@article{KruesemannSchwarzlMetzler2016, author = {Kruesemann, Henning and Schwarzl, Richard and Metzler, Ralf}, title = {Ageing Scher-Montroll Transport}, series = {Transport in Porous Media}, volume = {115}, journal = {Transport in Porous Media}, publisher = {Springer}, address = {New York}, issn = {0169-3913}, doi = {10.1007/s11242-016-0686-y}, pages = {327 -- 344}, year = {2016}, abstract = {We study the properties of ageing Scher-Montroll transport in terms of a biased subdiffusive continuous time random walk in which the waiting times between consecutive jumps of the charge carriers are distributed according to the power law probability with . As we show, the dynamical properties of the Scher-Montroll transport depend on the ageing time span between the initial preparation of the system and the start of the observation. The Scher-Montroll transport theory was originally shown to describe the photocurrent in amorphous solids in the presence of an external electric field, but it has since been used in many other fields of physical sciences, in particular also in the geophysical context for the description of the transport of tracer particles in subsurface aquifers. In the absence of ageing () the photocurrent of the classical Scher-Montroll model or the breakthrough curves in the groundwater context exhibit a crossover between two power law regimes in time with the scaling exponents and . In the presence of ageing a new power law regime and an initial plateau regime of the current emerge. We derive the different power law regimes and crossover times of the ageing Scher-Montroll transport and show excellent agreement with simulations of the process. Experimental data of ageing Scher-Montroll transport in polymeric semiconductors are shown to agree well with the predictions of our theory.}, language = {en} } @article{KoelmanPivovarovaRamichPfeifferetal.2019, author = {Koelman, Liselot A. and Pivovarova-Ramich, Olga and Pfeiffer, Andreas F. H. and Grune, Tilman and Aleksandrova, Krasimira}, title = {Cytokines for evaluation of chronic inflammatory status in ageing research}, series = {Immunity \& Ageing}, volume = {16}, journal = {Immunity \& Ageing}, publisher = {BMC}, address = {London}, issn = {1742-4933}, doi = {10.1186/s12979-019-0151-1}, pages = {12}, year = {2019}, abstract = {Background: There is a growing interest in the role of inflammageing for chronic disease development. Cytokines are potent soluble immune mediators that can be used as target biomarkers of inflammageing; however, their measurement in human samples has been challenging. This study aimed to assess the reliability of a pro- and anti-inflammatory cytokine panel in a sample of healthy people measured with a novel electrochemiluminescent multiplex immunoassay platform (Meso Scale Discovery, MSD), and to characterize their associations with metabolic and inflammatory phenotypes.}, language = {en} } @article{LauGossenLendleinetal.2022, author = {Lau, Skadi and Gossen, Manfred and Lendlein, Andreas and Jung, Friedrich}, title = {Differential sensitivity of assays for determining vein endothelial cell senescence}, series = {Clinical hemorheology and microcirculation : blood flow and vessels}, volume = {81}, journal = {Clinical hemorheology and microcirculation : blood flow and vessels}, number = {3}, publisher = {IOS Press}, address = {Amsterdam}, issn = {1386-0291}, doi = {10.3233/CH-211294}, pages = {191 -- 203}, year = {2022}, abstract = {In vivo endothelialization of polymer-based cardiovascular implant materials is a promising strategy to reduce the risk of platelet adherence and the subsequent thrombus formation and implant failure. However, endothelial cells from elderly patients are likely to exhibit a senescent phenotype that may counteract endothelialization. The senescence status of cells should therefore be investigated prior to implantation of devices designed to be integrated in the blood vessel wall. Here, human umbilical vein endothelial cells (HUVEC) were cultivated up to passage (P) 4, 10 and 26/27 to determine the population doubling time and the senescence status by four different methods. Determination of the senescence-associated beta-galactosidase activity (SA-beta-Gal) was carried out by colorimetric staining and microscopy (i), as well as by photometric quantification (ii), and the expression of senescence-associated nuclear proteins p16 and p21 as well as the proliferation marker Ki67 was assessed by immunostaining (iii), and by flow cytometry (iv). The population doubling time of P27-cells was remarkably greater (103 +/- 65 h) compared to P4-cells (24 +/- 3 h) and P10-cell (37 +/- 15 h). Among the four different methods tested, the photometric SA-beta-Gal activity assay and the flow cytometric determination of p16 and Ki67 were most effective in discriminating P27-cells from P4- and P10-cells. These methods combined with functional endothelial cell analyses might aid predictions on the performance of implant endothelialization in vivo.}, language = {en} } @phdthesis{Herpich2021, author = {Herpich, Catrin}, title = {Fibroblast growth factor 21 and its association with nutritional stimuli in older age}, school = {Universit{\"a}t Potsdam}, pages = {75}, year = {2021}, abstract = {Fibroblast growth differentiation factor 21 (FGF21) is known as a pivotal regulator of the glucose and lipid metabolism. As such, it is considered beneficial and has even been labelled a longevity hormone. Nevertheless, recent observational studies have shown that FGF21 is increased in higher age with possible negative effects such as loss of lean and bone mass as well as decreased survival. Hepatic FGF21 secretion can be induced by various nutritional stimuli such as starvation, high carbohydrate and fat intake as well as protein deficiency.. So far it is still unclear whether the FGF21 response to different macronutrients is altered in older age. An altered response would potentially contribute to explain the higher FGF21 concentrations found in older age. In this publication-based doctoral dissertation, a cross-sectional study as well as a dietary challenge were conducted to investigate the influence of nutrition on FGF21 concentrations and response in older age. In a cross-sectional study, FGF21 concentrations were assessed in older patients with and without cachexia anorexia syndrome anorexia syndrome compared to an older community-dwelling control group. Cachexia anorexia syndrome is a multifactorial syndrome frequently occurring in old age or in the context of an underlying disease. It is characterized by a severe involuntary weight loss, loss of appetite (anorexia) and reduced food intake, therefore representing a state of severe nutrient deficiency, in some aspects similar to starvation. The highest FGF21 concentrations were found in patients with cachexia anorexia syndrome. Moreover, FGF21 was positively correlated with weight loss and loss of appetite. In addition, cachexia anorexia syndrome itself was associated with FGF21 independent of sex, age and body mass index. As cachectic patients presumably exhibit protein malnutrition and FGF21 has been proposed a marker for protein insufficiency, the higher levels of FGF21 in patients with cachexia anorexia syndrome might be partly explained by insufficient protein intake. In order to investigate the acute response of FGF21 to different nutritional stimuli, a dietary challenge with a parallel group design was conducted. Here, healthy older (65-85 years) and younger (18-35 years) adults were randomized to one of four test meals: a dextrose drink, a high carbohydrate, high fat or high protein meal. Over the course of four hours, postprandial FGF21 concentrations (dynamics) were assessed and the FGF21 response (incremental area under the curve) to each test meal was examined.. In a sub-group of older and younger women, also the adiponectin response was investigated, as adiponectin is a known mediator of FGF21 effects on glucose and lipid metabolism. The dietary meal challenge revealed that dextrose and high carbohydrate intake result in higher FGF21 concentrations after four hours in older adults. This was partly explained by higher postprandial glucose concentrations in the old. For high fat ingestion no age differences were found. For the first time, acute FGF21 response to high protein intake was shown. Here, protein ingestion resulted in lower FGF21 concentrations in younger compared to older adults. Furthermore, sufficient protein intake, according to age-dependent recommendations, of the previous day, was associated with lower FGF21 concentrations in both age groups. The higher FGF21 response to dextrose ingestion resulted in a higher adiponectin response in older women, independent of fat mass, insulin resistance, triglyceride concentrations, inflammation and oxidative stress. Following the high fat meal, adiponectin concentrations declined in older women. Adiponectin response was not affected by meal composition in younger women. In summary, this thesis showed a positive association of FGF21 and cachexia anorexia syndrome with concomitant anorexia in older patients. Regarding the acute FGF21 response, a higher response following dextrose and carbohydrate ingestion was found in older compared with younger subjects. This might be attributed to a higher glucose response in older age. Furthermore, it was shown that the higher FGF21 response after dextrose ingestion possibly contributes to a higher adiponectin response in older women, independent of potential metabolic and inflammatory confounders. Acute protein ingestion resulted in a significant decrease in FGF21 concentrations. Moreover, protein intake of the previous day was inversely associated with fasting FGF21 concentrations. This might explain why FGF21 concentrations are higher in cachexia anorexia syndrome. These results therefore support the role of FGF21 as a sensor of protein restriction.}, language = {en} } @article{RaelingSchroederWartenburger2016, author = {R{\"a}ling, Romy and Schr{\"o}der, Astrid and Wartenburger, Isabell}, title = {The origins of age of acquisition and typicality effects: Semantic processing in aphasia and the ageing brain}, series = {Neuropsychologia : an international journal in behavioural and cognitive neuroscience}, volume = {86}, journal = {Neuropsychologia : an international journal in behavioural and cognitive neuroscience}, publisher = {Elsevier}, address = {Oxford}, issn = {0028-3932}, doi = {10.1016/j.neuropsychologia.2016.04.019}, pages = {80 -- 92}, year = {2016}, abstract = {Age of acquisition (AOA) has frequently been shown to influence response times and accuracy rates in word processing and constitutes a meaningful variable in aphasic language processing, while its origin in the language processing system is still under debate. To find out where AOA originates and whether and how it is related to another important psycholinguistic variable, namely semantic typicality (TYP), we studied healthy, elderly controls and semantically impaired individuals using semantic priming. For this purpose, we collected reaction times and accuracy rates as well as event-related potential data in an auditory category-member-verification task. The present results confirm a semantic origin of TYP, but question the same for AOA while favouring its origin at the phonology-semantics interface. The data are further interpreted in consideration of recent theories of ageing. (C) 2016 Elsevier Ltd. All rights reserved.}, language = {en} } @article{PliatsikasVerissimoBabcocketal.2019, author = {Pliatsikas, Christos and Verissimo, Joao Marques and Babcock, Laura and Pullman, Mariel Y. and Glei, Dana A. and Weinstein, Maxine and Goldman, Noreen and Ullman, Michael T.}, title = {Working memory in older adults declines with age, but is modulated by sex and education}, series = {The quarterly journal of experimental psychology}, volume = {72}, journal = {The quarterly journal of experimental psychology}, number = {6}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {1747-0218}, doi = {10.1177/1747021818791994}, pages = {1308 -- 1327}, year = {2019}, abstract = {Working memory (WM), which underlies the temporary storage and manipulation of information, is critical for multiple aspects of cognition and everyday life. Nevertheless, research examining WM specifically in older adults remains limited, despite the global rapid increase in human life expectancy. We examined WM in a large sample (N=754) of healthy older adults (aged 58-89) in a non-Western population (Chinese speakers) in Taiwan, on a digit n-back task. We tested not only the influence of age itself and of load (1-back vs. 2-back) but also the effects of both sex and education, which have been shown to modulate WM abilities. Mixed-effects regression revealed that, within older adulthood, age negatively impacted WM abilities (with linear, not nonlinear, effects), as did load (worse performance at 2-back). In contrast, education level was positively associated with WM. Moreover, both age and education interacted with sex. With increasing age, males showed a steeper WM decline than females; with increasing education, females showed greater WM gains than males. Together with other findings, the evidence suggests that age, sex, and education all impact WM in older adults, but interact in particular ways. The results have both basic research and translational implications and are consistent with particular benefits from increased education for women.}, language = {en} }