A Clinical Study On The Change Of Vascular Endothelial Function Of Accelerated Plateau People And Its Relationship With AMS

Background and ObjectivesAcute mountain sickness(AMS) is the pathological and physiological reactions of a body in a short time(a few hours or days) when a person quickly enter into a high altitude hypoxia environment(more that 3000 meters above sea level) from plain. Most patients with AMS will get relief or better within a few hours to several days. However, some patients will be worse or the conditions may even develop into high altitude pulmonary edema(HAPE) or high altitude cerebral edema(HACE) which is more fatal.Altitude environment contains many factors, including hypoxia, low humidity, low temperature and low pressure. Human body is stimulated mainly by hypoxia in altitude hypoxia environment and some of its basic physiological indexes will make some change to adapt to high altitude hypoxia environment. Meanwhile, a large number of studies on animals and cells demonstrate that vascular endothelial cells will present pathological reaction when they are in high altitude hypoxia environment and their functions will in disorder which causes regulatory secretion factors unbalanced. It is reported in domestic and foreign literature that high altitude hypoxia environment may decrease the synthesis and release of epoprostenol(GPI2) and Nitric oxide(NO) while inflammatory cytokine thromboxane A2(TXA2) and endothelin-1(ET-1) will be increasingly expressed. In the meantime, vascular permeability increases and antioxidant capacity is reduced, which may bring about mild AMS, or even HAPE or HAPE. Therefore, the change of vascular endothelial cells function plays a very important role in the occurrence and development of AMS and it can be a significant index for warning or diagnosis. However, most of the existing researches observe some indexes that reflect vascular endothelial cells function in hypoxia environment while few reports study the change of vascular endothelial function in acute high altitude environment and their relations with the occurrence of AMS comprehensively.Therefore, this paper will observe some basic physiological indexes of accelerated plateau people and their relative indexes change of vascular endothelial function. Then it will discuss the influence of acute high altitude environment on the change of vascular endothelial function and their relations with AMS.Objects and Methods1. Recruiting 340 healthy males from plain(Chongqing, meters above sea level). Then these males arrive plateau(some place in the southeast of Litang, 30 kilometers far and 3900 meters above sea level) in four days by bus. They need to fill in questionnaires both in plain and on the 5th day in plateau. Their basic physiological indexes are measured and their blood is collected and kept freezing for testing. Lake Louise score is accessible by CRF and the selected objects is divided into AMS+ group and AMS- group. 32 objects are selected in the whole crowd on random and get RHI test.2. Statistic analysis:clarifying the influence of different altitude on the incidence of AMS, some basic physiological indexes and some relative indexes change of vascular endothelial function; clarifying the difference of basic physiological indexes and relative indexes of vascular endothelial function between AMS+ group and AMS- group; clarifying the relationship between relative indexes of vascular endothelial function and AMS.Results:1. Comparing plateau environment with plain environment, the level of people’s HR, SBP, DBP and MABP all increases on the 5th day in acute high altitude environment(P<0.05 or 0.01); the level of pulse BP and Sp O2 decreases obviously(P<0.01). For AMS+ group, the level of HR, SBP and DBP increases obviously(P<0.05 or 0.01), comparing plateau environment with plain environment; the level of Sp O2 and MABP decreases obviously(P<0.05 or 0.01). For AMS- group, the level of HR, SBP and DBP increases obviously(P<0.05 or 0.01); the level of Sp O2 and pulse BP decreases obviously(P<0.01). Comparing AMS+ group with AMS- group,the level of Sp O2 and MABP obviously decreases(P<0.05 or 0.01).2. Comparing plateau environment with plain environment, the level of people’s blood NO decreases obviously on the 5th day in acute high altitude environment(P<0.01) while the level of ET-1, vescular perneabilit factar(VEGF) and von Willebrand factor(v WF) increases obviously(P<0.05 or 0.01).3.On the 5th day in acute high altitude environment, the level of ET-1 and VE-cadherin of people in AMS+ group is obviously higher that that of plain and AMS- group(P<0.05 or 0.01), and the level of v WF is higher than that of AMS- group(P<0.05). While the level of blood NO is obviously higher both than that of plain and AMS- group(P<0.01). For the accelerated plateau people in AMS- group, the level of blood ET-1 increases(P<0.05) while other indexes of vascular endothelial function has no obvious difference with that of plain.4. Comparing plateau environment with plain environment, the level of people’s RHI decreases obviously(P<0.01) on the 5th day in acute high altitude environment. Comparing AMS+ group with AMS- group, the level of RHI decreases obviously(P<0,05). And RHI level of AMS+ group is lower than that of plateau.5. Analysis of relationship shows: the level of NO and RHI has obvious negative correlation with AMS(r value:-0.123,-0.414; P value: 0.023, 0.019); the level of ET-1 and VE-cadherin has obvious positive correlation with AMS(r value:0.268, 0.115; P value:0.001, 0.033).Conclusion:1. As the altitude increases, the level of people’s HR, SBP, DBP all increases obviously while Sp O2 level decreases obviously.2. Acute high altitude exposure may induce the damage of the vascular endothelial function in subjects and affect the serum levels of NO, ET-1, VEGF, VE-cadherin, v WF and RHI.3. The plateau environment, The changes of the indexes(NO,ET-1, VE-cadherin,RHI) may provide the potential evidence for the prewarning and diagnosis of AMS.