Abstract Background Criteria for the clinical diagnosis of Alzheimer's disease (AD) were established in 1984. A broad consensus now exists that these criteria should be revised to incorporate ...state-of-the-art scientific knowledge. Methods The National Institute on Aging (NIA) and the Alzheimer's Association sponsored a series of advisory round table meetings in 2009 whose purpose was to establish a process for revising diagnostic and research criteria for AD. The recommendation from these advisory meetings was that three separate work groups should be formed with each assigned the task of formulating diagnostic criteria for one phase of the disease: the dementia phase; the symptomatic, pre-dementia phase; and the asymptomatic, preclinical phase of AD. Results Two notable differences from the AD criteria published in 1984 are incorporation of biomarkers of the underlying disease state and formalization of different stages of disease in the diagnostic criteria. There was a broad consensus within all three workgroups that much additional work is needed to validate the application of biomarkers for diagnostic purposes. In the revised NIA-Alzheimer's Association criteria, a semantic and conceptual distinction is made between AD pathophysiological processes and clinically observable syndromes that result, whereas this distinction was blurred in the 1984 criteria. Conclusions The new criteria for AD are presented in three documents. The core clinical criteria of the recommendations regarding AD dementia and MCI due to AD are intended to guide diagnosis in the clinical setting. However, the recommendations of the preclinical AD workgroup are intended purely for research purposes.
Cyclophilin D (CypD, encoded by Ppif) is an integral part of the mitochondrial permeability transition pore, whose opening leads to cell death. Here we show that interaction of CypD with ...mitochondrial amyloid-beta protein (Abeta) potentiates mitochondrial, neuronal and synaptic stress. The CypD-deficient cortical mitochondria are resistant to Abeta- and Ca(2+)-induced mitochondrial swelling and permeability transition. Additionally, they have an increased calcium buffering capacity and generate fewer mitochondrial reactive oxygen species. Furthermore, the absence of CypD protects neurons from Abeta- and oxidative stress-induced cell death. Notably, CypD deficiency substantially improves learning and memory and synaptic function in an Alzheimer's disease mouse model and alleviates Abeta-mediated reduction of long-term potentiation. Thus, the CypD-mediated mitochondrial permeability transition pore is directly linked to the cellular and synaptic perturbations observed in the pathogenesis of Alzheimer's disease. Blockade of CypD may be a therapeutic strategy in Alzheimer's disease.
Mutation in superoxide dismutase-1 (SOD1), which is a cause of ALS, alters the folding patterns of this protein. Accumulation of misfolded mutant SOD1 might activate endoplasmic reticulum (ER) stress ...pathways. Here we show that transgenic mice expressing ALS-linked SOD1 mutants exhibit molecular alterations indicative of a recruitment of ER's signaling machinery. We demonstrate by biochemical and morphological methods that mutant SOD1 accumulates inside the ER, where it forms insoluble high molecular weight species and interacts with the ER chaperone immunoglobulin-binding protein. These alterations are age- and region-specific, because they develop over the course of the disease and occur in the affected spinal cord but not in the nonaffected cerebellum in transgenic mutant SOD1 mice. Our results suggest a toxic mechanism for mutant SOD1 by which this ubiquitously expressed pathogenic protein could affect motor neuron survival and contribute to the selective motor neuronal degeneration in ALS.
OBJECT The object of this study was to perform a systematic review, according to Preferred Reporting Items of Systematic reviews and Meta-Analyses (PRISMA) and Agency for Healthcare Research and ...Quality (AHRQ) guidelines, of the clinical efficacy and adverse effect profile of dorsal anterior cingulotomy compared with anterior capsulotomy for the treatment of severe, refractory obsessive-compulsive disorder (OCD). METHODS The authors included studies comparing objective clinical measures before and after cingulotomy or capsulotomy (surgical and radiosurgical) in patients with OCD. Only papers reporting the most current follow-up data for each group of investigators were included. Studies reporting results on patients undergoing one or more procedures other than cingulotomy or capsulotomy were excluded. Case reports and studies with a mean follow-up shorter than 12 months were excluded. Clinical response was defined in terms of a change in the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) score. The authors searched MEDLINE, PubMed, PsycINFO, Scopus, and Web of Knowledge through October 2013. English and non-English articles and abstracts were reviewed. RESULTS Ten studies involving 193 participants evaluated the length of follow-up, change in the Y-BOCS score, and postoperative adverse events (AEs) after cingulotomy (n = 2 studies, n = 81 participants) or capsulotomy (n = 8 studies, n = 112 participants). The average time to the last follow-up was 47 months for cingulotomy and 60 months for capsulotomy. The mean reduction in the Y-BOCS score at 12 months' follow-up was 37% for cingulotomy and 55% for capsulotomy. At the last follow-up, the mean reduction in Y-BOCS score was 37% for cingulotomy and 57% for capsulotomy. The average full response rate to cingulotomy at the last follow-up was 41% (range 38%-47%, n = 2 studies, n = 51 participants), and to capsulotomy was 54% (range 37%-80%, n = 5 studies, n = 50 participants). The rate of transient AEs was 14.3% across cingulotomy studies (n = 116 procedures) and 56.2% across capsulotomy studies (n = 112 procedures). The rate of serious or permanent AEs was 5.2% across cingulotomy studies and 21.4% across capsulotomy studies. CONCLUSIONS This systematic review of the literature supports the efficacy of both dorsal anterior cingulotomy and anterior capsulotomy in this highly treatment-refractory population. The observational nature of available data limits the ability to directly compare these procedures. Controlled or head-to-head studies are necessary to identify differences in efficacy or AEs and may lead to the individualization of treatment recommendations.
Synaptic dysfunction and the loss of synapses are early pathological features of Alzheimer’s disease (AD). Synapses are sites of high energy demand and extensive calcium fluctuations; accordingly, ...synaptic transmission requires high levels of ATP and constant calcium fluctuation. Thus, synaptic mitochondria are vital for maintenance of synaptic function and transmission through normal mitochondrial energy metabolism, distribution and trafficking, and through synaptic calcium modulation. To date, there has been no extensive analysis of alterations in synaptic mitochondria associated with amyloid pathology in an amyloid β (Aβ)-rich milieu. Here, we identified differences in mitochondrial properties and function of synaptic vs. nonsynaptic mitochondrial populations in the transgenic mouse brain, which overexpresses the human mutant form of amyloid precursor protein and Aβ. Compared with nonsynaptic mitochondria, synaptic mitochondria showed a greater degree of age-dependent accumulation of Aβ and mitochondrial alterations. The synaptic mitochondrial pool of Aβ was detected at an age as young as 4 mo, well before the onset of nonsynaptic mitochondrial and extensive extracellular Aβ accumulation. Aβ-insulted synaptic mitochondria revealed early deficits in mitochondrial function, as shown by increased mitochondrial permeability transition, decline in both respiratory function and activity of cytochrome c oxidase, and increased mitochondrial oxidative stress. Furthermore, a low concentration of Aβ (200 nM) significantly interfered with mitochondrial distribution and trafficking in axons. These results demonstrate that synaptic mitochondria, especially Aβ-rich synaptic mitochondria, are more susceptible to Aβ-induced damage, highlighting the central importance of synaptic mitochondrial dysfunction relevant to the development of synaptic degeneration in AD.
Malignant gliomas are incurable, primary brain neoplasms noted for their potential to extensively invade brain parenchyma. Current methods of clinical imaging do not elucidate the full extent of ...brain invasion, making it difficult to predict which, if any, patients are likely to benefit from gross total resection. Our goal was to apply a mathematical modeling approach to estimate the overall tumor invasiveness on a patient-by-patient basis and determine whether gross total resection would improve survival in patients with relatively less invasive gliomas.
In 243 patients presenting with contrast-enhancing gliomas, estimates of the relative invasiveness of each patient's tumor, in terms of the ratio of net proliferation rate of the glioma cells to their net dispersal rate, were derived by applying a patient-specific mathematical model to routine pretreatment MR imaging. The effect of varying degrees of extent of resection on overall survival was assessed for cohorts of patients grouped by tumor invasiveness.
We demonstrate that patients with more diffuse tumors showed no survival benefit (P = 0.532) from gross total resection over subtotal/biopsy, while those with nodular (less diffuse) tumors showed a significant benefit (P = 0.00142) with a striking median survival benefit of over eight months compared to sub-totally resected tumors in the same cohort (an 80% improvement in survival time for GTR only seen for nodular tumors).
These results suggest that our patient-specific, model-based estimates of tumor invasiveness have clinical utility in surgical decision making. Quantification of relative invasiveness assessed from routinely obtained pre-operative imaging provides a practical predictor of the benefit of gross total resection.
When making decisions we often face the need to adjudicate between conflicting strategies or courses of action. Our ability to understand the neuronal processes underlying conflict processing is ...limited on the one hand by the spatiotemporal resolution of functional MRI and, on the other hand, by imperfect cross-species homologies in animal model systems. Here we examine the responses of single neurons and local field potentials in human neurosurgical patients in two prefrontal regions critical to controlled decision-making, the dorsal anterior cingulate cortex (dACC) and dorsolateral prefrontal cortex (dlPFC). While we observe typical modest conflict-related firing rate effects, we find a widespread effect of conflict on spike-phase coupling in the dACC and on driving spike-field coherence in the dlPFC. These results support the hypothesis that a cross-areal rhythmic neuronal coordination is intrinsic to cognitive control in response to conflict, and provide new evidence to support the hypothesis that conflict processing involves modulation of the dlPFC by the dACC.
Gliosarcoma is a rare histopathologic variant of glioblastoma traditionally associated with a poor prognosis. While gliosarcoma may represent a distinct clinical entity given its unique histologic ...composition and molecular features, its relative prognostic significance remains uncertain. While treatment of gliosarcoma generally encompasses the same standardized approach used in glioblastoma, supporting evidence is limited given its rarity. Here, we characterized 32 cases of gliosarcoma and retrospectively evaluated survival relative to 451 glioblastoma patients diagnosed during the same era within the same institution. Overall, we identified 22 primary gliosarcomas, representing 4.7% of WHO Grade IV primary glioblastomas, and 10 secondary gliosarcomas. With median age of 62, patients were predominately Caucasian (87.5%) and male (65.6%). Tumors with available molecular profiling were primarily MGMT-unmethylated (87.5%), IDH-1-preserved (100%) and EGFR wild-type (100%). Interestingly, while no significant median survival difference between primary gliosarcoma and glioblastoma was observed across the entire cohort (11.0 vs. 14.8 months, p = 0.269), median survival was worse for gliosarcoma specifically among patients who received modern temozolomide-based (TMZ) chemoradiotherapy (11.0 vs. 17.3 months, p = 0.006). Matched-pair analysis also trended toward worse median survival among gliosarcomas (11.0 vs. 19.6 months, log-rank p = 0.177, Breslow p = 0.010). While adjuvant radiotherapy (HR 0.206, p = 0.035) and TMZ-based chemotherapy (HR 0.531, p = 0.000) appeared protective, gliosarcoma emerged as a significantly poor prognostic factor on multivariate analysis (HR 3.27, p = 0.012). Collectively, our results suggest that gliosarcoma may still portend worse prognosis even with modern trimodality therapy.
Changing concepts of Alzheimer disease McKhann, Guy M
JAMA : the journal of the American Medical Association,
2011-Jun-15, Letnik:
305, Številka:
23
Journal Article
Introduction Frailty is an emerging means of assessing overall health status and guiding management for geriatric patients. Frailty is associated with outcomes for many surgical indications in this ...age group. While half of all glioblastoma patients are 65 years old or older, frailty has not been examined in relation to surgery for glioblastoma. Methods We performed a retrospective study of patients age 65 years and older with pathologically-confirmed glioblastoma at Columbia Presbyterian Hospital from 2000 to 2012. 319 patients were identified, 243 of whom underwent craniotomy for lobar lesions. Frailty was quantified using the Canadian Study of Health and Aging Modified Frailty Index (mFI). Post-operative complications were classified according the Glioma Outcomes Project system. Systemic, regional, neurologic, and overall complications were examined in relation to age, Karnofsky performance status (KPS), frailty, comorbid disease burden, cardiovascular risk, and tumor sidedness. Results Frailer patients were less likely to undergo surgical resection (p = 0.0002, OR 0.15 0.05, 0.40) as opposed to biopsy, had longer hospital stays (Logrank test for trend p = 0.0061), an increased overall risk of complications (p = 0.0123, OR 1.40 1.08, 1.83), and decreased overall survival (Logrank test for trend p = 0.0028). Conclusions Frailer patients with glioblastoma receive less aggressive intervention, have longer hospital stays, and experience more complications. Frailty may be an underutilized metric for the preoperative risk assessment of geriatric glioblastoma patients.
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