Peruvian contributions to the study on human reproduction at high altitude: From the chronicles of the Spanish conquest to the present

Gonzales, Gustavo F.

doi:10.1016/j.resp.2007.03.015

Cited by 57 publications

(50 citation statements)

References 46 publications

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“…La antigüedad generacional es mayor en Cusco que en Cerro de Pasco y ello puede contribuir a que en Cerro de Pasco se presente con mayor frecuencia la eritrocitosis excesiva, o en otras palabras que la población de Cusco se encuentre mejor adaptada que la de Cerro de Pasco a vivir en la altura (50) .…”

Section: Adaptación a La Alturaunclassified

Hemoglobina y testosterona: importancia en la aclimatación y adaptación a la altura

Gonzales

2011

Rev Peru Med Exp Salud Publica

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RESUMENLos diferentes tipos de mecanismos que emplea el organismo cuando se enfrenta a una situación de hipoxia incluyen la acomodación, la aclimatación y la adaptación. La acomodación es la respuesta inicial a la exposición aguda a la hipoxia de altura y se caracteriza por aumento de la ventilación y de la frecuencia cardiaca. La aclimatación se presenta en los individuos que están temporalmente expuestos a la altura y, que en cierto grado, les permite tolerar la altura. En esta fase hay un incremento en la eritropoyesis, se incrementa la concentración de hemoglobina y mejora la capacidad de transporte de oxígeno. La adaptación es el proceso de aclimatación natural donde entra en juego las variaciones genéticas y la aclimatación que les permiten a los individuos vivir sin dificultad en la altura. La testosterona es una hormona que regula la eritropoyesis y la ventilación, podría estar asociada con los procesos de aclimatación y adaptación a la altura. La eritrocitosis excesiva que conduce al mal de montaña crónico es causada por una baja saturación arterial de oxígeno, una ineficiencia ventilatoria y reducida respuesta ventilatoria a la hipoxia. La testosterona se incrementa en la exposición aguda en la altura y en los nativos de altura con eritrocitosis excesiva. Los resultados de las investigaciones actuales permitirían concluir que el incremento de la testosterona y de la hemoglobina son buenas para la aclimatación adquirida pues mejoran el transporte de oxígeno pero no para la adaptación a la altura, dado que valores altos de testosterona en suero se asocian con eritrocitosis excesiva.Palabras clave: Testosterona, Eritropoyesis, Altitud, Aclimatación, Adaptación Fisiológica (fuente: DeCS BIREME). HEMOGLOBIN AND TESTOSTERONE: IMPORTANCE ON HIGH ALTITUDE ACCLIMATIZATION AND ADAPTATION ABSTRACTThe different types of response mechanisms that the organism uses when exposed to hypoxia include accommodation, acclimatization and adaptation. Accommodation is the initial response to acute exposure to high altitude hypoxia and is characterized by an increase in ventilation and heart rate. Acclimatization is observed in individuals temporarily exposed to high altitude, and to some extent, it enables them to tolerate the high altitudes. In this phase, erythropoiesis is increased, resulting in higher hemoglobin and hematocrit levels to improve oxygen delivery capacity. Adaptation is the process of natural acclimatization where genetical variations and acclimatization play a role in allowing subjects to live without any difficulties at high altitudes. Testosterone is a hormone that regulates erythropoiesis and ventilation and could be associated to the processes of acclimatization and adaptation to high altitude. Excessive erythrocytosis, which leads to chronic mountain sickness, is caused by low arterial oxygen saturation, ventilatory inefficiency and reduced ventilatory response to hypoxia. Testosterone increases during acute exposure to high altitude and also in natives at high altitude with excessive erythrocytosis. R...

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Section: Adaptación a La Alturaunclassified

Hemoglobina y testosterona: importancia en la aclimatación y adaptación a la altura

Gonzales

2011

Rev Peru Med Exp Salud Publica

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“…But high altitude hypoxia is a challenge for people residing in or visiting high altitudes. Among those physiological effects of hypoxia, it has been suggested that newcomers from low-lying areas have difficulties in fertility at high altitude, though the fertility rate in native residents at high altitudes is not lower than in populations at sea level (Gonzales 2007). Previous studies indicated that hypoxia reduced the fertility of male rats (Gosney 1984), rhesus monkeys (Saxena 1995), and men (Okumura et al 2003, Verratti et al 2008) from lowland by decreasing sperm count and sperm motility in semen.…”

Section: Introductionmentioning

confidence: 99%

Hypobaric hypoxia causes deleterious effects on spermatogenesis in rats

Liao¹,

Cai²,

Chen³

et al. 2010

Reproduction

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The study was conducted to explore the effects of hypobaric hypoxia on spermatogenesis in rats. Adult male Wistar rats were randomly divided into four groups: three hypoxia-exposed groups and one normoxic control group. Rats in the normoxic control group were raised at an altitude of 300 m, while rats in the 5-, 15-, and 30-day hypoxic groups were raised in a hypobaric chamber simulating a high altitude of 5000 m for 5, 15, and 30 days respectively. Flow cytometry was used to detect the DNA content of testicular spermatogenic cells in rats. The apoptosis of germ cells in testis was analyzed by using TUNEL assay. Spermatogenesis was also evaluated by morphology. Flow cytometry analysis revealed that 5-30 days of hypobaric hypoxia exposure significantly reduced the percentage of tetraploid cell population in rat testis. After rats were exposed to hypobaric hypoxia for 30 days, the ratio of haploid and diploid cell populations in testis reduced significantly. Seminiferous tubules with apoptotic germ cell increased after exposure to hypoxia. Most apoptotic germ cells were spermatogonia and spermatocytes. Hypoxia also caused decrease of cellularity of seminiferous epithelium, degeneration and sloughing of seminiferous epithelial cells occasionally. The data suggest that hypobaric hypoxia inhibits the spermatogenesis in rats. Decrease of tetraploid spermatogenic cells (primary spermatocytes) induced by hypoxia is an important approach to suppress spermatogenesis. The apoptosis of primary spermatocytes and spermatogonia may contribute to the loss of tetraploid cell populations.

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“…Neonatal and infant mortality are directly related to increasing altitude (McCullough et al, 1977). Nevertheless, native Andean highland populations are characterized by a lower perinatal mortality and higher birth weight than nonindigenous lowland populations living at high altitude (Gonzales, 2007). In addition to a better uteroplacental oxygen supply in the indigenous highland population (Moore et al, 1986(Moore et al, , 2004, there might be genetic adaptations resulting in a better oxygen supply to the fetus.…”

Section: Introductionmentioning

confidence: 99%

Native highland and lowland populations differ in .GAMMA.-globin gene promoter polymorphisms related to altered fetal hemoglobin levels and delayed fetal to adult globin switch after birth

Rottgardt

Rothhammer

Dittmar

2010

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Lowered partial oxygen pressure at high altitude exerts a strong selection pressure. Since hypoxia is most serious for the fetus, fetal hemoglobin genes (HBG1, HBG2) are candidates for genetic adaptation to high altitude. The aim of this study was to compare promoter polymorphisms of these genes for differences between highland and lowland populations. In 50 native highlanders of the Chilean Andes and 50 lowlanders of European ancestry, the promoters of HBG1 and HBG2 genes were sequenced. In the HBG1 promoter, the 4-basepair AGCA deletion was less frequently present in highlanders than in lowlanders (10% vs. 24%, P = 0.014). In the HBG2 promoter, the frequency of the T allele of the common −158 C > T polymorphism was decreased in highlanders, compared with lowlanders (8% vs. 34%, P = 0.000009). A combined analysis of both markers showed that none of the highlanders with the AGCA deletion carried the HBG2 T allele, in contrast to 43% of lowlanders (P = 0.030). Since the AGCA deletion is associated with diminished expression of fetal γ globin chains, it might affect fetal oxygen supply at high altitude. Both the AGCA deletion and the HBG2 −158 T allele are associated with a delayed fetal to adult globin switch after birth, resulting in a delayed production of adult hemoglobin, thereby possibly affecting the oxygen supply of infants at high altitude.

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Peruvian contributions to the study on human reproduction at high altitude: From the chronicles of the Spanish conquest to the present

Cited by 57 publications

References 46 publications

Hemoglobina y testosterona: importancia en la aclimatación y adaptación a la altura

Hemoglobina y testosterona: importancia en la aclimatación y adaptación a la altura

Hypobaric hypoxia causes deleterious effects on spermatogenesis in rats

Native highland and lowland populations differ in .GAMMA.-globin gene promoter polymorphisms related to altered fetal hemoglobin levels and delayed fetal to adult globin switch after birth

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