Blood-based biomarkers of antidepressant response to ketamine and esketamine: A systematic review and meta-analysis.

(R,S)-ketamine (ketamine) and its enantiomer (S)-ketamine (esketamine) can produce rapid and substantial antidepressant effects. However, individual response to ketamine/esketamine is variable, and there are no well-accepted methods to differentiate persons who are more likely to benefit. Numerous potential peripheral biomarkers have been reported, but their current utility is unclear. We conducted a systematic review/meta-analysis examining the association between baseline levels and longitudinal changes in blood-based biomarkers, and response to ketamine/esketamine. Of the 5611 citations identified, 56 manuscripts were included (N = 2801 participants), and 26 were compatible with meta-analytical calculations. Random-effect models were used, and effect sizes were reported as standardized mean differences (SMD). Our assessments revealed that more than 460 individual biomarkers were examined. Frequently studied groups included neurotrophic factors (n = 15), levels of ketamine and ketamine metabolites (n = 13), and inflammatory markers (n = 12). There were no consistent associations between baseline levels of blood-based biomarkers, and response to ketamine. However, in a longitudinal analysis, ketamine responders had statistically significant increases in brain-derived neurotrophic factor (BDNF) when compared to pre-treatment levels (SMD [95% CI] = 0.26 [0.03, 0.48], p = 0.02), whereas non-responders showed no significant changes in BDNF levels (SMD [95% CI] = 0.05 [-0.19, 0.28], p = 0.70). There was no consistent evidence to support any additional longitudinal biomarkers. Findings were inconclusive for esketamine due to the small number of studies (n = 2). Despite a diverse and substantial literature, there is limited evidence that blood-based biomarkers are associated with response to ketamine, and no current evidence of clinical utility.

Impact of childhood maltreatment on outcomes of antidepressant medication in chronic and/or recurrent depression.

BACKGROUND: While childhood maltreatment (CMT) is associated with higher rates of chronicity and recurrence in depression, whether CMT results in poorer outcomes with antidepressant medication remains unclear. METHODS: We performed secondary analyses with data from the large, representative, multisite trial Combining Medications to Enhance Depression Outcomes (CO-MED). CO-MED was a randomized, single-blinded, placebo-controlled study with 665 individuals (663 assessed for CMT) with chronic and/or recurrent Major Depressive Disorder (MDD). CMT was determined by a brief self-reported questionnaire assessing the four types of CMT defined by the Centers for Disease Control and Prevention: sexual abuse, emotional abuse, physical abuse, and neglect. Repeated measures and logistic regression analyses were used. RESULTS: Individuals with CMT did not have a differential improvement of depressive symptoms when compared to those without CMT (adjusted p=.203 for continuous analysis; adjusted p=.320 for remission rates). Neither type of antidepressant medication (adjusted p=.302) nor the age at which CMT occurred (adjusted p=.509) affected depressive symptom outcomes. There was no difference in functional improvement between individuals with and without CMT (adjusted p=.228). A history of CMT was associated with greater antidepressant side effects (p=.009). LIMITATIONS: This study investigated treatment-seeking individuals with chronic and/or recurrent MDD. Intensity and duration of CMT were not assessed. CONCLUSION: In a sample of treatment-seeking outpatients with chronic and/or recurrent MDD, a history of CMT was not associated with differential symptomatic or functional response to pharmacological treatment. However, those with CMT reported greater antidepressant side effect burden.

Childhood maltreatment and impact on clinical features of major depression in adults.

OBJECTIVES: This study examined: 1) the prevalence of childhood maltreatment (CMT) in individuals with chronic and/or recurrent depression, 2) the association between CMT and depressive symptoms, 3) the link between CMT and worse clinical presentation of depression, 4) the effects of accumulation of different types of CMT, and 5) the relationship between the age at CMT and depression. METHODS: We analyzed the baseline data of 663 individuals from the CO-MED study. CMT was determined by a brief self-reported questionnaire assessing sexual abuse, emotional abuse, physical abuse, and neglect. Correlational analyses were conducted. RESULTS: Half of the sample (n = 331) reported CMT. Those with CMT had higher rates of panic/phobic, cognitive and anhedonic symptoms than those without CMT. All individual types of maltreatment were associated with a poorer clinical presentation including: 1) earlier MDD onset; 2) more severe MDD, 3) more suiccidality, 4) worse quality of life, and functioning, and 5) more psychiatric comorbidities. Clinical presentation was worse in participants who reported multiple types of CMT. CONCLUSIONS: In chronic and/or recurrent depression, CMT is common, usually of multiple types and is associated with a worse clinical presentation in MDD. The combination of multiple types of CMT is associated with more impairment.

Specific glycosaminoglycan chain length and sulfation patterns are required for cell uptake of tau versus α-synuclein and ß-amyloid aggregates.

Transcellular propagation of protein aggregate "seeds" has been proposed to mediate the progression of neurodegenerative diseases in tauopathies and α-synucleinopathies. We previously reported that tau and α-synuclein aggregates bind heparan sulfate proteoglycans (HSPGs) on the cell surface, promoting cellular uptake and intracellular seeding. However, the specificity and binding mode of these protein aggregates to HSPGs remain unknown. Here, we measured direct interaction with modified heparins to determine the size and sulfation requirements for tau, α-synuclein, and ß-amyloid (Aß) aggregate binding to glycosaminoglycans (GAGs). Varying the GAG length and sulfation patterns, we next conducted competition studies with heparin derivatives in cell-based assays. Tau aggregates required a precise GAG architecture with defined sulfate moieties in the N- and 6-O-positions, whereas the binding of α-synuclein and Aß aggregates was less stringent. To determine the genes required for aggregate uptake, we used CRISPR/Cas9 to individually knock out the major genes of the HSPG synthesis pathway in HEK293T cells. Knockouts of the extension enzymes exostosin 1 (EXT1), exostosin 2 (EXT2), and exostosin-like 3 (EXTL3), as well as N-sulfotransferase (NDST1) or 6-O-sulfotransferase (HS6ST2) significantly reduced tau uptake, consistent with our biochemical findings, and knockouts of EXT1, EXT2, EXTL3, or NDST1, but not HS6ST2 reduced α-synuclein uptake. In summary, tau aggregates display specific interactions with HSPGs that depend on GAG length and sulfate moiety position, whereas α-synuclein and Aß aggregates exhibit more flexible interactions with HSPGs. These principles may inform the development of mechanism-based therapies to block transcellular propagation of amyloid protein-based pathologies.