associated with a lower StO ( = 0.001) and oxygenated hemoglobin (OHb) ( = 0.05) signal range. The StO slope 2 was significantly steeper in males versus females ( = 0.001) but not after correcting for ATT ( = 0.295). There were no sex differences in StO T ½ ( = 0.067) or OHb T ½ ( = 0.197). In a subset of males ( = 26) and females ( = 21) with similar ATT, there were no sex differences in StO slope 2 ( = 0.068), StO T ½ ( = 0.491), or OHb T ½ ( = 0.899). An ATT-corrected StO slope 2 or the T ½ approach is recommended for analysis of NIRS-based microvascular reperfusion when differences in ATT are present between sexes. Sex differences in near-infrared spectroscopy (NIRS)-based microvascular reperfusion have been previously reported. We found that greater adipose tissue thickness in females reduces kinetic measures of NIRS-based microvascular reperfusion. Sex differences are eliminated when performing an adipose tissue thickness correction, when the NIRS signal range is accounted for, or when adipose tissue thickness is similar between sexes. This highlights the importance of considering factors that affect NIRS signals, such as adipose tissue thickness, when drawing comparisons between groups.
近红外光谱（NIRS）血管闭塞试验（VOT）评估微血管再灌注。已经使用了两种策略来量化反应性充血后的再灌注，但尚不清楚在比较生物学性别时，这两种策略是否会产生相似的结果。本研究旨在确定使用组织饱和度指数（StO）信号的 10 秒反应性充血斜率（斜率 2）和达到最大再灌注的半衰期（T ½），是否同样明显存在基于 NIRS 的微血管再灌注的性别差异。本研究纳入了 31 名 18 至 82 岁的健康、有规律运动的男性和 31 名女性。在前胫骨肌上进行 NIRS VOT，并使用斜率 2（% s）和 T ½（s）来量化再灌注。女性的脂肪组织厚度（ATT）更高（ = 0.009），这与较低的 StO（ = 0.001）和氧合血红蛋白（OHb）（ = 0.05）信号范围相关。男性的 StO 斜率 2 明显高于女性（ = 0.001），但校正 ATT 后则无差异（ = 0.295）。StO T ½（ = 0.067）或 OHb T ½（ = 0.197）在性别之间无差异。在 ATT 相似的一部分男性（ = 26）和女性（ = 21）中，StO 斜率 2（ = 0.068）、StO T ½（ = 0.491）或 OHb T ½（ = 0.899）在性别之间无差异。当 ATT 在性别之间存在差异时，建议使用 ATT 校正的 StO 斜率 2 或 T ½ 方法来分析基于 NIRS 的微血管再灌注。先前已经报道了基于近红外光谱（NIRS）的微血管再灌注的性别差异。我们发现，女性的脂肪组织厚度较大降低了基于 NIRS 的微血管再灌注的动力学测量值。当进行脂肪组织厚度校正、考虑 NIRS 信号范围或男女之间的脂肪组织厚度相同时，性别差异就会消除。这凸显了在进行组间比较时考虑影响 NIRS 信号的因素（如脂肪组织厚度）的重要性。
