Dietary Restriction Ameliorates Age-Related Increase in DNA Damage, Senescence and Inflammation in Mouse Adipose Tissuey

Ageing is associated with redistribution of fat around the body and saturation of visceral adipose depots. Likewise, the presence of excess fat in obesity or during ageing places extra stress on visceral depots, resulting in chronic inflammation and increased senescence. This process can contribute to the establishment of the metabolic syndrome and accelerated ageing. Dietary restriction (DR) is known to alleviate physiological signs of inflammation, ageing and senescence in various tissues including adipose tissue.

OBJECTIVES

Our pilot study aimed to analyse senescence and inflammation parameters in mouse visceral fat tissue during ageing and by short term, late-onset dietary restriction as a nutritional intervention. Design, measurements: In this study we used visceral adipose tissue from mice between 5 and 30 months of age and analysed markers of senescence (adipocyte size, γH2A.X, p16, p21) and inflammation (e.g. IL-6, TNFα, IL-1β, macrophage infiltration) using immuno-staining, as well as qPCR for gene expression analysis. Fat tissues from 3 mice per group were analysed.

RESULTS

We found that the amount of γH2A.X foci as well as the expression of senescence and inflammation markers increased during ageing but decreased with short term DR. In contrast, the increase in amounts of single or aggregated macrophages in fat depots occurred only at higher ages. Surprisingly, we also found that adipocyte size as well as some senescence parameters decreased at very high age (30 months).

CONCLUSIONS

Our results demonstrate increased senescence and inflammation during ageing in mouse visceral fat while DR was able to ameliorate several of these parameters as well as increased adipocyte size at 17.5 months of age. This highlights the health benefits of a decreased nutritional intake over a relatively short period of time at middle age.

Detection of antileishmanial IgG antibodies and Leishmania-specific antigens in sera from Yemeni patients with visceral leishmaniasis

As part of an attempt to develop an effective method for the serodiagnosis of visceral leishmaniasis (VL), the sera from 43 Yemeni cases of the disease were screened both for antileishmanial IgG antibodies and for Leishmania-specific antigens. Indirect ELISA and capture ELISA were used to test each serum for the antibodies and antigens, respectively. Sera from patients with diseases other than leishmaniasis (29 for the antibody-detection assays and 42 for the antigen-detection) and from apparently healthy volunteers were also tested. For each type of assay, the threshold for seropositivity was set three standard deviations above the mean absorbance value for the sera from the healthy volunteers. Thirty-seven of the 43 VL sera were found positive for Leishmania-specific IgG antibodies and 37 were found positive for Leishmania-specific antigens. The sensitivities of the antibody- and antigen-detection assays were both therefore 86%. The overall specificity of the antibody-detection ELISA (67%) was, however, slightly higher than that of the capture-ELISA (64%).