SummaryRecent studies have demonstrated a strong relationship between aging-associated reductions in mitochondrial function, dysregulated intracellular lipid metabolism, and insulin resistance. Given the important role of the AMP-activated protein kinase (AMPK) in the regulation of fat oxidation and mitochondrial biogenesis, we examined AMPK activity in young and old rats and found that acute stimulation of AMPK-α2 activity by 5′-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) and exercise was blunted in skeletal muscle of old rats. Furthermore, mitochondrial biogenesis in response to chronic activation of AMPK with β-guanidinopropionic acid (β-GPA) feeding was also diminished in old rats. These results suggest that aging-associated reductions in AMPK activity may be an important contributing factor in the reduced mitochondrial function and dysregulated intracellular lipid metabolism associated with aging.

Hyperferritinemia occurs in Gaucher disease but its clinical spectrum or its association with systemic iron overload and HFE mutations are not known. In 114 patients with Type 1 Gaucher disease, we determined serum ferritin, transferrin saturation and HFE genotype. The results were correlated with the extent of hepatosplenomegaly, overall Gaucher disease severity score index, and response to enzyme replacement therapy. In a subset of patients with radiological and/or laboratory evidence of systemic iron overload, liver biopsy was performed. There was a mean 3.7-fold elevation of serum ferritin over the upper limit of normal (ULN). Prior splenectomy was associated with most severe hyperferritinemia compared to patients with intact spleen (6.53 3 ULN vs. 2.69 3 ULN, P 5 0.003). HFE genotyping revealed two patients homozygous for H63D mutation and 30% of patients heterozygote carriers of H63D mutation; no patients harbored C282Y mutation; there was no correlation of ferritin with HFE genotype. Ferritin level correlated with liver volume (Pearson correlation coefficient 5 0.254, P 5 0.035) and it was negatively correlated with hemoglobin (r 5 20.315, P 5 0.004); there was no relationship with other indicators of Gaucher disease activity. Enzyme replacement therapy (ERT) resulted in amelioration of hyperferritinemia: 707 ± 898 ng/ml vs. 301 ± 310 ng/ ml (P 5 0.001), transferrin saturation remained normal. Three patients were suspected of clinical iron overload, confirmed on liver biopsy. Iron accumulation was variably noted in hepatocytes and Kupffer cells. There is a high prevalence of hyperferritinemia in Type 1 Gaucher disease that is associated with indicators of disease severity, reversed by ERT and is not related to HFE mutations. Am. J. Hematol. 85:472-476, 2010. V