Amyloid-ß levels and cognitive trajectories in non-demented pTau181-positive subjects without amyloidopathy.

Phosphorylated Tau181 (pTau181) in CSF and recently in plasma has been associated with Alzheimer's disease. In the absence of amyloidopathy, individuals with increased total Tau levels and/or temporal lobe atrophy experience no or only mild cognitive decline compared with biomarker-negative controls, leading to the proposal to categorize this constellation as suspected non-Alzheimer's disease pathophysiology (SNAP). We investigated whether the characteristics of SNAP also applied to individuals with increased CSF-pTau181 without amyloidopathy. In this long-term observational study, 285 non-demented individuals, including 76 individuals with subjective cognitive impairment and 209 individuals with mild cognitive impairment, were classified based on their CSF levels of pTau181 (T), total Tau (N), amyloid-ß42 (Aß42) and Aß42/Aß40 ratio (A) into A+T+N±, A+T-N±, A-T+N±, and A-T-N-. The longitudinal analysis included 154 subjects with a follow-up of more than 12 months who were followed to a median of 4.6 years (interquartile range = 4.3 years). We employed linear mixed models on psychometric tests and region of interest analysis of structural MRI data. Cognitive decline and hippocampal atrophy rate were significantly higher in A+T+N± compared to A-T+N±, whereas there was no difference between A-T+N± and A-T-N-. Furthermore, there was no significant difference between A-T+N± and controls in dementia risk [hazard ratio 0.3, 95% confidence interval (0.1, 1.9)]. However, A-T+N± and A-T-N- could be distinguished based on their Aß42 and Aß40 levels. Both Aß40 and Aß42 levels were significantly increased in A-T+N± compared to controls. Long term follow-up of A-T+N± individuals revealed no evidence that this biomarker constellation was associated with dementia or more severe hippocampal atrophy rates compared to controls. However, because of the positive association of pTau181 with Aß in the A-T+N± group, a link to the pathophysiology of Alzheimer's disease cannot be excluded in this case. We propose to refer to these individuals in the SNAP group as 'pTau and Aß surge with subtle deterioration' (PASSED). The investigation of the circumstances of simultaneous elevation of pTau and Aß might provide a deeper insight into the process under which Aß becomes pathological.

PASSED: Brain atrophy in non-demented individuals in a long-term longitudinal study from two independent cohorts.

Introduction: Alzheimer's disease (AD) is indicated by a decrease in amyloid beta 42 (Aß42) level or the Aß42/Aß40 ratio, and by increased levels of Tau with phosphorylated threonine at position 181 (pTau181) in cerebrospinal fluid (CSF) years before the onset of clinical symptoms. However, once only pTau181 is increased, cognitive decline in individuals with subjective or mild cognitive impairment is slowed compared to individuals with AD. Instead of a decrease in Aß42 levels, an increase in Aß42 was observed in these individuals, leading to the proposal to refer to them as nondemented subjects with increased pTau-levels and Aß surge with subtle cognitive deterioration (PASSED). In this study, we determined the longitudinal atrophy rates of AD, PASSED, and Biomarker-negative nondemented individuals of two independent cohorts to determine whether these groups can be distinguished by their longitudinal atrophy patterns or rates. Methods: Depending on their CSF-levels of pTau 181 (T), total Tau (tTau, N), Aß42 or ratio of Aß42/Aß40 (A), 185 non-demented subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI) and 62 non-demented subjects from Erlangen AD cohort were assigned to an ATN group (A-T-N-, A-T+N±, A+T-N±and A+T+N±) and underwent T1-weighted structural magnetic resonance imaging (sMRI). Longitudinal grey matter (GM) atrophy patterns were assessed with voxel-based morphometry (VBM) using the cat12 toolbox on spm12 (statistical parametric mapping) of MRI scans from individuals in the ADNI cohort with a mean follow-up of 2 and 5 years, respectively. The annualized atrophy rate for individuals in the Erlangen cohort was determined using region of interest analysis (ROI) in terms of a confirmatory analysis. Results: In the A-T+N± group, VBM did not identify any brain region that showed greater longitudinal atrophy than the A+T+N±, A+T+N± or biomarker negative control group. In contrast, marked longitudinal atrophy in the temporal lobe was evident in the A+T-N± group compared with A+T-N± and biomarker-negative subjects. The ROI in the angular gyrus identified by VBM analysis of the ADNI cohort did not discriminate better than the hippocampal volume and atrophy rate between AD and PASSED in the confirmatory analysis. Discussion: In this study, nondemented subjects with PASSED did not show a unique longitudinal atrophy pattern in comparison to nondemented subjects with AD. The nonsignificant atrophy rate compared with controls suggests that increased pTau181-levels without concomitant amyloidopathy did not indicate a neurodegenerative disorder.

Testosterone deficiency in male heart failure patients and its effect on endothelial progenitor cells.

BACKGROUND: Endothelial progenitor cells (EPCs) are thought to contribute to reendothelialization and neoangiogenesis. Since it is known that EPCs express a testosterone receptor, we wanted to assess the prevalence of testosterone deficiency in patients with CHF and its impact on circulating EPCs. METHODS: 137 male patients with chronic heart failure (CHF) were included (age 61 ± 13 years; BMI 29 ± 5 kg/m(2); New York Heart Association classification (NYHA) I: n = 47, NYHA II: n = 51, NYHA III: n = 39). Numbers of different populations of circulating EPCs were quantified using flow cytometry. Levels of free testosterone and EPC-regulating cytokines were determined using ELISA. RESULTS: The prevalence of testosterone deficiency in our University CHF clinic was 39%. However, there was no difference between patients with and without testosterone deficiency regarding their levels of EPCs. Testosterone levels were inversely correlated with age (R(2) = -0.32, p = 0.001) and NYHA status (R(2) = 0.28, p = 0.001) and correlated with cardiorespiratory capacity (R(2) = 0.26, p = 0.03). CONCLUSION: Testosterone deficiency is frequent in male patients with CHF but does not appear to impact the regenerative EPCs.

Positive effect of eplerenone treatment on endothelial progenitor cells in patients with chronic heart failure.

BACKGROUND: Endothelial progenitor cells (EPCs) are known to play a significant role in reendothelialization and vascular repair. Recently, a mineralocorticoid receptor was demonstrated to be expressed by EPCs. The study aimed to evaluate a potential influence of eplerenone treatment on the total number of EPCs in patients with chronic heart failure. METHODS: Eighty-seven male patients with chronic heart failure were included (age: 23-83 years; body mass index 29.1 ± 5.1 kg/m²; New York Heart failure classification (NYHA) I: 29 patients, NYHA II: 32 patients, NYHA III: 26 patients). Numbers of circulating EPCs were quantified immediately using flow cytometry. Twenty-eight patients received therapy with eplerenone. Patients were further characterized by echocardiography, spirometry and laboratory markers. RESULTS: Patients with ongoing eplerenone administration showed higher levels of circulating cells expressing CD34+ (p<0.05) and CD34+KDR+ (p<0.05) and CD34+CD133+KDR+ cells (p<0.05). The effects of eplerenone treatment could be shown to be independent of NYHA status, genesis of the underlying cardiovascular morbidity, left ventricular function and co-medication. CONCLUSION: Patients with chronic heart failure treated with eplerenone show higher numbers of EPCs. The clinical benefit for treatment with eplerenone has been demonstrated even for patients with mild heart failure and might be partially mediated by EPCs.