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Age‐related reduction in adult hippocampal neurogenesis is correlated with cognitive impairment. Diabetes is a chronic systemic disease that negatively affects adult neural stem cells and memory functions in the hippocampus. Despite growing concern regarding the potential role of diabetic drugs in neural abnormalities, their effects on progressive deterioration of neurogenesis and cognitive functions remain unknown. Here, we show that the combination of aging and diabetes in mice causes a marked decrease in hippocampal neurogenesis along with memory impairment and elevated neuroinflammation. Prolonged treatment with metformin, a biguanide antidiabetic medication, promotes cell proliferation and neuronal differentiation and inhibits aging‐ and diabetes‐associated microglial activation, which is related to homeostatic neurogenesis, leading to enhanced hippocampal neurogenesis in middle‐aged diabetic mice. Although chronic therapy with metformin fails to achieve recovery from hyperglycemia, a key feature of diabetes in middle‐aged diabetic mice, it improves hippocampal‐dependent spatial memory functions accompanied by increased phosphorylation of adenosine monophosphate‐activated protein kinase ( AMPK ), atypical protein kinase C ζ ( aPKC ζ), and insulin receptor substrate 1 ( IRS 1) at selective serine residues in the hippocampus. Our findings suggest that signaling networks acting through long‐term metformin‐stimulated phosphorylation of AMPK , aPKC ζ/λ, and IRS 1 serine sites contribute to neuroprotective effects on hippocampal neurogenesis and cognitive function independent of a hypoglycemic effect.

Purpose To investigate the prognostic role of the preoperative systemic immune–inflammation index (SII) in patients with upper tract urothelial carcinoma (UTUC) treated with radical nephroureterectomy (RNU). Materials and methods We retrospectively analyzed our multi-institutional database to identify 2492 patients. SII was calculated as platelet count × neutrophil/lymphocyte count and evaluated at a cutoff of 485. Logistic regression analyses were performed to investigate the association of SII with muscle-invasive and non-organ-confined (NOC) disease. Cox regression analyses were performed to investigate the association of SII with recurrence-free, cancer-specific, and overall survival (RFS/CSS/OS). Results Overall, 986 (41.6%) patients had an SII > 485. On univariable logistic regression analyses, SII > 485 was associated with a higher risk of muscle-invasive (P = 0.004) and NOC (P = 0.03) disease at RNU. On multivariable logistic regression, SII remained independently associated with muscle-invasive disease (P = 0.01). On univariable Cox regression analyses, SII > 485 was associated with shorter RFS (P = 0.002), CSS (P = 0.002) and OS (P = 0.004). On multivariable Cox regression analyses SII remained independently associated with survival outcomes (all P < 0.05). Addition of SII to the multivariable models improved their discrimination of the models for predicting muscle-invasive disease (P = 0.02). However, all area under the curve and C-indexes increased by < 0.02 and it did not improve net benefit on decision curve analysis. Conclusions Preoperative altered SII is significantly associated with higher pathologic stages and worse survival outcomes in patients treated with RNU for UTUC. However, the SII appears to have relatively limited incremental additive value in clinical use. Further study of SII in prognosticating UTUC is warranted before routine use in clinical algorithms.

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Type 2 diabetes—associated with impaired insulin/insulin-like growth factor-1 (IGF1) signaling (IIS)—is a risk factor for cognitive impairment and dementia including Alzheimer’s disease (AD). The insulin receptor substrate (IRS) proteins are major components of IIS, which transmit upstream signals via the insulin receptor and/or IGF1 receptor to multiple intracellular signaling pathways, including AKT/protein kinase B and extracellular-signal-regulated kinase cascades. Of the four IRS proteins in mammals, IRS1 and IRS2 play key roles in regulating growth and survival, metabolism, and aging. Meanwhile, the roles of IRS1 and IRS2 in the central nervous system with respect to cognitive abilities remain to be clarified. In contrast to IRS2 in peripheral tissues, inactivation of neural IRS2 exerts beneficial effects, resulting in the reduction of amyloid β accumulation and premature mortality in AD mouse models. On the other hand, the increased phosphorylation of IRS1 at several serine sites is observed in the brains from patients with AD and animal models of AD or cognitive impairment induced by type 2 diabetes. However, these serine sites are also activated in a mouse model of type 2 diabetes, in which the diabetes drug metformin improves memory impairment. Because IRS1 and IRS2 signaling pathways are regulated through complex mechanisms including positive and negative feedback loops, whether the elevated phosphorylation of IRS1 at specific serine sites found in AD brains is a primary response to cognitive dysfunction remains unknown. Here, we examine the associations between IRS1/IRS2-mediated signaling in the central nervous system and cognitive decline.

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Purpose:The primary advantage of en bloc resection of bladder tumors is to provide better diagnostic accuracy. However, the clinical significance of horizontal and vertical margin has not been demonstrated. We evaluated the clinical importance of surgical margins in patients who underwent en bloc resection of bladder tumors.Materials and Methods:We retrospectively analyzed the records of 140 consecutive patients who underwent en bloc resection of bladder tumors for nonmuscle invasive bladder cancer. We analyzed perioperative and oncological outcome, and compared patient demographics and recurrence-free survival for horizontal findings. The relationship between surgical margin and second transurethral resection outcome in pT1 bladder cancer was also analyzed.Results:Mean tumor diameter was 17.2±9.8 mm. Pathological stages were 93 cases in pTa and 47 cases in pT1. Diagnostic rates for the horizontal and vertical margins were 63% and 99%, respectively. The rates of sessile, carcinoma in situ, high grade, and pT1 tumors were significantly higher in the horizontal margin positive group (41) than in the negative group (47). There was no significant difference in 2-year recurrence-free survival based on horizontal margin findings (negative: 72.4%, positive: 75.4%, p=0.87). A second transurethral resection was performed in 31 of the 47 pT1 patients; pT1 residue was seen only in vertical margin positive cases, and 5 pTa/pTis residues at the transurethral resection scar were seen in 15 horizontal margin positive patients.Conclusions:Horizontal margin positive findings were not associated with recurrence-free survival, but careful assessment is warranted regarding residue at the original site. A second transurethral resection should be considered in patients with horizontal and vertical margin positive pT1 bladder cancer.