Leptin May Not Be Responsible for High Altitude Anorexia

Vats, Praveen; Singh, Som Nath; Shyam, Radhey; Singh, Vijay Kumar; Singh, Shashi Bala; Banerjee, P. K.; Selvamurthy, W.

doi:10.1089/152702904322963753

Cited by 28 publications

(23 citation statements)

References 5 publications

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“…Lower levels of circulating leptin were observed in HA natives as compared to sea level residents (Woolcott et al 2002;Cabrera de Leon et al 2004). Decrease in circulating leptin levels was also reported by this laboratory (Vats et al 2004) and by Zaccaria et al (2004) on HA exposure. Leptin inhibits the activity of orexigenic NPY neurons and reduces expression of NPY in the hypothalamus.…”

Section: Discussionsupporting

confidence: 79%

High altitude induced anorexia: Effect of changes in leptin and oxidative stress levels

Vats

Singh

et al. 2007

Nutritional Neuroscience

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High altitude (HA) exposure usually leads to a significant weight loss in non-acclimatized humans. Anorexia is believed to be the main cause of this body weight loss. Appetite regulatory peptides, i.e. leptin and neuropeptide Y play a key role in food intake and energy homeostasis. Recent studies suggests increased oxidative stress during HA exposure. In present study effect of HA exposure on levels of leptin and NPY was evaluated along with N-acetyl cysteine (NAC) and vitamin E supplementation in relation to food intake and body weight changes. The study was conducted on 30 healthy male volunteers (age 19-29 years). Subjects were divided randomly into three groups of 10 each. Group 1 (placebo) supplemented with 400 mg of calcium gluconate, group 2 and 3 were supplemented with 400 mg of NAC and 400 mg vitamin E, respectively per day. The study was conducted at low altitude (320 m, Phase I), at HA 3600 m (Phase II) and at an altitude of 4580 m (Phase III). On HA exposure significant reduction in plasma leptin levels was observed in all the groups on day 2 (Phase II) along with decrease in food intake and reduction in body weight. Statistically significant increase in blood malondialdehyde (MDA) levels was seen in all the groups on HA exposure (Phase II, Day 2), but the maximum increase was in case of placebo group (65.1%) on day 2 (Phase II) in comparison to low altitude values. The decrease in energy intake was almost same in all the groups indicating that antioxidant supplementation did not provide any protection against HA anorexia. From the study, it may be concluded that leptin and oxidative stress possibly are not the key players for HA anorexia.

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Section: Discussionsupporting

confidence: 79%

High altitude induced anorexia: Effect of changes in leptin and oxidative stress levels

Vats

Singh

et al. 2007

Nutritional Neuroscience

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“…Yasumasu et al (2002) have reported about 50% decreased leptin secretion in case of in vitro cultured adipocytes exposed to low oxygen concentration. There are two studies on human subjects in which decrease in leptin levels are reported at HA (Vats et al 2004, Zaccaria et al 2004). These conflicting results may be due to certain other factors such as levels of cold exposure and physical activity, which are probably not uniformly controlled under different studies.…”

Section: Discussionmentioning

confidence: 99%

Ghrelin and leptin levels of sojourners and acclimatized lowlanders at high altitude

Shukla

Singh

Vats

et al. 2005

Nutritional Neuroscience

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The circulatory levels of two appetite regulatory hormones i.e. leptin and ghrelin were estimated in sojourners and acclimatized subjects to investigate their possible role in high altitude (HA) induced anorexia. A group of 30 lowlanders who had never visited HA were inducted to a height of 3600 m by air and after 48 h they were further taken to an altitude of 4300 m by road. Blood samples were collected after 48 h stay at 3600 m and again after 48 h and 7 days of stay at 4300 m during 0700-0730 h. There was a decrease in energy intake (850 kcal/day) of sojourners, which resulted in loss of body weight by 2.12 kg at HA. At an altitude of 4300 m there was a significant increase in leptin over basal levels (54.9%, p < 0.001) at 48 h that persisted even after 7 days of stay at this altitude. Ghrelin levels of sojourners decreased by more than 30% in comparison to basal values at 48 h of ascent to HA. Leptin levels of acclimatized lowlanders were also higher in comparison with control group (acclimatized group 7.6 + 0.6 ng/ml vs. control 5.6 + 0.5 ng/ml, p < 0.01, n = 50).

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“…Similarly, a transient decrease in ghrelin levels was observed in individual moving from low to high altitude. 12 In contrast, individuals acclimatized to high altitude, as discussed in the review, show a decrease in leptin levels, 13,14 and leptin levels in mountain dwellers show an inverse relationship with altitude. 15,16 This inverse relationship persisted even after adjusting for age, body-mass index, physical activity, blood pressure, and alcohol.…”

Section: In Responsementioning

confidence: 90%

Response by Bhatnagar to Letter Regarding Article, “Environmental Determinants of Cardiovascular Disease”

Bhatnagar

2017

Circulation Research

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Leptin May Not Be Responsible for High Altitude Anorexia

Cited by 28 publications

References 5 publications

High altitude induced anorexia: Effect of changes in leptin and oxidative stress levels

High altitude induced anorexia: Effect of changes in leptin and oxidative stress levels

Ghrelin and leptin levels of sojourners and acclimatized lowlanders at high altitude

Response by Bhatnagar to Letter Regarding Article, “Environmental Determinants of Cardiovascular Disease”

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