Citations

AbstractBackgroundThe brainstem nucleus incertus (NI) or ‘uncertain nucleus’, was originally described by Streeter in 1903 as a midline region in the floor of the fourth ventricle of the human brain with an ‘unknown’ function. A century later, the NI has been shown to play a key role in memory formation in rodents, through direct and indirect inhibition of the hippocampus; and the anatomy of the NI and its projections throughout the brain have been systematically mapped in rats, mice, and primates, but not in humans. In these novel studies, we mapped the human NI using the neuropeptide, relaxin‐3 (RLN3), as neurochemical marker. In rodents, RLN3 is produced mostly in NI neurons with some subsidiary positive cells in the periaqueductal gray and an area dorsal to the substantia nigra.MethodsSerial, free‐floating coronal sections of formalin‐fixed postmortem tissue were prepared from the pons of an adult female (aged 96 years) without a history of dementia or other neurological disorders, provided by the Banner Brain and Body Donation Program, Sun City, Arizona, USA. Using immunohistochemistry, we first identified the NI by mapping the distribution of microtubule‐associated protein‐2 (MAP2) and RLN3. The specificity of the RLN3 antibody used was verified in a dot‐blot using native RLN3 peptide. We also investigated the presence of markers detected in the NI of rats ‐ glutamic acid dehydrogenase‐65/67 (GAD65/67) and corticotropin‐releasing factor type 1 receptor (CRF1); and used a phosphorylated‐tau (AT8) to determine if the NI displayed tau accumulation.ResultsDetection of MAP2‐immunoreactivity revealed the neuronal distribution throughout the pons. RLN3‐immunoreactivity was detected in neurons in the dorsal, anterior‐medial region, revealing the broad anatomy of the human NI. Neurons within this same area were also positive for GAD65/67‐ and CRF1‐immunoreactivity, in line with previous studies; and AT8‐immunoreactivity was also detected.ConclusionsRLN3 is present in neurons of the human NI and aspects of its anatomy are shared across species, including the macaque. Accumulation of phosphorylated‐tau in the NI suggests its possible involvement in the pathology of Alzheimer’s disease and related dementias. Further comparative studies are required to better understand the neurochemical anatomy of the human NI.

AbstractBackgroundPredictive models of tau‐PET accumulation have largely relied on the functional connectome to estimate its spatial patterns in Alzheimer’s disease (AD). Patterns of global functional organization represent a promising avenue as they encapsulate many biological properties relevant to neurodevelopment, cognition and degeneration. We compared approaches based on local connectivity (from task‐free fMRI) and global organization (from FDG‐PET) to predict regional tau‐PET across AD phenotypes.MethodWe included 430 cognitively unimpaired (CU) individuals (214 A+T‐, 216 A+T+) and 62 amnestic mild cognitive impairment (aMCI), 64 amnestic AD, 21 dysexecutive AD (dAD), 41 logopenic progressive aphasia (LPA) and 49 posterior cortical atrophy (PCA) patients (all A+T+) from the Alzheimer’s Disease Research Center, Mayo Clinic Study of Aging, and Neurodegenerative Research Groups (referred to as “Mayo cohort”). The connectivity approach consisted of assessing the relationship between a region’s tau level and its functional connectivity to the region of highest tau (epicenter). The global organization approach consisted of 1) performing a principal component analysis on 3000 FDG‐PET images that did not overlap with the Mayo cohort, 2) projecting FDG‐PET images of the Mayo cohort onto the low‐dimensional space generated in Step 1 and extracting corresponding weighted values across the first 100 components, 3) using these weighted values as predictors of regional tau‐PET in a linear model and determining optimal parameters based on predicted R2 values, and 4) using the parameters from the model built in Step 3 to predict tau‐PET in the ADNI cohort (n = 86) (Fig.2).ResultThe connectivity‐based approach yielded adjusted R2 values ranging from 0.19‐0.45 across diagnostic groups (Fig.1). The global organization approach yielded averaged adjusted R2 and predicted R2 values of 0.71 and 0.63, respectively, in the Mayo cohort. Out‐of‐sample median R2 in the ADNI cohort was 0.41 (range 0.10‐0.60) (Fig.3).ConclusionAn unbiased approach based on the global functional organization of the brain and using an imaging modality widely used in clinical settings outperformed a connectome‐based one to predict regional tau‐PET across the AD phenotypic spectrum. Patterns of tau accumulation may better relate to the large‐scale physiology of the brain underlying specific mental functions rather than local connectivity factors.

AbstractBackgroundDisruption of default mode network (DMN) connectivity is common in Alzheimer’s disease. We investigated cross‐sectional and one‐year longitudinal changes in DMN sub‐systems in atypical clinical presentations of AD, in relation to age and tau.MethodSixty‐four amyloid‐positive atypical AD (Aty‐AD) patients diagnosed with posterior cortical atrophy (n = 35) or logopenic progressive aphasia (n = 29) were recruited by the Neurodegenerative Research Group. Patients underwent structural and resting‐state functional MRI, and [18F]flortaucipir PET at baseline and one‐year follow‐up. 140 amyloid‐negative cognitively unimpaired (CU) individuals from the Mayo Clinic Study of Aging were included as controls. Global tau SUVR was calculated in a meta‐ROI including parietal, temporal, and occipital regions. DMN connectivity was calculated in native space for posterior (pDMN), ventral (vDMN), anterior ventral (avDMN) and anterior dorsal (adDMN) DMN sub‐systems using the dual regression method. A global measure of DMN connectivity, the Network Failure Quotient (NFQ), was calculated as (vDMN_to_pDMN+ adDMN_to_pDMN)/(pDMN+vDMN). Linear mixed‐effects models were computed for each DMN connectivity measure, including diagnosis (Aty‐AD, CU), age, time and their interaction, and a per‐person random effect. SPM paired t‐tests were run to compare baseline and follow‐up images in Aty‐AD and CU separately. Linear mixed‐effect models were run in the Aty‐AD cohort only to investigate the effect of global baseline tau SUVR on each DMN connectivity measure.ResultMixed‐effects models showed evidence of lower cross‐sectional pDMN and higher adDMN connectivity in Aty‐AD relative to CU, with no significant time effects (Fig. 1). While connectivity in all DMN sub‐systems declined with age in CU, connectivity was higher in older Aty‐AD patients relative to younger, particularly in vDMN and pDMN. A similar trend was observed for NFQ, which was significantly higher in Aty‐AD, with a negative age effect (Fig. 1). In Aty‐AD, voxel‐based analyses showed moderate evidence of decline in vDMN connectivity and increase in avDMN connectivity over time (Fig. 2). Greater baseline global tau SUVR was associated with lower vDMN connectivity, cross‐sectionally and longitudinally (Fig. 3).ConclusionDMN connectivity was altered in Aty‐AD, with strongest alterations in younger patients. The vDMN declined over time, suggesting a shift in DMN connectivity with disease progression that was likely related to tau pathology.

AbstractBackgroundPosterior cortical atrophy (PCA) and logopenic progressive aphasia (LPA) are atypical variants of Alzheimer’s disease which typically show different cross‐sectional patterns of atrophy and tau deposition. Patterns of atrophy remain distinct longitudinally. A direct comparison of rates of atrophy and tau accumulation between these syndromes has not yet been reported.MethodWe evaluated 20 PCA and 20 LPA patients; all were amyloid‐positive on [11C]PiB‐PET. Structural MRI and tau‐PET were performed at baseline and one‐year follow‐up. Annualized rates of change in grey matter volume (log Jacobians from tensor‐based morphometry) and flortaucipir‐PET SUVRs were calculated at the lobar level. A global tau SUVR was calculated using parietal, temporal, and occipital regions. Lobar rates were compared between PCA and LPA with linear models, accounting for education, sex, age, baseline global tau SUVR (for tau‐PET), with significance set at p = 0.05. SPM voxel‐level comparisons were performed, with the same covariates, with significance set at p = 0.001.ResultGroups did not differ in age, Apoe status, baseline global tau SUVR or whole brain volume, or their annualized rates of change. LPA had shorter disease duration. In the lobar models, PCA had faster rates of atrophy in the occipital lobe and there were no significant differences on rates of tau accumulation, but a trend for LPA having faster rates of tau accumulation in all lobes. Baseline global tau SUVR was negatively associated with rate of tau accumulation in parietal and temporal lobes. Age was negatively associated with rates of tau accumulation in frontal, temporal and occipital lobes and with rates of atrophy in frontal and parietal lobes. Voxel‐level analysis confirmed these results, with PCA showing faster rates of occipital atrophy, and LPA showing subtle evidence for diffuse faster rates of tau accumulation (Figure 1).ConclusionLongitudinal patterns of neuroimaging abnormalities differ between PCA and LPA, although with divergent results for tau accumulation and atrophy that may reflect differences in disease stage. Rates of change are strongly influenced by age and severity of baseline tau, with faster rates of tau accumulation in patients with younger age and lower baseline tau deposition.

AbstractINTRODUCTIONTau is a key pathology in chronic traumatic encephalopathy (CTE). Here, we report our findings in tau positron emission tomography (PET) measurements from the DIAGNOSE CTE Research Project.METHODWe compare flortaucipir PET measures from 104 former professional players (PRO), 58 former college football players (COL), and 56 same‐age men without exposure to repetitive head impacts (RHI) or traumatic brain injury (unexposed [UE]); characterize their associations with RHI exposure; and compare players who did or did not meet diagnostic criteria for traumatic encephalopathy syndrome (TES).RESULTSSignificantly elevated flortaucipir uptake was observed in former football players (PRO+COL) in prespecified regions (p < 0.05). Association between regional flortaucipir uptake and estimated cumulative head impact exposure was only observed in the superior frontal region in former players over 60 years old. Flortaucipir PET was not able to differentiate TES groups.DISCUSSIONAdditional studies are needed to further understand tau pathology in CTE and other individuals with a history of RHI.

Background: Posterior cortical atrophy (PCA) and logopenic progressive aphasia (LPA) are two common atypical Alzheimer’s disease (AD) variants. Little is known about behavioral and neuropsychiatric symptoms or activities of daily living (ADLs) in PCA and LPA, and whether they differ across syndromes. Objective: To characterize the behavioral and neuropsychiatric profiles and ADLs of PCA and LPA and compare presence/absence and severity of symptoms between syndromes. Methods: Seventy-eight atypical AD patients, 46 with PCA and 32 with LPA, completed the Neuropsychiatric Inventory Questionnaire (NPI-Q) and Cambridge Behavioral Inventory-Revised (CBI-R) at baseline and longitudinally over-time. Mann-Whitney U and Fisher’s Exact Tests assessed for differences in symptoms between the two syndromes with significance set at p ≤0.01. To eliminate demographic differences as confounders the groups were matched, and differences reanalyzed. Results: PCA were younger at onset ( p = 0.006), at time of baseline assessment ( p = 0.02) and had longer disease duration ( p = 0.01). Neuropsychiatric symptoms were common in PCA and LPA, although more common and severe in PCA. At baseline, PCA had a higher NPI-Q total score ( p = 0.01) and depression subscore ( p = 0.01) than LPA. Baseline total CBI-R scores were also higher in PCA than LPA ( p = 0.001) with PCA having worse scores in all 10 CBI-R categories. Longitudinally, there was no difference between groups on the NPI-Q. However, on the CBI-R, PCA had faster rates of worsening on self-grooming ( p = 0.01) and self-dressing ( p = 0.01) compared to LPA. Conclusions: Behavioral and neuropsychiatric symptoms are common in PCA and LPA although these symptoms are more common and severe in PCA.

Abstract Background Diagnosis of breast cancer in young women has been shown to affect their decision‐making with regard to fertility and family planning. Limited data are available from populations across the U.S. regarding this issue; thus, we sought to describe fertility concerns and efforts to preserve fertility in a national clinical trial population of young breast cancer patients. Methods The young and strong study was a cluster‐randomized controlled trial testing an intervention program for young women with breast cancer. Patients were surveyed within 3 months after diagnosis and at 3, 6, and 12 months after. Surveys asked about sociodemographics, psychosocial domains, fertility concerns, and fertility preservation strategies. Univariable and multivariable models were used to investigate sociodemographic, clinical, and psychosocial predictors of fertility concerns. Results Of 467 women from 54 clinical sites across the U.S. (14 academic, 40 community), 419 were evaluable regarding fertility concerns. Median age was 40 years (range 22–45), 11% were Black, 6% Hispanic, and 75% had children. Tumor stage was I (35%), II (51%), or III (14%); 82% received chemotherapy. At time of the treatment decision, 133 (32%) participants had fertility concerns, among whom 47% indicated this affected their treatment decisions. Sixty percent of participants reported having discussed fertility with their physician. Twenty percent of those with fertility concerns used fertility preservation strategies. History of difficulty becoming pregnant and younger age were associated with higher odds of fertility concerns in multivariable modeling. Conclusion Many young women with newly diagnosed breast cancer are concerned about fertility in a way that impacts their treatment decisions. Concerns were discussed, but few used fertility preservation strategies. These findings have implications for counseling young patients.

Abstract Objectives VEXAS syndrome is an adult-onset autoinflammatory disease caused by a somatic pathogenic mutation in the UBA1 (ubiquitin-like modifier activating enzyme 1) gene. Patients present with rheumatologic manifestations and cytopenias and may have an increased predisposition to myelodysplastic syndrome (MDS) and plasma cell neoplasms. Prior studies have reported on the peripheral blood and bone marrow findings in patients with VEXAS syndrome. Due to the protean clinical presentation and lack of specificity of morphologic features (eg, vacuoles in early erythroid and granulocytic precursors), an optimal screening methodology to identify these patients in a timely fashion is desirable. Methods To further evaluate and describe the salient diagnostic morphologic features in VEXAS syndrome, we carried out a comprehensive study of the largest single-institution cohort to date. Diagnostic and follow-up bone marrow biopsy specimens from 52 male patients with molecularly identified VEXAS syndrome underwent central review. Results Cytopenias were common in all cases, primarily macrocytic anemia, monocytopenia, and thrombocytopenia. Bone marrow aspirate and biopsy were often hypercellular, with an increased myeloid/erythroid ratio, granulocytic hyperplasia with left shift, erythroid left shift, and megakaryocyte hyperplasia, which exhibited a range of striking morphologic findings. Distinctly vacuolated myeloid and erythroid precursors were seen in more than 95% of cases. Conclusions Our data reveal potential novel diagnostic features, such as a high incidence of monocytopenia and distinct patterns of atypical megakaryopoiesis, that appear different from dysmegakaryopoiesis typically associated with MDS. In our experience, those findings are suggestive of VEXAS, in the appropriate clinical context.

Abstract Osteoarthritis (OA) is a degenerative joint disease characterized by pain, stiffness, and limited joint motion affecting 7% of the world’s population. PH domain leucine-rich repeat protein phosphates (PHLPPs) have been identified as modifiable targets for cartilage regeneration and joint pain. PHLPP1 and PHLPP2 are abnormally expressed in osteoarthritic cartilage and sensory neurons. PHLPP1-/- mice are protected from cartilage degradation and pain-related behaviors (allodynia and reduced mobility) after surgery that destabilizes the medial meniscus (DMM). Here, we investigate the effects of PHLPP inhibitors (i) on human chondrocytes and the effect of Phlpp1 deletion on cell populations within lumbar dorsal root ganglia (DRGs). Immunohistochemistry was performed on mouse DRGs by cryosectioning fixed L3-5 DRGs and using primary antibodies against Fabp7, Anti tubulin beta 3, and PGP9.5/UCHL1. Human chondrocytes were subjected to Cycloheximide chase experiments and treated with PHLPPi (NSC117079 or NSC45586), followed by Western blot analysis to assess protein levels including Phlpp1, Phlpp2, Sox9, p-AKT (Ser473), total AKT, and B-actin, at various time points. We found that PHLPPi prolongs the phosphorylated AKT response when compared to controls and does not affect degradation of Phlpp1 or Phlpp2; additionally, NSC117079 increased production of cartilage extracellular matrix components (glycosaminoglycans and aggrecan) in over 90% of human articular cartilage explants from OA patients. These data advance our understanding of how PHLPPi function within chondrocytes and provide a basis toward understanding their activity and safety in vivo. Our results indicate that PHLPPi NSC117079 is a novel osteoarthritis disease-modifying drug candidate that may have palliative effects.

Abstract Lower income in familial caregivers has been shown to associate with increased distress, depression, and burden during active caregiving. However, findings are less clear on whether lower income associates with changes in well-being that occur after caregiving ends. To investigate this question further, we recruited familial caregivers (CGs) of people with neurodegenerative diseases (PWD; N=36). Emotional well-being was assessed using the SF-36 Emotional Well-being and Energy scales both during active caregiving and after caregiving had ended (predominantly due to the PWD’s death or transition to institutional care, ~10 years later). Household income was measured after active caregiving had ended. Overall, CG’s emotional well-being and energy improved between active caregiving and after caregiving had ended (emotional well-being change: t(35) = 2.22, p = .033; energy change: t(35) = 2.88, p = .007). However, this improvement associated with household income, such that when controlling for levels during active caregiving, income associated with worse emotional well-being (B = -6.72, t(33) = -4.56, p &lt; .001) and energy (B = -8.07, t(33) = -4.99, p &lt; .001) in caregivers after caregiving had ended. During the adjustment period after caregiving ends, lower income may limit opportunities for caregivers to take time away from work to mourn the loss of their loved one or address their own health concerns adequately. Thus, low-income caregivers may experience fewer of the benefits associated with these activities. These findings underscore the importance of providing support for lower income caregivers during the critical period after caregiving ends.