To date it was known that the susceptibility of contracting nafld had, apart from environmental influences (daily lifestyle habits, diet, etc.), a genetic basis, but the actual genes involved were poorly defined. The aim of this research was to identify the genetic variants associated with this disease in order to better understand the genetic basis underlying its development. The end goal of the investigation, is thereby, to contribute to finding possible new targets for the diagnosis and treatment of this illness.
This research, recently published in the prestigious scientific journal Hepatology, involved 20 bodies from Spain, France, Germany, Denmark and the USA, and amongst which there was an important Basque presence. Besides CIC bioGUNE, the OWL Genomics company, the Physiology Department of the Faculty of Medicine at the University of the Basque Country and the Galdakao Hospital participated.
In the first phase, variations in the DNA sequences of 92 genes were sought and which, based on previous research, were deemed candidates. To this end, the DNA of 69 patients diagnosed with nafld and that of 217 healthy individuals were studied. Various genes which demonstrated significant differences in their sequences were identified, and these genes subsequently studied again in another 451 patients with nafld and in those of 304 healthy individuals.
Here the correlation between changes in the sequence of the SLC2A1 gene was found. Then it was studied to see if the presence of this gene at RNA level was the same in the livers of healthy individuals as those of patients with nafld, being demonstrated that the RNA of the SLC2A1 gene was much less present in patients with nafld.
Finally, in an in-vitro experiment with hepatocytes (one of the cell types making up the liver), it was observed that, on avoiding the SLC2A1 gene complying with its function, an accumulation of lipids much greater than in cells with normal levels of this gene was produced, as well as greater oxidative damage. These are precisely the most representative characteristics of the state of the liver amongst patients with nafld.
In the words of CIC bioGUNE researcher and project leader, Ms. Ana Mª Aransay, “the involvement of the SLC2A1 gene in the pathology of nafld has to be corroborated with other populations of patients in different countries”, and added that “nafld is a complex disease, and so contrasting these results with those obtained in other recent studies is crucial”.
“This is why”, continued Ms. Aransay, “understanding the appearance of nafld has to take into account all the causes associated with this illness, both genetic and environmental, as well as the study of the interaction between these variables. The interpretation of the interactions revealed will help to describe the reality of many complex diseases”.
Nafld is a progressive pathology which goes from being a simple accumulation of fat (steatosis) to non-alcoholic steatosis hepatitis or NASH (inflammation around the liver). Non-alcoholic fatty liver disease is the most common hepatic disease in Europe and the United States, and its prevalence is on the increase in many parts of the world such as Asia and India.
In the West, the prevalence of steatosis and NASH amongst adults is about 30% and 3%, respectively. NASH is the most serious state of nafld, as about 20% of patients with NASH develop cirrhosis within 10 years, and more than a quarter of these end up developing a hepatocellular carcinoma or HCC (liver cancer) within a period of approximately 10 years.
Solute Carrier Family 2 Member1 Is Involved in the Development of Nonalcoholic Fatty Liver Disease. Mercedes Vazquez-Chantada, Aintzane Gonzalez-Lahera, Ibon Martinez-Arranz, Carmelo Garcia-Monzon, Manuela M. Regueiro, Juan L. Garcia-Rodriguez, Karin A. Schlangen, Iñaki Mendibil, Naiara Rodriguez-Ezpeleta, Juan J. Lozano, Karina Banasik, Johanne M. Justesen, Torben Joergensen, Daniel R. Witte, Torsten Lauritzen, Torben Hansen, Oluf Pedersen, Nicolas Veyrie, Karine Clement, Joan Tordjman, Albert Tran, Yannik Le Marchand-Brustel, Xabier Buque, Patricia Aspichueta, Jose J. Echevarria-Uraga, Antonio Martin-Duce, Joan Caballeria, Philippe Gual, Azucena Castro, Jose M. Mato, Maria L. Martinez-Chantar, and Ana M. Aransay. Hepatology Volume 57, Issue 2, pages 505–514, February 2013.