TY  - JOUR
A1  - Strunz, Patrick-Pascal
A1  - Vuille-Dit-Bille, Raphael N.
A1  - Fox, Mark R.
A1  - Geier, Andreas
A1  - Maggiorini, Marco
A1  - Gassmann, Max
A1  - Fruehauf, Heiko
A1  - Lutz, Thomas A.
A1  - Goetze, Oliver
T1  - Effect of high altitude on human postprandial \(^{13}\)C-octanoate metabolism, intermediary metabolites, gastrointestinal peptides, and visceral perception
JF  - Neurogastroenterology and Motility
N2  - Objective
At high altitude (HA), acute mountain sickness (AMS) is accompanied by neurologic and upper gastrointestinal symptoms (UGS). The primary aim of this study was to test the hypothesis that delayed gastric emptying (GE), assessed by \(^{13}\)C-octanoate breath testing (OBT), causes UGS in AMS. The secondary aim was to assess post-gastric mechanisms of OBT, which could confound results under these conditions, by determination of intermediary metabolites, gastrointestinal peptides, and basal metabolic rate.

Methods
A prospective trial was performed in 25 healthy participants (15 male) at 4559 m (HA) and at 490 m (Zurich). GE was assessed by OBT (428 kcal solid meal) and UGS by visual analogue scales (VAS). Blood sampling of metabolites (glucose, free fatty acids (FFA), triglycerides (TG), beta-hydroxyl butyrate (BHB), L-lactate) and gastrointestinal peptides (insulin, amylin, PYY, etc.) was performed as well as blood gas analysis and spirometry. Statistical analysis: variance analyses, bivariate correlation, and multilinear regression analysis.

Results
After 24 h under hypoxic conditions at HA, participants developed AMS (p < 0.001). \(^{13}\)CO\(_{2}\) exhalation kinetics increased (p < 0.05) resulting in reduced estimates of gastric half-emptying times (p < 0.01). However, median resting respiratory quotients and plasma profiles of TG indicated that augmented beta-oxidation was the main predictor of accelerated \(^{13}\)CO\(_{2}\)-generation under these conditions.

Conclusion
Quantification of \(^{13}\)C-octanoate oxidation by a breath test is sensitive to variation in metabolic (liver) function under hypoxic conditions. \(^{13}\)C-breath testing using short-chain fatty acids is not reliable for measurement of gastric function at HA and should be considered critically in other severe hypoxic conditions, like sepsis or chronic lung disease.
KW  - acute hypobaric hypoxia
KW  - beta-oxidation
KW  - gastric emptying
KW  - stable isotope breath tests
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259611
VL  - 34
IS  - 3
ER  - 
TY  - JOUR
A1  - Bensaad, Karim
A1  - Favaro, Elena
A1  - Lewis, Caroline A.
A1  - Peck, Barrie
A1  - Lord, Simon
A1  - Collins, Jennifer M.
A1  - Pinnick, Katherine E.
A1  - Wigfield, Simon
A1  - Buffa, Francesca M.
A1  - Li, Ji-Liang
A1  - Zhang, Qifeng
A1  - Wakelam, Michael J. O.
A1  - Karpe, Fredrik
A1  - Schulze, Almut
A1  - Harris, Adrian L.
T1  - Fatty Acid Uptake and Lipid Storage Induced by HIF-1 alpha Contribute to Cell Growth and Survival after Hypoxia-Reoxygenation
JF  - Cell Reports
N2  - An in vivo model of antiangiogenic therapy allowed us to identify genes upregulated by bevacizumab treatment, including Fatty Acid Binding Protein 3 (FABP3) and FABP7, both of which are involved in fatty acid uptake. In vitro, both were induced by hypoxia in a hypoxia-inducible factor-1 alpha (HIF-1 alpha)-dependent manner. There was a significant lipid droplet (LD) accumulation in hypoxia that was time and O-2 concentration dependent. Knockdown of endogenous expression of FABP3, FABP7, or Adipophilin (an essential LD structural component) significantly impaired LD formation under hypoxia. We showed that LD accumulation is due to FABP3/7-dependent fatty acid uptake while de novo fatty acid synthesis is repressed in hypoxia. We also showed that ATP production occurs via beta-oxidation or glycogen degradation in a cell-type-dependent manner in hypoxia-reoxygenation. Finally, inhibition of lipid storage reduced protection against reactive oxygen species toxicity, decreased the survival of cells subjected to hypoxia-reoxygenation in vitro, and strongly impaired tumorigenesis in vivo.
KW  - inducible factor-I
KW  - binding protein
KW  - triglyceride accumulation
KW  - cancer cell
KW  - complex-III
KW  - beta-oxidation
KW  - metabolism
KW  - lipogenesis
KW  - proliferation
KW  - resistance
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115162
SN  - 2211-1247
VL  - 9
IS  - 1
ER  -