👤 Mohammad Hossein Ghahremani

BackgroundFunctional independence is crucial for healthy aging, and its loss is a diagnostic criterion for dementia, including Alzheimer's disease. However, functional impairment (FI) can emerge before dementia diagnosis. Early and accurate characterization of FI may help identify individuals at elevated risk of cognitive decline and dementia.ObjectiveExploring the utility of capturing persistent versus impersistent FI, to identify a higher-risk group for incident cognitive decline and dementia.MethodData from 11,793 cognitively normal (CN) older adults from the National Alzheimer's Coordinating Center were analyzed. Exploratory factor analysis identified four Functional Activities Questionnaire items-preparing hot drinks, preparing balanced meals, shopping, and traveling-representing primarily functional abilities. An FI composite score was calculated as the sum of these items. Persistent FI was operationalized as FI present (composite score ≥ 2) at more than two-thirds of all visits prior to cognitive decline and dementia. Comparator groups were impersistent/transient FI and no FI. Time-dependent covariate Cox models compared incidence of cognitive decline and dementia across time-dependent FI groups, adjusted for demographics, Show less

Functional impairment (FI) is a key criterion for diagnosing dementia. However, subtle functional changes may occur during preclinical and prodromal phases but may not be accurately characterized. Furthermore, research linking FI to Alzheimer disease (AD) biofluid biomarkers is limited. Here we examined cross-sectional associations between cerebrospinal fluid (CSF) AD biomarkers and persistent versus transient FI in dementia-free older adults, and the longitudinal association of FI with incident dementia. Data from 1000 participants (age 72.9 ± 7.0; 45.2% female; 62.8% MCI) from the Alzheimer's Disease Neuroimaging Initiative were analyzed. CSF biomarkers included p-tau181, Aβ42, and ptau-181/Aβ42 ratio. Three Functional Activities Questionnaire items of "preparing a hot beverage," "preparing a balanced meal," and "shopping alone" were identified by factor analysis as assessing function rather than cognition directly. Persistent-FI was operationalized as FI present at> two-thirds of pre-dementia visits. Comparator groups included Transient-FI and No-FI. Linear regression modeled the association between FI status and baseline biomarker levels, while Cox regression assessed the association between FI and incident dementia. Models adjusted for age, sex, education, APOE-ε4 status, and MMSE. Compared to No-FI, Persistent-FI was associated with lower Aβ42 (Beta = -8.93; 95% CI: -13.56 to -4.03; p < 0.001), higher p-tau181 (Beta = 10.81; 95% CI: 0.44-22.26; p = 0.041), and ptau181/Aβ42 ratio (Beta = 21.66; 95% CI: 7.02-38.31; p = 0.003). In contrast, Transient-FI showed no significant associations. APOE-ε4 carrier status was more prevalent in the Persistent-FI group compared to No-FI (p = 0.009), but not in Transient-FI (p = 0.931). Compared to No-FI, Persistent-FI had a 6.66-fold greater dementia incidence rate (95% CI: 4.98-8.91, p < 0.001), while Transient-FI had a 1.72-fold greater incidence rate (95% CI: 1.09-2.72, p = 0.021). Findings extend the limited research on the association of FI with CSF AD biomarkers in dementia-free populations. Operationalizing FI-related risk by persistence enhances prognostication, identifying individuals with greater AD pathology and progression risk. This approach could enhance screening, early detection, and risk stratification, informing timely interventions before dementia onset. Show less

Acute Respiratory Distress Syndrome is a lung disorder defined by the acute onset of hypoxemia, the commonest being abdominal sepsis.Many biomarkers have been studied for diagnostic prognostication and ARDS pharmacotherapy. The current study aim to assess the protective effects of UFH versus Enoxaparin in sepsis-induced ARDS and related metabolic sequelae. Sepsis was initiated through cecal ligation and puncture (CLP). Wistar rats were divided to: sham, CLP, CLP + unfractionated Heparin, and CLP + Enoxaparin and CLP + distilled water groups. Levels of serum Lipoxin A4 (LXA4), lipoprotein lipase (LPL), leukotriene E4 (LTE4), leukotriene B4 (LTB4), interleukin-8 (IL-8), were quantified. Furthermore, mRNA expression of receptors for advanced glycation end products (RAGE) and angiopoietin-2 (ANG-2) were assessed. Histopathological study was conducted to assess any lung injuries. Septic rats demonstrated higher levels of leukotriene E4, leukotriene B4, and interleukin-8, while treatment with unfractionated Heparin attenuated these levels but enoxaparin effectiveness on LTB-4 and IL-8 was not as significant as heparin while its was equally effective on LTE-4. Moreover, mRNA levels of RAGE and ANG-2 were enhanced in CLP rats. These elevations were mitigated by treatment with unfractionated Heparin and reduced by enoxaparin to a lesser extent. Treatment with unfractionated Heparin increased the lipoxin A4 and lipoprotein lipase levels but enoxaparin had no effect on the LPL level. Lung protective effect of unfractionated Heparin was further confirmed by histopathological observations of lung tissue samples. Our study demonstrates that UFH can modulate ARDS and metabolic dysfunction in hyperinflammatory conditions like sepsis. Show less

To identify novel regulators of Galpha(o), the most abundant G-protein in brain, we used yeast two-hybrid screening with constitutively active Galpha(o) as bait and identified a new regulator of G-protein signaling (RGS) protein, RGS17 (RGSZ2), as a novel human member of the RZ (or A) subfamily of RGS proteins. RGS17 contains an amino-terminal cysteine-rich motif and a carboxyl-terminal RGS domain with highest homology to hRGSZ1- and hRGS-Galpha-interacting protein. RGS17 RNA was strongly expressed as multiple species in cerebellum and other brain regions. The interactions between hRGS17 and active forms of Galpha(i1-3), Galpha(o), Galpha(z), or Galpha(q) but not Galpha(s) were detected by yeast two-hybrid assay, in vitro pull-down assay, and co-immunoprecipitation studies. Recombinant RGS17 acted as a GTPase-activating protein (GAP) on free Galpha(i2) and Galpha(o) under pre-steady-state conditions, and on M2-muscarinic receptor-activated Galpha(i1), Galpha(i2), Galpha(i3), Galpha(z), and Galpha(o) in steady-state GTPase assays in vitro. Unlike RGSZ1, which is highly selective for G(z), RGS17 exhibited limited selectivity for G(o) among G(i)/G(o) proteins. All RZ family members reduced dopamine-D2/Galpha(i)-mediated inhibition of cAMP formation and abolished thyrotropin-releasing hormone receptor/Galpha(q)-mediated calcium mobilization. RGS17 is a new RZ member that preferentially inhibits receptor signaling via G(i/o), G(z), and G(q) over G(s) to enhance cAMP-dependent signaling and inhibit calcium signaling. Differences observed between in vitro GAP assays and whole-cell signaling suggest additional determinants of the G-protein specificity of RGS GAP effects that could include receptors and effectors. Show less