Mean hemoglobin (Hb) concentration of about 3 500 subjects derived from 17 studies of Himalayan highlanders (Tibetans, Sherpas, and Ladakhis) was compared with lowlanders (Chinese Han, Indian Tamils) lived in the Himalayas, and European climbers during Everest expeditions as well as Andean natives. The results found that Hb concentration in Himalayan highlanders was systemically lower than those reported for Andean natives and lowland immigrants. These comparative data demonstrated that a healthy native population may successfully reside at high altitude without a significant elevation in Hb, and the lower Hb levels of Himalayan highlanders than those of migrated lowlanders and Andean natives are an example of favourable adaptation over the generations. In addition, excessive polycythemia has frequently been used as a marker of chronic mountain sickness (CMS). Altitude populations who have a higher Hb concentration also have a higher incidence of CMS. The low Hb in Himalayans suggested as showing adaptation over many generations in Tibetan stock. Recent work in Tibet, suggested that Tibetans there may have adapted to high altitude as a result of evolutionary pressure selecting for genes which give an advantage at altitude. All of the population genomic and statistical analysis indicated that EPAS1 and EGLN1 are mostly likely responsible for high altitude adaptation and closely related to low Hb concentration in Tibetans. These data supported the hypothesis that Himalayan highlanders have evolved a genetically different erythropoietic response to chronic hypoxia by virtue of their much longer exposure to high altitude.
Adaptation, Physiological ; Altitude ; Asian Continental Ancestry Group ; genetics ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; Evolution, Molecular ; Hemoglobins ; genetics ; Humans ; Hypoxia-Inducible Factor-Proline Dioxygenases ; genetics ; Tibet

Prolyl-4-hydroxylase domain (PHDs) family is one of the most important regulatory factors in hypoxic stress. PHD2 plays a critical role in cells and tissues adaptation to the low oxygen environment. Its hydroxylation activity regulates the stability and transcriptional activity of the hypoxia-inducible factor 1 (HIF-1), which is the key factor in response to hypoxic stress. Subsequently, PHD2 acts as an important factor in oxygen homeostasis. Studies have shown that PHD2, through its regulation on HIF-1, plays an important role in the post-ischemic neovascularization. Furthermore, under hypoxic condition, PHD2 also regulates other pathways that positively regulate angiogenesis factors HIF-1 independently. Moreover, recently, several evidences have also shown that PHD2 also affects tumor growth and metastasis in a tumor microenvironment. Based on these facts, PHD2 have been considered as a potential therapeutic target both in treating ischemic diseases and tumors. Here, we review the molecular regulation mechanism of PHD2 and its physiological and pathological functions. We focus on the role of PHD2 in both therapeutic angiogenesis for ischemic disease and tumor angiogenesis, and the current progress in utilizing PHD2 as a therapeutic target.
Animals ; Humans ; Hydroxylation ; Hypoxia-Inducible Factor 1 ; metabolism ; Hypoxia-Inducible Factor-Proline Dioxygenases ; antagonists & inhibitors ; physiology ; Neoplasms ; blood supply ; metabolism ; pathology ; therapy ; Neovascularization, Pathologic ; metabolism ; pathology ; Tumor Microenvironment ; Vascular Diseases ; pathology ; therapy

OBJECTIVETo detect the expression of the plateau adaptablity gene(EPAS1, EGLN1 and PPARα) and proteins(HIF-2, PHD2 and PPARα) in rats blood, heart, liver, lung and kidney tissue after the rats exposed to high altitude.

METHODSThe Wistar rats were randomly divided into plain group(Shanghai, 55 m), acute exposure to high altitude 3400 m group, acute exposure to high altitude 4300 m group. Blood and organs of rats were collected in 1, 3, 5 days after arrival. Real time PCR and ELISA were used to compare the expression of plateau adaptablity gene and related protein between plain group and high altitude exposure groups.

RESULTSThe count of red blood cells, hemoglobin and HCT in high altitude 4300 m were higher than those in plain group. Compared with plain group, the expression of EPAS1 gene in blood, heart, liver and kidney tissue of rats at high altitude increased obviously(all P<0.05); the expression of EGLN1 in the heart, liver, brain and kidney increased, and PPARα gene in the heart, liver and kidney increased(all P<0.05). Compared with plain group, the expression of HIF-2 protein increased significantly at high altitudes in the liver, brain and kidney tissues. PHD2 and PPARα increased in the heart, liver and kidney.

CONCLUSIONPlateau adaptive genes(EPAS1, EGLN1 and PPARα) and protein(HIF-2, PHD2 and PPARα) differed in different altitude and different organizations. They might be used as target markers of plateau hypoxia.

Adaptation, Physiological ; Altitude ; Animals ; Basic Helix-Loop-Helix Transcription Factors ; metabolism ; Brain ; China ; Heart ; Hypoxia ; Hypoxia-Inducible Factor-Proline Dioxygenases ; metabolism ; Kidney ; Liver ; Lung ; PPAR alpha ; metabolism ; Procollagen-Proline Dioxygenase ; metabolism ; Rats ; Rats, Wistar

OBJECTIVETo investigate the protective effect of Crocin against hypoxia damage of cardiac myocytes of neonatal rats and the regulation of HIF-1 and prolyhydroxylase (PHDs).

METHODSA model of CoCl2 simulated hypoxia damage was established in primary cultural myocardial cell. Expression levels of HIF-1alpha, VEGF, iNOS, as well as PHD1, 2, 3 protein in myocardial cells were detected by Western blot.

RESULTSCompared with CoCl2 group, the viability of myocardial cell was significantly increased after treated 24 h at 10(-5)mol/L Crocin (P < 0.01), HIF-1alpha, VEGF and iNOS were expressed higher than those in Crocin + CoCl2 group (P < 0.01), the expression of PHD2 was significantly increased (P < 0.01), while the expression of PHD3 was remarkably reduced in Crocin + CoCl2 Group (P < 0.01).

CONCLUSIONCrocin has better protective effect on hypoxic damage of myocardial cell. The mechanisms of protective effect of Crocin may be related to the activation of HIF-1-mediated pathway of the hypoxia response. PHDs may be involved in the pathophysiology regulated process of myocardial cells.

Animals ; Carotenoids ; pharmacology ; Cell Hypoxia ; drug effects ; Cells, Cultured ; Homeodomain Proteins ; metabolism ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Hypoxia-Inducible Factor-Proline Dioxygenases ; metabolism ; Myocytes, Cardiac ; drug effects ; metabolism ; Nitric Oxide Synthase Type II ; metabolism ; Procollagen-Proline Dioxygenase ; metabolism ; Rats ; Rats, Sprague-Dawley ; Vascular Endothelial Growth Factor A ; metabolism

Humans ; Hypoxia-Inducible Factor-Proline Dioxygenases ; metabolism ; Ki-67 Antigen ; metabolism ; MicroRNAs ; metabolism ; Neoplasm Grading ; Neoplasm Staging ; Neprilysin ; metabolism ; Neuroendocrine Tumors ; classification ; diagnosis ; metabolism ; pathology ; surgery ; PAX8 Transcription Factor ; Paired Box Transcription Factors ; metabolism ; Pancreatic Neoplasms ; classification ; diagnosis ; metabolism ; pathology ; surgery ; Prognosis ; Tumor Suppressor Proteins ; metabolism