In 8 of the pairs of twins, the obese twin was as 'metabolically healthy' as his or her lean co-twin, while in the other 8 pairs, the obese twin had a poorer blood fat profile, higher liver fat and increased insulin production and resistance, and higher blood pressure -- all hallmarks of unhealthy obesity that can lead to diabetes, heart problems and other complications.
The study is by Dr Kirsi Pietiläinen, Dr Jussi Naukkarinen and colleagues from the Obesity Research Unit, University of Helsinki, Helsinki, Finland, and is published in Diabetologia, the journal of the European Association for the Study of Diabetes (EASD).
Not all obese individuals display the metabolic disturbances commonly associated with excess fat accumulation. Mechanisms maintaining this 'metabolically healthy obesity' (MHO) are as yet unknown. In this new research, the authors studied different fat depots and transcriptional pathways in subcutaneous adipose tissue (SAT) of participants to analyse their relationship to the MHO phenomenon.
The sixteen rare young adult obesity-discordant identical (monozygotic) twin pairs (intra-pair difference in BMI ≥3kg/m2 and BMI range 20-40 and aged 23-36 years, were examined for detailed characteristics of metabolic health (subcutaneous-, intra-abdominal- and liver fat [magnetic resonance imaging (MRI)/ spectroscopy]), an oral glucose tolerance test (OGTT-to determine how quickly glucose is cleared from the blood), lipids, and certain markers of inflammation such as adipokines and C-reactive protein (CRP). The function of the mitochondria (part of the cell machinery) and inflammation in the SAT were also studied.
In all 16 pairs, the average weight difference between the obese co-twin and the lean-co-twin was 17kg. In half (8/16) of the pairs the obese co-twin had significantly higher liver fat (around 7 times higher), a 78% increase in insulin production during OGTT, increased CRP, significantly more disturbance in the blood fat profile and greater tendency for high blood pressure compared with the lean co-twin. In these obese co-twins, SAT expression of mitochondrial oxidative phosphorylation, branched-chain, amino acid catabolism, fatty acid oxidation and adipocyte differentiation pathways were downregulated and chronic inflammation upregulated, all of which are metabolic problems that can lead to complications and disease.
In the other eight pairs, the obese co-twin did not differ from the non-obese co-twin in liver fat, insulin sensitivity, CRP, lipids, blood pressure or SAT metabolic characteristics.
The authors discuss that it is also possible that the MHO stage will change with age or with advanced obesity. However, at present the two metabolically distinct groups were of the same age and had similar age of onset of obesity difference between the twin pair. They speculate: "Weight differences between the groups were similar, but a given weight difference may have different metabolic effects depending on where in the distribution of BMI a pair is located."
The authors conclude: "Our results suggest that maintenance of high mitochondrial transcription and lack of inflammation in SAT are associated with low liver fat and MHO...Future studies of the MHO phenotype may suggest new potentially drug targets -- with the most effective intervention point perhaps being improving mitochondrial function and prevention of inflammation in adipose tissue.
Dr. Jussi Naukkarinen | EurekAlert!
Drone vs. truck deliveries: Which create less carbon pollution?
31.05.2017 | University of Washington
New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology