Age-Associated Decline in Dendritic Cell Function and the Impact of Mediterranean Diet Intervention in Elderly Subjects

Abstract

IntroductionAging is accompanied by increased susceptibility to infection and age-associated chronic diseases. It is also associated with reduced vaccine responses, which is often attributed to immunosenescence and the functional decline of the immune system. Immunosenescence is characterized by a chronic, low-grade, inflammatory state termed inflammaging. Habitants of Mediterranean (MED) regions maintain good health into old age; often attributed to MED diets.HypothesisAdoption of a MED-diet by elderly subjects, in Norfolk (UK), may improve immune responses of these individuals and in particular, dendritic cell (DC) function.Experimental approachA total of 120 elderly subjects (65–79 years old) recruited onto the Nu-AGE study, a multicenter European dietary study specifically addressing the needs of the elderly, across five countries, and were randomized to the control or MED-diet groups, for one year. Blood samples were taken pre- and post-intervention for DC analysis and were compared with each other, and to samples obtained from 45 young (18–40 years old) subjects. MED-diet compliance was assessed using high performance liquid chromatography-with tandem mass spectrometry analysis of urine samples. Immune cell and DC subset numbers and concentrations of secreted proteins were determined by flow cytometric analysis.ResultsAs expected, reduced myeloid DC numbers were observed in blood samples from elderly subjects compared with young. The elevated secretion of the adipokine, resistin, after ex vivo stimulation of peripheral blood mononuclear cells from elderly subjects, was significantly reduced after MED-diet intervention.ConclusionThis study provides further evidence of numerical and functional effects of aging on DCs. The MED-diet showed potential to impact on the aging immune cells investigated and could provide an economical approach to address problems associated with our aging population.

One-Year Consumption of a Mediterranean-Like Dietary Pattern With Vitamin D3 Supplements Induced Small Scale but Extensive Changes of Immune Cell Phenotype, Co-receptor Expression and Innate Immune Responses in Healthy Elderly Subjects: Results From the United Kingdom Arm of the NU-AGE Trial

“…It has been shown that DC populations are affected by the aging process, and we have previously shown that the MedDiet had no effect on the numbers of mDCs or pDCs ( Jing et al, 2009 ; Clements et al, 2017 ). Here we determined whether the MedDiet intervention had an impact on the ratio between mDCs and pDCs.…”

“…In the elderly people, a decrease in pDCs but not mDCs ( Shodell and Siegal, 2002 ; Pérez-Cabezas et al, 2007 ; Jing et al, 2009 ) was reported although others have reported conflicting results ( Della Bella et al, 2007 ). However, it appeared that in frail individuals both populations are affected ( Jing et al, 2009 ; Clements et al, 2017 ). Our data did not show any significant change in the mDCs and pDC populations in the control group compared to the intervention group, but it would appear that the mDC/pDC ratio tend to decrease.…”

Bovine Lactoferrin Enhances TLR7-Mediated Responses in Plasmacytoid Dendritic Cells in Elderly Women: Results From a Nutritional Intervention Study With Bovine Lactoferrin, GOS and Vitamin D

“…Interestingly, two recent publications have also reported effects of dietary intervention in elderly people on the innate immune response after TLR activation ( 43 , 44 ). In the first study, a mediterranean diet did not have an effect on circulating mDC and pDC numbers, but reduced the cytokine responses of PBMC in response to TLR-mediated stimulation ( 44 ).…”

“…Interestingly, two recent publications have also reported effects of dietary intervention in elderly people on the innate immune response after TLR activation ( 43 , 44 ). In the first study, a mediterranean diet did not have an effect on circulating mDC and pDC numbers, but reduced the cytokine responses of PBMC in response to TLR-mediated stimulation ( 44 ). In the second study, a mediterranean diet with additional vitamin D3 supplementation was shown to have gender-specific effects on TLR-mediated activation of PBMC in women, that in analogy with the data presented here for pDC showed increased induction of CD40 + CD86 + cells upon stimulation ( 43 ).…”

Reversing the immune ageing clock: lifestyle modifications and pharmacological interventions

“…Increased intake of specific dietary components, such as omega 3 fatty acids (Molfino et al 2014 ) also has anti-inflammatory effects. Interestingly, the adoption of the mediterranean diet by older adults has also been associated improvement in immune responses, particularly dendritic cell function (Clements et al 2017 ).…”