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Background: Neurodegenerative pathologies, including tau depositions, have been implicated in late‐onset depression (LOD), while there is a lack of in‐vivo evidence for the neuropathological basis of late‐onset bipolar disorder (LOBD) despite postmortem findings of cerebral tau accumulations. The current study aimed to assess tau pathologies in LOBD and LOD patients positron emission tomography (PET) with 18F‐florzolotau, a radioligand for Alzheimer's disease (AD) and non‐AD tau fibrils. Methods: We studied LOBD and LOD patients who developed the first episode of mania or depression after age 45. Twenty‐one patients with LOBD (68.8 ± 9.6 years old; 11 females), 15 patients with LOD (73.0 ± 5.8 years old; 11 females), and 39 age‐matched healthy controls (HCs) (67.1 ± 9.1 years old; 19 females) underwent tau and amyloid PET scans with 18F‐florzolotau and 11C‐PiB, respectively. Amyloid positivity was determined by a visual read of 11C‐PiB‐PET images, and tau depositions were assessed by calculating standardized uptake value ratios (SUVRs) in 52 regions covering the cerebral grey matter and basal ganglia to the optimized reference tissue. All SUVRs were corrected for age and sex and converted to Z‐score relative to HCs. The positivity and topology of tau pathologies were determined according to the presence of a region with a Z‐score ≥ 2.0. Results: 18F‐florzolotau‐PET positivity was observed in 13 LOBD (62%), 7 LOD (47%), and 11 HC (28%) subjects, whereas 4 LOBD, 4 LOD, and no HC individuals were 11C‐PiB‐PET‐positive. A significant difference in the prevalence of tau pathologies was only found between LOBD and HCs (P = 0.043, corrected for multiple comparisons). Tau topologies in the cases with 11C‐PiB‐PET‐positive AD pathologies consisted of predominant frontal (1 LOBD and 3 LODs), lateral temporal (3 LOBDs and 1 LOD), and posterior (1 LOBD) accumulations. Meanwhile, tau pathologies in 11C‐PiB‐negative cases showed predominant frontal (2 LOBDs and 1 LOD), temporal (1 LOBD and 1 LOD), posterior (4 LOBDs and 1 LOD), and basal ganglia (2 LOBDs) localizations. Conclusion: Our findings suggest that a significant subset of LOBD patients harbor tau lesions linked to various AD subtypes and non‐AD tauopathies indicative of distinct early‐stage frontotemporal lobar degeneration subcategories. [ABSTRACT FROM AUTHOR]

Background: Chronic traumatic encephalopathy (CTE), formerly known as "boxer's encephalopathy" is a neurodegenerative disease associated with mild‐repetitive TBI. CTE is characterized by the deposition of hyperphosphorylated tau as neurofibrillary tangles around small blood vessels of the cortex, typically at the sulcal depths. Although tau PET studies on American football players reported findings consistent with neuropathological changes identified by postmortem brains, there are no reports of tau PET studies in boxers, and longitudinal changes of tau depositions following boxing remains unknown. The present study was aimed to characterize cerebral retention patterns of 18F‐florzolotau (18F‐APN‐1607) in the former professional boxers. Method: Twenty‐nine former boxers (43.4 ± 10.3 years) and 27 age‐matched healthy control (HC) subjects underwent PET scans with 18F‐florzolotau and 11C‐PiB. Eleven former boxers underwent a second tau PET scan (average interval: 874days). Standard uptake value ratio (SUVR) with the optimized reference tissue was calculated. Regions of interest were defined on brain regions of the gray matter (GM), white matter (WM) and the gray‐white matter boundary (GWB). Association of regional SUVR values with neurocognitive symptoms and various indexes related boxing was investigated. Result: One boxer was [11C]PiB positive. Former boxers showed higher 18F‐florzolotau retentions than HC subjects in the bilateral frontal GM, right parietal GM, bilateral frontal WM, right parietal WM (P < 0.001). There was a significant correlation between SUVR values in the whole GM and the total number of bouts (p = 0.07,r = 0.40). Subtyping using z‐score heatmap with predetermined criteria revealed heterogeneity in 18F‐florzolotau retention patterns in boxers. Of the 29 boxers, (1) 10 showed increased retention of 18F‐florzolotau in GM (GM dominant), (2) 4 showed increased accumulation mainly in WM (WM dominant), (3) 5 showed increased accumulation in GWB (GWB dominant), and (4) 10 showed no significant increased accumulation in the brain (No tau). These types vary in longitudinal changes of 18F‐florzolotau retention patterns, as well as in clinical features. Conclusion: The present study not only supports pathological heterogeneity of late‐sequalae of professional boxing, but also suggests utility of 18F‐florzolotau PET in detection of late‐life neurodegenerative diseases following mild‐repetitive TBI. [ABSTRACT FROM AUTHOR]

Background: We recently developed a positron emission tomography (PET) probe, [18F]PM‐PBB3, to detect tau lesions in diverse tauopathies, including mixed three‐repeat and four‐repeat (3R + 4R) tau fibrils in Alzheimer's disease (AD) and 4R tau aggregates in progressive supranuclear palsy (PSP). For wider availability of this technology for clinical settings, bias‐free quantitative evaluation of tau images without a priori disease information is needed. Objective: We aimed to establish tau PET pathology indices to characterize PSP and AD using a machine learning approach and test their validity and tracer capabilities. Methods: Data were obtained from 50 healthy control subjects, 46 patients with PSP Richardson syndrome, and 37 patients on the AD continuum. Tau PET data from 114 regions of interest were subjected to Elastic Net cross‐validation linear classification analysis with a one‐versus‐the‐rest multiclass strategy to obtain a linear function that discriminates diseases by maximizing the area under the receiver operating characteristic curve. We defined PSP‐ and AD‐tau scores for each participant as values of the functions optimized for differentiating PSP (4R) and AD (3R + 4R), respectively, from others. Results: The discriminatory ability of PSP‐ and AD‐tau scores assessed as the area under the receiver operating characteristic curve was 0.98 and 1.00, respectively. PSP‐tau scores correlated with the PSP rating scale in patients with PSP, and AD‐tau scores correlated with Mini‐Mental State Examination scores in healthy control–AD continuum patients. The globus pallidus and amygdala were highlighted as regions with high weight coefficients for determining PSP‐ and AD‐tau scores, respectively. Conclusions: These findings highlight our technology's unbiased capability to identify topologies of 3R + 4R versus 4R tau deposits. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society [ABSTRACT FROM AUTHOR]

Background: Several cohort studies have recently reported associations between late‐life psychosis and dementia, and postmortem studies have demonstrated that most individuals with late‐onset schizophrenia and delusional disorder had tau pathologies. The present study was aimed to assess the prevalence and topology of tau pathologies by positron emission tomography (PET) with a specific probe, 18F‐PM‐PBB3 (18F‐APN‐1607), in patients with late‐onset psychosis (LOP). Method: We included LOP patients who experienced the first episode of psychosis after 65 years old and excluded those with dementia. Fourteen patients with LOC (74.2 ± 4.0 years old; 7 females and 7 males)and 16 age‐matched healthy controls (HCs) (72.6 ± 5.7 years old; 9 females and 7 males) underwent PET scans with 18F‐PM‐PBB3 and an amyloid‐β probe, 11C‐PiB. The radioprobe retention was calculated as standardized uptake value ratio (SUVR), and the laterality index (LI) of SUVR was estimated as [Left‐Right/(Left+Right)]. We compared 18F‐PM‐PBB3 SUVRs and LIs in the frontal, temporal, parietal, and occipital cortices between patients and HCs using an independent t‐test after Bonferroni correction (p‐value ≤ 0.05/4). Result: All HCs were negative for 11C‐PiB‐PET. By contrast, unequivocally increased 18F‐PM‐PBB3 retentions were found in 4 out of 4 11C‐PiB‐positive patients (100%) and 7 out of 10 11C‐PiB‐negative patients (70%) with variable localizations. Tau topologies in four 11C‐PiB‐positive cases were characteristic of Alzheimer's disease and consisted of limbic predominant (N = 2), medial temporal lobe‐sparing (N = 1), and lateral temporal (N = 1) deposition subtypes. Meanwhile, tau topologies in 7 11C‐PiB‐negative cases were composed of lateral‐posterior diffuse (N = 3), posterior mild (N = 2), lateral temporal local (N = 1), and progressive supranuclear palsy‐like (N = 1) accumulations. None of the target regions exhibited significant differences in 18F‐PM‐PBB3 SUVR between patients and HCs, reflecting the heterogeneous distributions of tau deposits in patients. There was significant rightward lateralization of tau pathologies indicated by a reduced LI in the frontal cortex (P = 0.0093) but not the other cortical regions. Conclusion: Our findings indicate that LOP is associated with tau topologies of diverse Alzheimer's and non‐Alzheimer's disease subtypes. The rightward lateralization of tau pathologies in the frontal cortex might be involved in the development of psychotic manifestations. [ABSTRACT FROM AUTHOR]

Background: We recently developed a positron emission tomography (PET) probe, [ 18 F]PM-PBB3, to detect tau lesions in diverse tauopathies, including mixed three-repeat and four-repeat (3R + 4R) tau fibrils in Alzheimer's disease (AD) and 4R tau aggregates in progressive supranuclear palsy (PSP). For wider availability of this technology for clinical settings, bias-free quantitative evaluation of tau images without a priori disease information is needed., Objective: We aimed to establish tau PET pathology indices to characterize PSP and AD using a machine learning approach and test their validity and tracer capabilities., Methods: Data were obtained from 50 healthy control subjects, 46 patients with PSP Richardson syndrome, and 37 patients on the AD continuum. Tau PET data from 114 regions of interest were subjected to Elastic Net cross-validation linear classification analysis with a one-versus-the-rest multiclass strategy to obtain a linear function that discriminates diseases by maximizing the area under the receiver operating characteristic curve. We defined PSP- and AD-tau scores for each participant as values of the functions optimized for differentiating PSP (4R) and AD (3R + 4R), respectively, from others., Results: The discriminatory ability of PSP- and AD-tau scores assessed as the area under the receiver operating characteristic curve was 0.98 and 1.00, respectively. PSP-tau scores correlated with the PSP rating scale in patients with PSP, and AD-tau scores correlated with Mini-Mental State Examination scores in healthy control-AD continuum patients. The globus pallidus and amygdala were highlighted as regions with high weight coefficients for determining PSP- and AD-tau scores, respectively., Conclusions: These findings highlight our technology's unbiased capability to identify topologies of 3R + 4R versus 4R tau deposits. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

The status of ascorbic acid (AA) in dialysis patients is the subject of debate. Some reports have found AA to be deficient in dialysis patients, while others have found that AA is not deficient. In an attempt to confirm AA serum concentrations in dialysis patients, we analyzed the concentrations of AA as well as its metabolites using the specific determination of AA with chemical derivatization and the HPLC method. We studied 131 patients under maintenance hemodialysis therapy (HD), 23 patients with chronic renal failure (CRF) and 48 healthy controls (C). Serum concentrations of AA and the AA metabolites dehydroascorbic acid (DHA) and 2, 3-diketogulonate (DKG) were measured by HPLC. Nine HD patients were taking AA supplements. Seventy-six (62.3%) of the 122 HD patients not taking AA supplements exhibited deficient levels of AA (< 20 microM), while 13 (56.5%) of the 23 CRF patients and 9 (18.8%) of the 48 C showed deficient levels of AA. Analysis of AA metabolites in the normal-range AA (20-80 microM) group revealed that the DHA/AA ratio in HD patients was significantly higher than in C (3.3 +/- 2.6% and 1.2 +/- 2.2%, respectively). The DKG/AA ratio in HD patients was higher than in CRF patients (3.6 +/- 5.2% vs. 0.9 +/- 1.9%), whereas DKG was not detected in C. When compared to serum levels before the start of dialysis, serum AA, DHA and DKG concentrations at the end of the dialysis session decreased by an average of 74.2, 84.0 and 78.8% respectively. In HD patients, serum levels of thiobarbituric reactive substances (TBARS) were significantly lower in the higher AA (> 80 microM) group than in the deficient and normal-range AA groups. In 12 AA-deficient patients, after 1 month of taking AA supplements (200 mg/day), serum AA levels rose to 79.9 microM, while serum TBARS level declined when compared with levels before supplementation. In conclusion, the frequency of AA deficiency in dialysis patients is extremely high. AA deficiency in HD patients may result in high TBARS levels, which reflect increased oxidative stress. Adequate AA supplementation should therefore be considered in such patients.