Effect of Oxidative Stress on Cardiovascular System in Response to Gravity.

Ken Takahashi,Rui Guo,Hiroki Okumura,Keiji Naruse

doi:10.3390/ijms18071426

Abstract

Long-term habitation in space leads to physiological alterations such as bone loss, muscle atrophy, and cardiovascular deconditioning. Two predominant factors—namely space radiation and microgravity—have a crucial impact on oxidative stress in living organisms. Oxidative stress is also involved in the aging process, and plays important roles in the development of cardiovascular diseases including hypertension, left ventricular hypertrophy, and myocardial infarction. Here, we discuss the effects of space radiation, microgravity, and a combination of these two factors on oxidative stress. Future research may facilitate safer living in space by reducing the adverse effects of oxidative stress.

Highlights

Five million years after the birth of humankind, we are living in the space age, with the International Space Station continuously accommodating crew members orbiting around the Earth, planning commercial flights to the Moon, and even discussing Mars exploration realistically [1,2,3]
4-week hindlimb unloading led to an increase in superoxide levels along with an elevation in the levels of the pro-oxidative enzymes NOX2 and NOX4 and a decrease in the levels of the anti-oxidative enzymes Mn-SOD and GPx-1 in cerebral arteries, this effect was not observed in mesenteric arteries [60,61]
The space environment is predominantly characterized by space radiation and microgravity

Summary

Introduction

Five million years after the birth of humankind, we are living in the space age, with the International Space Station continuously accommodating crew members orbiting around the Earth, planning commercial flights to the Moon, and even discussing Mars exploration realistically [1,2,3]. While the program represented a significant and unshakable milestone in human history, an alarming fact regarding health risks was reported 40 years later; this report indicated that the Apollo lunar astronauts show higher cardiovascular disease mortality rate [11], caused by heart failure, myocardial infarction, stroke, brain aneurysm, or blood clots than their counterparts who experienced the space environment only at low Earth orbit (LEO) and who did not experience space travel [11]. One of the alterations caused by long-term space stay is the development of pro-oxidative conditions, including elevated expression of oxidative enzymes (e.g., nicotinamide adenine dinucleotide phosphate (NADP+) oxidase (NOX)) and decreased expression of anti-oxidative enzymes (e.g., superoxide dismutase, SOD, and glutathione peroxidase, GPx). GeGneenraetriaotnioonf orefarcetiavcetivoxeyogxeyngsepnecsipese.cSieusp. erSouxipdeeroaxniidoen aisnpiornodiuscpedrobdyucxeadnthbiynexaonxitdhainse o(XxOid)a,sme i(tXoOch)o, nmditroiac,haonnddNriaA, DanPd+ oNxAidDasPe+(NoxOidXa)s.eSu(NpeOrXox).idSuepaenrioxnidisecaonnivoenrtiesdcotonvheyrdterodgteonhpyedrrooxgidene p(Her2oOx2i)dbey(sHu2pOe2ro) xbiydesudpisemrouxtiadseed1is(SmOuDta1s)e, a1n(dSOthDen1)t,oanHd2OthaenndtoOH2 b2yOcantadlaOse (bCyAcTa)taalnadseg(lCutAaTth)iaonnde gpleurtoaxtihdiaosnee(pGeProxx).idase (GPx)

ROS Generation in Response to Radiation

Combination of Radiation and Microgravity

Conclusions