Pathways underlying the gut-brain axis and pro-inflammatory cytokine production influence brain functions and behavior. Alcohol use disorder (AUD) patients exhibit domains such as alcohol withdrawal, depression, and craving; and the gut-immune response may play a significant role in these domains of AUD. This study examined the role of intestinal permeability, pro-inflammatory cytokines, and hormones levels on the domains of AUD. Forty-eight AUD patients [male (n=34) and female (n=14)] aged 23-63 yrs. were grouped categorically using the Clinical Institute Withdrawal Assessment of alcohol scale (CIWA) as either clinically significant CIWA group (CS-CIWA [score>10] Gr.1 [n=22]), and clinically not-significant group (NCS-CIWA [score≤10] Gr.2 [n=26]). A sub-set of 13 AUD patient were also tested for reward response for drug-seeking using Penn-Alcohol Craving Score (PACS). Clinical data and blood samples were collected upon enrollment. Blood samples were analyzed for pro-inflammatory cytokines, and hormones, and markers of intestinal permeability. CIWA, 90-day timeline followback (TLFB90), and lifetime drinking history (LTDH) were also collected for comparison. As expected, recent and chronic heavy drinking were significantly higher in Gr.1: HDD90 (heavy drinking days), NDD90 (number of drinking days), as was LTDH, especially in Gr.1 females. Further, in Gr.1, adiponectin (associated with withdrawal) was significantly higher; and numerically higher levels of lipopolysaccharide (LPS) and LPS-binding protein (LBP) were also reported. Gr.1 patients exhibited higher effects of association on the withdrawal-associated depression domain for the parameters of LPS, sCD14, IL-6 and IL-8. Leptin also showed a significantly high effect of association with HDD90 in those AUD patients with craving. The craving domain (assessed by PACS, Penn-Alcohol Craving Scale) could be described as a gut-immune-brain model by the gut-dysregulation (LBP and Leptin) markers, and specific pro-inflammatory activity (IL-1β and TNF-α). Such pathway model describes the heavy drinking phenotype, HDD90 with even higher effects (R2=0.955, p=0.006) in the AUD patients who had higher ratings for craving (PACS>5). Interaction of gut-dysfunction, cytokines involved in both inflammation and in mediating-chemotactic activity constitute a novel pathophysiological gut-brain axis for withdrawal, and alcohol-associated depression and craving domains of AUD. AUD patient with higher craving show higher reinforcing effects of the gut-brain axis response for heavy drinking.

Over the past 3 years, J.C.V. has acted as a consultant/advisor for KNMP, More Labs, Red Bull, Sen-Jam Pharmaceutical, Toast!, and Tomo. All other authors declare no conflict of interests.

Study was supported by NIH: Z99-AA999999, K23AA029198-01 (VV), R15CA170091-01A1 (MK), ZIA AA000466 (VAR), R01AA023190 (WF), P50AA024337-8301 and P20GM113226-6169 (XZ), and P50AA024337, P20GM113226, U01AA026934, U01AA026926, U01AA026980 (CJM), and the VA (CJM). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

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This study was approved by the Institutional Review Board (IRB) of the University of Louisville, Louisville, KY USA, and the Central Neuroscience (CNS) IRB of the National Institute on Alcohol Abuse and Alcoholism, Bethesda MD USA. The study has been indexed at the National Clinical Trial website (www.clinicaltrials.gov): NCT00106106. All patients included in this study consented to participate before the beginning of the study.

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The datasets analyzed during the current study are available from the corresponding author on reasonable request. Email address for the readers to contact the author to obtain the data: v0vats01@louisville.edu.