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Interleukin 10tm1Cgn (IL 10tm) mice have been utilized as a model of chronic inflammation and declining health span because of their propensity to develop chronic activation in NFkB pathways, skeletal muscle and cardiac changes, and mitochondrial dysfunction. We hypothesized that older IL 10tm frail mice would have alterations similar to frail, older humans in measured parameters of glucose metabolism, oxygen consumption (VO2), respiratory quotient (RQ), spontaneous locomotor activity, body composition and plasma adipokine levels. To test this hypothesis, we investigated these metabolic parameters in cohorts of 3, 10, and 20 month old IL 10tm female mice and age and gender matched C57Bl/6 mice. Insulin sensitivity, glucose homeostasis, locomotor activity and RQ were not significantly altered between the two strains of mice. Interestingly, old IL 10tm mice had significantly decreased VO2 when normalized by lean mass, but not when normalized by fat mass or the lean/fat mass ratio. NMR based body composition analysis and dissection weights show that fat mass is decreased with age in IL 10tm mice compared to controls. Further, plasma adiponectin and leptin were also decreased in IL 10tm.These findings suggest that frailty observed in this mouse model of chronic inflammation may in part be driven by alterations in fat mass, hormone secretion and energy metabolism.

Sarcopenia is an age-related decline in skeletal muscle mass and function that is multifactorial in etiology. Age-related changes in the renin-angiotensin system (RAS), increased oxidative stress, and chronic inflammation likely all contribute to its development. Losartan, an angiotensin II type I receptor blocker (ARB) decreases RAS activity and likely influences oxidative stress and inflammation. Given this, we hypothesized that losartan would improve activity levels and parameters related to inflammation and oxidative stress in older mice. We sought to test this hypothesis by comparing functional and molecular parameters between 18-month-old C57BL/6 mice treated with 50-70 mg/kg/day of losartan over a 4 month-period and age- and gender-matched mice receiving placebo. Losartan treatment significantly improved several activity measurements during treatment period compared to placebo controlled group, including increased time on treadmill, traveling activity, standing activity, and decreased grid contacts (p-values<0.05, 0.001, 0.01; and 0.04 respectively). Grip strength did not improve in treatment group relative to control group over time. Serum IL-6 level in the treated group was significantly lower than that in the control group at the end of treatment (30.3±12.9 vs. 173.0±59.5pg/ml, p<0.04), and mRNA expression of antioxidant enzymes catalase (3.9±0.9 vs. 1.0±0.4) and glutathione peroxidase (4.7±1.1 vs. 1.0±0.4) was significantly higher (p-value: 0.02, and 0.03 respectively) in quadriceps muscle after 4 months of treatment in treated and control groups. These results support the hypothesis that chronic losartan treatment improves skeletal muscle related activity measures in older mice, and that it is associated with more favorable relevant biological profiles in the treatment group. Additional studies are needed to 1) further quantify this functional improvement, 2) further identify mechanisms that influence this improvement, and 3) provide additional rationale for translating these findings into older adults., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Increased hepcidin antimicrobial peptide correlates with hypoferremia and anemia in various disease states, but its requirement for anemia of inflammation has not been adequately demonstrated. Anemia of inflammation is usually described as normocytic and normochromic, while diseases associated with over expression of hepcidin, alone, are often microcytic and hypochromic. These differences in erythrocyte parameters suggest anemia in many inflammatory states may not be fully explained by hepcidin-mediated iron sequestration. We used turpentine-induced sterile abscesses to model chronic inflammation in mice with targeted disruption of Hepcidin 1 [Hepc1 (-/-)] or its positive regulator, Interleukin-6 [IL-6 (-/-)], to determine whether these genes are required for features characteristic of anemia of inflammation. Although hemoglobin levels did not decline in Hepc1 (-/-) mice with sterile abscesses, erythrocyte numbers were significantly reduced compared to untreated Hepc1 (-/-) mice. In contrast, both hemoglobin concentration and erythrocyte number declined significantly in wild type and IL-6 (-/-) mice with sterile abscesses. Both Hepc1 (-/-) and IL-6 (-/-) mice had increased erythrocyte mean cell volume and mean cell hemoglobin following sterile abscesses, while wild types had no change. Thus, IL-6 (-/-) mice with sterile abscesses exhibit an intermediate phenotype between wild type and Hepc1 (-/-). Our results demonstrate the requirement of Hepc1 for the development of anemia in this rodent model. Simultaneously, our results demonstrate hepcidin-independent effects of inflammation on the suppression of erythropoiesis. Our results suggest chronic anemia associated with inflammation may benefit from interventions protecting erythrocyte number in addition to anti-hepcidin interventions aimed at enhancing iron availability., (Copyright © 2014 Wiley Periodicals, Inc.)

Anemia of inflammation develops in settings of chronic inflammatory, infectious, or neoplastic disease. In this highly prevalent form of anemia, inflammatory cytokines, including IL-6, stimulate hepatic expression of hepcidin, which negatively regulates iron bioavailability by inactivating ferroportin. Hepcidin is transcriptionally regulated by IL-6 and bone morphogenetic protein (BMP) signaling. We hypothesized that inhibiting BMP signaling can reduce hepcidin expression and ameliorate hypoferremia and anemia associated with inflammation. In human hepatoma cells, IL-6-induced hepcidin expression, an effect that was inhibited by treatment with a BMP type I receptor inhibitor, LDN-193189, or BMP ligand antagonists noggin and ALK3-Fc. In zebrafish, the induction of hepcidin expression by transgenic expression of IL-6 was also reduced by LDN-193189. In mice, treatment with IL-6 or turpentine increased hepcidin expression and reduced serum iron, effects that were inhibited by LDN-193189 or ALK3-Fc. Chronic turpentine treatment led to microcytic anemia, which was prevented by concurrent administration of LDN-193189 or attenuated when LDN-193189 was administered after anemia was established. Our studies support the concept that BMP and IL-6 act together to regulate iron homeostasis and suggest that inhibition of BMP signaling may be an effective strategy for the treatment of anemia of inflammation.

Background & Aims: Red cell distribution width (RDW), a measure of heterogeneity in the size of circulating erythrocytes, is associated with some chronic diseases and predicts mortality. Although oxidative damage and inflammation have been theorized to affect RDW, the relationships of antioxidants and inflammation with RDW have not been well characterized. The aims were to determine whether total serum carotenoids, α-tocopherol, selenium, protein carbonyls, and interleukin-6 (IL-6) are associated with RDW and predict RDW over time., Methods: RDW was measured at baseline, 12 months, and 24 months follow-up in 786 moderately to severely disabled community-dwelling women, aged ≥65 years, in the Women's Health and Aging Study I in Baltimore, Maryland., Results: Selenium was significantly associated with RDW at baseline and predicted RDW over two years' follow-up in separate multivariate mixed-effects models that adjusted for other covariates. As expected, the addition of IL-6 to the models attenuated the association of serum selenium with RDW, as low antioxidant levels are known to upregulate IL-6. Total carotenoids were associated with RDW at baseline and one year follow-up. Protein carbonyls and α-tocopherol were not significantly associated with RDW., Conclusion: Serum selenium is an independent predictor of RDW and may potentially mediate effects on RDW through IL-6., (Copyright © 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Inflammation arising from various etiologies, including infection, autoimmune disorders, chronic diseases, and aging, can promote anemia. The anemia of inflammation (AI) is most often normocytic and normochromic and is usually mild. Characteristic changes in systemic iron handling, erythrocyte production, and erythrocyte life span all contribute to AI. The preferred treatment is directed at the underlying disease. However, when the inflammatory insult is intractable, or the cause has not been diagnosed, there are limited options for treatment of AI. Because anemia is a comorbid condition that is associated with poor outcomes in various chronic disease states, understanding its pathogenesis and developing new tools for its treatment should remain a priority. Hepcidin antimicrobial peptide has taken center stage in recent years as a potent modulator of iron availability. As the technology for quantitative hepcidin analysis improves, hepcidin's role in various disease states is also being revealed. Recent insights concerning the regulatory pathways that modify hepcidin expression have identified novel targets for drug development. As the field advances with such therapeutics, the analysis of the impact of normalized hemoglobin on disease outcomes will confirm whether anemia is a reversible independent contributor to the morbidity and mortality associated with inflammatory diseases.

Inflammation influences iron balance in the whole organism. A common clinical manifestation of these changes is anemia of chronic disease (ACD; also called anemia of inflammation). Inflammation reduces duodenal iron absorption and increases macrophage iron retention, resulting in low serum iron concentrations (hyposideremia). Despite the protection hyposideremia provides against proliferating microorganisms, this 'iron withholding' reduces the iron available to maturing red blood cells and eventually contributes to the development of anemia. Hepcidin antimicrobial peptide (Hamp) is a hepatic defensin-like peptide hormone that inhibits duodenal iron absorption and macrophage iron release. Hamp is part of the type II acute phase response and is thought to have a crucial regulatory role in sequestering iron in the context of ACD. Mice with deficiencies in the hemochromatosis gene product, Hfe, mounted a general inflammatory response after injection of lipopolysaccharide but lacked appropriate Hamp expression and did not develop hyposideremia. These data suggest a previously unidentified role for Hfe in innate immunity and ACD.