There are 2 clinical trials
This project, "A double-blind placebo-controlled randomized clinical trial assessing the efficacy of metformin for hepatic fat in adolescents and young adults with polycystic ovary syndrome", proposes exploring the use of novel and noninvasive methodologies in an at-risk adolescent and young adult population with polycystic ovary syndrome (PCOS) who may gain long-term health benefits from early detection and treatment of non-alcoholic fatty liver disease (NAFLD). PCOS is a common condition that frequently presents in adolescence and young adulthood and is defined by elevated androgens (male hormones) in the blood leading to 1. hirsutism and acne and 2. menstrual abnormalities or amenorrhea. Affected individuals are at increased risk of developing insulin resistance (a precursor of diabetes), NAFLD and lipid (cholesterol) abnormalities.These features are all associated with the metabolic syndrome, a rising major public health concern. Recently, an association between PCOS and NAFLD has been noted but has only been superficially studied in the adolescent and young adult population. The susceptibility of certain PCOS patients to developing NAFLD is theorized to be due to having underlying insulin resistance, elevated androgen levels, and a genetic predisposition. Metformin is an insulin sensitizing medication widely used to treat type 2 diabetes mellitus that may have beneficial effects on insulin resistance-related conditions including PCOS and NAFLD. Although widely used in PCOS, its effect on NAFLD in this group has not been previously studied. The primary aims of this proposal are: 1) To determine whether PCOS with liver fat >/=4.8% treated with metformin for six months will have a decline in percentage liver fat compared to a placebo group. 2) To measure the association of the PNPLA3 I148M allele with NAFLD in PCOS at baseline (n=40). 2b) To measure the association of percentage liver fat with biomarkers of NAFLD, dyslipidemia, insulin resistance and body composition at baseline (n=40) and after a placebo-controlled intervention with metformin in PCOS with liver fat >4.8% (n=20). The goal of this research proposal is to explore the use of novel and noninvasive technologies in a young and at risk population. Dr. Sopher hopes to use the results of this research to lay the groundwork for the prevention and treatment of NAFLD and other metabolic disorders in adolescents and young adults with PCOS and to prevent lifelong morbidity associated with PCOS.
2) To measure the association of the PNPLA3 I148M allele with NAFLD in PCOS at baseline (n=40). --- I148M ---
The proportion of PCOS subjects with the high risk I148M PNPLA3 allele in the PCOS groups with elevated and normal liver fat will be compared using a chi-squared or Fisher's Exact test.. --- I148M ---
Other IR indices that will be evaluated are whole body insulin sensitivity (WBIS) and insulin area under the curve; 6) Genetic evaluation: A blood sample for the PNPLA3 I148M allele (baseline only). --- I148M ---
Description: To compare percentage liver fat by magnetic resonance spectroscopy in the metformin group and placebo group to baseline and between the groups in order to determine if metformin is efficacious for reducing liver fat compared to placebo in adolescents and young women with Polycystic Ovary Syndrome (PCOS)
Measure: Difference in percentage liver fat between Metformin arm and Placebo arm in adolescents and young adults with PCOS and with elevated percentage liver fat (>/=4.8%) Time: 6 monthsDescription: The proportion of PCOS subjects with the high risk I148M PNPLA3 allele in the PCOS groups with elevated and normal liver fat will be compared using a chi-squared or Fisher's Exact test.
Measure: Proportion of PCOS subjects with the PNPLA3 allele comparing those with elevated percentage liver fat (>/=4.8%) and those with normal percentage liver fat (<4.8%) by magnetic resonance spectroscopy Time: 6 monthsDescription: The association of percent liver fat with insulin resistance as measured by HOMA-IR will be measured by correlation/regression. Change in HOMA-IR with change in percent liver fat following metformin will be assessed using multiple regression analysis.
Measure: The association of percentage liver fat by magnetic resonance spectroscopy with insulin resistance as measured by HOMA-IR in adolescents with PCOS Time: 6 monthsDescription: The association of percent liver fat with triglycerides will be measured by correlation/regression. Change in triglycerides with change in percent liver fat following metformin will be assessed using multiple regression analysis.
Measure: The association of percentage liver fat with triglycerides Time: 6 monthsDescription: The association of percent liver fat with visceral adipose tissue will be measured by correlation/regression. Change in visceral adipose tissue with change in percent liver fat following metformin will be assessed using multiple regression analysis.
Measure: The association of percentage liver fat with visceral adipose tissue Time: 6 monthsDescription: The association of percent liver fat with total body adipose tissue will be measured by correlation/regression. Change in total body adipose tissue with change in percent liver fat following metformin will be assessed using multiple regression analysis.
Measure: The association of percentage liver fat with total body adipose tissue Time: 6 monthsDescription: The association of percent liver fat with pancreatic polypeptide will be measured by correlation/regression. Change in pancreatic polypeptide with change in percent liver fat following metformin will be assessed using multiple regression analysis.
Measure: The association of percentage liver fat with pancreatic polypeptide Time: 6 monthsDescription: The association of percent liver fat with M30 will be measured by correlation/regression. Change in M30 with change in percent liver fat following metformin will be assessed using multiple regression analysis.
Measure: The association of percentage liver fat with M30, a hepatic apoptosis marker Time: 6 monthsA. BACKGROUND Accumulation of fat in the liver due to non-alcoholic causes (NAFLD) is associated with hepatic insulin resistance, which impairs the ability of insulin to inhibit the production of glucose and VLDL . This leads to increases in serum glucose, insulin and triglyceride concentrations as well as hyperinsulinemia. Recent epidemiologic studies have shown that a major reason for the metabolic syndrome as well as the accompanying increased risk of cardiovascular disease and type 2 diabetes is overconsumption of simple sugars. The investigators have recently shown that overeating simple sugars (1000 extra calories/day, "CANDY" diet) increases liver fat content by 30% within 3 weeks (4), and recapitulates features of the metabolic syndrome such as hypertriglyceridemia and a low HDL cholesterol concentration. The fatty acids in intrahepatocellular triglycerides may originate from peripheral lipolysis, de novo lipogenesis, uptake of chylomicron remnants by the liver and from hepatic uptake of fatty acids released during intravascular hydrolysis of triglyceride-rich lipoproteins (the spillover pathway). A classic study using stable isotope methodology by the group of Elisabeth Parks showed that in subjects with NAFLD, the excess intrahepatocellular triglycerides originate from peripheral lipolysis and de novo lipogenesis. It is well-established that ingestion of a high carbohydrate as compared to high fat diet stimulates de novo lipogenesis in humans. Meta-analyses comparing isocaloric high fat and high carbohydrate diets have shown that high carbohydrate but not high fat diets increase increase serum triglycerides and lower HDL cholesterol. Since hypertriglyceridemia results from overproduction of VLDL from the liver, these data suggest the composition of the diet influences hepatic lipid metabolism. Whether this is because overfeeding fat leads to preferential deposition of fat in adipose tissue while high carbohydrate diets induce a relative greater increase in liver fat is unknown. There are no previous studies comparing effects of chronic overfeeding of fat as compared to carbohydrate on liver fat or and the sources of intrahepatic fatty acids. A common polymorphism in PNPLA3 at rs738409 (adiponutrin) gene is associated with a markedly increase liver fat content. This finding has been replicated in at least 20 studies across the world. The investigators have shown that PNPLA3 is regulated by the carbohydrate response element binding protein 1. Mice overexpressing the human I148M PNPLA3 variant in the liver exhibit an increase in liver triglycerides and cholesteryl esters on a high sucrose but not high fat diet. These data suggest that overfeeding a high carbohydrate as compared to a high fat diet may increase liver fat more in subjects carrying the I148M allele than in non-carriers. B. HYPOTHESIS The investigators hypothesize that overfeeding a high fat as compared to an isocaloric high carbohydrate diet influences the source of intrahepatocellular triglycerides. During a high fat diet, relatively more of intrahepatocellular triglycerides originate from peripheral lipolysis and less from DNL than during a high carbohydrate diet in the face of a similar increase in liver fat. It is also possible given the lack of previous overfeeding data comparing 2 different overfeeding diets that the high fat diet induces a smaller increase in liver fat than a high carbohydrate diet even in the face of an identical increase in caloric intake because a greater fraction of ingested fat is channeled to adipose tissue than the liver. The investigators also hypothesize that liver fat may increase more in carriers than non-carriers of the I148M variant in PNPLA3 during a high carbohydrate than a high fat diet. C. SPECIFIC AIMS The investigators wish to randomize, using the method of minimization (considers baseline age, BMI, gender, liver fat, PNPLA3 genotype) 40 non-diabetic subjects with NAFLD as determined by the non-invasive score developed in our laboratory or previous knowledge of liver fat content based on MRS to overeat either a high carbohydrate or high fat diet (1000 extra calories per day) for 3 weeks. Before and after the overfeeding diets, will measure liver fat content by 1H-MRS and the rate of adipose tissue lipolysis using doubly labeled water (DDW) and [1,1,2,3,3-2H5] glycerol as described in detail below. The investigators also wish to characterize glucose, insulin, fatty acid and triacylglyceride profiles before and while on the experimental diet. An adipose tissue biopsy is taken to determine whether expression of genes involved in lipogenesis or lipolysis, or those involved in adipose tissue inflammation change in response to overfeeding, and for measurement of LPL activity. After overfeeding, both groups will undergo weight loss to restore normal weight as described in our recent study. The metabolic study is repeated after weight loss.
The investigators have shown that PNPLA3 is regulated by the carbohydrate response element binding protein 1. Mice overexpressing the human I148M PNPLA3 variant in the liver exhibit an increase in liver triglycerides and cholesteryl esters on a high sucrose but not high fat diet. --- I148M ---
These data suggest that overfeeding a high carbohydrate as compared to a high fat diet may increase liver fat more in subjects carrying the I148M allele than in non-carriers. --- I148M ---
The investigators also hypothesize that liver fat may increase more in carriers than non-carriers of the I148M variant in PNPLA3 during a high carbohydrate than a high fat diet. --- I148M ---
Description: the rate of DNL and adipose tissue lipolysis is measured using doubly labeled water (DDW) and [1,1,2,3,3-2H5] glycerol
Measure: De novo lipogenesis (DNL) and measurement of lipolysis Time: 3 weeksDescription: Laboratory tests including fasting glucose, insulin, C-peptide, liver enzymes, total, LDL and HDL cholesterol and TG concentrations PNPLA3 genotyping is performed also
Measure: Analytical procedures Time: 3 weeksDescription: Needle biopsies of abdominal subcutaneus tissue will be taken for subsequent isolation of RNA for measurements of gene expression (by quantitative PCR). Fat cell size is also measured.
Measure: Biopsies and analysis of subcutaneus adipose tissue Time: 3 weeksDescription: Indirect calorimetry is the method by which metabolic rate is estimated from measurements of oxygen (O2) consumption and carbon dioxide (CO2) production.
Measure: Indirect calorimetry Time: 3 week