The blood-based diagnosis has a potential to provide an alternative approach for easy diagnosis of Alzheimer’s disease (AD) with less invasiveness and low-cost. However, present blood-based AD diagnosis mainly focuses on measuring the plasma Aβ level because no other biomarkers are found to possess evident transport mechanisms to pass the blood-brain barrier. In order to avoid diagnosing non-demented individuals with Aβ abnormality, finding additional biomarkers to supplement plasma Aβ is essential. In this study, we introduce potential neurodegenerative biomarkers for blood-based diagnosis. We observed severe splenomegaly and structural destruction in the spleen with significantly decreased B lymphocytes in senile APPswe, PS1M146V and TauP301L transgenic mice. We also found that inflammatory cytokines associated with splenic dysfunction were altered in the plasma of these mice. These findings suggest potential involvement of the splenic dysfunction in AD and the importance of biomarker level alterations in the plasma as putative diagnostic targets for AD.

Amyloid-β (Aβ) plays a critical role as a biomarker in Alzheimer’s disease (AD) diagnosis. In addition to its diagnostic potential in the brain, recent studies have suggested that changes of Aβ level in the plasma can possibly indicate AD onset. In this study, we found that plasma Aβ(1–42) concentration increases with age, while the concentration of Aβ(1–42) in the cerebrospinal fluid (CSF) decreases in APPswe, PS1M146V and TauP301L transgenic (3xTg-AD) mice, if measurements were made before formation of ThS-positive plaques in the brain. Our data suggests that there is an inverse correlations between the plasma and CSF Aβ(1–42) levels until plaques form in transgenic mice’s brains and that the plasma Aβ concentration possesses the diagnostic potential as a biomarker for diagnosis of early AD stages.

1606 Background: While the COVID pandemic elevated the usage of telehealth to unprecedented levels, it remains unclear whether telehealth use is sustained after the initial pandemic era, and whether there remain demographic differences in telehealth utilization. In this study, we compared telehealth trends amongst different demographic populations in a large integrated healthcare system. Methods: Utilization of various visit types (office, video, telephone) was investigated in this population-based retrospective cohort study at 22 Kaiser Permanente Northern California Hematology and Oncology clinics from 10/1/2020 to 6/1/2022. We explored trends associated with the COVID 19 pandemic and after the initial pandemic era as well as demographic differences, using Chi-square for categorical and the Mann-Whitney U Test for non-parametric comparisons. Results: During the study period, there were 341,089 hematology/oncology visits with MD/DO providers, including 83,756 (24.5%) office, 125,162 (36.7%) video, and 132,171 (38.7%) telephone. Total monthly visits remained stable, with a monthly average of 1,765 (10.9%) for new visits and 14,476 (89.1%) for return visits. Monthly telehealth visits (telephone + video) peaked in January, 2021 (85.6% of total visits) and subsequently declined by June, 2022 (68.7% of total visits). Telephone visits increased from 46.1% of telehealth visits to 58.9% over the study period. Amongst telehealth visits, video visits remained popular for new appointments (56.9%) while telephone visits were more common for return appointments (60.7%). After the initial pandemic era, telehealth utilization continued to differ amongst different demographic populations. Video visits remained a significantly higher fraction of all visits (p<0.01) in: (1) less than 45 year-old (60.0%) compared to older than 80 year-old (33.2%); (2) primary English speakers (50.7%) compared to those who require an interpreter (41.5%); (3) patients with commercial insurance (58.2%) compared to those with Medicaid (47.0%) or Medicare (45.2%); (4) non-Hispanic Whites (51.4%) and Asians (52.2%) compared to Hispanic Whites (45.0%) and Blacks (43.6%); (5) patients with the lowest neighborhood deprivation index (NDI) quartile (living in the least deprived neighborhood) (54.0%) vs the highest quartile (46.1%). Conclusions: After the initial pandemic era, telehealth utilization declined slightly over time but remained a common method of providing oncology care. Video visits continued to be widely utilized for initial visits whereas there was a shift to telephone visits for follow up appointments over time. Disparities in telehealth, especially in video visits, continued to be seen in various demographic populations by age, English proficiency, insurance plan, race/ethnicity and neighborhood deprivation index. Continued high utilization of telehealth should inform policy and practices in the post-pandemic era.