Changes in the serum metabolites of tryptophan in abstinent cocaine and alcohol users and their relationship with co-morbid disorders October 24, 2017 Rebeca Vidal

Last year prevalence of cocaine use among young adults (15-34) Spain is the country reporting the largest seizures of cocaine among the EU member States Statistical bulletin 2017, EMCDDA

Projected estimates consumption (litres/year) Total alcohol per capita (>15 years of age) consumption, projected estimates, 2015 Projected estimates consumption (litres/year) <2.5 2.5 – 5.4 5.5-8.4 8.5-11.9 >12

The kynurenine pathway in the periphery and CNS Liver Spleen 5-HT QA KA TRP KYN 3-HK Tryptophan (TRP) Kynurenine (KYN) 3-Hydroxykynurenine (3-HK) Quinolinic acid (QA) Kynurenic acid (KA) TDO IDO KMO Neuroprotective arm Tryptophan Kynurenic acid Gut Neuron Astrocyte HPA axis activation CNS Periphery Glucocorticoids Immune cells Microglia Neurotoxic arm Quinolinic acid Blood brain barrier KAT TPH2 TPH1 IFN-γ IL-1β IL-6 NAD+

Is the Kynurenine Pathway altered in abstinent cocaine and alcohol-addicted patients?

Is the Kynurenine Pathway disbalanced in abstinent cocaine and alcohol-addicted patients? Plasma levels of TRP, 5-HT, KYN, KA were measured by HPLC (QA using a ELISA kit) and evaluated according to relevant substance use disorder variables and psychiatric comorbidity.

ABSTINENT PATIENTS DIAGNOSED WITH COCAINE USE DISORDERS VARIABLE COCAINE GROUP N=100 CONTROL GROUP N=60 P-value Age [mean (SD)] Years 35.4 (7.5) 36.4 (10.4) ns a Body mass index Kg/m2 25.4 (4.4) 24.6 (4.3) Sex [N (%)] Female Male 18 (18.0) 82 (82.0) 30 (50.0) <0.001 b Cocaine users exclusively by intranasal use and abstinent for at least 2 weeks before testing (average abstienence 7.3 months).

Plasma levels in abstinent cocaine-addicted patients and control subjects Tryptophan 10 20 30 Control Cocaine nmol/mL Serotonin Control Cocaine pmol/mL 50 100 150 200 ** Kynurenine 0.0 0.5 1.0 1.5 2.0 Control Cocaine nmol/mL

Plasma levels in abstinent cocaine-addicted patients and control subjects Tryptophan 10 20 30 Control Cocaine nmol/mL Serotonin Control Cocaine pmol/mL 50 100 150 200 ** Kynurenic acid 10 20 30 40 Control Cocaine pmol/mL * Kynurenine 0.0 0.5 1.0 1.5 2.0 Control Cocaine nmol/mL Quinolinic acid 5 10 15 20 25 Control Cocaine pmol/mL

Plasma levels in abstinent cocaine-addicted patients and control subjects Tryptophan 10 20 30 Control Cocaine nmol/mL Serotonin Control Cocaine pmol/mL 50 100 150 200 ** 5HT/TRYP 1 2 Control Cocaine * 4 3 Ratio (x 103) Kynurenic acid 10 20 30 40 Control Cocaine pmol/mL * Kynurenine 0.0 0.5 1.0 1.5 2.0 Control Cocaine nmol/mL KA/KYN 0.5 1.0 1.5 2.0 2.5 Control Cocaine * Ratio (x 103) KYN/TRP 20 40 60 80 100 Control Cocaine Ratio (x 103) Quinolinic acid 5 10 15 20 25 Control Cocaine pmol/mL

Characteristics related to cocaine use in cocaine-addicted patients VARIABLE COCAINE GROUP (N=100) Current cocaine abstinence (duration) [mean (SD)] days 221.8 (429.4) Problematic cocaine use (duration) years 7.34 (6.47) DSM-IV criteria for cocaine abuse and dependence (0-11) 8.4 (2.2) Comorbid substance use disorders [N (%)] No Yes 32 (32.0) 68 (68.0)

COMORBID MENTAL DISORDERS Psychiatric characteristics of cocaine-addicted patients grouped according to diagnosis of comorbid mental disorders VARIABLE COMORBID MENTAL DISORDERS NO N=41 YES N=59 P-value Prescribed psychotropic medication use [N (%)] No Yes 24 (58.5) 17 (41.5) 14 (23.7) 45 (76.3) <0.001 Treatment for substance use disorders 10 (24.4) 31 (75.6) 4 (6.8) 55 (93.2) <0.05 Outpatient Income 29 (70.7) 2 (4.9) 47 (79.7) 8 (13.6) -- Lifetime substance use disorders (excluding cocaine) 18 (43.9) 23 (56.1) Alcohol 21 (51.2) 38 (64.4) Cannabis 4 (9.8) 13 (22.0) Heroin 0 (0.0) 9 (15.3) Sedatives 3 (7.3) Others 7 (11.9) Common lifetime mental disorders 41 (100.0) 59 (100.0) Mood - 28 (47.5) Anxiety 22 (37.3) Psychosis 16 (27.1) Personality

Abstinent cocaine-addicted patients and comorbid mental disorders Tryptophan Non-comorbid Comorbid nmol/mL 10 20 30 40 Serotonin pmol/mL 50 100 150 200 250 ** Non-comorbid Comorbid Kynurenine nmol/mL 0.0 0.5 1.0 1.5 2.0 Non-comorbid Comorbid Kynurenic acid pmol/mL 10 20 30 Non-comorbid Comorbid 5 10 15 20 25 Quinolinic acid pmol/mL Non-comorbid Comorbid * vs non-comorbid

Plasma serotonin levels and comorbid mental disorders in abstinent CUD patients * Personality disorders 5-HT (pmol/mL) 75 150 225 300 Non-comorbid Non-personality disorders Mood disorders 75 150 225 300 * 5-HT (pmol/mL) Non-comorbid Non-mood disorders Anxiety disorders ** 5-HT (pmol/mL) 75 150 225 300 Non-comorbid Non-anxiety disorders * 5-HT (pmol/mL) Psychotic disorders 75 150 225 300 Non-comorbid Non-psychotic disorders * vs non-comorbid

In summary: Kynurenic acid is affected by historial of cocaine use disorder Serotonin is associated to psychiatric comorbidity in abstinent cocaine-adicted patients

ABSTINENT PATIENTS DIAGNOSED WITH COCAINE USE DISORDERS VARIABLE ALCOHOL GROUP N=130 CONTROL GROUP N=80 p-value Age [mean (SD)] Years 48.6 (7.9) 43.0 (10.9) <0.001 a Body mass index Kg/m2 26.0 (4.4) 25.6 (4.4) ns a Sex [N (%)] Female Male 35 (26.9) 95 (73.1) 40 (50.0) 0.001 b Alcohol users were abstinent for at least 4 weeks (mean 11.5 months) before testing

Plasma levels in abstinent alcohol-addicted patients and control subjects nmol/mL 10 20 30 40 Control Alcohol Tryptophan Serotonin pmol/mL 20 40 60 80 100 Control Alcohol Kynurenine nmol/mL 0.0 0.5 1.0 1.5 2.0 2.5 ** Control Alcohol Kynurenic acid pmol/mL 10 20 30 * Control Alcohol

Plasma levels in abstinent alcohol-addicted patients and control subjects nmol/mL 10 20 30 40 Control Alcohol Tryptophan Serotonin pmol/mL 20 40 60 80 100 Control Alcohol 2 4 6 8 Ratio (x 103) KYN/TRP Ratio ** Control Alcohol Kynurenine nmol/mL 0.0 0.5 1.0 1.5 2.0 2.5 ** Control Alcohol Kynurenic acid pmol/mL 10 20 30 * Control Alcohol 0.0 0.5 1.0 1.5 2.0 Ratio (x 103) KA/KYN Ratio *** Control Alcohol

Characteristics related to alcohol use in abstinent AUD patients VARIABLE ALCOHOL GROUP N=130 Current alcohol abstinence (duration) [mean (SD)] Months 11.5 (17.4) Problematic alcohol use (duration) Years 14.5 (7.7) DSM-IV criteria for AUD Criteria (0-11) 7.2 (2.3) Alcohol-related liver/pancreas diseases [N (%)] No Yes 96 (73.8) 34 (26.2) Psychoactive medication use [N (%)] Last year 90 (69.2) Lifetime psychiatric comorbidity No SUD Mental disorders Both 36 (27.7) 9 (6.9) 40 (30.8) 45 (34.6) Comorbid substance use disorders (SUD) Yes 76 (58.5) 54 (41.5) Comorbid mental disorders 85 (65.4)

Plasma concentrations of TRP-derived metabolites in abstinent AUD patients relative to psychiatric comorbidity VARIABLE PSYCHIATRIC COMORBIDITY NO COMORBIDITY N=36 SUBSTANCE USE DISORDERS (SUD) N=9 MENTAL DISORDERS N=40 SUD+MENTAL DISORDERS N=45 Tryptophan (TRP) [mean (95%CI)] nmol/mL 34.77 (32.21-37.33) 31.01 (26.00-36.03) 33.21 (29.94-36.48) 28.16 (25.76-30.57) ** Kynurenine (KYN) 1.92 (1.69-2.19) 1.79 (1.38-2.31) 2.07 (1.75-2.44) 1.78 (1.57-2.01) Kynurenic acid (KA) pmol/mL 20.23 (17.18-23.88) 19.95 (14.42-27.54) 17.06 (13.83-21.04) 17.66 (13.84-20.61) Serotonin (5-HT) 60.12 (47.42-76.21) 68.87 (43.25-109.65) 47.75 (35.24-64.71) 76.74 (61.38-95.94) KYN/TRP Ratio   0.058 (0.052-0.071) 0.056 (0.045-0.071) 0.062 (0.053-0.072) 0.067 (0.060-0.075) KA/KYN Ratio 0.0018 (0.0014-0.0023) 0.0023 (0.0014-0.0037) 0.0015 (0.0010-0.0021) 0.0028 (0.0022-0.0035) 5-HT/TRP Ratio 0.0016 (0.0013-0.0020) 0.0026 (0.0020-0.0033) 0.0019 (0.0015-0.0025) (0.0022-0.0036)

Plasma concentrations of TRP-derived metabolites in abstinent AUD patients relative to psychiatric comorbidity VARIABLE PSYCHIATRIC COMORBIDITY NO COMORBIDITY N=36 SUBSTANCE USE DISORDERS (SUD) N=9 MENTAL DISORDERS N=40 SUD+MENTAL DISORDERS N=45 Tryptophan (TRP) [mean (95%CI)] nmol/mL 34.77 (32.21-37.33) 31.01 (26.00-36.03) 33.21 (29.94-36.48) 28.16 (25.76-30.57) ** Kynurenine (KYN) 1.92 (1.69-2.19) 1.79 (1.38-2.31) 2.07 (1.75-2.44) 1.78 (1.57-2.01) Kynurenic acid (KA) pmol/mL 20.23 (17.18-23.88) 19.95 (14.42-27.54) 17.06 (13.83-21.04) 17.66 (13.84-20.61) Serotonin (5-HT) 60.12 (47.42-76.21) 68.87 (43.25-109.65) 47.75 (35.24-64.71) 76.74 (61.38-95.94) KYN/TRP Ratio   0.058 (0.052-0.071) 0.056 (0.045-0.071) 0.062 (0.053-0.072) 0.067 (0.060-0.075) KA/KYN Ratio 0.0018 (0.0014-0.0023) 0.0023 (0.0014-0.0037) 0.0015 (0.0010-0.0021) 0.0028 (0.0022-0.0035) 5-HT/TRP Ratio 0.0016 (0.0013-0.0020) 0.0026 (0.0020-0.0033) 0.0019 (0.0015-0.0025) (0.0022-0.0036)

Plasma TRP concentrations in the alcohol group according to psychiatric comorbidity Comorbid substance use disorders (SUD) [N (%)] No Yes 76 (58.5) 54 (41.5) Cocaine Cannabis Other drugs 41 (31.5) 20 (15.4) 15 (11.5) Comorbid mental disorders 45 (34.6) 85 (65.4) Mood disorders Anxiety disorders Psychosis disorders Personality disorders 59 (45.4) 25 (19.2) 12 (9.2) 31 (23.8) 10 20 30 40 50 ** TRP (nmol/mL) Total SUD Cocaine *** Cannabis Other SUD * No comorbid disorder Comorbid SUD + MD Comorbid SUD Comorbid MD

Conclusions Kynurenic acid is affected by both history of cocaine and alcohol use disorders Serotonin is associated to psychiatric comorbidity in abstinent cocaine-adicted patients AUD patients diagnosed with comorbid SUD and mental disorders showed lower TRP concentrations than AUD patients with no comorbidity

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