👤 Mohammadreza Nasiri

Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) accumulation and brain atrophy; however, the assocation between plasma Aβ biomarkers and regional neurodegeneration remains unclear. We investigated whether plasma Aβ42, Aβ40, and the Aβ42/40 ratio are associated with temporal lobe atrophy measured using tensor-based morphometry (TBM) in cognitively healthy controls (HC) and participants with mild cognitive impairment (MCI). We analyzed longitudinal MRI and plasma biomarkers data from 29 participants from ADNI (HC = 14, MCI = 15) with imaging and blood samples available at baseline, 24 months, and 48 months. TBM Jacobian maps were summarized within temporal lobe regions of interest (ROIs). Associations between plasma Aβ measures and TBM-derived atrophy were examined with linear mixed-effects models, adjusting for age, sex, and APOE ε4 status, with false-discovery-rate correction. Participants with MCI showed greater temporal lobe atrophy compared with HC people, with significantly lower TBM values at follow-up. Plasma Aβ42, Aβ40, and Aβ42/40 levels showed no consistent or robust differences between diagnostic groups. After covariate adjustment and FDR correction, no plasma Aβ-TBM associations were significant at baseline or 24 months. At 48 months, positive associations were identified between Aβ42 and temporal lobe atrophy (measure 2) in HC participants (β = 0.70, p = 0.046) and between Aβ40 and measure 2 in participants with MCI (β = 0.60, p = 0.036). In contrast, a negative association was observed between the Aβ42/40 and temporal lobe atrophy (measure 2) in MCI group (β = -0.53, p = 0.049). TBM captured greater temporal lobe atrophy in participants with MCI compared with HC. Plasma amyloids showed only limited and inconsistent associations with temporal lobe atrophy over time. These findings suggest that plasma Aβ measures alone may not reliably reflect longitudinal regional neurodegeneration in early AD. Show less

Early diagnosis of Alzheimer's disease (AD), particularly during its preclinical and prodromal phases, remains a major challenge. Plasma biomarkers such as phosphorylated tau at threonine 217 (p-tau217), amyloid-β (Aβ) isoforms, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) show promise for early detection; however, their relationships with medial temporal lobe (MTL) subfield atrophy and potential inter-biomarker pathways remain unclear. This study aimed to address this gap by investigating the associations between plasma biomarkers and MTL subfield atrophy, and by assessing potential mediation pathways. We conducted a cross-sectional study using data from 330 participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI), including cognitively normal (CN) and mild cognitive impairment (MCI) groups. High-resolution coronal T2-weighted MRI quantified MTL subfield volumes using the ASHS protocol. Plasma biomarkers were measured using ultrasensitive immunoassays. The cohort included 209 CN participants (mean age [SD] = 69.3 [6.9] years; 64.2% women; 24.4% APOE ε4 carriers) and 121 MCI participants (mean age [SD] = 71.3 [7.3] years; 48.8% women; 27.9% APOE ε4 carriers). MCI individuals showed significantly higher plasma concentrations of p-tau217, p-tau217/Aβ Show less

White matter hyperintensity (WMH), indicative of cerebral small vessel disease, has emerged as a potential biomarker for cognitive decline in Alzheimer's disease (AD). However, their predictive role across specific cognitive domains within the AD spectrum remains unclear. This study investigates the relationship between WMH volume and cognitive performance in memory, executive function, and language across the AD continuum. A cross-sectional analysis was conducted using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), comprising 557 participants categorized into cognitively normal (CN; n = 158), mild cognitive impairment (MCI; n = 334), and Alzheimer's dementia (AD; n = 65) groups. Cognitive function was assessed using composite scores for memory (ADNI-MEM), executive function (ADNI-EF), and language (ADNI-LAN). WMH volume was quantified through validated Bayesian segmentation of MRI data. Associations between cognitive scores and WMH volume, adjusted for age, gender, APOE ε4 status, and vascular risk factors, were evaluated via multiple linear regression analyses. WMH volume showed numerically progressive increases from CN to MCI and AD groups; however, between-group differences did not reach statistical significance. Within the MCI group, significant negative associations emerged between WMH volume and memory (β=-0.13, adjusted p = 0.045) and language scores (β=-0.12, adjusted p = 0.045). Conversely, these relationships were absent in both the CN and AD groups. WMH volume relates specifically to declines in memory and language abilities, particularly in individuals with MCI. These results support using WMH measurements as early markers to identify cognitive decline in AD, potentially helping to guide earlier diagnosis and treatment decisions. Show less

Autophagy is a homeostatic process that can promote cell survival or death. However, the exact role of autophagy in Clostridioides difficile infection (CDI) is still not precisely elucidated. Here, we investigate the role of distinct C. difficile ribotypes (RTs) in autophagy induction using Caco-2 cells. The expression analysis of autophagy-associated genes and related miRNAs were examined following treatment of Caco-2 cells with C. difficile after 4 and 8 h using RT-qPCR. Toxin production was assessed using enzyme-linked immunosorbent assay (ELISA). Immunofluorescence analysis was performed to detect MAP1LC3B/LC3B, followed by an autophagic flux analysis. C. difficile significantly reduced the viability of Caco-2 cells in comparison with untreated cells. Elevated levels of LC3-II and SQSTM1/p62 by C. difficile RT001 and RT084 in the presence of E64d/leupeptin confirmed the induction of autophagy activity. Similarly, the immunofluorescence analysis demonstrated that C. difficile RT001 and RT084 significantly increased the amount of LC3-positive structures in Caco-2 cells. The induction of autophagy was further demonstrated by increased levels of LC3B, ULK1, ATG12, PIK3C3/VPS34, BECN1 (beclin 1), ATG5, and ATG16L1 transcripts and reduced levels of AKT and MTOR gene expression. The expression levels of MIR21 and MIR30B, microRNAs that suppress autophagy, were differentially affected by C. difficile. In conclusion, the present work revealed that C. difficile bacteria can induce autophagy through both toxin-dependent and -independent mechanisms. Also, our results suggest the potential role of other C. difficile virulence factors in autophagy modulation using intestinal cells in vitro. Show less

Non-alcoholic fatty liver disease (NAFLD) comprises a range of chronic liver diseases that result from the accumulation of excess triglycerides in the liver, and which, in its early phases, is categorized NAFLD, or hepato-steatosis with pure fatty liver. The mortality rate of non-alcoholic steatohepatitis (NASH) is more than NAFLD; therefore, diagnosing the disease in its early stages may decrease liver damage and increase the survival rate. In the current study, we screened the gene expression data of NAFLD patients and control samples from the public dataset GEO to detect DEGs. Then, the correlation betweenbetween the top selected DEGs and clinical data was evaluated. In the present study, two GEO datasets (GSE48452, GSE126848) were downloaded. The dysregulated expressed genes (DEGs) were identified by machine learning methods (Penalize regression models). Then, the shared DEGs between the two training datasets were validated using validation datasets. ROC-curve analysis was used to identify diagnostic markers. R software analyzed the interactions between DEGs, clinical data, and fatty liver. Ten novel genes, including ABCF1, SART3, APC5, NONO, KAT7, ZPR1, RABGAP1, SLC7A8, SPAG9, and KAT6A were found to have a differential expression between NAFLD and healthy individuals. Based on validation results and ROC analysis, NR4A2 and IGFBP1b were identified as diagnostic markers. These key genes may be predictive markers for the development of fatty liver. It is recommended that these key genes are assessed further as possible predictive markers during the development of fatty liver. Show less

Our primary aim was to assess the effects of two different training modalities: sprint interval training (SIT) or combined aerobic and resistance training (A + R) on circulating myokines related to metabolic profile and adiposity in type 2 diabetes (T2D). Fifty-two overweight women with T2D [55 ± 6 yrs., BMI 28.9 ± 4.1 kg/m Show less