Citations

Regular exercise has multi-system anti-aging effects. Here we summarize how exercise impacts the major hallmarks of aging. We propose that, besides searching for novel pharmaceutical targets of the aging process, more research efforts should be devoted to gaining insights into the molecular mediators of the benefits of exercise and to implement effective exercise interventions for elderly people.

The heterotopic thoracic pig‐to‐baboon heart transplantation has been established by our group as a safe preclinical model. Since the recipient's own heart remains in place, it is possible to evaluate immunological reactions of various types and the symptoms of the thrombotic microangiopathy under working heart conditions. However, these experiments are complex and costly. In order to limit the number of transplants, we tested our multi‐transgenic porcine donor hearts in an ex‐vivo perfusion model first.Ex‐vivo model: Both beating ventricles were perfused with heparinized freshly drawn human whole blood using a centrifugal pump and a membrane oxygenator. During 3 h of observation, cardiac function parameters were obtained continuously; specimens from the perfusate, coronary sinus blood, and myocardial biopsies were assessed. Various genetically modified porcine donor hearts were tested; we are currently evaluating the impact of human thrombomodulin on the porcine microcirculation; the efficacy of complement regulation is another work package.Pig‐to‐baboon heterotopic cardiac xenotransplantation: In our latest group, seven baboons received five double (Gal‐KO/hCD46), and two triple (Gal‐KO/hCD46/hTM resp./HLA‐E) transgenic pig hearts. Our immunosuppressive regimen included preoperative anti‐CD20‐antibody, bortezomib, dexamethasone and cyclophosphamide; postoperatively, ATG, tacrolimus, MMF, anti‐CD20‐antibody, bortezomib and dexamethasone were administered. Total lymph node irradiation (6 Gy) was applied on postoperative day five.The triple transgenic hearts survived 35 and 37 days respectively. Both hearts maintained function throughout the experiment. Both recipients succumbed to fungal infections. Humoral rejection was seen only once. The next barrier appears to be the complex event of thrombotic microangiopathy that needs to be addressed with the additional expression of human thrombomodulin strategies.

Recently, during critical illness, cortisol metabolism was found to be reduced. We hypothesize that such reduced cortisol breakdown may suppress pulsatile ACTH and cortisol secretion via feedback inhibition. To test this hypothesis, nocturnal ACTH and cortisol secretory profiles were constructed by deconvolution analysis from plasma concentration time series in 40 matched critically ill patients and eight healthy controls, excluding diseases or drugs that affect the hypothalamic-pituitary-adrenal axis. Blood was sampled every 10 min between 2100 and 0600 to quantify plasma concentrations of ACTH and (free) cortisol. Approximate entropy, an estimation of process irregularity, cross-approximate entropy, a measure of ACTH-cortisol asynchrony, and ACTH-cortisol dose-response relationships were calculated. Total and free plasma cortisol concentrations were higher at all times in patients than in controls (all P < 0.04). Pulsatile cortisol secretion was 54% lower in patients than in controls ( P = 0.005), explained by reduced cortisol burst mass ( P = 0.03), whereas cortisol pulse frequency ( P = 0.35) and nonpulsatile cortisol secretion ( P = 0.80) were unaltered. Pulsatile ACTH secretion was 31% lower in patients than in controls ( P = 0.03), again explained by a lower ACTH burst mass ( P = 0.02), whereas ACTH pulse frequency ( P = 0.50) and nonpulsatile ACTH secretion ( P = 0.80) were unchanged. ACTH-cortisol dose response estimates were similar in patients and controls. ACTH and cortisol approximate entropy were higher in patients ( P ≤ 0.03), as was ACTH-cortisol cross-approximate entropy ( P ≤ 0.001). We conclude that hypercortisolism during critical illness coincided with suppressed pulsatile ACTH and cortisol secretion and a normal ACTH-cortisol dose response. Increased irregularity and asynchrony of the ACTH and cortisol time series supported non-ACTH-dependent mechanisms driving hypercortisolism during critical illness.

Background— A simple risk score to predict long-term mortality after percutaneous coronary intervention (PCI) using preprocedural risk factors is currently not available. In this study, we created one by simplifying the results of a Cox proportional hazards model. Methods and Results— A total of 11 897 patients who underwent PCI from October through December 2003 in New York State were randomly divided into derivation and validation samples. Patients’ vital statuses were tracked using the National Death Index through the end of 2008. A Cox proportional hazards model was fit to predict death after PCI using the derivation sample, and a simplified risk score was created. The Cox model identified 12 separate risk factors for mortality including older age, extreme body mass indexes, multivessel disease, a lower ejection fraction, unstable hemodynamic state or shock, several comorbidities (cerebrovascular disease, peripheral vascular disease, congestive heart failure, chronic obstructive pulmonary disease, diabetes mellitus, and renal failure), and a history of coronary artery bypass graft surgery. The C statistics of this model when applied to the validation sample were 0.787, 0.785, and 0.773 for risks of death within 1, 3, and 5 years after PCI, respectively. In addition, the point-based risk score demonstrated good agreement between patients’ observed and predicted risks of death. Conclusions— A simple risk score created from a more complicated Cox proportional hazards model can be used to accurately predict a patient’s risk of long-term mortality after PCI.

Aberrant connectivity is implicated in many neurological and psychiatric disorders, including Alzheimer’s disease and schizophrenia. However, other than a few disease-associated candidate genes, we know little about the degree to which genetics play a role in the brain networks; we know even less about specific genes that influence brain connections. Twin and family-based studies can generate estimates of overall genetic influences on a trait, but genome-wide association scans (GWASs) can screen the genome for specific variants influencing the brain or risk for disease. To identify the heritability of various brain connections, we scanned healthy young adult twins with high-field, high-angular resolution diffusion MRI. We adapted GWASs to screen the brain’s connectivity pattern, allowing us to discover genetic variants that affect the human brain’s wiring. The association of connectivity with the SPON1 variant at rs2618516 on chromosome 11 (11p15.2) reached connectome-wide, genome-wide significance after stringent statistical corrections were enforced, and it was replicated in an independent subsample. rs2618516 was shown to affect brain structure in an elderly population with varying degrees of dementia. Older people who carried the connectivity variant had significantly milder clinical dementia scores and lower risk of Alzheimer’s disease. As a posthoc analysis, we conducted GWASs on several organizational and topological network measures derived from the matrices to discover variants in and around genes associated with autism ( MACROD2 ), development ( NEDD4 ), and mental retardation ( UBE2A ) significantly associated with connectivity. Connectome-wide, genome-wide screening offers substantial promise to discover genes affecting brain connectivity and risk for brain diseases.