Adiponectin, Leptin and Visfatin in Hypoxia and its Effect for Weight Loss in Obesity

Rationale: Hypoxia induces leptin gene expression in human adipocytes via hypoxia-inducible factors (HIF-α/β). Under ambient moderate hypoxia, leptin in adipocytes is elevated for at least 14 days. Leptin is supposedly involved in the reduced food intake, increased utilization of fatty acids for energy production and possible weight loss observed at high altitudes. Literature on adiponectin and visfatin in high altitude is inconsistent with reports of elevated levels and non-elevated levels. Exercise in hypoxia studies in obese subjects have shown a significant weight loss after up to 3 weeks, but it is unclear if this effect holds up for longer time periods. Therefore, we aimed to investigate 32 obese subjects completing 52 exercise and rest sessions within 8 months at either moderate or sham hypoxia and to analyze leptin, adiponectin, and visfatin mRNA-expression at different time points of exposure.Methods: Abdominal subcutaneous fat biopsies were taken from 32 obese subjects before, after 3 months and after 8 months of intervention. Subjects were randomly divided into two groups and exercised at moderate intensity at two different study sites twice a week. The IG was exposed to normobaric hypoxia (FiO2: 14.0 ± 0.2%,) at exercise and at rest (FiO2: 12.0 ± 0.2%) and the CG to sham hypoxia. Quantitative real-time polymerase chain reaction (qPCR) was used in order to determine mRNA-levels of leptin, adiponectin, and visfatin.Results: No differences in leptin levels after 3 and 8 months compared to baseline and between groups were found. There was no significant difference regarding adiponectin or visfatin at any time point compared to baseline in the hypoxia group, but an increase after 3 months was seen in the control group at normoxia compared to the hypoxia group (adiponectin: p = 0.029 and visfatin: p = 0.014).Conclusion: In this first several months' duration randomized sham controlled hypoxia exercise and rest study with obese subjects, we found no time extended leptin mRNA-expression in subjects under hypoxia after 3 and 8 months compared to baseline levels. Moderate exercise in normoxia not in hypoxia leads to elevated adiponectin and visfatin levels after 3 months

Körperliche Belastung in Hypoxie als adjuvante Therapie beim metabolischen Syndrom

Ziel der Studie war es, nachzuweisen, dass übergewichtige Menschen bei Training in simulierter Höhenluft, langfristig mehr Gewicht verlieren und eine positive Entwicklung der Lipidratio haben. Als Eingangsuntersuchung wurden eine Ergospirometrie und ein Höhenverträglichkeitstest durchgeführt. Als letzter Schritt wurde eine Fettzellenbiospie aus dem Bauchfettgewebe durchgeführt. Alle Probanden wurden aufgeklärt und haben eine Einverständniserklärung unterschrieben. Die Gesamtgruppe bestand aus 51 Probanden, (35 Frauen / 16 Männer) mit einem durchschnittlichen Alter 49,3 Jahren, einem durchschnittlichen Gewicht von 106,5 kg und einem BMI von 37,1. Zu Ende geführt haben die Studie 32 Probanden, jeweils 16 in der Interventionsgruppe (IG) und der Kontrollgruppe (KG). Alle Probanden wurden mittels eines randomisierten Verfahrens aufgeteilt. Da es sich um eine Einfach-Blind-Studie handelte, wussten die Studienteilnehmer nicht, in welcher Gruppe sie trainierten. Alle Teilnehmer trainierten über einen Zeitraum von 26 Wochen, zweimal pro Woche für drei Stunden, jeweils 90 Min. aktives Training und 90 Min. passiver Aufenthalt unter Höhenbedingungen. Die IG trainierten in einer Höhe von 3500 m und einem Aufenthalt in 4500 m, die KG befand sich jeweils auf einer Höhe von 500 m. Die Hauptmesspunkte waren T0 unmittelbar vor Beginn, T1 nach 13 Wochen und T2 nach 26 Wochen. Hier wurden jeweils die Biopsie und die Leistungsdiagnostik wiederholt. Wöchentlich erfasst wurden folgende Parameter: Gewicht, BMI, Körperfettanteil, Muskelmasse und viszerales Fett. Das Gewicht reduzierte sich bei allen Teilnehmern, (IG -3,3 kg, KG -2,8 kg), BMI (IG -1,34, KG -1,01). Beide Gruppen reduzierten ihr Körperfett um 0,79 % (IG) bzw. 0,78 % (KG). Beim Muskelzuwachs hat die IG einen Vorteil von 0,03 %. Bei keinem der erhobenen Werte konnten signifikante Vorteile zu Gunsten der IG ermittelt werden

Susceptibility-weighted Imaging: Technical Essentials and Clinical Neurologic Applications

Susceptibility-weighted imaging (SWI) evolved from simple two-dimensional T2*-weighted sequences to three-dimensional sequences with improved spatial resolution and enhanced susceptibility contrast. SWI is an MRI sequence sensitive to compounds that distort the local magnetic field (eg, calcium and iron), in which the phase information can differentiate. But the term SWI is colloquially used to denote high-spatial-resolution susceptibility-enhanced sequences across different MRI vendors and sequences even when phase information is not used. The imaging appearance of SWI and related sequences strongly depends on the acquisition technique. Initially, SWI and related sequences were mostly used to improve the depiction of findings already known from standard two-dimensional T2*-weighted neuroimaging: more microbleeds in patients who are aging or with dementia or mild brain trauma; increased conspicuity of superficial siderosis in Alzheimer disease and amyloid angiopathy; and iron deposition in neurodegenerative diseases or abnormal vascular structures, such as capillary telangiectasia. But SWI also helps to identify findings not visible on standard T2*-weighted images: the nigrosome 1 in Parkinson disease and dementia with Lewy bodies, the central vein and peripheral rim signs in multiple sclerosis, the peripheral rim sign in abscesses, arterial signal loss related to thrombus, asymmetrically prominent cortical veins in stroke, and intratumoral susceptibility signals in brain neoplasms

Normobaric Intermittent Hypoxia over 8 Months Does Not Reduce Body Weight and Metabolic Risk Factors - a Randomized, Single Blind, Placebo-Controlled Study in Normobaric Hypoxia and Normobaric Sham Hypoxia

Objective: Both a 1- to 4-week continuous or intermittent stay and moderate exercise in hypoxia versus normoxia can lead to weight loss. We examined the reproducibility and durability of added hypoxic exposure in a feasible health program of several months. Methods: 32 obese persons, randomly assigned to either a hypoxia (age 50.3 ± 10.3 years, BMI 37.9 ± 8.1 kg/m²) or a normoxia (age 52.4 ± 7.9 years, BMI 36.3 ± 4.0 kg/m²) group, completed 52 exercise sessions within 8 months. Participants exercised for 90 min (65-70% HRpeak) either at a simulated altitude of 3,500 m or in normoxia, and rested for further 90 min at 4,500 m or normoxia. Before, after 5 weeks, after 3 months, and after the intervention, body composition and exercise capacity were determined. Risk markers (e.g., blood pressure, cholesterol) were measured before, after 3 months, and after the intervention period. Results: Body weight, BMI, waist and hip circumference, Ppeak and BPsys improved over time (p Conclusion: Long-term, moderate intensity exercise and rest in hypoxia does not lead to higher reductions in body weight than normoxia alone. Therefore, for weight loss and metabolic markers hypoxic exposure does not add effects at least when stimuli (i.e., hypoxia dose, exercise intensity/duration) are unaltered throughout the intervention