Pilot study with randomised control of dual site theta burst transcranial magnetic stimulation (TMS) for methamphetamine use disorder: a protocol for the TARTAN study.

BACKGROUND: Transcranial magnetic stimulation (TMS) (including the theta burst stimulation (TBS) form of TMS used in this study) is a non-invasive means to stimulate nerve cells in superficial areas of the brain. In recent years, there has been a growth in the application of TMS to investigate the modulation of neural networks involved in substance use disorders. This study examines the feasibility of novel TMS protocols for the treatment of methamphetamine (MA) use disorder in an ambulatory drug and alcohol treatment setting. METHODS: Thirty participants meeting the criteria for moderate to severe MA use disorder will be recruited in community drug and alcohol treatment settings and randomised to receive active TMS or sham (control) intervention. The treatment is intermittent TBS (iTBS) applied to the left dorsolateral prefrontal cortex (DLPFC), then continuous TBS (cTBS) to the left orbitofrontal cortex (OFC). Twelve sessions are administered over 4 weeks with opt-in weekly standardized cognitive behaviour therapy (CBT) counselling and a neuroimaging sub-study offered to participants. Primary outcomes are feasibility measures including recruitment, retention and acceptability of the intervention. Secondary outcomes include monitoring of safety and preliminary efficacy data including changes in substance use, cravings (cue reactivity) and cognition (response inhibition). DISCUSSION: This study examines shorter TBS protocols of TMS for MA use disorder in real-world drug and alcohol outpatient settings where withdrawal and abstinence from MA, or other substances, are not eligibility requirements. TMS is a relatively affordable treatment and staff of ambulatory health settings can be trained to administer TMS. It is a potentially scalable and translatable treatment for existing drug and alcohol clinical settings. TMS has the potential to provide a much-needed adjuvant treatment to existing psychosocial interventions for MA use disorder. A limitation of this protocol is that the feasibility of follow-up is only examined at the end of treatment (4 weeks). TRIAL REGISTRATION: Australia New Zealand Clinical Trial Registry ACTRN12622000762752. Registered on May 27, 2022, and retrospectively registered (first participant enrolled) on May 23, 2022, with protocol version 7 on February 24, 2023.

Metaorganismal choline metabolism shapes olfactory perception.

Microbes living in the intestine can regulate key signaling processes in the central nervous system that directly impact brain health. This gut-brain signaling axis is partially mediated by microbe-host-dependent immune regulation, gut-innervating neuronal communication, and endocrine-like small molecule metabolites that originate from bacteria to ultimately cross the blood-brain barrier. Given the mounting evidence of gut-brain crosstalk, a new therapeutic approach of "psychobiotics" has emerged, whereby strategies designed to primarily modify the gut microbiome have been shown to improve mental health or slow neurodegenerative diseases. Diet is one of the most powerful determinants of gut microbiome community structure, and dietary habits are associated with brain health and disease. Recently, the metaorganismal (i.e., diet-microbe-host) trimethylamine N-oxide (TMAO) pathway has been linked to the development of several brain diseases including Alzheimer's, Parkinson's, and ischemic stroke. However, it is poorly understood how metaorganismal TMAO production influences brain function under normal physiological conditions. To address this, here we have reduced TMAO levels by inhibiting gut microbe-driven choline conversion to trimethylamine (TMA), and then performed comprehensive behavioral phenotyping in mice. Unexpectedly, we find that TMAO is particularly enriched in the murine olfactory bulb, and when TMAO production is blunted at the level of bacterial choline TMA lyase (CutC/D), olfactory perception is altered. Taken together, our studies demonstrate a previously underappreciated role for the TMAO pathway in olfactory-related behaviors.

Tobacco treatment incorporating contingency management, nicotine replacement therapy, and behavioral counseling for pregnant women who use substances: a feasibility trial.

Introduction: Most pregnant women with substance use problems smoke, and few will quit during their pregnancy. Tobacco treatment is often overlooked, with the focus usually placed on other substance use. Additionally, few targeted effective treatments for this group exist. To address this, the feasibility of an intensive tobacco treatment incorporating contingency management (CM) that featured non-face-to-face delivery was examined. Methods: A single-arm pre-post design feasibility trial was conducted in three antenatal services that support women who use substances in metropolitan Australia. Participants were over the age of 15, had <33-week gestation, and smoked tobacco daily. They received financial incentives for daily carbon monoxide-verified smoking abstinence or reduction through an internet-based CM programme, nicotine replacement therapy (NRT) posted to women and partners or household members who smoked and telephone-delivered behavioral counseling from study enrolment to birth. Results: Of the 101 referrals, 46 women (46%) consented. The mean (SD) age was 31(±6) years, and the gestation period was 22(±6) weeks. Nineteen (41%) of those enrolled were retained for 12-week postpartum. Of 46 women, 32 (70%) utilized CM; 32 (70%) used NRT for ≥2 weeks; 23 (50%) attended ≥1 counseling session; and 15 (22%) received NRT for partners/household members. Fifteen (33%) were verified abstinent from tobacco at delivery after a median (IQR) period of abstinence of 65(36-128) days. All non-smokers at birth utilized NRT and financial incentives, and 9/15 (60%) utilized counseling. Four (9%) were abstinent at 12-week postpartum. Median cigarettes smoked/day reduced from baseline to delivery (10(6-20) to 1(0-6) p =< 0.001). Women who quit smoking had more education (72% vs. 33% p =< 0.02), completed more CO samples (median (IQR) 101(59-157) vs. 2(0-20) p =< 0.001), and received more incentives (median (IQR) $909($225-$1980) vs. $34($3-$64) p =< 0.001). Intervention acceptability was rated favorably by participants (9 items rated 0-10 with scores >5 considered favorable). Discussion: This study demonstrated the feasibility and acceptability of a consumer-informed, non-face-to-face intensive tobacco treatment, highlighting the potential of remotely delivered technology-based CM to reduce the health impact of tobacco smoking in high-priority populations. The intervention demonstrates scale-up potential. Future studies should extend treatment into the postpartum period, utilizing new technologies to enhance CM delivery and improve counseling provision and partner support. Clinical trial registration: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374196, ACTRN1261800056224.

MBOAT7-driven lysophosphatidylinositol acylation in adipocytes contributes to systemic glucose homeostasis.

We previously demonstrated that antisense oligonucleotide-mediated knockdown of Mboat7, the gene encoding membrane bound O-acyltransferase 7, in the liver and adipose tissue of mice promoted high fat diet-induced hepatic steatosis, hyperinsulinemia, and systemic insulin resistance. Thereafter, other groups showed that hepatocyte-specific genetic deletion of Mboat7 promoted striking fatty liver and NAFLD progression in mice but does not alter insulin sensitivity, suggesting the potential for cell autonomous roles. Here, we show that MBOAT7 function in adipocytes contributes to diet-induced metabolic disturbances including hyperinsulinemia and systemic insulin resistance. We generated Mboat7 floxed mice and created hepatocyte- and adipocyte-specific Mboat7 knockout mice using Cre-recombinase mice under the control of the albumin and adiponectin promoter, respectively. Here, we show that MBOAT7 function in adipocytes contributes to diet-induced metabolic disturbances including hyperinsulinemia and systemic insulin resistance. The expression of Mboat7 in white adipose tissue closely correlates with diet-induced obesity across a panel of ∼100 inbred strains of mice fed a high fat/high sucrose diet. Moreover, we found that adipocyte-specific genetic deletion of Mboat7 is sufficient to promote hyperinsulinemia, systemic insulin resistance, and mild fatty liver. Unlike in the liver, where Mboat7 plays a relatively minor role in maintaining arachidonic acid-containing PI pools, Mboat7 is the major source of arachidonic acid-containing PI pools in adipose tissue. Our data demonstrate that MBOAT7 is a critical regulator of adipose tissue PI homeostasis, and adipocyte MBOAT7-driven PI biosynthesis is closely linked to hyperinsulinemia and insulin resistance in mice.

Correction: Autologous Muscle-Derived Nerve Wrap for Prevention of Symptomatic Microneuromas in Primary Nerve Repair.

[This corrects the article DOI: 10.7759/cureus.22513.].

Scaphoid Dislocation Reconstruction with Scapholunotriquetral Ligament Tenodesis.

Traumatic injuries leading to complex scaphoid dislocations are uncommon. We present a successful reconstructive case after a complex intercarpal instability injury using scapholunotriquetral tenodesis without the need for Kirschner wire fixation and early controlled range of motion therapy. At 3 months, the patient had a pain-free wrist with a 100-degree arc of motion and returned to work with full functionality. A literature review was performed to describe the previously published surgical treatments of this injury pattern and compare functional outcomes.

SPINE: An Initiative to Reduce Pressure Sore Recurrence.

The recurrence rate after pressure sore reconstruction remains high. Primary inciting factors can be organized into efforts aimed at wound prevention: spasticity relief, pressure off-loading, infection and contamination prevention, nutrition optimization, and maximizing extremity function. This article presents our detailed protocol, SPINE, to address each inciting factor with a summary of cases at our facility and review best practices from evidence-based medicine in the literature.

Using mixed methods to establish tobacco treatment acceptability from the perspective of clients and clinicians of antenatal substance use services.

BACKGROUND: Up to 95% of pregnant women with alcohol and other drug (AOD) problems also smoke tobacco. Challenging psychosocial circumstances and a lack of targeted tobacco interventions contribute to low rates of prenatal abstinence and more effective treatment strategies are required. This study explores smoking in pregnant clients of AOD treatment services from a consumer and healthcare provider perspective to examine characteristics of behaviour change and the acceptability of evidence-based tobacco treatment strategies. Outcomes will support the design and implementation of a comprehensive tobacco intervention. METHODS: A mixed methods triangulated design was used. Thirteen women who smoked and attended antenatal AOD services in New South Wales, Australia, were interviewed and 28 clinicians from the same services were surveyed. Domains including experiences of tobacco smoking in pregnancy, motivators and barriers to cessation and evidence-based strategies to assist cessation during pregnancy were explored. Interviews were analysed using Iterative Categorization, with interpretation guided by Qualitative Description. Online surveys were analysed descriptively. A convergent-parallel mixed methods analysis was performed. RESULTS: Women and clinicians agreed that improving baby's health outcomes was the primary motivation to stop smoking. Negative experiences with nicotine replacement therapy (NRT), financial constraints and maternal contraindications restricted its uptake and effectiveness during pregnancy. Both groups agreed that other AOD use, stopping multiple substances concurrently, difficulty coping with stress and the influence of partners who smoke had the biggest impacts on cessation efforts. Clinicians favoured harm-reduction rather than abstinence-based tobacco interventions and women appeared satisfied with reduction efforts. Both views may influence the attainment of prenatal abstinence-based goals. Although previous evidence suggested the contrary, clinicians were willing to encourage simultaneous cessation of tobacco and other substances. Non-judgmental treatment approaches that provide extra support, education and motivation were important for women. Women and clinicians supported use of NRT despite concerns. Financial incentives, counselling, partner support and offering tobacco treatment with antenatal AOD care were considered acceptable treatment options. CONCLUSIONS: NRT, incentives, counselling and partner support could be utilized in a tobacco intervention for pregnant women with substance use concerns. Non-judgmental education, motivation, and provision of NRT including instruction for correct use are important considerations.

Single midline incision approach for decompression of greater, lesser and third occipital nerves in migraine surgery.

BACKGROUND: The traditional approach for occipital migraine surgery encompasses three separate surgical incisions in the posterior neck to decompress the greater occipital nerves (GON), lesser occipital nerves (LON), and third occipital nerves (TON). Other incisions have been investigated, including singular transverse incisions. We sought to evaluate a single, vertical midline incision approach for decompression of all six occipital nerves. METHODS: Using 10 cadaveric hemi-sides (5 fresh cadaver head and necks). Anatomic landmarks and the location of the bilateral GON, LON, and TON were marked according to previous anatomic studies. A single, midline 9-cm incision was made, and lateral skin flaps were raised to decompress or avulse all six nerves. RESULTS: Through the midline incision, the GON and TON were identified at 3.5 and 6.2 cm, respectively, inferior to a line bisecting the external auditory canal (EAC) and 1.5 cm lateral to the midline. The LON was identified as 6-cm inferior and 6.5-cm medial to a line bisecting the EAC in the plane just above the investing layer of the deep cervical fascia until the posterior border of the sternocleidomastoid was encountered. The LON had the greatest amount of variation but was identified lateral to the posterior border of the SCM. CONCLUSIONS: A single midline incision approach allows for successful identification and decompression of all six occipital nerves in migraine surgery.

Autologous Muscle-Derived Nerve Wrap for Prevention of Symptomatic Microneuromas in Primary Nerve Repair.

Regeneration of peripheral nerves after repair is incomplete. Painful microneuromas may form at the site of an appropriately performed primary microsurgical nerve repair leading to a persistent Tinel's sign and hypersensitivity in that location. Here, we describe an autologous option using a free muscle-derived nerve wrap with the intent to capture axonal escape at the site of primary nerve coaptation. We demonstrate this technique on a patient undergoing primary nerve repair of a laceration to the superficial branch of the radial nerve using extensor digitorum communis muscle as a donor graft. This has become our preferred technique over commercially available nerve wraps as the muscle wrap is autologous, not limited by cost, and has the potential to limit microneuroma formation at the coaptation site.

Gut microbe-targeted choline trimethylamine lyase inhibition improves obesity via rewiring of host circadian rhythms.

Obesity has repeatedly been linked to reorganization of the gut microbiome, yet to this point obesity therapeutics have been targeted exclusively toward the human host. Here, we show that gut microbe-targeted inhibition of the trimethylamine N-oxide (TMAO) pathway protects mice against the metabolic disturbances associated with diet-induced obesity (DIO) or leptin deficiency (Lepob/ob). Small molecule inhibition of the gut microbial enzyme choline TMA-lyase (CutC) does not reduce food intake but is instead associated with alterations in the gut microbiome, improvement in glucose tolerance, and enhanced energy expenditure. We also show that gut microbial CutC inhibition is associated with reorganization of host circadian control of both phosphatidylcholine and energy metabolism. This study underscores the relationship between microbe and host metabolism and provides evidence that gut microbe-derived trimethylamine (TMA) is a key regulator of the host circadian clock. This work also demonstrates that gut microbe-targeted enzyme inhibitors have potential as anti-obesity therapeutics.

Gut microbial trimethylamine is elevated in alcohol-associated hepatitis and contributes to ethanol-induced liver injury in mice.

There is mounting evidence that microbes residing in the human intestine contribute to diverse alcohol-associated liver diseases (ALD) including the most deadly form known as alcohol-associated hepatitis (AH). However, mechanisms by which gut microbes synergize with excessive alcohol intake to promote liver injury are poorly understood. Furthermore, whether drugs that selectively target gut microbial metabolism can improve ALD has never been tested. We used liquid chromatography tandem mass spectrometry to quantify the levels of microbe and host choline co-metabolites in healthy controls and AH patients, finding elevated levels of the microbial metabolite trimethylamine (TMA) in AH. In subsequent studies, we treated mice with non-lethal bacterial choline TMA lyase (CutC/D) inhibitors to blunt gut microbe-dependent production of TMA in the context of chronic ethanol administration. Indices of liver injury were quantified by complementary RNA sequencing, biochemical, and histological approaches. In addition, we examined the impact of ethanol consumption and TMA lyase inhibition on gut microbiome structure via 16S rRNA sequencing. We show the gut microbial choline metabolite TMA is elevated in AH patients and correlates with reduced hepatic expression of the TMA oxygenase flavin-containing monooxygenase 3 (FMO3). Provocatively, we find that small molecule inhibition of gut microbial CutC/D activity protects mice from ethanol-induced liver injury. CutC/D inhibitor-driven improvement in ethanol-induced liver injury is associated with distinct reorganization of the gut microbiome and host liver transcriptome. The microbial metabolite TMA is elevated in patients with AH, and inhibition of TMA production from gut microbes can protect mice from ethanol-induced liver injury.

Smoking cessation interventions for pregnant women attending treatment for substance use disorders: A systematic review.

BACKGROUND AND AIMS: Up to 95% of pregnant women seeking treatment for alcohol and other drug (AOD) use smoke tobacco. Previous reviews indicate few effective smoking cessation treatments for this group. This updated review aimed to identify and measure the efficacy of smoking cessation interventions trialled among pregnant women in AOD treatment settings who smoke tobacco. METHODS: A narrative synthesis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Studies involving psychological, behavioural or pharmacological interventions used to treat tobacco use, including electronic nicotine delivery systems, for pregnant women of any age, who smoked tobacco and were seeking/receiving treatment, or in post-treatment recovery for AOD concerns, were reviewed. MEDLINE, PsycINFO, CINAHL, EMBASE and ProQuest databases, grey literature and reference lists were searched, and field experts were contacted for unpublished study data. The Effective Public Health Practice Project tool assessed study quality. The review was pre-registered with PROSPERO no. CRD42018108777. RESULTS: Seven interventions (two randomised controlled trials, two single-arm pilot studies, two program evaluations and one causal comparative study) treating 875 women were identified. All were United States (US)-based and targeted women with drug dependence, but not alcohol dependence. Three interventions used contingency management, five provided behavioural counselling, and one offered nicotine replacement therapy. All reported reductions in cigarette consumption; one contingency management-based study demonstrated higher abstinence rates compared with controls at treatment-end that were not maintained at follow-up. Four of six studies were rated as methodologically weak and one unpublished study was not rated. CONCLUSIONS: Conclusions about the efficacy of smoking interventions for pregnant women with alcohol and other drug concerns who also smoke tobacco are hindered by the paucity of available data and poor methodological quality of included studies.

A Single Human-Relevant Fast Food Meal Rapidly Reorganizes Metabolomic and Transcriptomic Signatures in a Gut Microbiota-Dependent Manner.

BACKGROUND: A major contributor to cardiometabolic disease is caloric excess, often a result of consuming low cost, high calorie fast food. Studies have demonstrated the pivotal role of gut microbes contributing to cardiovascular disease in a diet-dependent manner. Given the central contributions of diet and gut microbiota to cardiometabolic disease, we hypothesized that microbial metabolites originating after fast food consumption can elicit acute metabolic responses in the liver. METHODS: We gave conventionally raised mice or mice that had their microbiomes depleted with antibiotics a single oral gavage of a liquified fast food meal or liquified control rodent chow meal. After four hours, mice were sacrificed and we used untargeted metabolomics of portal and peripheral blood, 16S rRNA gene sequencing, targeted liver metabolomics, and host liver RNA sequencing to identify novel fast food-derived microbial metabolites and their acute effects on liver function. RESULTS: Several candidate microbial metabolites were enriched in portal blood upon fast food feeding, and were essentially absent in antibiotic-treated mice. Strikingly, at four hours post-gavage, fast food consumption resulted in rapid reorganization of the gut microbial community and drastically altered hepatic gene expression. Importantly, diet-driven reshaping of the microbiome and liver transcriptome was dependent on an intact microbial community and not observed in antibiotic ablated animals. CONCLUSIONS: Collectively, these data suggest a single fast food meal is sufficient to reshape the gut microbial community in mice, yielding a unique signature of food-derived microbial metabolites. Future studies are in progress to determine the contribution of select metabolites to cardiometabolic disease progression and the translational relevance of these animal studies.

Hepatocyte activity of the cholesterol sensor smoothened regulates cholesterol and bile acid homeostasis in mice.

Cellular cholesterol is regulated by at least two transcriptional mechanisms involving sterol-regulatory-element-binding proteins (SREBPs) and liver X receptors (LXRs). Although SREBP and LXR pathways are the predominant mechanisms that sense cholesterol in the endoplasmic reticulum and nucleus to alter sterol-regulated gene expression, evidence suggests cholesterol in plasma membrane can be sensed by proteins in the Hedgehog (Hh) pathway which regulate organ self-renewal and are a morphogenic driver during embryonic development. Cholesterol interacts with the G-protein-coupled receptor Smoothened (Smo), which impacts downstream Hh signaling. Although evidence suggests cholesterol influences Hh signaling, it is not known whether Smo-dependent sterol sensing impacts cholesterol homeostasis in vivo. We examined dietary-cholesterol-induced reorganization of whole-body sterol and bile acid (BA) homeostasis in adult mice with inducible hepatocyte-specific Smo deletion. These studies demonstrate Smo in hepatocytes plays a regulatory role in sensing and feedback regulation of cholesterol balance driven by excess dietary cholesterol.

Reconstruction of a Giant Congenital Melanocytic Nevus Defect With a Submental Flap in a Global Health Setting.

Excision of a facial congenital melanocytic nevus (CMN) is a common reason for consultation in pediatric plastic surgery. Facial nevi are generally small and uncomplicated to remove and become more complex when large or giant. The available resources determine treatment and excision options. The indication for excision is generally based on esthetic criteria; however, the risk of melanoma increases with the nevi diameter. This patient with a giant CMN (GCMN) was encountered on an international medical mission trip. The palm-sized lesion spanned from her left zygomatic arch down to the jawline. Due to the esthetic impact and lack of resources to continue monitoring the lesion, complete excision was performed. The resultant defect was reconstructed with a pedicled submental flap. This article presents management and reconstruction of a facial GCMN encountered in the global setting and presents a brief literature review of GCMN.

The use and effects of synthetic cannabinoid receptor agonists by New South Wales cannabis treatment clients.

INTRODUCTION: Despite decreasing consumption by general populations, use of synthetic cannabinoid receptor agonists (SCRAs) persists in some marginalised groups, including those who use other substances. This article explores SCRA consumption in an Australian cannabis treatment sample, comparing those who report ever using SCRAs with those who have never used SCRAs. METHODS: A questionnaire orally administered in person to a convenience sample of 154 cannabis treatment service clients from New South Wales, Australia (71% male, median age 35) collected information regarding cannabis and SCRA use including motivations, effects and health-related consequences of use, demographics, other substance use and overall health. Demographic profiles and between-group differences were explored. McNemar tests compared effects of SCRA and cannabis. Logistic regression analysis determined predictors of SCRA use. RESULTS: Half (53%) reported lifetime SCRA use; 20% reported previous-month use. The SCRA + cannabis group displayed greater polysubstance use and psychological distress. Reduced dependence on cannabis but higher levels of other substance use may predict SCRA use. Although curiosity motivated initial SCRA consumption, perceived psychoactive strength drove continued use. SCRAs appear to induce more negative side-effects than cannabis. Of the SCRA + cannabis group, 27% sought medical assistance for SCRA use. Most (90%) preferred cannabis to SCRAs, citing superior safety, effects and consistency of cannabis. CONCLUSIONS: Among clients seeking treatment for cannabis use, SCRA use was relatively common, although not a preferred substance. Hazardous substance use and poor mental health characterised SCRA consumers, highlighting the need for continued monitoring by researchers and treatment providers of SCRA consumption in populations who use substances.

Intensive Behavioural and Pharmacological Treatment for Tobacco Dependence in Pregnant Women with Complex Psychosocial Challenges: A Case Report.

Up to 95% of women who use other substances also smoke tobacco during pregnancy. Challenging psychosocial circumstances and other barriers that contribute to high levels of tobacco dependence result in few quitting successfully. This case report describes the treatment of a highly tobacco dependent 34-year-old pregnant woman with a history of recent substance use, mental illness and trauma, enrolled in the Incentives to Quit Tobacco in Pregnancy program. Heavy smoking, both during the day and overnight, was reported. An extensive history of quit attempts, as well as a strong desire to cease tobacco use during pregnancy, was also noted. Treatment utilising extensive behavioural supports, including financial incentives for carbon monoxide verified abstinence and telephone-based counselling, in combination with nicotine replacement therapy (NRT), was offered to assist cessation. Excellent uptake and adherence to all aspects of treatment saw tobacco cessation achieved and maintained for 24 weeks while on the program. NRT used at doses well above those recommended for pregnancy was required to alleviate strong withdrawal symptoms and maintain abstinence. Daily monitoring of carbon monoxide, financial incentives for continued abstinence and regular phone support were critical to maintaining motivation and preventing relapse to smoking. Post-program relapse to smoking did occur, as is common, and highlights the need for longer-term intensive support for pregnant women with complex behavioural and social problems. Given the prevalence of tobacco smoking in such populations, long-term harm reduction treatment models using extensive behavioural support in combination with NRT should be considered for inclusion in current smoking cessation guidelines.

Small molecule inhibition of gut microbial choline trimethylamine lyase activity alters host cholesterol and bile acid metabolism.

The gut microbe-derived metabolite trimethylamine-N-oxide (TMAO) has recently been linked to cardiovascular disease (CVD) pathogenesis, prompting the development of therapeutic strategies to reduce TMAO. Previous work has shown that experimental alteration of circulating TMAO levels via dietary alterations or inhibition of the host TMAO producing enzyme flavin containing monooxygenase 3 (FMO3) is associated with reorganization of host cholesterol and bile acid metabolism in mice. In this work, we set out to understand whether recently developed nonlethal gut microbe-targeting small molecule choline trimethylamine (TMA) lyase inhibitors also alter host cholesterol and bile acid metabolism. Treatment of mice with the mechanism-based choline TMA lyase inhibitor, iodomethylcholine (IMC), increased fecal neutral sterol loss in the form of coprostanol, a bacteria metabolite of cholesterol. In parallel, IMC treatment resulted in marked reductions in the intestinal sterol transporter Niemann-pick C1-like 1 (NPC1L1) and reorganization of the gut microbial community, primarily reversing choline supplemented diet-induced changes. IMC also prevented diet-driven hepatic cholesterol accumulation, causing both upregulation of the host hepatic bile acid synthetic enzyme CYP7A1 and altering the expression of hepatic genes critical for bile acid feedback regulation. These studies suggest that the gut microbiota-driven TMAO pathway is closely linked to both microbe and host sterol and bile acid metabolism. Collectively, as gut microbe-targeting choline TMA lyase inhibitors move through the drug discovery pipeline from preclinical models to human studies, it will be important to understand how these drugs impact both microbe and host cholesterol and bile acid metabolism.NEW & NOTEWORTHY The gut microbe-dependent metabolite trimethylamine-N-oxide (TMAO) has been strongly associated with cardiovascular mortality, prompting drug discovery efforts to identify points of therapeutic intervention within the microbe host TMAO pathway. Recently, mechanism-based small molecule inhibitors of the major bacterial trimethylamine (TMA) lyase enzymes have been developed, and these drugs show efficacy as anti-atherothrombotic agents. The novel findings of this study are that small molecule TMA lyase inhibition results in beneficial reorganization of host cholesterol and bile acid metabolism. This study confirms previous observations that the gut microbial TMAO pathway is intimately linked to host cholesterol and bile acid metabolism and provides further rationale for the development of small molecule choline TMA lyase inhibitors for the treatment of cardiometabolic disorders.

Dietary Choline Supplementation Attenuates High-Fat-Diet-Induced Hepatocellular Carcinoma in Mice.

BACKGROUND: Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death in the world. Choline deficiency has been well studied in the context of liver disease; however, less is known about the effects of choline supplementation in HCC. OBJECTIVE: The objective of this study was to test whether choline supplementation could influence the progression of HCC in a high-fat-diet (HFD)-driven mouse model. METHODS: Four-day-old male C57BL/6J mice were treated with the chemical carcinogen, 7,12-dimethylbenz[a]anthracene, and were randomly assigned at weaning to a cohort fed an HFD (60% kcal fat) or an HFD with supplemental choline (60% kcal fat, 1.2% choline; HFD+C) for 30 wk. Blood was isolated at 15 and 30 wk to measure immune cells by flow cytometry, and glucose-tolerance tests were performed 2 wk prior to killing. Overall tumor burden was quantified, hepatic lipids were measured enzymatically, and phosphatidylcholine species were measured by targeted MS methods. Gene expression and mitochondrial DNA were quantified by quantitative PCR. RESULTS: HFD+C mice exhibited a 50-90% increase in both circulating choline and betaine concentrations in the fed state (P ≤ 0.05). Choline supplementation resulted in a 55% decrease in total tumor numbers, a 67% decrease in tumor surface area, and a 50% decrease in hepatic steatosis after 30 wk of diet (P ≤ 0.05). Choline supplementation increased the abundance of mitochondria and the relative expression of ß-oxidation genes by 21% and ∼75-100%, respectively, in the liver. HFD+C attenuated circulating myeloid-derived suppressor cells at 15 wk of feeding (P ≤ 0.05). CONCLUSIONS: Choline supplementation attenuated HFD-induced HCC and hepatic steatosis in male C57BL/6J mice. These results suggest a therapeutic benefit of choline supplementation in blunting HCC progression.