With growing use for hyperthermia as a cardiovascular therapeutic, there is surprisingly little information regarding the acute effects it may have on the integrity of the neurovascular unit (NVU). Indeed, relying on animal data would suggest hyperthermia comparable to levels attained in thermal therapy will disrupt the blood-brain barrier (BBB) and damage the cerebral parenchymal cells. We sought to address the hypothesis that controlled passive hyperthermia is not sufficient to damage the NVU in healthy humans. Young men (n=11) underwent acute passive heating until +2°C or absolute esophageal temperature of 39.5°C. The presence of BBB opening was determined by trans-cerebral exchange kinetics (radial-arterial and jugular venous cannulation) of S100B. Neuronal parenchymal damage was determined by the trans-cerebral exchange of tau protein, neuron specific enolase (NSE) and neurofilament-light protein (NF-L). Cerebral blood flow to calculate exchange kinetics was measured by duplex ultrasound of the right internal carotid and left vertebral artery. Passive heating was performed via warm-water perfused suit. In hyperthermia, there was no increase in the cerebral exchange of S100B (p=0.327), tau protein (p=0.626), NF-L (p=0.0.447) or NSE (p=0.908) suggesting +2°C core temperature is not sufficient to acutely stress the NVU in healthy men. However, there was a significant condition effect (p=0.028) of NSE, corresponding to a significant increase in arterial (p=0.023) but not venous (p=0.173) concentrations in hyperthermia, potentially indicating extra-cerebral release of NSE. Collectively, results from the present study support the notion that in young men there is little concern for NVU damage with acute hyperthermia of +2°C.

中文翻译：

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中度至重度热疗对健康男性血脑屏障通透性和神经元实质完整性的影响可忽略不计

随着热疗​​作为心血管治疗剂的使用越来越多，令人惊讶的是，关于它可能对神经血管单元 (NVU) 的完整性产生的急性影响的信息很少。事实上，依赖动物数据表明，与热疗达到的水平相当的热疗会破坏血脑屏障 (BBB) 并损害脑实质细胞。我们试图解决受控被动热疗不足以损害健康人的 NVU 的假设。年轻男性 (n=11) 接受急性被动加热直至 +2°C 或绝对食道温度 39.5°C。BBB 开口的存在由 S100B 的跨脑交换动力学（桡动脉和颈静脉插管）确定。神经元实质损伤由 tau 蛋白的跨脑交换决定，神经元特异性烯醇化酶 (NSE) 和神经丝轻蛋白 (NF-L)。通过右颈内动脉和左椎动脉的双工超声测量用于计算交换动力学的脑血流量。通过温水灌注服进行被动加热。在热疗中，S100B (p=0.327)、tau 蛋白 (p=0.626)、NF-L (p=0.0.447) 或 NSE (p=0.908) 的脑交换没有增加，表明 +2°C 核心温度不足以对健康男性的 NVU 产生急性压力。然而，NSE 有显着的条件效应 (p=0.028)，对应于在热疗中动脉 (p=0.023) 而非静脉 (p=0.173) 浓度的显着增加，这可能表明 NSE 的脑外释放。总的来说，