It takes two to tango: Phagocyte and lymphocyte numbers in a small mammalian hibernator

Havenstein, Nadine; Langer, Franz; Stefanski, Volker; Fietz, Joanna

doi:10.1016/j.bbi.2015.09.018

Cited by 21 publications

(9 citation statements)

References 108 publications

(136 reference statements)

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“…The alternative, that is, repeated collection of adequate quantities of blood (containing non-nucleated blood cells) is not feasible for free-living edible dormice. Further, numbers and ratios of the different fractions of white blood cells in edible dormice vary within and between seasons55, which make this cell type impractical for longitudinal studies. Cell turnover rates of the buccal mucosa cells are relatively constant and unlikely to vary within and between seasons56.…”

Section: Methodsmentioning

confidence: 99%

Telomeres are elongated in older individuals in a hibernating rodent, the edible dormouse (Glis glis)

Hoelzl

Smith

Cornils

et al. 2016

Sci Rep

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Telomere shortening is thought to be an important biomarker for life history traits such as lifespan and aging, and can be indicative of genome integrity, survival probability and the risk of cancer development. In humans and other animals, telomeres almost always shorten with age, with more rapid telomere attrition in short-lived species. Here, we show that in the edible dormouse (Glis glis) telomere length significantly increases from an age of 6 to an age of 9 years. While this finding could be due to higher survival of individuals with longer telomeres, we also found, using longitudinal measurements, a positive effect of age on the rate of telomere elongation within older individuals. To our knowledge, no previous study has reported such an effect of age on telomere lengthening. We attribute this exceptional pattern to the peculiar life-history of this species, which skips reproduction in years with low food availability. Further, we show that this “sit tight” strategy in the timing of reproduction is associated with an increasing likelihood for an individual to reproduce as it ages. As reproduction could facilitate telomere attrition, this life-history strategy may have led to the evolution of increased somatic maintenance and telomere elongation with increasing age.

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Section: Methodsmentioning

confidence: 99%

Telomeres are elongated in older individuals in a hibernating rodent, the edible dormouse (Glis glis)

Hoelzl

Smith

Cornils

et al. 2016

Sci Rep

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“…However, contrary to androgens, the action of glucocorticoids on the innate and the acquired immune response differs. Indeed, glucocorticoids favour myeloid-derived cells at the expense of lymphocytes (Havenstein, Langer, Stefanski, & Fietz, 2016), presumably because the developmental cost of lymphocyte proliferation and diversification is too high to sustain under chronic stress (McDade, Georgiev, & Kuzawa, 2016). Moreover, because of this high cost and because of increased maintenance costs with age (Monaghan, Charmantier, Nussey, & Ricklefs, 2008;McDade et al, 2016), the ratio between lymphocytes and myeloid-derived cells also decreases with age (Lin et al, 2015).…”

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confidence: 99%

Mind the cell: Seasonal variation in telomere length mirrors changes in leucocyte profile

et al. 2017

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Leucocytes are typically considered as a whole in studies examining telomere dynamics in mammals. Such an approach may be precarious, as leucocytes represent the only nucleated blood cells in mammals, their composition varies temporally, and telomere length differs between leucocyte types. To highlight this limitation, we examined here whether seasonal variation in leucocyte composition was related to variation in telomere length in free-ranging mandrills (Mandrilllus sphinx). We found that the leucocyte profile of mandrills varied seasonally, with lower lymphocyte proportion being observed during the long dry season presumably because of the combined effects of high nematode infection and stress at that time of the year. Interestingly, this low lymphocyte proportion during the long dry season was associated with shorter telomeres. Accordingly, based on longitudinal data, we found that seasonal changes in lymphocyte proportion were reflected by corresponding seasonal variation in telomere length. Overall, these results suggest that variation in lymphocyte proportion in blood can significantly affect telomere measurements in mammals. However, lymphocyte proportion did not entirely explain variation in telomere length. For instance, a lower lymphocyte proportion with age could not fully explain shorter telomeres in older individuals. Overall, our results show that telomere length and leucocyte profile are strongly although imperfectly intertwined, which may obscure the relationship between telomere dynamics and ageing processes in mammals.

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“…Notably, the edible dormouse is extremely long lived for a small rodent species and lives up to 11 years with an average lifespan of 3-4 years in the wild (Ruf et al 2006). Furthermore, this dormouse species may occur in population densities as high as 50 individuals/ha (Havenstein et al 2015). In contrast to most other rodent hosts, edible dormice lead a mostly arboreal life spending relatively little time on the ground or in ground vegetation (Müller 1988;Hönel 1991;Negro et al 2013).…”

Section: Introductionmentioning

confidence: 97%

The vector tick Ixodes ricinus feeding on an arboreal rodent—the edible dormouse Glis glis

et al. 2015

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The reservoir competence and long life expectancy of edible dormice, Glis glis, suggest that they serve as efficient reservoir hosts for Lyme disease (LD) spirochetes. Their arboreality, however, may reduce the probability to encounter sufficient questing Ixodes ricinus ticks to acquire and perpetuate LD spirochetes. To define the potential role of this small arboreal hibernator in the transmission cycle of LD spirochetes, we examined their rate and density of infestation with subadult ticks throughout the season of activity. Of the 1081 edible dormice that we captured at five study sites in Southern Germany and inspected for ticks at 2946 capture occasions, 26 % were infested with at least one and as many as 26 subadult ticks on their ear pinnae. The distribution of ticks feeding on edible dormice was highly aggregated. Although only few individuals harbored nymphal ticks soon after their emergence from hibernation, the rate of nymphal infestation increased steadily throughout the season and reached about 35 % in September. Dormice inhabiting a site with few conspecifics seemed more likely to be infested by numerous ticks, particularly nymphs, than those individuals living in densely populated sites. Male dormice were more likely to be parasitized by numerous nymphs than were females, independent of their age and body mass. Our observation that season, population density, and sex affect the rates of ticks feeding on edible dormice suggests that the contribution of edible dormice to the transmission cycle of LD spirochetes depends mainly on their ranging behavior and level of activity.

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It takes two to tango: Phagocyte and lymphocyte numbers in a small mammalian hibernator

Cited by 21 publications

References 108 publications

Telomeres are elongated in older individuals in a hibernating rodent, the edible dormouse (Glis glis)

Telomeres are elongated in older individuals in a hibernating rodent, the edible dormouse (Glis glis)

Mind the cell: Seasonal variation in telomere length mirrors changes in leucocyte profile

The vector tick Ixodes ricinus feeding on an arboreal rodent—the edible dormouse Glis glis

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