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Purpose: Akathisia is a common adverse effect associated with use of dopamine receptor blocking agents.1,2 Symptoms of akathisia, in severe cases, may lead to discontinuation of treatment. Cariprazine is a dopamine D3-preferring D3/D2 receptor partial agonist and serotonin 5-HT1A receptor partial agonist approved to treat schizophrenia and acute manic, mixed, and depressive episodes of bipolar 1 disorder. Cariprazine is well tolerated in patients across its indications, but is associated with a higher incidence of akathisia compared with placebo.3,4 This pooled post hoc analysis of data from phase 3 clinical trials of adjunctive cariprazine aimed to characterize the incidence, severity, and management of akathisia and other extrapyramidal symptoms (EPS) in adult patients with MDD. Methods: Patients with MDD and inadequate response to ongoing antidepressant therapy (ADT) were randomized to cariprazine 1.5 mg/d + ADT, cariprazine 3 mg/d + ADT, or placebo + ADT for 6 weeks of double-blind treatment. Post hoc analysis evaluated incidence, severity, and time to resolution of akathisia, restlessness, and other EPS; use of rescue medications; and the rate of discontinuation due to these treatment-emergent adverse events (TEAEs). Results: A total of 1508 patients (cariprazine + ADT: 1.5 mg/d, n=502, 3 mg/d, n=503; placebo + ADT, n=503) were included in these 2 studies. The incidence of akathisia was greater with cariprazine 3 mg/d + ADT (9.7%) than with cariprazine 1.5 mg/d + ADT (6.4%) and placebo + ADT (2.0%). Most patients treated with cariprazine + ADT (94%) experienced only mild or moderate akathisia. The incidence of restlessness was 3.8% for patients treated with cariprazine 3 mg/d + ADT, 3.6% for cariprazine 1.5 mg/d + ADT, and 1.8% for placebo + ADT. The incidence of EPS excluding akathisia and restlessness was 4.4% for patients treated with cariprazine 3 mg/d + ADT, 4.6% for cariprazine 1.5 mg/d + ADT, and 3.2% for placebo + ADT. For patients treated with cariprazine + ADT and placebo + ADT, respectively, EPS-related study discontinuations were 1.4% and 0.4% due to akathisia, 0.2% and 0.0% due to restlessness, and 0.1% and 0.4% due to EPS excluding akathisia and restlessness. Rescue medications were used to treat EPS-related TEAEs during the double-blind treatment period in 3% of cariprazine-treated patients and 0.4% of placebo-treated patients. The mean time to resolution of akathisia during treatment was slightly shorter in cariprazine-treated patients (15.6 days) versus placebo-treated patients (19.5 days). Importance: Incidence of akathisia was higher for cariprazine than placebo, with a lower incidence observed for patients treated with cariprazine 1.5 + ADT than with cariprazine 3 mg/d + ADT, suggestive of a dose related effect. Most patients experienced mild or moderate akathisia. Rates of study discontinuation and rescue medication use due to akathisia were low, suggesting that akathisia was tolerated by most patients. This data was previously presented at the CINP World Congress; Montreal, Canada; May 7-10, 2023. Funding: AbbVie [ABSTRACT FROM AUTHOR]

Purpose: Anhedonia, a multidimensional domain including the reduced ability to experience pleasure, is a core diagnostic symptom of major depressive disorder (MDD) and a common residual symptom. In patients with MDD, anhedonia has been associated with poor treatment outcomes, suicide and reduced functioning and quality of life. This post-hoc analysis of data from a phase 3 trial (NCT03738215) evaluated the efficacy of adjunctive cariprazine (CAR) treatment on anhedonia symptoms in patients with MDD. Methods: Patients with MDD and inadequate response to ongoing antidepressant therapy (ADT) were randomized to CAR 1.5 mg/d + ADT, CAR 3 mg/d + ADT, or placebo + ADT for 6 weeks of double-blind treatment. Post hoc analyses evaluated the change from baseline to Week 6 in Montgomery–Åsberg Depression Rating Scale (MADRS) total score, MADRS anhedonia subscale score (items: 1 [apparent sadness], 2 [reported sadness], 6 [concentration difficulties], 7 [lassitude], and 8 [inability to feel]), and MADRS anhedonia item 8 in the overall modified intent-to-treat (mITT) population and in subgroups of patients with baseline MADRS anhedonia item 8 score of ≥4 or baseline anhedonia subscale score of ≥18. Least square (LS) mean change from baseline to Week 6 was analyzed using a mixed-effects model for repeated measures. Results: There were 751 patients in the mITT population (CAR + ADT: 1.5 mg/d=250, 3 mg/d=252; placebo + ADT=249). At baseline, 508 (67.6%) patients had MADRS anhedonia item 8 scores ≥4, and 584 (77.8%) had MADRS anhedonia subscale scores ≥18. In the overall mITT population, LS mean change from baseline to Week 6 in anhedonia subscale score was significantly greater for CAR 1.5 mg/d + ADT (-8.4) and CAR 3 mg/d + ADT (-7.9) than for placebo + ADT (-6.8; both P <.05). The LS mean change from baseline in MADRS individual item 8 was also significantly greater for CAR 1.5 mg/d + ADT (-1.7) vs placebo + ADT (-1.3; P =.0085). In both subgroups of patients with baseline anhedonia, CAR 1.5 mg/d + ADT was associated with significantly greater reduction in MADRS total score, MADRS anhedonia subscale score, and MADRS item 8 score compared with placebo + ADT (all P <.05). In the CAR 3 mg/d + ADT group, significantly greater reductions vs placebo + ADT were observed for MADRS total score and MADRS anhedonia subscale score in the subgroup of patients with baseline anhedonia subscale scores ≥18 (both P <.05). Importance: Adjunctive treatment with CAR was associated with a reduction in symptoms of anhedonia relative to adjunctive placebo in patients with MDD and inadequate response to ADT alone. In subgroups of patients with moderate-to-severe anhedonia at baseline, CAR + ADT demonstrated greater improvements than placebo + ADT in overall depressive symptoms and symptoms of anhedonia. These results suggest that adjunctive CAR treatment may be effective for improving symptoms of anhedonia in patients with MDD who have symptoms of anhedonia. Funding: AbbVie [ABSTRACT FROM AUTHOR]

Introduction: Alzheimer's disease (AD) is a growing socioeconomic problem worldwide. Early diagnosis and prevention of this devastating disease have become a research priority. Consequently, the identification of clinically significant and sensitive blood biomarkers for its early detection is very important. Apolipoprotein E (APOE) is a well-known and established genetic risk factor for late-onset AD; however, the impact of the protein level on AD risk is unclear. We assessed the utility of plasma ApoE protein as a potential biomarker of AD in the large, well-characterised Australian Imaging, Biomarkers and Lifestyle Study of Ageing (AIBL) cohort. Methods: Total plasma ApoE levels were measured at 18-month follow-up using a commercial bead-based enzyme-linked immunosorbent assay: the Luminex xMAP human apolipoprotein kit. ApoE levels were then analysed between clinical classifications (healthy controls, mild cognitive impairment (MCI) and AD) and correlated with the data available from the AIBL cohort, including but not limited to APOE genotype and cerebral amyloid burden. Results: A significant decrease in ApoE levels was found in the AD group compared with the healthy controls. These results validate previously published ApoE protein levels at baseline obtained using different methodology. ApoE protein levels were also significantly affected, depending on APOE genotypes, with e2/e2 having the highest protein levels and e4/e4 having the lowest. Plasma ApoE levels were significantly negatively correlated with cerebral amyloid burden as measured by neuroimaging. Conclusions: ApoE is decreased in individuals with AD compared with healthy controls at 18-month follow-up, and this trend is consistent with our results published at baseline. The influence of APOE genotype and sex on the protein levels are also explored. It is clear that ApoE is a strong player in the aetiology of this disease at both the protein and genetic levels. [ABSTRACT FROM AUTHOR]

Alterations in iron metabolism or oxidative damage in response to hypoxic incidents have been examined following re-oxygenation of the hypoxic tissue. To understand the consequences of decreased tissue oxygen on iron load, metal-catalyzed redox activity and oxidative modifications in isolation from re-oxygenation, the present study exposed mice to either normoxia, or mild hypoxia (380 Torr; ∼10% normobaric oxygen) where the tissue was not allowed to re-oxygenate prior to examination. Brain, liver and skeletal muscle were examined for Fe3+ load, metal-catalyzed redox activity and oxidative modifications to proteins (Nε-(carboxymethyl)lysine), lipids (4-hydroxynonenal pyrrole) and nucleic acids (8-hydroxyguanosine). Hypoxia induced a 43% increase in the iron content of the liver (P < 0.001) as determined by ICP-MS and a 3.8-fold increase in Fe3+ load (P < 0.001) as determined by Perl's stain. There was a corresponding 2-fold increase in metal-catalyzed redox activity (P < 0.01) in the liver, but no change in the expression of oxidative markers. In contrast, non-significant increases in Fe3+ and metal-catalyzed redox activity were observed in the cerebral cortex, and molecular and granular layers of the hippocampus and cerebellum. Interestingly, hypoxia significantly decreased oxidative modifications to proteins and lipids, but not nucleic acids in most brain regions examined. In addition, hypoxia did not alter the Fe content of skeletal muscle, or the contents of Zn, Cu, Ni or Mn in liver, skeletal muscle, cerebral cortex or hippocampus. Together, these results indicate that there is a tighter regulation of iron metabolism in the brain than the liver, which limits the redistribution of Fe3+ following hypoxia. [ABSTRACT FROM AUTHOR]

Transactive response DNA-binding protein of 43 kDa (TDP-43), an RNA and DNA binding protein involved in transcriptional repression, RNA splicing and RNA metabolism during the stress response, is the major component of neuronal inclusions in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin inclusions, now referred to as FTLD-TDP. While initially thought to be relatively specific to ALS and FTLD-TDP, TDP-43 pathology has now been detected in a number of other neurodegenerative diseases, many associated with tau pathology, including Guam Parkinson dementia complex and Alzheimer's disease (AD). TDP-43 pathology is detected in 25% to 50% of AD cases, especially those with more severe clinical phenotype and greater Alzheimer type pathology, as well as AD cases with hippocampal sclerosis (HS). HS is characterized by selective neuronal loss affecting CA1 sector of the hippocampus, and most cases of HS, with or without AD, have TDP-43 pathology. Whether TDP-43 pathology is merely an incidental finding in AD or actually contributing to the more severe clinical phenotype remains unresolved. Presence of TDP-43 in normal elderly, who are at increased risk for AD, would strengthen the argument that it is not merely a secondary or incidental finding in end stage AD. Limited studies suggest that TDP-43 pathology is infrequent in neurologically normal elderly (3% or less). We provide an overview of what is known about TDP-43 in AD, normal aging and in other disorders and suggest that TDP-43 proteinopathies be considered in two classes - primary and secondary.

Senescence is characterized neurologically by a decline in cognitive function, which we propose is the result of degenerative processes initiated by the dysregulation of the hypothalamic-pituitary-gonadal (HPG) axis with menopause and andropause. Compelling epidemiologic evidence to support this assertion includes the increased prevalence of Alzheimer disease (AD) in women, the correlation of serum HPG hormones with disease and the decreased incidence, and delay in the onset of AD following hormone replacement therapy. Dysregulation of the axis at this time leads to alterations in the concentrations of all serum HPG hormones (decreased neuronal sex steroid signaling, but increased neuronal gonadotropin releasing hormone, luteinizing hormone, and activin signaling). Hormones of the HPG axis, receptors for which are present in the adult brain, are important regulators of cell proliferation and differentiation during growth and development. Based on this, we propose that dysregulated HPG hormone signaling with menopause/andropause leads to the abortive reentry of differentiated neurons into the cell cycle via a process we term "dyosis." Interestingly, the major biochemical and neuropathologic changes reported for the AD brain also are intimately associated with neuron division: altered AbetaPP metabolism, Abeta deposition, tau phosphorylation, mitochondrial alterations, chromosomal replication, synapse loss, and death of differentiated neurons. Recent evidence supports the premise that AD-related biochemical changes are likely the combined result of increased mitotic signaling by gonadotropins and GnRH, decreased differentiative and neuroprotective signaling via sex steroids, and increased differentiative signaling via activins. This results in a hormonal milieu that is permissive of cell cycle reentry but does not allow completion of metaphase. Partial resetting of the axis following administration of normal endogenous sex steroids delays the onset and decreases the incidence of AD. Ideally, supplementation with HPG hormones should mimic closely the serum concentrations of all HPG hormones in reproductive men and cycling women to prevent dyotic signaling and attempted neuron division.