Author

E. Dursun

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Jul 2026

Serum hypoxia-inducible factors, heat shock proteins, and mitochondrial biomarkers in relation to neurocognitive performance in obstructive sleep apnea: a cross-sectional study.

STUDY OBJECTIVES Obstructive sleep apnea(OSA) is linked to impaired cognitive functions through a variety of underlying mechanisms. We investigated possible hypoxic, inflammatory and mitochondrial mediators of cognitive dysfunction in OSA. METHODS We prospectively enrolled 146 adult patients with OSA and 103 healthy controls. We analyzed demographic and clinical data, neurocognitive assessments by a set of cognitive batteries(Montreal Cognitive Assessment[MoCA], Digit Span Test[backward/forward], and Stroop test), and full night polysomnography(PSG) recordings. We also analyzed biochemical parameters including hypoxia-induced factors(HIF-1α,HIF-2α), interleukin-6, tumor necrosis factor-alpha(TNF-α), alpha-enolase(Eno1), and members of heat shock proteins-70 family(HspA1A,HspA8) by the ELISA method. mtDNA copy number was measured and mRNA expressions of peroxisome proliferator-activated receptor gamma coactivator-1-alpha(PGC-1α) and mitochondrial transcription factor-A(TFAM) were determined. RESULTS Mean age was similar between groups, while male-to-female ratio and body mass index(BMI) were significantly higher in patients with OSA, for which all statistical analyses were corrected. We observed positive correlations between HIF-1α and average time/number of errors in Stroop test; Eno1 and number of errors in Stroop test; HSPA1A and average time in Stroop test; mtDNA copy number and numbers in DST-backward. Negative correlations were observed between HIF-2α and MoCA; TNF-α and number of errors in Stroop test; Eno1 and numbers in DST-backward; HSPA1A and MoCA. Of PSG parameters, WASO negatively correlated with mtDNA copy number; duration of REM-sleep positively correlated with PPARGC1A-mRNA expressions; apnea-hypopnea index negatively correlated with HIF-1α. CONCLUSIONS Our results demonstrated complex and important correlations between neurocognitive assessments and mediators of hypoxia, inflammation, protein misfolding, and mitochondrial trafficking, which may serve as biochemical biomarkers of cognitive impairment in OSA.

G. Şenel, Pelin Sordu, M. Sahin et al. · Sleep Medicine · 0 citations

Aug 2026

Prognostic significance of cerebrospinal fluid tau biomarkers in amyloid-negative A-T + N + neurodegeneration: A retrospective cohort study.

BackgroundAmyloid-negative tau-related neurodegeneration represents a non-Alzheimer biomarker-defined profile; however, its clinical heterogeneity and prognostic relevance remain unclear within Alzheimer's disease-related frameworks.ObjectiveTo characterize the clinical spectrum and identify predictors of mortality in patients with this profile.MethodsIn this retrospective cohort study, 1280 patients evaluated at a tertiary neurology center were screened, and 130 with an amyloid-negative cerebrospinal fluid (CSF) pattern [amyloid-β (Aβ)42 normal, phosphorylated tau (pTau), and total tau (tTau) elevated] were included. Survival was assessed using Kaplan-Meier analysis, and predictors of mortality were evaluated using Cox models.ResultsThe cohort (mean age 68.8 ± 10.1 years; 45.4% female) showed heterogeneous diagnoses, mainly mild cognitive impairment and frontotemporal dementia (each 30%). Survival differed across diagnostic groups (log-rank p = 0.037), with more favorable outcomes in mild cognitive impairment. Male sex was more frequent among non-survivors (88.9% versus 45.6%, p < 0.001). Higher CSF tTau levels were associated with mortality in the joint Cox model (HR 1.003, 95% CI 1.001-1.006, p = 0.006) and faster clinical progression (r = 0.22, p = 0.011). When modeled separately, neither tTau nor pTau was independently associated with mortality; however, both became significant in opposite directions when included jointly.ConclusionsThe amyloid-negative A-T + N + profile represents a clinically heterogeneous subgroup with prognostic relevance. CSF tTau was associated with mortality and faster clinical progression, but the joint-model findings involving tTau and pTau should be interpreted cautiously as hypothesis-generating. Further studies are needed to clarify the prognostic value of tau-related biomarkers in this population.

Aslı Aksoy Gündoğdu, B. Samancı, M. Alaylıoğlu et al. · Journal of Alzheimer's Disea... · 0 citations