Sustained Acclimatization in Chilean Mine Workers Subjected to Chronic Intermittent Hypoxia

Farías, Jorge G.; Osorio, Jorge; Soto, G Sebastián; Siqués, Patricia; Reyes, Juan G.

doi:10.1089/ham.2006.7.302

Cited by 25 publications

(22 citation statements)

References 14 publications

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“…Since data was not available yet, the effect of altitude on blood count was not evaluated. Further investigations will [11], but the decrease in SO 2 during the night shift deserves further investigation. Probably, it may be attributable to an increased metabolic request due to both altitude and the shift performed during the night, that requires more energy [11].…”

Section: Discussionmentioning

confidence: 94%

“…Further investigations will [11], but the decrease in SO 2 during the night shift deserves further investigation. Probably, it may be attributable to an increased metabolic request due to both altitude and the shift performed during the night, that requires more energy [11]. Unfortunately, we did not have the possibility to perform polysomnography, deepening the study of obstructive lung damage due to exposure to unusual shift.…”

Section: Discussionmentioning

confidence: 94%

“…Unusual work shifts and night shifts are physically, mentally and emotionally stressful; they may cause obesity, diabetes [8,9] and sleep disorders [10]. In previous researches, acclimatization in Chilean mine workers exposed to altitude was investigated, reproducing working conditions through submaximal exercise, but without carefully considering the unusual work shifts [11,12]. The aim of this study has been to evaluate the current working conditions in mining industry in altitude and to assess the risks for this work category, evaluating the risk factors airborne silica, altitude and work shift, and relating them with cardiovascular, laboratory and ventilatory parameters.…”

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confidence: 99%

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Respiratory parameters at varied altitudes in intermittent mining work

Bacaloni¹,

Saà²,

Sinibaldi³

et al. 2017

Int J Occup Med Environ Health

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Objectives: Workers in the mining industry in altitude are subjected to several risk factors, e.g., airborne silica and low barometric pressure. The aim of this study has been to assess the risks for this work category, evaluating single risk factors as airborne silica, altitude and work shift, and relating them with cardiovascular and ventilatory parameters. Material and Methods: Healthy miners employed in a mining company, Chile, working at varied altitudes, and subjected to unusual work shifts, were evaluated. Cardiovascular and respiratory parameters were investigated. Exposure to airborne silica was evaluated and compared to currently binding exposure limits. Results: At varied altitudes and work shifts, alterations emerged in haemoglobin, ventilation and respiratory parameters, related to employment duration, due to compensatory mechanisms for hypoxia. Haemoglobin increased with altitude, saturation fell down under 90% in the highest mines. The multiple linear regression analysis showed a direct relationship, in the higher mine, between years of exposure to altitude and increased forced vital capacity percent (FVC%), and forced expiratory volume in 1 s (FEV 1 ). An inverse relationship emerged between forced vital capacity (FVC) and years of exposure to airborne silica. In the workplace Mina Subterrànea (MT-3600), statistically significant inverse relationship emerged between the Tiffeneau index and body weight. Conclusions: The working conditions in the mining industry in altitude appeared to be potentially pathogenic; further investigations should be realized integrating risk assessment protocols even in consideration of their undeniable unconventionality. Int J Occup Med Environ Health 2018;31(2):129 -138

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 94%

mentioning

confidence: 99%

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Respiratory parameters at varied altitudes in intermittent mining work

Bacaloni¹,

Saà²,

Sinibaldi³

et al. 2017

Int J Occup Med Environ Health

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“…A large number of people live at a high altitude of more than 3000 meters around the world, especially in China (Wu et al, 2010). Moreover, there are also a number of people that ascend daily to these altitudes and are repeatedly exposed to hypoxia (Farias et al, 2006). Epidemiological studies have demonstrated that the risk of sudden cardiac death in populations with repetitive acute ascents to high altitude is much higher than that in populations living at low altitude (Burtscher and Ponchia 2010;Rimoldi et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Intermittent Hypobaric Hypoxia Promotes Atherosclerotic Plaque Instability in ApoE-Deficient Mice

Jiang

Jin

et al. 2013

High Altitude Medicine & Biology

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. Intermittent hypobaric hypoxia promotes atherosclerotic plaque instability in ApoE-deficient mice. High Alt Med Biol 14:175-180, 2013.-Aim: Sudden cardiac death is one of the most frequent causes of death at high altitude. It has been reported that the intermittent normobaric hypoxia experienced by patients with obstructive sleep apnea may enhance the development of atherosclerosis. However, the effect of hypobaric hypoxia, which mimics the ambient air at high altitude, in the development of atherosclerosis has not been investigated. Methods: Twenty male ApoE-deficient mice, 8 weeks of age, were subjected to either control conditions or intermittent hypobaric hypoxia (IHH) for 8 weeks. Mice in the IHH group were exposed to a hypobaric chamber that replicated the hypobaric hypoxia conditions found at 4000 m altitude for 8 hours a day. Results: IHH-exposed mice did not significantly differ from control mice in plasma lipid levels, including triglyceride, total cholesterol, low-density lipoprotein, and high-density lipoprotein. The hematoxylin and eosinstained sections of the aortic root showed similar plaque size between the groups. However, IHH-treated mice exhibited significantly decreased plaque collagen content, a feature of atherosclerotic plaque stability. Additionally, matrix metalloproteinase (MMP)-9 protein expression was significantly increased, whereas tissue inhibitor of MMP (TIMP)-2 expression was decreased after exposure to IHH. Conclusion: IHH may promote atherosclerotic plaque instability in ApoE-deficient mice by changing the balance of MMPs and TIMPs.

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“…Second, is intermittency a necessary factor? Short-term sustained hypoxia in humans (2,19,71) and animals (43,47) also induces hypertriglyceridemia. Surprisingly, no studies have systematically examined the mechanisms by which acute hypoxic exposures elevate TG.…”

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confidence: 99%

Acute hypoxia induces hypertriglyceridemia by decreasing plasma triglyceride clearance in mice

Jun

Shin

Yao

et al. 2012

American Journal of Physiology-Endocrinology and Metabolism

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(TG). We previously demonstrated that mice exposed to chronic IH develop elevated TG. We now hypothesize that a single exposure to acute hypoxia also increases TG due to the stimulation of free fatty acid (FFA) mobilization from white adipose tissue (WAT), resulting in increased hepatic TG synthesis and secretion. Male C57BL6/J mice were exposed to FiO2 ϭ 0.21, 0.17, 0.14, 0.10, or 0.07 for 6 h followed by assessment of plasma and liver TG, glucose, FFA, ketones, glycerol, and catecholamines. Hypoxia dosedependently increased plasma TG, with levels peaking at FiO2 ϭ 0.07. Hepatic TG levels also increased with hypoxia, peaking at FiO2 ϭ 0.10. Plasma catecholamines also increased inversely with FiO2. Plasma ketones, glycerol, and FFA levels were more variable, with different degrees of hypoxia inducing WAT lipolysis and ketosis. FiO2 ϭ 0.10 exposure stimulated WAT lipolysis but decreased the rate of hepatic TG secretion. This degree of hypoxia rapidly and reversibly delayed TG clearance while decreasing [ 3 H]triolein-labeled Intralipid uptake in brown adipose tissue and WAT. Hypoxia decreased adipose tissue lipoprotein lipase (LPL) activity in brown adipose tissue and WAT. In addition, hypoxia decreased the transcription of LPL, peroxisome proliferator-activated receptor-␥, and fatty acid transporter CD36. We conclude that acute hypoxia increases plasma TG due to decreased tissue uptake, not increased hepatic TG secretion.lipolysis; lipases; adipose; thermoregulation; metabolism OBSTRUCTIVE SLEEP APNEA (OSA) causes recurrent episodes of asphyxia and intermittent hypoxia (IH) during sleep. Several studies reveal an association between OSA and elevated circulating triglycerides (TG) (16). In some cases, the severity of hypoxia during sleep correlates with the magnitude of increased TG (18, 48). Furthermore, therapy for OSA with continuous positive airway pressure (CPAP) decreases fasting (61) and postprandial TG levels (51); yet, the mechanisms by which OSA affects TG levels are unclear. One possibility is that repetitive IH increases TG levels. Our laboratory has simulated hypoxic desaturations of OSA in mice, exposing them to diurnal IH (60 desaturations/h, 12 h/day). After chronic IH exposure, mice exhibited ϳ40% increases in plasma TG after 5 days (40), with similar elevations persisting after 4 and 12 wk of ongoing IH exposure (32). We have also shown that chronic IH increases TG via two major mechanisms, increased hepatic secretion (39) and decreased lipoprotein clearance (17).Two important questions have not been addressed by chronic IH experiments. First, is chronicity of hypoxia necessary to affect lipid metabolism? Second, is intermittency a necessary factor? Short-term sustained hypoxia in humans (2, 19, 71) and animals (43, 47) also induces hypertriglyceridemia. Surprisingly, no studies have systematically examined the mechanisms by which acute hypoxic exposures elevate TG. It is conceivable that acute sustained hypoxia increases TG via the same mechanisms that we have described for chronic IH. We ther...

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Sustained Acclimatization in Chilean Mine Workers Subjected to Chronic Intermittent Hypoxia

Cited by 25 publications

References 14 publications

Respiratory parameters at varied altitudes in intermittent mining work

Respiratory parameters at varied altitudes in intermittent mining work

Intermittent Hypobaric Hypoxia Promotes Atherosclerotic Plaque Instability in ApoE-Deficient Mice

Acute hypoxia induces hypertriglyceridemia by decreasing plasma triglyceride clearance in mice

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