While inflammation has been implicated in psychopathology, relationships between immune-suppressing processes and psychiatric constructs remain elusive. This study sought to assess whether β 2 -agonist clenbuterol (CBL) would attenuate immune activation in adolescents with mood and anxiety symptoms following ex vivo exposure of whole blood to lipopolysaccharide (LPS). Our focus on adolescents aimed to target a critical developmental period when psychiatric conditions often emerge and prior to chronicity effects. To capture a diverse range of immunologic and symptomatologic phenotypes, we included 97 psychotropic-medication free adolescents with mood and anxiety symptoms and 33 healthy controls. All participants had comprehensive evaluations and dimensional assessments of psychiatric symptoms. Fasting whole-blood samples were collected and stimulated with LPS in the presence and absence of CBL for 6 hours, then analyzed for 41 cytokines, chemokines, and hematopoietic growth factors. Comparison analyses used Bonferroni-corrected nonparametric tests. Levels of nine immune biomarkers—including IL-1RA, IL-1β, IL-6, IP-10, MCP-1, MIP-1α, MIP-1β, TGF-α, and TNF-α—were significantly reduced by CBL treatment compared to LPS alone. Exploratory factor analysis reduced 41 analytes into 5 immune factors in each experimental condition, and their relationships with psychiatric symptoms were examined as a secondary aim. CBL+LPS Factor 4—comprising EGF, PDGF-AA, PDGF-AB/BB, sCD40L, and GRO—significantly correlated with anticipatory and consummatory anhedonia, even after controlling for depression severity. This study supports the possible inhibitory effect of CBL on immune activation. Using a data-driven method, distinctive relationships between CBL-affected immune biomarkers and dimensional anhedonia were reported, further elucidating the role of β 2 -agonism in adolescent affective symptomatology.

ObjectivesAdolescence is a critical period marked by rapid maturation of reward circuitry and often by the onset of psychiatric symptoms. Elevated inflammatory biomarkers are also frequently reported in depressed youth. Here, we investigated associations between reward networks properties, clinical symptomatology, and inflammation in a transdiagnostic cohort of adolescents.MethodsSubjects were adolescents (N = 87; age 15.2 ± 2.1 years) with primarily mood and anxiety symptoms (n = 68) or healthy controls (n = 19). Self-reports assessed depression (Beck Depression Inventory [BDI]), anxiety (Multidimensional Anxiety Scale for Children [MASC]), and anhedonia (Temporal Experience of Pleasure Scale [TEPS]) severity. Resting-state fMRI was collected at 3T (10 minutes; 2.3 mm isotropic; TR = 1s; 5x MB), preprocessed via Human Connectome Project pipelines, and parcellated into whole-brain and 3 task-derived networks preferentially activated by Reward Anticipation, Reward Attainment, and Reward Prediction Error (RPE). Graph theory metrics of Strength Centrality (CStr), Eigenvector Centrality (CEig), and Local Efficiency (ELoc) were computed via the Brain Connectivity Toolbox. Luminex assays quantified 41 immune biomarkers from whole-blood cultured for 6 hours with growth medium (Baseline) or 0.1 μg/mL lipopolysaccharide (LPS) to stimulate immune response. Principal component analysis (PCA) identified 5 principal components (PCs) that accounted for ≥5% of total biomarker variance. Graph theory metrics were correlated with symptom scores and immune components using permutation tests (pFWE < .05, controlled for age and sex) in FreeSurfer Permutation Analysis of Linear Models (FSL PALM).ResultsAs shown in Figure 1, both depression and anhedonia severity (top) were associated with network properties in key reward-related regions, including the dorsal anterior cingulate (dACC), orbitofrontal (OFC), ventromedial prefrontal (vmPFC), dorsolateral prefrontal (dlPFC), and ventral striatum. Immune PCs (bottom) were associated with altered network properties in many of the same regions as well as the subgenual anterior cingulate (sgACC), particularly following lipopolysaccharide (LPS) stimulation.ConclusionsBoth psychiatric symptoms and inflammatory biomarkers were associated with altered network properties in the reward-related prefrontal and striatal regions, suggesting that inflammatory processes early in the course of depression may disproportionally interfere with the function and development of reward networks.NI, IMAGS, DDD ObjectivesAdolescence is a critical period marked by rapid maturation of reward circuitry and often by the onset of psychiatric symptoms. Elevated inflammatory biomarkers are also frequently reported in depressed youth. Here, we investigated associations between reward networks properties, clinical symptomatology, and inflammation in a transdiagnostic cohort of adolescents. Adolescence is a critical period marked by rapid maturation of reward circuitry and often by the onset of psychiatric symptoms. Elevated inflammatory biomarkers are also frequently reported in depressed youth. Here, we investigated associations between reward networks properties, clinical symptomatology, and inflammation in a transdiagnostic cohort of adolescents. MethodsSubjects were adolescents (N = 87; age 15.2 ± 2.1 years) with primarily mood and anxiety symptoms (n = 68) or healthy controls (n = 19). Self-reports assessed depression (Beck Depression Inventory [BDI]), anxiety (Multidimensional Anxiety Scale for Children [MASC]), and anhedonia (Temporal Experience of Pleasure Scale [TEPS]) severity. Resting-state fMRI was collected at 3T (10 minutes; 2.3 mm isotropic; TR = 1s; 5x MB), preprocessed via Human Connectome Project pipelines, and parcellated into whole-brain and 3 task-derived networks preferentially activated by Reward Anticipation, Reward Attainment, and Reward Prediction Error (RPE). Graph theory metrics of Strength Centrality (CStr), Eigenvector Centrality (CEig), and Local Efficiency (ELoc) were computed via the Brain Connectivity Toolbox. Luminex assays quantified 41 immune biomarkers from whole-blood cultured for 6 hours with growth medium (Baseline) or 0.1 μg/mL lipopolysaccharide (LPS) to stimulate immune response. Principal component analysis (PCA) identified 5 principal components (PCs) that accounted for ≥5% of total biomarker variance. Graph theory metrics were correlated with symptom scores and immune components using permutation tests (pFWE < .05, controlled for age and sex) in FreeSurfer Permutation Analysis of Linear Models (FSL PALM). Subjects were adolescents (N = 87; age 15.2 ± 2.1 years) with primarily mood and anxiety symptoms (n = 68) or healthy controls (n = 19). Self-reports assessed depression (Beck Depression Inventory [BDI]), anxiety (Multidimensional Anxiety Scale for Children [MASC]), and anhedonia (Temporal Experience of Pleasure Scale [TEPS]) severity. Resting-state fMRI was collected at 3T (10 minutes; 2.3 mm isotropic; TR = 1s; 5x MB), preprocessed via Human Connectome Project pipelines, and parcellated into whole-brain and 3 task-derived networks preferentially activated by Reward Anticipation, Reward Attainment, and Reward Prediction Error (RPE). Graph theory metrics of Strength Centrality (CStr), Eigenvector Centrality (CEig), and Local Efficiency (ELoc) were computed via the Brain Connectivity Toolbox. Luminex assays quantified 41 immune biomarkers from whole-blood cultured for 6 hours with growth medium (Baseline) or 0.1 μg/mL lipopolysaccharide (LPS) to stimulate immune response. Principal component analysis (PCA) identified 5 principal components (PCs) that accounted for ≥5% of total biomarker variance. Graph theory metrics were correlated with symptom scores and immune components using permutation tests (pFWE < .05, controlled for age and sex) in FreeSurfer Permutation Analysis of Linear Models (FSL PALM). ResultsAs shown in Figure 1, both depression and anhedonia severity (top) were associated with network properties in key reward-related regions, including the dorsal anterior cingulate (dACC), orbitofrontal (OFC), ventromedial prefrontal (vmPFC), dorsolateral prefrontal (dlPFC), and ventral striatum. Immune PCs (bottom) were associated with altered network properties in many of the same regions as well as the subgenual anterior cingulate (sgACC), particularly following lipopolysaccharide (LPS) stimulation. As shown in Figure 1, both depression and anhedonia severity (top) were associated with network properties in key reward-related regions, including the dorsal anterior cingulate (dACC), orbitofrontal (OFC), ventromedial prefrontal (vmPFC), dorsolateral prefrontal (dlPFC), and ventral striatum. Immune PCs (bottom) were associated with altered network properties in many of the same regions as well as the subgenual anterior cingulate (sgACC), particularly following lipopolysaccharide (LPS) stimulation. ConclusionsBoth psychiatric symptoms and inflammatory biomarkers were associated with altered network properties in the reward-related prefrontal and striatal regions, suggesting that inflammatory processes early in the course of depression may disproportionally interfere with the function and development of reward networks.NI, IMAGS, DDD Both psychiatric symptoms and inflammatory biomarkers were associated with altered network properties in the reward-related prefrontal and striatal regions, suggesting that inflammatory processes early in the course of depression may disproportionally interfere with the function and development of reward networks.

Reward dysfunction has been hypothesized to play a key role in the development of psychiatric conditions during adolescence. To help capture the complexity of reward function in youth, we used the Reward Flanker fMRI Task, which enabled us to examine neural activity during expectancy and attainment of both certain and uncertain rewards. Participants were 84 psychotropic-medication-free adolescents, including 67 with diverse psychiatric conditions and 17 healthy controls. Functional MRI used high-resolution acquisition and high-fidelity processing techniques modeled after the Human Connectome Project. Analyses examined neural activation during reward expectancy and attainment, and their associations with clinical measures of depression, anxiety, and anhedonia severity, with results controlled for family-wise errors using non-parametric permutation tests. As anticipated, reward expectancy activated regions within the fronto-striatal reward network, thalamus, occipital lobe, superior parietal lobule, temporoparietal junction, and cerebellum. Unexpectedly, however, reward attainment was marked by widespread deactivation in many of these same regions, which we further explored using cosine similarity analysis. Across all subjects, striatum and thalamus activation during reward expectancy negatively correlated with anxiety severity, while activation in numerous cortical and subcortical regions during reward attainment positively correlated with both anxiety and depression severity. These findings highlight the complexity and dynamic nature of neural reward processing in youth.

While the link between peripheral immune activation and mental health symptoms has been supported, the role of immune-modulating processes by the adrenergic nervous system in psychopathology remains unclear. Here, we sought to investigate the β2-agonist clenbuterol (CBL) as a promising agent to model adrenergic-driven immune attenuation following ex vivo immune activation with lipopolysaccharide (LPS). Further, we explored the relationships between CBL-modulated cytokine levels and mental health measures in our adolescent sample. Depression, anxiety, and anhedonia levels were measured with the Beck Depression Inventory (BDI), the Multidimensional Anxiety School for Children (MASC), and the Temporal Experience of Pleasure Scale (TEPS) questionnaires. Fasting whole-blood samples were acquired and stimulated with LPS (0.1 μg/mL) in the presence and absence of CBL (10-6 M) for 6 hours. Supernatants were collected and subjected to Luminex multiplex assay for 41 cytokines. Cytokine levels were compared between 3 conditions: control, LPS, and LPS+CBL. Then, an exploratory factor analysis (EFA) was utilized to dimensionally reduce cytokine data from the 3 conditions and the differences between them. Correlations between each latent factor and mental health symptoms were examined. The statistical significance of all associations was assessed after Bonferroni correction for multiple comparisons. Ten cytokines were significantly affected by CBL treatment compared to LPS alone. In each of the 6 examined conditions, EFA reduced 41 cytokines into 5 orthogonal factors. Only factor 3 of the LPS+CBL condition was found to be significantly correlated with both anticipatory anhedonia (rho = –0.39; p = 6.25 × 10-5) and consummatory anhedonia (rho = –0.36; p = 3.21 × 10-4). No significant correlation was found between any cytokine factor alone and depression or anxiety. Post hoc analysis revealed differences in intercytokine correlation structures between LPS+CBL and LPS conditions, possibly explaining CBL's effects on the relationships between peripheral immune response and anhedonia subcomponents. Findings support our hypothesis that CBL attenuates inflammatory effects thought to underlie mental health conditions in youth. Following data-driven analyses, distinctive associations between CBL-affected immune response and dimensional anhedonia were identified.

Lipopolysaccharide (LPS) is well known to induce “sickness behavior”, characterized by lethargy and attenuated reward response, as well as immune activation in humans. Preclinical data further suggest that clenbuterol (CBL), a β2-agonist, might attenuate pro-inflammatory cytokines production following LPS exposure. Our study aimed to explore this potential anti-inflammatory property of CBL in the context of human psychopathology by examining ex vivo cytokine levels from adolescents with diverse psychiatric symptoms.