Elevated concentrations of liver enzymes and ferritin identify a new phenotype of insulin resistance: effect of weight loss after gastric banding.
BACKGROUND
Several studies have associated elevated liver enzymes (LFTs), obesity, and type 2 diabetes (T2DM), and a link has been established between insulin resistance (IR) and elevated ferritin concentrations. We examined the relationship between LFTs, ferritin, and IR in morbid obese subjects and the effect of weight loss after bariatric surgery.


METHODS
We measured liver enzymes, ferritin, insulin resistance, and glucose tolerance (by OGTT) in 159 morbid obese subjects (BMI = 44.4 +/- 0.4 kg/m(2)) at baseline, 6 months and 1 year after laparoscopic-adjustable-gastric banding (LAGB). Subjects were divided in two groups: increased LFTs (ALT > 30; AST/ALT < 1) vs. normal LFTs.


RESULTS
A large proportion of morbid obese subjects had increased LFTs (44%) which were associated with increased IR and ferritin, suggesting potential liver disease. A majority of the morbidly obese with increased LFTs, IGT, and T2DM, were male and had almost double ferritin concentrations, strongly correlated with ALT (r = 0.43, p < 0.0001). Both ferritin and ALT correlated with waist circumference and IR. One year after, LAGB glucose tolerance improved, LFTs and IR were reduced; ferritin did not change significantly, but was still correlated with IR.


CONCLUSIONS
Ferritin may be an additional useful marker for more severe hepatic IR.
Gastaldelli
Amalia
A
Institute of Clinical Physiology, National Research Council Pisa, Pisa, Italy.
Perego
Lucia
L
Paganelli
Michele
M
Sesti
Giorgio
G
Hribal
Marta
M
Chavez
Alberto O
AO
Defronzo
Ralph A
RA
Pontiroli
Antonio
A
Folli
Franco
F
D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005293:Ferritins / Q000097:blood*; D015391:Gastroplasty; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D010535:Laparoscopy; D008111:Liver Function Tests; D008297:Male; D009767:Obesity, Morbid / Q000378:metabolism* / Q000601:surgery; D012189:Retrospective Studies; D000637:Transaminases / Q000097:blood*; D015431:Weight Loss / Q000502:physiology*
D005293:Ferritins; D000637:Transaminases