Publications

BACKGROUND

Unintentional loss of weight and muscle due to aging and disease has been associated with increased mortality. Wasting and weight loss occur in HIV infection even in the modern era of effective antiretroviral therapy.

METHODS

We determined the association of MRI-measured regional and total skeletal muscle and adipose tissue with 5-year, all-cause mortality in 922 HIV-infected persons in the study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM).

RESULTS

After 5 years of follow-up, HIV-infected participants with arm skeletal muscle in the lowest tertile had a mortality rate of 23%, compared with 11 and 8% for those in the middle and highest tertiles. After multivariable adjustment for demographics, cardiovascular risk factors, HIV-related factors, inflammatory markers, and renal disease, we found that lower arm skeletal muscle, lower leg skeletal muscle and higher visceral adipose tissue (VAT) were each independently associated with increased mortality. Those in the lowest tertile of arm or leg skeletal muscle had higher odds of death [arm: odds ratio (OR) = 2.0, 95% confidence interval (CI) 0.96-4.0; leg: OR = 2.4, 95% CI 1.2-4.8] compared with the highest respective tertiles. Those in the highest tertile of VAT had 2.1-fold higher odds of death (95% CI 1.1-4.0) compared with the lowest VAT tertile.

CONCLUSION

Lower muscle mass and central adiposity appear to be important risk factors for mortality in HIV-infected individuals. A substantial proportion of this risk may be unrecognized because of the current reliance on body mass index in clinical practice.

Adenoviruses are DNA viruses that naturally infect many vertebrates, including humans and monkeys, and cause a wide range of clinical illnesses in humans. Infection from individual strains has conventionally been thought to be species-specific. Here we applied the Virochip, a pan-viral microarray, to identify a novel adenovirus (TMAdV, titi monkey adenovirus) as the cause of a deadly outbreak in a closed colony of New World monkeys (titi monkeys; Callicebus cupreus) at the California National Primate Research Center (CNPRC). Among 65 titi monkeys housed in a building, 23 (34%) developed upper respiratory symptoms that progressed to fulminant pneumonia and hepatitis, and 19 of 23 monkeys, or 83% of those infected, died or were humanely euthanized. Whole-genome sequencing of TMAdV revealed that this adenovirus is a new species and highly divergent, sharing <57% pairwise nucleotide identity with other adenoviruses. Cultivation of TMAdV was successful in a human A549 lung adenocarcinoma cell line, but not in primary or established monkey kidney cells. At the onset of the outbreak, the researcher in closest contact with the monkeys developed an acute respiratory illness, with symptoms persisting for 4 weeks, and had a convalescent serum sample seropositive for TMAdV. A clinically ill family member, despite having no contact with the CNPRC, also tested positive, and screening of a set of 81 random adult blood donors from the Western United States detected TMAdV-specific neutralizing antibodies in 2 individuals (2/81, or 2.5%). These findings raise the possibility of zoonotic infection by TMAdV and human-to-human transmission of the virus in the population. Given the unusually high case fatality rate from the outbreak (83%), it is unlikely that titi monkeys are the native host species for TMAdV, and the natural reservoir of the virus is still unknown. The discovery of TMAdV, a novel adenovirus with the capacity to infect both monkeys and humans, suggests that adenoviruses should be monitored closely as potential causes of cross-species outbreaks.

OBJECTIVE AND DESIGN

The aim of this study was to examine the expression of G protein-coupled receptor 81 (GPR81) in mouse adipose tissue in response to inflammatory stimuli. GPR81 is activated by lactate resulting in the inhibition of lipolysis.

MATERIALS AND TREATMENT

Mice were injected with saline, lipopolysaccharide (LPS), zymosan, or turpentine, N = 5 per group. 3T3-L1 adipocytes were treated with tumor necrosis factor alpha, interleukin (IL)-l beta, IL-6, or interferon gamma.

METHODS

GPR81 expression levels were measured by real-time PCR and statistical significance was determined by Student's t test.

RESULTS

LPS resulted in a marked decrease in GPR81 mRNA level in mouse adipose tissue in C57BL/6 and OuJ mice, an effect that was not observed in HeJ mice, which have a mutation in TLR4. Zymosan and turpentine also decreased adipose tissue GPR81 expression. Cytokine treatment of 3T3-L1 adipocytes had no effect on GPR81 expression. GPR81 expression was decreased in ob/ob mice, an animal model of type 2 diabetes that is characterized by inflammation.

CONCLUSION

Inflammation decreases the expression of GPR81 in adipose tissue.