Association of hsp70-2 and hsp-hom gene polymorphisms with risk of acute high-altitude illness in a Chinese population

Association of heat shock protein70-2 genotypes with hypertension among textile workers occupationally exposed to noise

Noise exposure is a primary cause of hearing loss with a broad range of auditory and non-auditory effects. It is one of the occupational health risks in both developed and industrialized countries. Heat shock proteins (HSPs) are induced after severe noise exposure. Those proteins protect the ear from damage following excessive noise exposure. This protection showed high variability between individuals. The aim of the study was to investigate the variation in hearing loss and blood pressure in textile workers and its association with genetic predisposition related to HSP70 genes. Also, the role of smoking was studied. We genotyped HSP-70 (hsp70-1, hsp70-2, and hsp70-hom) genes in 109 textile workers working in a noisy environment. Diastolic and systolic blood pressure was measured for workers. Hearing was assessed using an audiogram. We reported significant variation in HSP70-homo genotypes among smoker workers and nonsmoker ones. Only HSP70-2 genotypes were associated with high significant variations in both systolic and diastolic blood pressure among textile workers. Positive correlation between duration of exposure and both systolic (P < 0.047) and diastolic blood pressure (P < 0.033) was observed among workers. Our study recorded that HSP70-2 genotypes were associated with hypertension among textile workers with absence of that association with either HSP70-1 or HSP70-homo genotypes. We also confirmed the relationship between noise exposure and blood pressure (both systolic and diastolic blood pressure). Furthermore, significant variation was shown in HSP70-hom genotypes among smoker and nonsmoker workers.

Differences in Tolerance to Hypoxia: Physiological, Biochemical, and Molecular-Biological Characteristics

Hypoxia plays an important role in the development of many infectious, inflammatory, and tumor diseases. The predisposition to such disorders is mostly provided by differences in basic tolerance to oxygen deficiency, which we discuss in this review. Except the direct exposure of different-severity hypoxia in decompression chambers or in highland conditions, there are no alternative methods for determining organism tolerance. Due to the variability of the detection methods, differences in many parameters between tolerant and susceptible organisms are still not well-characterized, but some of them can serve as biomarkers of susceptibility to hypoxia. At the moment, several potential biomarkers in conditions after hypoxic exposure have been identified both in experimental animals and humans. The main potential biomarkers are Hypoxia-Inducible Factor (HIF)-1, Heat-Shock Protein 70 (HSP70), and NO. Due to the different mechanisms of various high-altitude diseases, biomarkers may not be highly specific and universal. Therefore, it is extremely important to conduct research on hypoxia susceptibility biomarkers. Moreover, it is important to develop a method for the evaluation of organisms' basic hypoxia tolerance without the necessity of any oxygen deficiency exposure. This can contribute to new personalized medicine approaches' development for diagnostics and the treatment of inflammatory and tumor diseases, taking into account hypoxia tolerance differences.

HSPA1A gene polymorphism rs1008438 is associated with susceptibility to acute mountain sickness in Han Chinese individuals

Background

Acute mountain sickness (AMS) usually occurs among non‐acclimated individuals after rapid ascending to high‐altitude environments (generally ≥2,500 m). However, the precise molecular mechanism of AMS remains unclear. Our study aimed to investigate the relationship between several single nucleotide polymorphisms (SNPs) and AMS susceptibility.

Methods

In this work, sequencing data were obtained from 69 AMS patients and 95 matched acclimated Han Chinese individuals from southwest China. Five SNPs (rs1008438, rs150877473, rs1799983, rs2153364, and rs3025039) were systematically investigated in all the participants.

Results

In our study, we found that allele frequencies of “A” (AMS 69.57% vs. non‐AMS 54.74%) and “C” (AMS 30.43% vs. non‐AMS 45.26%) in the HSPA1A gene rs1008438 were significantly different between the AMS and non‐AMS groups (p = .01). Genotypes “CC” and “CA” of the HSPA1A gene (rs1008438) were associated with lower risk of developing AMS than the genotype “AA.” Comparing the genotypes “CC + CA” and “AA,” we also observed that the “CC + CA” genotype of rs1008438 was associated with lower AMS risk.

Conclusions

In our case‐control study, there was a significant association between the rs1008348 polymorphism and AMS susceptibility, suggesting that this particular SNP might be a Han‐specific risk factor for AMS. We believe that this study establishes a foundation for further elucidation of the genetic mechanisms underlying AMS.

Genetic profiling of Hsp70 gene in Murrah buffalo (Bubalus bubalis) under sub-tropical climate of India

This study was aimed to genetic profiling of heat shock protein 70 (Hsp70) gene in Murrah buffalo investigating 50 unrelated adult animals at ICAR-Research Complex for Eastern Region, Patna (India) in winter, spring, and summer. PCR ready genomic DNA samples and season-wise total RNA samples were prepared. The PCR products of Hsp70 eluted from agarose gel were sequenced and analyzed. The first-strand cDNA was synthesized and concentration was equalized to 25 ng/μl. Expression kinetics of mRNA transcripts in different seasons was studied using Brilliant SYBR Green QPCR technique and the data retrieved was analyzed by least-squares ANOVA. DNA sequencing by primer walking revealed four allelic variants of Hsp70 gene. Alignment study revealed one substitution in 5'UTR, six substitutions in coding region, and one addition in 3'UTR. The highest percent identity and negligible phylogenetic distance were found among the alleles and reference bovine sequences. The relative mRNA expression was significantly higher in summer when THI ≥ 84 than the spring and winter; fold change increased by 4.5 times in summer than the spring whereas found nearly half in winter. These findings can be useful for heat stress management in buffaloes and help in understanding the mechanism of thermo-regulation well.

Interaction of heat shock protein 70 (HSP70) polymorphisms and occupational hazards increases the risk of hypertension in coke oven workers

OBJECTIVES

The interaction between genetic, epigenetic inheritance and environmental factors determines susceptibility to hypertension. Previous epidemiology studies have shown that coke oven workers who are frequently exposed to various occupational hazards have remarkable increase in the risk for hypertension. Among many genetic variants identified in hypertension, heat shock protein 70 (HSP70) was found to play important roles in the pathogenesis of hypertension and associated diseases. We therefore explore the possible role of HSP70 polymorphisms and their interaction with occupational environment in hypertension risk.

METHODS

We carried out a case-control study among 367 coke oven workers in northwest China, focused on three common HSP70 polymorphisms (HSP70-1 G190C, HSP70-2 A1267G and HSP70-hom T2437C), and evaluated the association of HSP70 gene polymorphisms with work sites for high risk of hypertension.

RESULTS

The results indicated that HSP70-1 GC and CC genotype had 2.73-fold and 4.26-fold increased relative risk (95% CI 1.33 to 5.55 and 1.17 to 15.53), respectively, comparing with HSP70-1 GG genotype. HSP70-2 AG and GG conferred a 47% and 36% reduced risk (95% CI 0.23 to 0.99 and 0.14 to 0.92) comparing with HSP70-2 AA genotype. Further analysis of the interaction of HSP70 polymorphisms with occupational environment indicated a strong positive interaction between HSP70 genotype (HSP70-1 GC+CC, HSP70-2 AA and HSP70-hom TC+CC) and oven top workplace.

CONCLUSIONS

Collectively, these data indicate that HSP70 polymorphisms interact with occupational hazards might increase the risk of hypertension in coke oven workers.

Association between acute mountain sickness (AMS) and age: a meta-analysis

BACKGROUND

Acute mountain sickness (AMS) is a potentially lethal condition caused by acute hypoxia after ascending to altitudes higher than 2500 m in a short time. The main symptom of AMS is headache. Numerous risk factors of AMS have been examined, including gender, obesity, ascent rate, age and individual susceptibility. In previous studies, age was considered a predisposing factor for AMS. However, different opinions have been raised in recent years. To clarify the association between AMS and age, we conducted this meta-analysis.

METHODS

We obtained observational studies that explored risk factors for AMS by searching PubMed, Embase, China National Knowledge Internet (CNKI), the Wanfang database and CQVIP for articles published before March 2017. The studies included were required to provide the mean age and its standard deviation for subjects with and without AMS, the maximum altitude attained and the mode of ascent. The Lake Louse Score (LLS) or the Chinese AMS score (CAS) was used to judge the severity of AMS symptoms and incidence. Studies were pooled for the analysis by using a random effects model in RevMan 5.0. Meta-regression and subgroup analyses were conducted to identify sources of heterogeneity using Stata 14.2 and RevMan 5.0.

RESULTS

In total, 17 studies were included, and the overall number of subjects with and without AMS was 1810 and 3014, respectively. The age ranged from 10 to 76 years. Analysis of the 17 included studies showed that age was not associated with AMS (mean difference (MD) = 0.10; 95% CI: -0.38-0.58; P = 0.69).

CONCLUSION

This meta-analysis suggests that there is no association between age and the risk of AMS. Race, age, and ascent mode are common sources of heterogeneity, which may provide an analytical orientation for future heterogeneity analyses.

Polymorphisms of heat shock protein 70 genes (HSPA1A, HSPA1B and HSPA1L) and susceptibility of noise-induced hearing loss in a Chinese population: A case-control study

Noise-induced hearing loss (NIHL) is the second-most frequent form of sensorineural hearing loss. When exposed to the same noise, some workers develop NIHL while others do not, suggesting that NIHL may be associated with genetic factors. To explore the relationship between single nucleotide polymorphisms (SNPs) in heat shock protein 70 (HSP70) genes (HSPA1A, HSPA1B and HSPA1L) and susceptibility to NIHL in Han Chinese workers exposed to noise, a case-control association study was carried out with 286 hearing loss cases and 286 matched with gender, age, type of work, and exposure time, drawn from a population of 3790 noise-exposed workers. Four SNPs were selected and genotyped. Subsequently, the effects of the alleles and genotypes of the three HSP70 genes (HSPA1A, HSPA1B and HSPA1L) on NIHL were analyzed by using a conditional logistic regression. A generalized multiple dimensionality reduction (GMDR) was applied to further detect an interaction between the four SNPs. Compared with the combined genotypes CC/TC, carriers of the TT genotype of rs2763979 appeared to show greater susceptibility to NIHL (P = 0.042, adjusted OR = 1.731, 95% CI 1.021-2.935). A significant interaction between rs2763979 and CNE was found (P = 0.029), and a significant association was found between TT of s2763979 and NIHL (P = 0.024, adjusted OR = 5.694, 95%CI 1.256-25.817) in the 96 dB (A)≤CNE<101 dB (A) group. The results suggest that the rs2763979 locus of the HSP70 genes may be associated with susceptibility to NIHL in Chinese individuals, and other HSP70 genes may also be susceptibility genes for NIHL, but the results must be further replicated in additional independent sample sets.

Evidence for and Against Genetic Predispositions to Acute and Chronic Altitude Illnesses

MacInnis, Martin J., and Michael S. Koehle. Evidence for and against genetic predispositions to acute and chronic altitude illnesses. High Alt Med Biol. 17:281-293, 2016.-Humans exhibit marked variation in their responses to hypoxia, with susceptibility to acute and chronic altitude illnesses being a prominent and medically important example. Many have hypothesized that genetic differences are the cause of these variable responses to hypoxia; however, until recently, these hypotheses were based primarily on small (and sometimes anecdotal) reports pertaining to apparent differences in altitude illness susceptibility between populations, the notion that a history of altitude illness is indicative of subsequent risk, the heritability of hypoxia-related traits, and candidate gene association studies. In the past 5 years, the use of genomic techniques has helped bolster the claim that susceptibility to some altitude illnesses is likely the result of genetic variation. For each of the major altitude illnesses, we summarize and evaluate the evidence stemming from three important characteristics of a genetic trait: (1) individual susceptibility and repeatability across assessments, (2) biogeographical differences and familial aggregation, and (3) association(s) with genetic variants. Evidence to support a genetic basis for susceptibilities to acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) is limited, owing partially to the subjective and unclear phenotype of AMS and the rarity and severity of HACE. In contrast, recent genomic studies have identified genes that influence susceptibility to high-altitude pulmonary edema, chronic mountain sickness, and high-altitude pulmonary hypertension. The collection of more individual, familial, and biogeographical susceptibility data should improve our understanding of the extent to which genetic variation contributes to altitude illness susceptibility, and genomic and molecular investigations have the potential to elucidate the mechanisms that underpin altitude illness susceptibility.

Analysis of heat shock protein 70 gene polymorphisms Mexican patients with idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease of unknown etiology. Genetic variation within different major histocompatibility complex (MHC) loci contributes to the susceptibility to IPF. The effect of 70 kDa heat shock proteins (HSP70) gene polymorphisms in the susceptibility to IPF is unknown. The aim of this study was to explore the association between HSP70 polymorphisms and IPF susceptibility in the Mexican population.

Methods

Four HSP70 single nucleotide polymorphisms (SNPs) were evaluated using real time PCR assays in 168 IPF patients and 205 controls: +2763 C>T of HSPA1L (rs2075800), +2437 of HSP HSPA1L A>G (rs2227956), +190 of HSPA1A G>C (rs1043618) and +1267 of HSPA1B G>A (rs1061581).

Results

The analysis of the recessive model revealed a significant decrease in the frequency of the genotype HSPA1B AA (rs1061581) in IPF patients (OR = 0.27, 95 % CI = 0.13–0.57, Pc = 0.0003) when compared to controls. Using a multivariate logistic regression analysis in a codominant model the HSPA1B (rs1061581) GA and AA genotypes were associated with a lower risk of IPF compared with GG (OR = 0.22, 95 % CI = 0.07–0.65; p = 0.006 and OR = 0.17, 95 % CI = 0.07–0.41; p = <0.001). Similarly, HSPA1L (rs2227956) AG genotype (OR = 0.34, 95 % CI = 0.12–0.99; p = 0.04) and the dominant model AG + GG genotypes were also associated with a lower risk of IPF (OR = 0.24, 95 % CI = 0.08–0.67; p = 0.007). In contrast, the HSPA1L (rs2075800) TT genotype was associated with susceptibility to IPF (OR = 2.52, 95 % CI = 1.32–4.81; p = 0.005).

Conclusion

Our findings indicate that HSPA1B (rs1061581), HSPA1L (rs2227956) and HSPA1 (rs1043618) polymorphisms are associated with a decreased risk of IPF.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0127-7) contains supplementary material, which is available to authorized users.

HSP70-hom gene polymorphisms modify the association of diethylhexyl phthalates with insulin resistance

Recent studies suggest that diethylhexyl phthalates (DEHP) could contribute to the development of insulin resistance (IR) through oxidative stress, and that heat shock protein (HSP) could be related with the association between DEHP and IR. Therefore, we evaluated the effect modification of genetic polymorphisms of HSP70-hom, an oxidative stress related gene, on the relation between exposure to DEHP and IR. We obtained repeated blood and urine samples from 414 elderly female participants and measured urinary levels of mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) as metabolites of DEHP. We also measured serum levels of fasting glucose and insulin, derived the homeostatic model assessment (HOMA) index to assess IR, and genotyped two HSP70-hom polymorphisms (rs2227956 and rs2075800). A mixed effect model and penalized regression spline were used to estimate the associations between DEHP exposure and IR by genetic polymorphisms. The molar sum of MEHHP and MEOHP (∑DEHP) were significantly associated with HOMA (β = 0.30, P = 0.022). When stratified by genotype at rs2227956, the relationship between ∑DEHP and HOMA was statistically significant in participants with TT (β = 0.32, P = 0.048) or TC (β = 0.60, P = 0.008), while at rs2075800 there was a marginal association for the GA genotype (β = 0.33, P = 0.097). When haplotypes were constituted across the two HSP70-hom polymorphisms (rs2227956 and rs2075800), the association was apparent only in participants with the T-A haplotype (β = 0.39, P = 0.029). Our study suggests that HSP70-hom polymorphisms modify the association of DEHP with IR.

Heat-shock protein 70-2 BB genotype is associated with reduced risks of the steroid-dependent and refractory phenotypes of ulcerative colitis

Previous studies have demonstrated the protective role of inducible heat-shock protein (HSP) 70 in intestinal cells. The HSP70-2 gene has a PstI site due to an A-G transition at the 1,267 position and different genotypes are associated with various levels of mRNA expression. The present study aimed to clarify the effect of the HSP70-2 polymorphism on the risk of ulcerative colitis (UC), including its clinical phenotypes. A total of 121 patients with UC and 500 healthy control (HC) subjects participated in the study. To assess the polymorphisms at the 1,267 position of the HSP70-2 gene, restriction fragment length polymorphism analysis was performed. The subjects in the study were classified by disease behavior, severity and extent of disease. Although no significant difference of the HSP70-2 genotype distribution was identified between the HC and UC groups, the BB genotype exhibited a lower risk of the steroid-dependent phenotype [odds ratio (OR), 0.12; 95% confidence interval (CI), 0.02-0.95; P=0.02]. The same genotype was also associated with a lower risk of the refractory phenotype (OR, 0.16; 95% CI, 0.04-0.73; P=0.01). There was no direct correlation between the polymorphism of the HSP70-2 gene and UC susceptibility. However, there was an association between a reduced risk of the steroid-dependent and refractory phenotypes of UC and the BB genotype.

Genetic polymorphisms of HSP70 in age-related cataract

Polymorphisms have been identified in several HSP70 genes, which may affect HSP70 repair efficiency. We investigated the association of the polymorphisms in HSPA1A, HSPA1B, and HSPA1L genes in the HSPs repair pathway with the risk of cataract in a Chinese population. The study included 415 cataract patients and 386 controls. Genotyping was done by the polymerase chain reaction-restriction fragment length polymorphism method. HSPA1B 1267 A/A genotype seems to have a protective role against cataract (p = 0.014, odds ratio (OR) = 0.664, 95 % confidence intervals (CI) = 0.480-0.919), and the G allele (p = 0.057, OR = 1.216, 95 % CI = 0.999-1.479) does not seem to have a deleterious role in the development of cataract. Haplotypes with frequencies of GAT were significantly different than those of controls (p = 0.005). In HSPA1A G190C and HSPA1L T2437C polymorphisms, there were no significant differences in frequencies of the variant homozygous in patients compared to controls. We conclude that the A/A genotype of HSPA1B A1267G polymorphism seem to have a protective role against age-related cataract.

Polymorphisms in genes coding for HSP-70 are associated with gastric cancer and duodenal ulcer in a population at high risk of gastric cancer in Costa Rica

BACKGROUND AND AIMS

Costa Rica has among the highest incidence and mortality rates for gastric cancer worldwide. The reasons for this are largely unknown. Polymorphisms of inflammatory response genes including genes encoding heat shock proteins (HSP) have been shown to be associated with the risk of gastric cancer in some populations. This study addresses the possible association between the HSP70-2 +1267 and HSP70-Hom +2437 polymorphisms and the risk of developing gastric cancer in a high-risk population in Costa Rica.

METHODS

DNA from 39 individuals diagnosed with gastric cancer, 79 healthy controls, 55 individuals with chronic gastritis and 52 individuals with duodenal ulcer was genotyped for the polymorphisms HSP70-2 +1267 and HSP70-Hom +2437 by RFLP. Logistic regression analysis was used to determine possible associations with the diagnoses and lineal regression analysis to determine associations with blood pepsinogen (PGs) levels as measured by serology.

RESULTS

The GA genotype of HSP70-2 was associated with increased risk of gastric cancer (OR = 3.42; 95% CI = 1.27-9.21; p = 0.015) and duodenal ulcer (OR = 2.57; 95% CI = 1.03-6.36; p = 0.042) as compared to the GG genotype. Persons with C carrier genotypes of HSP70-Hom were significantly less susceptible to gastric cancer than those with the TT genotype (OR = 0.29; 95% CI = 0.09-0.87; p = 0.027). The C carrier genotype was associated with lower PGI concentrations but none of the polymorphisms were associated with PGI/PGII.

CONCLUSIONS

Polymorphisms of HSP70 genes are associated with the development of gastric cancer and duodenal ulcers in a population at high risk for gastric cancer in Costa Rica.

Associations between Vascular Endothelial Growth Factor Gene Polymorphisms and Susceptibility to Acute Mountain Sickness

Objective:

This study investigated associations between polymorphisms in the vascular endothelial growth factor (VEGF) gene and susceptibility to acute mountain sickness.

Methods:

Two hundred Han Chinese soldiers who developed acute mountain sickness after rapidly ascending to an altitude of < 3600 m and 200 control soldiers (who did not develop the condition) were enrolled in the study. Twelve single nucleotide polymorphisms (SNPs) of the VEGF gene were genotyped in all the study participants. Plasma VEGF concentrations were measured by enzyme-linked immunosorbent assay in 40 subjects with acute mountain sickness and 40 controls before and after exposure to high altitude.

Results:

The frequencies of the rs3025039 genotype and allele were significantly different between the groups. Two SNPs, rs3025039 (which involves a C→T allele variation at position 936 in the 3′ untranslated region) and rs3025030 (which involves a G→C allele variation in the intronic sequence), were associated with a decreased risk of acute mountain sickness.

Conclusion:

The SNPs rs3025039 and rs3025030 of the VEGF gene may be associated with a decreased risk of acute mountain sickness development.

Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Environmentally induced periods of heat stress decrease productivity with devastating economic consequences to global animal agriculture. Heat stress can be defined as a physiological condition when the core body temperature of a given species exceeds its range specified for normal activity, which results from a total heat load (internal production and environment) exceeding the capacity for heat dissipation and this prompts physiological and behavioral responses to reduce the strain. The ability of ruminants to regulate body temperature is species- and breed-dependent. Dairy breeds are typically more sensitive to heat stress than meat breeds, and higher-producing animals are more susceptible to heat stress because they generate more metabolic heat. During heat stress, ruminants, like other homeothermic animals, increase avenues of heat loss and reduce heat production in an attempt to maintain euthermia. The immediate responses to heat load are increased respiration rates, decreased feed intake and increased water intake. Acclimatization is a process by which animals adapt to environmental conditions and engage behavioral, hormonal and metabolic changes that are characteristics of either acclimatory homeostasis or homeorhetic mechanisms used by the animals to survive in a new 'physiological state'. For example, alterations in the hormonal profile are mainly characterized by a decline and increase in anabolic and catabolic hormones, respectively. The response to heat load and the heat-induced change in homeorhetic modifiers alters post-absorptive energy, lipid and protein metabolism, impairs liver function, causes oxidative stress, jeopardizes the immune response and decreases reproductive performance. These physiological modifications alter nutrient partitioning and may prevent heat-stressed lactating cows from recruiting glucose-sparing mechanisms (despite the reduced nutrient intake). This might explain, in large part, why decreased feed intake only accounts for a minor portion of the reduced milk yield from environmentally induced hyperthermic cows. How these metabolic changes are initiated and regulated is not known. It also remains unclear how these changes differ between short-term v. long-term heat acclimation to impact animal productivity and well-being. A better understanding of the adaptations enlisted by ruminants during heat stress is necessary to enhance the likelihood of developing strategies to simultaneously improve heat tolerance and increase productivity.

The Effect of Path and Beginning Time of Ascending on Incidence of Acute Mountain Sickness around Mount Damavand in Iran (5671 m)

Background. This study was designed to evaluate the incidence of acute mountain sickness (AMS) occurring on different climbing routes on Mount Damavand and the effect of beginning time of ascent in Iranian trekkers. Methods. This study was a descriptive cohort investigation, performed in summer 2007. All trekkers who ascended Mount Damavand from northern, western, eastern, and southern paths and passed 4200 m altitude were included in the study. Two questionnaires were completed for each trekker (personal information and Lake Louise score questionnaire). Multiple logistic regression analysis was used to explore the independent predicting variables for AMS. Results. Overall incidence rate of AMS was 53.6%. This rate was the highest in south route (61.5%) (P < 0.001). There was no difference in the incidence of AMS on other paths. AMS history, AMS history on Damavand, the beginning time of climbing, sleeping at 4200 m altitude, and home altitude had significant effect on AMS incidence, but by multiple logistic regression analysis south route and AMS history on Mount Damavand had positive effect on incidence of AMS (P = 0.019 and P < 0.001). Conclusion. The path and the beginning time of ascent can affect incidence of AMS. The risk of occurrence of AMS was 1.9 times as large for trekkers who ascended from southern route.

Population level determinants of acute mountain sickness among young men: a retrospective study

Background

Many visitors, including military troops, who enter highland regions from low altitude areas may suffer from acute mountain sickness (AMS), which negatively impacts workable man-hours and increases healthcare costs. The aim of this study was to evaluate the population level risk factors and build a multivariate model, which might be applicable to reduce the effects of AMS on Chinese young men traveling to this region.

Methods

Chinese highland military medical records were used to obtain data of young men (n = 3727) who entered the Tibet plateau between the years of 2006-2009. The relationship between AMS and travel profile, demographic characteristics, and health behaviors were evaluated by logistic regression. Univariate logistic models estimated the crude odds ratio. The variables that showed significance in the univariate model were included in a multivariate model to derive adjusted odds ratios and build the final model. Data corresponding to odd and even years (2 subsets) were analyzed separately and used in a simple cross-validation.

Results

Univariate analysis indicated that travel profile, prophylactic use, ethnicity, and province of birth were all associated with AMS in both subsets. In multivariate analysis, young men who traveled from lower altitude (600-800 m vs. 1300-1500 m, adjusted odds ratio (AOR) = 1.32-1.44) to higher altitudes (4100-4300 m vs. 2900-3100 m, AOR = 3.94-4.12; 3600-3700 m vs. 2900-3100 m, AOR = 2.71-2.74) by air or rapid land transport for emergency mission deployment (emergency land deployment vs. normal land deployment, AOR = 2.08-2.11; normal air deployment vs. normal land deployment, AOR = 2.00-2.20; emergency air deployment vs. normal land deployment, AOR = 2.40-3.34) during the cold season (cold vs. warm, AOR = 1.25-1.28) are at great risk for developing AMS. Non-Tibetan male soldiers (Tibetan vs. Han, AOR = 0.03-0.08), born and raised in lower provinces (eastern vs. northwestern, AOR = 1.32-1.39), and deployed without prophylaxis (prophylactic drug vs. none, AOR = 0.75-0.76), also represented a population at significantly increased risk for AMS. The predicted model was built; the area under receiver operating characteristic curve was 0.703.

Conclusion

Before a group of young men first enter a high altitude area, it is important that a health service plan should be made referring to the group's travel profile and with respect to young men's ethnicity and province of birth. Low-cost Chinese traditional prophylactic drugs might have some effect on decreasing the risk of AMS, although this needs further verification.

The genetics of altitude tolerance: the evidence for inherited susceptibility to acute mountain sickness

OBJECTIVE

Acute mountain sickness (AMS) has become a significant environmental health issue as improvements in transportation, "environmental tourism," and resource development lure more people to the highlands. Whether there is a genetic contribution to AMS susceptibility is a central question in high-altitude medicine. This article provides a systematic review of the evidence supporting such an innate predisposition.

METHODS

Scientific literature databases were screened using the terms "acute mountain sickness/AMS" and "altitude illness" combined with the terms "DNA," "gene," "genetic," or "polymorphism."

RESULTS

Sixteen genes from a variety of pathways have been tested for association with AMS and variants in eight showed positive associations suggesting that AMS is an environmentally mediated polygenic disorder.

CONCLUSIONS

The data suggest that genotype contributes to capacity to rapidly and efficiently acclimatize to altitude; nevertheless, the mechanisms by which this occurs have yet to be elucidated.

Evidence for a genetic basis for altitude illness: 2010 update

Altitude illness refers to a group of environmentally mediated pathophysiologies. Many people will suffer acute mountain sickness shortly after rapidly ascending to a moderately hypoxic environment, and an unfortunate few will develop potentially fatal conditions such as high altitude pulmonary edema or high altitude cerebral edema. Some individuals seem to be predisposed to developing altitude illness, suggesting an innate contribution to susceptibility. The implication that there are altitude-sensitive and altitude-tolerant individuals has stimulated much research into the contribution of a genetic background to the efficacy of altitude acclimatization. Although the effect of altitude attained and rate of ascent on the etiology of altitude illness is well known, there are only tantalizing, but rapidly accumulating, clues to the genes that may be involved. In 2006, we reviewed what was then known about the genetics of altitude illness. This article updates that review and attempts to tabulate all the available genetic data pertaining to these conditions. To date, 58 genes have been investigated for a role in altitude illness. Of these, 17 have shown some association with the susceptibility to, or the severity of, these conditions, although in many cases the effect size is small or variable. Caution is recommended when evaluating the genes for which no association was detected, because a number of the investigations reviewed in this article were insufficiently powered to detect small effects. No study has demonstrated a clear-cut altitude illness gene, but the accumulating data are consistent with a polygenic condition with a strong environmental component. The genes that have shown an association affect a variety of biological pathways, suggesting that either multiple systems are involved in altitude pathophysiology or that gene-gene interactions play a role. Although numerous studies have been performed to investigate specific genes, few have looked for evidence of heritability or familial transmission, or for epidemiological patterns that would be consistent with genetically influenced conditions. Future trends, such as genome-wide association studies and epigenetic analysis, should lead to enhanced understanding of the complex interactions within the genome and between the genome and hypoxic environments that contribute to an individual's capacity to acclimatize rapidly and effectively to altitude.

Patient HSP70-hom TG haplotype is associated with decreased transplant-related mortality and improved survival after sibling HLA-matched hematopoietic stem cell transplantation

Heat shock protein 70-hom (HSP70-hom) plays an important role in protein folding and immune responses. Therefore, HSP70-hom gene polymorphisms may act as important factors in predicting the prognosis of patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). To evaluate the role of HSP70-hom gene polymorphisms in the prognosis of patients receiving sibling human leukocyte antigen (HLA)-matched allogeneic HSCT, the HSP70-hom polymorphisms, T2437C and G2763A, were genotyped in 147 patients receiving sibling HLA-matched allogeneic HSCT. Individual diplotypes were estimated from genotype data of the two HSP70-hom polymorphisms using the expectation maximization algorithm. Patients with the 2763GG or GA genotype showed longer overall survival compared with those with the 2763AA genotype, and patients with a TG haplotype (TG/TA, TG/TG or TG/CG) also showed longer overall survival compared with those with a non-TG haplotype (TA/TA or TA/CG) (both G2763A genotype and diplotype, p<0.01). Moreover, the 2437TT genotype was found to be protective for treatment-related death compared with the 2437TC genotype, and a TG haplotype was found to be very protective for treatment-related death compared with a non-TG haplotype (T2437C genotype, p=0.04; and diplotype, p=0.02). Therefore, our results suggest that HSP70-hom polymorphisms play an important role in the prognosis of patients receiving sibling HLA-matched allogeneic HSCT.

The relationship between three heat shock protein 70 gene polymorphisms and susceptibility to lung cancer

BACKGROUND

Heat shock protein 70 (Hsp70) has been shown to act as a chaperone and be associated with a variety of tumors. We investigated HSP70-1 G+190C, HSP70-2 A+1267G, and HSP70-hom T+2437C polymorphisms to assess whether genetic variation in HSP70 plays a role in the occurrence and development of lung cancer.

METHODS

A case-control study was conducted using 159 patients with lung cancer and 202 control subjects. Genomic DNA was typed for HSP70 polymorphisms using polymerase chain reactions with restriction fragment length polymorphism (PCR-RFLP). Unconditional logistic regression was used to estimate the relative risks of lung cancer.

RESULTS

There were significant differences in genotype and allele distributions between patients and controls for the HSP70-1 G+190C polymorphisms with and without adjustment for age, gender, smoking history, drinking history and family history of cancer (p<0.05). No significant differences were found in the polymorphisms of HSP70-2 A+1267G and HSP70-hom T+2437C. The haplotype analysis showed that the G/A/C and C/G/T haplotypes were associated with a significantly increased risk of lung cancer compared to the G/G/T haplotype. After adjustments for other risk factors, such as age, gender, drinking history and family history of cancer, the interactions between the HSP70-1 and HSP70-hom genotypes and smoking were confirmed [I(AB), 2.56 and 5.12, respectively].

CONCLUSIONS

HSP70-1 G+190C may be a functional polymorphism and affect susceptibility to lung cancer, and homozygous C/C genotype may enhance the risk of lung cancer. In addition, smoking along with HSP70-1 G+190C and HSP70-hom T+2437C, may increase the risk of lung cancer.

A role for succinate dehydrogenase genes in low chemoresponsiveness to hypoxia?

The detection of hypoxia by the carotid bodies elicits a ventilatory response of utmost importance for tolerance to high altitude. Germline mutations in three genes encoding subunit B, C and D of succinate dehydrogenase (SDHB, SDHC and SDHD) have been associated with paragangliomas of the carotid body. We hypothesized that SDH dysfunction within the carotid body could result in low chemoresponsiveness and intolerance to high altitude. The frequency of polymorphisms of SDHs, hypoxia-inducible factor type 1 (HIF1alpha) and angiotensin converting enzyme (ACE) genes was compared between 40 subjects with intolerance to high altitude and a low hypoxic ventilatory response at exercise (HVRe < or = 0.5 ml min(-1) kg(-1); HVR- group) and 41 subjects without intolerance to high altitude and a high HVRe (> or = 0.80 ml min(-1) kg(-1); HVR+). We found no significant association between low or high HVRe and (1) the allele frequencies for nine single nucleotide polymorphisms (SNPs) in the SDHD and SDHB genes, (2) the ACE insertion/deletion polymorphism and (3) four SNPs in the HIF1alpha gene. However, a marginal significant association was found between the synonymous polymorphism c.18A>C of the SDHB gene and chemoresponsiveness: 8/40 (20%) in the HVR- group and 3/41 (7%) in the HVR+ group (p = 0.12). A principal component analysis showed that no subject carrying the 18C allele had both high ventilatory and cardiac response to hypoxia. In conclusion, no clear association was found between gene variants involved in oxygen sensing and chemoresponsiveness, although some mutations in the SDHB and SDHD genes deserve further investigations in a larger population.

Genotype at the missense G894T polymorphism (Glu298Asp) in the NOS3 gene is associated with susceptibility to acute mountain sickness

Acute mountain sickness (AMS) is a potentially serious affliction that frequently occurs in travelers to altitudes above 2500 m. The probability of developing AMS depends on environmental factors such as rate of ascent and altitude attained; however, familial clustering and recurrence rates suggest that there may be a genetic contribution to the etiology of the condition. The underlying pathophysiology of AMS is unknown, but it may involve vasogenic edema secondary to hypoxia-induced sympathetic response and endothelial dysfunction. Nitric oxide is a potent vasomodulator, and variants in the gene that encodes endothelial nitric oxide synthase (NOS3) have been shown to affect blood pressure. We tested the hypothesis that haplotypes, as determined by tagSNPs, in NOS3 would be differentially represented in individuals with and without AMS sampled at the Janai Purnima Festival at Lake Gosain Kunda, Nepal, at 4380 m. Seven SNPs were tested, and a highly significant association (p = 0.004) was found for genotypes of the commonly studied missense polymorphism Glu298Asp (rs 1799983; G/T transversion at base 894). The T allele, which previously has been associated with hypertension, was overrepresented in individuals with AMS (0.30 vs. 0.10), but not significantly when the data were corrected for multiple testing (p = 0.024). These data suggest that a variant in a gene involved in nitric oxide synthesis is a risk factor for developing AMS.

Interacting contribution of the five polymorphisms in three genes of Hsp70 family to essential hypertension in Uygur ethnicity

Experimental evidence suggesting that heat shock protein 70 (Hsp70) gene or associated genes are responsible for the pathophysiology of hypertension is accumulating. In this study, we focused on five polymorphisms in three genes (HSPA1A, HSPA1B, and HSPA1L) of Hsp70 family to explore the genetic contribution, alone and in combination, of these polymorphisms to essential hypertension risk in a Uygur population. Genotyping was performed using PCR-RFLP and direct sequencing techniques. Data were analyzed using haplotype and multifactor dimensionality reduction (MDR) methods. Genotype distributions of all the polymorphisms satisfied the Hardy-Weinberg proportions in cases and controls. Statistical significance was only observed in the genotype (P = 0.0028) and (P = 0.0146) allele distributions of -110A/C polymorphism, with the -110C allele conferring a 1.45- and 2.83-fold of relative risk, assuming the additive and recessive models, respectively, and in 1267A/G genotype distribution (P = 0.0106) with the 1267G allele conferring a 44% reduced risk. The interaction information analysis indicated that polymorphisms -110A/C and 1267A/G had a strong synergistic effect, while polymorphisms 2074G/C and 2437T/C had a moderate synergistic effect. Haplotype analyses further strengthened the interaction information. Using the haplotype H(1) as a reference, haplotype H(4) had a 40% reduced risk, while haplotypes H(5) and H(8) had a significantly 5.00- and 3.75-fold increased risk for essential hypertension, respectively. Taken together, our results supported strong genetic interaction of the studied polymorphisms with the risk of having essential hypertension in Uygur ethnicity. Functional studies are warranted to confirm or refute these findings. This is the first study to evaluate the genetic interaction information of the Hsp70 in Uygur ethnicity, which represents one of the major nationalities in China with high homogeneity and unique lifestyles. Moreover, we employed the haplotype and MDR methods to explore the potential interaction of Hsp70 genetic polymorphisms in the pathogenesis of essential hypertension in Uygur.

Variations in HSP70 genes associated with noise-induced hearing loss in two independent populations

Noise-induced hearing loss (NIHL) is one of the most important occupational health hazards. Millions of people worldwide are exposed daily to harmful levels of noise. NIHL is a complex disease resulting from an interaction between genetic and environmental factors. Although the environmental risk factors have been studied extensively, little is known about the genetic factors. Heat-shock proteins (HSPs) are induced after exposure to severe noise. When first induced by exposure to moderate sound levels, they can protect the ear from damage from excessive noise exposure. This protection is highly variable between individuals. An association of HSP70 genes with NIHL has been described by Yang et al (2006) in a Chinese sample set of noise-exposed workers. In this study, three polymorphisms (rs1043618, rs1061581 and rs2227956) in HSP70-1, HSP70-2 and HSP70-hom, respectively, were genotyped in 206 Swedish and 238 Polish DNA samples of noise-exposed subjects and analyzed. One SNP, rs2227956 in HSP70-hom, resulted in a significant association with NIHL in both sample sets. In addition, rs1043618 and rs1061581 were significant in the Swedish sample set. Analysis of the haplotypes composed of the three SNPs revealed significant associations between NIHL and haplotype GAC in both sample sets and with haplotype CGT in the Swedish sample set. In conclusion, this study replicated the association of HSP70 genes with NIHL in a second and third independent noise-exposed sample set, hereby adding to the evidence that HSP70 genes may be NIHL susceptibility genes.

Interaction of serum 70-kDa heat shock protein levels and HspA1B (+1267) gene polymorphism with disease severity in patients with chronic heart failure

BACKGROUND

Circulating heat shock protein 70 (Hsp70) is present in the circulation of healthy individuals and in patients with various disorders, including chronic heart failure (CHF). However, the source and routes of release of Hsp70 is only partially characterised in clinical samples.

AIMS

The purpose of this study was to study the clinical and biological correlates of Hsp70 in a CHF population and, for the first time, to investigate the association of HspA1B (also known as Hsp70-2) +1267 alleles with serum Hsp70 levels.

METHODS

A total of 167 patients (123 men, 44 women) with <45% left ventricular ejection fraction (LVEF) were enrolled; serum Hsp70 level was determined by enzyme-linked immunosorbent assay and HspA1B +1267 polymorphism by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Increased Hsp70 levels were present in patients with severe CHF (NYHA III-IV) as compared to the group of NYHA I-II (p = 0.003). Hsp70 levels correlated with LVEF, NT-proBNP, serum bilirubin, aspartate aminotransferase, alanine aminotransferase, gammaGT (p < 0.05) concentrations in patients with severe CHF, although no correlation was observed between Hsp70 and CRP, TNF-alpha, or IL-6. HspA1B allele G was associated with higher Hsp70 levels (p = 0.001) in patients in NYHA IV class as compared to carriers of allele A.

CONCLUSIONS

Serum Hsp70 levels were associated with disease severity in heart failure patients. An interaction with the presence of HspA1B +1267 allele G was observed for Hsp70 concentrations. Hsp70 correlates with markers of heart function and hepatic injury, but not with signs of inflammation.

Association of Met439Thr substitution in heat shock protein 70 gene with postoperative atrial fibrillation and serum HSP70 protein levels

BACKGROUND

Atrial fibrillation (AF) is a common arrhythmia encountered following cardiac surgery. Previously, we have shown that higher expression of heat shock protein (HSP) 70 was associated with decreased incidence of postoperative AF (PoAF), suggestive of an antiarrhythmic role.

OBJECTIVE

We have hypothesised that Met493Thr substitution of one of the important hsp70 genes may cause loss of these protective antiarrhythmic effects. We therefore set out to examine the influence of hsp70 genotype on the incidence of PoAF.

METHODS AND RESULTS

We prospectively recruited 244 Caucasian patients undergoing elective coronary artery bypass surgery. The median age was 65 years (40-80 years). PoAF was defined as the characteristic arrhythmia lasting for at least 15 min, occurring within first week following surgery and requiring treatment. This occurred in 48 patients (19.7%). Validated Met493Thr substitution in hsp70-Hom was determined using established techniques. Of 244 patients, genotype was determined for 242 cases. The three genotypes (MM, MT, and TT) were present at frequencies of 0.66, 0.31, and 0.03, respectively, and were in Hardy-Weinberg equilibrium. In unifactorial analysis patients carrier or homozygous for 493Thr mutation had significantly higher incidence of PoAF (Pearson chi(2) = 4.3, p = 0.037). Multivariate analysis confirmed the positive association of hsp70-Hom with PoAF (OR, 2.43; p = 0.016) independent of age, sex, previous myocardial infarction, number of distal anastomoses, and duration of ventilation, respectively. Serum HSP70 was ranging from 0.74 to 31.91 ng/ml (median, 2.89) and was not correlated with PoAF. Presence of 493Thr mutation was also significantly correlated with higher levels of serum HSP70 (p = 0.009).

CONCLUSIONS

Our data show that a mutation in hsp70-Hom gene is associated with higher incidence of PoAF. These findings are consistent with our previous results and may suggest that patients harbouring this substitution will have less endogenous myocardial protection against AF in stressful situations.

Association of HSP70-hom genetic variant with prostate cancer risk

Because of the importance of androgens to prostate cancer (PCa) development, several candidate genes along androgen pathway have been under intensive study. Given the role of the molecular chaperone HSP70 in the regulation of the androgen receptor (AR) transactivation function, we first chose to explore the association between the HSP70-hom functional genetic variant (+2437 T > C) and prostate cancer risk by genotyping DNA samples from 101 unselected PCa patients and 105 healthy men. There was a trend towards lower frequency of TC and CC genotypes among patients when compared with healthy controls, however the difference did not reach the statistical significance (TC genotype: OR = 0.53, P = 0.05; CC genotype: OR = 0.42, P = 0.16). Moreover, individuals carrying at least one C allele have a statistically significant lower susceptibility for PCa (OR = 0.51 (0.26-0.97); P = 0.02). Since some factors may influence tumor progression rather than initiation, we also examined the relationship between the HSP70-hom polymorphism and the clinical characteristics of the malignancy at the time of diagnosis. The stratified analysis of the genotypes with the clinical stage and tumor grade showed that there was no significant difference in the risk estimates according to prognostic indicators of PCa disease in our population study. This is the first report on the studies of HSP70 SNPs in PCa and our data suggest that this genetic variant may be a genetic marker for PCa susceptibility in Tunisians.

Association of hsp70 polymorphisms with risk of noise-induced hearing loss in Chinese automobile workers

Severe noise exposure can induce heat shock proteins (Hsps), and exposure to moderate noise has been reported to confer protection against noise-induced damage to hearing. Whether there is any association of genetic variation in both constitutive and inducible hsp70 genes with noise-induced hearing loss (NIHL) is presently unknown. Using polymerase chain reaction-restriction fragment length polymorphism, we genotyped 3 polymorphisms (+190A/ B, +1267A/B, and +2437A/B) in the hsp70-1 (rs1043618), hsp70-2 (rs1061581), and hsp70-hom (rs2227956) genes, respectively, and investigated the associations of these polymorphisms with risk of developing NIHL in 194 automobile workers working in a similar noise environment as evaluated by audiological assessment. Multivariate logistic regression models were used to assess the associations with the risk genotypes, and Whap software was used to analyze their haplotypes. Our results showed that there was no statistically significant difference in the genotype and allele distributions of hsp70-1, hsp70-2, and hsp70-hom between the NIHL group and the normal group (P > 0.05) with and without adjustment for age, sex, smoking, history of explosive noise exposure, and cumulative noise exposure. However, haplotype analysis revealed that the Hap5 (ie, haplotype +190A/+1267B/+2437A) and Hap6 (ie, haplotype +190A/+1267B/+2437B) were significantly more frequent in the NIHL group than in the normal group (20/9, P = 0.022, and 7/0, P = 0.005, respectively). Compared with Hap1 (ie, +190A/+1267A/+2437A), Hap5 was associated with a nearly 3-fold increased risk of NIHL (adjusted odds ratio, 2.67; 95% confidence interval, 1.13-6.27). Seven of the NIHL patients had Hap6, but none of the controls had this haplotype. Our results suggest that some haplotypes of the hsp70 genes may be associated with a higher susceptibility to NIHL.