MedicalResearch.com Interview with:
Jussi Naukkarinen, M.D., Ph.D
Institute for Molecular Medicine Finland (FIMM)
Nordic EMBL Partnership for Molecular Medicine
and National Institute for Health and Welfare (THL)
Division of Welfare and Health Promotion
Public Health Genomics Unit
and University of Helsinki
School of Medicine Dept. of Medical Genetics
MedicalResearch.com: What are the main findings of the study?
Answer: We found in this sample of relatively young, Finnish twins that there are clearly two different kinds of obesity. While most individuals with BMIs in the “obese” category will go on to develop the usual pathologies associated with obesity (namely diabetes, hypertensio, dyslipidemia), a fraction of the obese population seems to be spared. These “metabolically healthy obese” individuals displayed a number of features that were associated with a healthy metabolic profile despite considerable overweight: a capacity for hyperplasia of the adipose tissue (as opposed to just hypertrophy) seemed to be associated with maintained mitochondrial function, lack of inflammation and liver fat.
MedicalResearch.com: Were any of the findings unexpected?
Answer: I think the 7-fold difference in the amount of liver fat between the lean and heavier co-twins in the non-healthy obesity group was a surprisingly large difference. Many of the obesity associated features (mitochondrial dysfunction, inflammation etc) had been observed in our earlier studies, but to see the same features here restricted only to the non-healthy obesity group was perhaps also surprising. Realising that all obesity was lumped together as one group in earlier studies makes one wonder how could many studies have been effected by the presence of MHO individuals in the study groups. This probably has a larger effect on studies with more young participants.
MedicalResearch.com: What should clinicians and patients take away from your report?
Answer: A general guideline should be that with limited resources (and with the knowledge that many treatments also have their risks), the most aggressive treatments to any condition should be targeted to those groups that can most benefit. Realising that certain obese individuals are clearly more at risk than others should help to focus treatment on those individuals. Being “metabolically healthy obese” should not necessarily be seen as an excuse to continue with unhealthy eating/exercise habits, as we do not currently know whether the MHO phenomenon persists with increased exposure (the length of time one carries excess weight), not to mention the other negative effects associated with obesity (ex. joint problems).
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Answer: It would be important to know whether the MHO phenomenon persists throughout an individual’s lifetime. Also, as our research points that remaining free of adipose tissue inflammation and the maintenance of mitochondrial function seem to be hallmarks of MHO, testing whether the usual complications of obesity could be avoided by targeting these processes with medication would be important.
Naukkarinen J, Heinonen S, Hakkarainen A, Lundbom J, Vuolteenaho K, Saarinen L, Hautaniemi S, Rodriguez A, Frühbeck G, Pajunen P, Hyötyläinen T, Orešič M, Moilanen E, Suomalainen A, Lundbom N, Kaprio J, Rissanen A, Pietiläinen KH.