The involvement of TRPV1 in emesis and anti-emesis

Migraine inhibitor olcegepant reduces weight loss and IL-6 release in SARS-CoV-2-infected older mice with neurological signs

COVID-19 can cause neurological symptoms such as fever, dizziness, and nausea. However, such neurological symptoms of SARS-CoV-2 infection have been hardly assessed in mouse models. In this study, we infected two commonly used wild-type mouse lines (C57BL/6J and 129/SvEv) and a 129S calcitonin gene-related peptide (αCGRP) null-line with mouse-adapted SARS-CoV-2 and demonstrated neurological signs including fever, dizziness, and nausea. We then evaluated whether a CGRP receptor antagonist, olcegepant, a "gepant" antagonist used in migraine treatment, could mitigate acute neuroinflammatory and neurological signs of SARS-COV-2 infection. First, we determined whether CGRP receptor antagonism provided protection from permanent weight loss in older (>18 m) C57BL/6J and 129/SvEv mice. We also observed acute fever, dizziness, and nausea in all older mice, regardless of treatment. In both wild-type mouse lines, CGRP antagonism reduced acute interleukin 6 (IL-6) levels with virtually no IL-6 release in mice lacking αCGRP. These findings suggest that migraine inhibitors such as those blocking CGRP receptor signaling protect against acute IL-6 release and subsequent inflammatory events after SARS-CoV-2 infection, which may have repercussions for related pandemic or endemic coronavirus outbreaks.IMPORTANCECoronavirus disease (COVID-19) can cause neurological symptoms such as fever, headache, dizziness, and nausea. However, such neurological symptoms of severe acute respiratory syndrome CoV-2 (SARS-CoV-2) infection have been hardly assessed in mouse models. In this study, we first infected two commonly used wild-type mouse lines (C57BL/6J and 129S) with mouse-adapted SARS-CoV-2 and demonstrated neurological symptoms including fever and nausea. Furthermore, we showed that the migraine treatment drug olcegepant could reduce long-term weight loss and IL-6 release associated with SARS-CoV-2 infection. These findings suggest that a migraine blocker can be protective for at least some acute SARS-CoV-2 infection signs and raise the possibility that it may also impact long-term outcomes.

Cannabis Use Patterns and Whole-Blood Cannabinoid Profiles of Emergency Department Patients With Suspected Cannabinoid Hyperemesis Syndrome

STUDY OBJECTIVES

The objectives of this study were to characterize the detailed cannabis use patterns (eg, frequency, mode, and product) and determine the differences in the whole-blood cannabinoid profiles during symptomatic versus asymptomatic periods of participants with suspected cannabinoid hyperemesis syndrome recruited from the emergency department (ED) during a symptomatic episode.

METHODS

This is a prospective observational cohort study of participants with symptomatic cyclic vomiting onset after chronic cannabis use. Standardized assessments were conducted to evaluate for lifetime and recent cannabis use, cannabis use disorder, and cannabis withdrawal symptoms. Quantitative whole-blood cannabinoid testing was performed at 2 times, first when symptomatic (ie, baseline) and at least 2 weeks after the ED visit when asymptomatic. The differences in cannabinoid concentrations were compared between symptomatic and asymptomatic testing. The study was conducted from September 2021 to August 2022.

RESULTS

There was a difference observed between delta-9-tetrahydrocannabinol metabolites, but not the parent compound during symptomatic episodes and asymptomatic periods. Most participants (84%) reported using cannabis > once per day (median 3 times per day on weekdays, 4 times per day on weekends). Hazardous cannabis use was universal among participants; the mean cannabis withdrawal discomfort score was 13, indicating clinically significant rates of cannabis withdrawal symptoms with cessation of use. Most participants (79%) previously tried to stop cannabis use, but a few (13%) of them had sought treatment.

CONCLUSION

Patients presenting to the ED with cannabinoid hyperemesis syndrome have high cannabis use disorder scores. Further studies are needed to better understand the influence of THC metabolism and concentrations on symptomatic cyclic vomiting.

Comparison of the Anticancer Effects of Arvanil and Olvanil When Combined with Cisplatin and Mitoxantrone in Various Melanoma Cell Lines-An Isobolographic Analysis

Due to the unique structures of arvanil and olvanil, the drugs combine certain properties of both cannabinoids and vanilloids, which makes them able to stimulate both TPRV1 and CB1 receptors and causes them to be interesting agents in the setting of carcinoma treatment. The aim of this study was to investigate the cytotoxic and anti-proliferative effects of arvanil and olvanil when administered alone and in combination with cisplatin (CDDP) and mitoxantrone (MTX), using various primary (A375, FM55P) and metastatic (SK-MEL 28, FM55M2) human malignant melanoma cell lines. The results indicate that both arvanil and olvanil inhibited (dose-dependently) the viability and proliferation of various malignant melanoma cells, as demonstrated by MTT and BrdU assays. The safety profile of both arvanil and olvanil tested in human keratinocytes (HaCaT) and normal human melanocytes (HEMa-LP) revealed that neither arvanil nor olvanil caused significant cytotoxicity in HaCaT and HEMa-LP cell lines in LDH and MTT assays. Isobolographically, it was found that both arvanil and olvanil exerted additive interactions with MTX and antagonistic interactions with CDDP in the studied malignant melanoma cell lines. In conclusion, the combinations of arvanil or olvanil with MTX may be considered as a part of melanoma multi-drug therapy; however, the combination of these compounds with CDDP should be carefully considered due to the antagonistic interactions observed in the studied malignant melanoma cell lines.

TRPV1: A Common Denominator Mediating Antinociceptive and Antiemetic Effects of Cannabinoids

The most common medicinal claims for cannabis are relief from chronic pain, stimulation of appetite, and as an antiemetic. However, the mechanisms by which cannabis reduces pain and prevents nausea and vomiting are not fully understood. Among more than 450 constituents in cannabis, the most abundant cannabinoids are Δ⁹-tetrahydrocannabinol (THC) and cannabidiol (CBD). Cannabinoids either directly or indirectly modulate ion channel function. Transient receptor potential vanilloid 1 (TRPV1) is an ion channel responsible for mediating several modalities of pain, and it is expressed in both the peripheral and the central pain pathways. Activation of TRPV1 in sensory neurons mediates nociception in the ascending pain pathway, while activation of TRPV1 in the central descending pain pathway, which involves the rostral ventral medulla (RVM) and the periaqueductal gray (PAG), mediates antinociception. TRPV1 channels are thought to be implicated in neuropathic/spontaneous pain perception in the setting of impaired descending antinociceptive control. Activation of TRPV1 also can cause the release of calcitonin gene-related peptide (CGRP) and other neuropeptides/neurotransmitters from the peripheral and central nerve terminals, including the vagal nerve terminal innervating the gut that forms central synapses at the nucleus tractus solitarius (NTS). One of the adverse effects of chronic cannabis use is the paradoxical cannabis-induced hyperemesis syndrome (HES), which is becoming more common, perhaps due to the wider availability of cannabis-containing products and the chronic use of products containing higher levels of cannabinoids. Although, the mechanism of HES is unknown, the effective treatment options include hot-water hydrotherapy and the topical application of capsaicin, both activate TRPV1 channels and may involve the vagal-NTS and area postrema (AP) nausea and vomiting pathway. In this review, we will delineate the activation of TRPV1 by cannabinoids and their role in the antinociceptive/nociceptive and antiemetic/emetic effects involving the peripheral, spinal, and supraspinal structures.

Mechanisms of Chemotherapy-Induced Neurotoxicity

Since the first clinical trials conducted after World War II, chemotherapeutic drugs have been extensively used in the clinic as the main cancer treatment either alone or as an adjuvant therapy before and after surgery. Although the use of chemotherapeutic drugs improved the survival of cancer patients, these drugs are notorious for causing many severe side effects that significantly reduce the efficacy of anti-cancer treatment and patients’ quality of life. Many widely used chemotherapy drugs including platinum-based agents, taxanes, vinca alkaloids, proteasome inhibitors, and thalidomide analogs may cause direct and indirect neurotoxicity. In this review we discuss the main effects of chemotherapy on the peripheral and central nervous systems, including neuropathic pain, chemobrain, enteric neuropathy, as well as nausea and emesis. Understanding mechanisms involved in chemotherapy-induced neurotoxicity is crucial for the development of drugs that can protect the nervous system, reduce symptoms experienced by millions of patients, and improve the outcome of the treatment and patients’ quality of life.

Assessment of PDE4 Inhibitor-Induced Hypothermia as a Correlate of Nausea in Mice

Simple Summary

Type 4 cAMP-phosphodiesterases (PDE4s) comprise a family of four isoenzymes, PDE4A to D, that hydrolyze and inactivate the second messenger cAMP. Non/PAN-selective PDE4 inhibitors, which inhibit all four PDE4 subtypes simultaneously, produce many promising therapeutic benefits, such as anti-inflammatory or cognition- and memory-enhancing effects. However, unwanted side effects, principally, nausea, diarrhea, and emesis, have long hampered their clinical and commercial success. Targeting individual PDE4 subtypes has been proposed for developing drugs with an improved safety profile, but which PDE4 subtype(s) is/are actually responsible for nausea and emesis remains ill-defined. Based on the observation that nausea is often accompanied by hypothermia in humans and other mammals, we used the measurement of core body temperatures of mice as a potential correlate of nausea induced by PDE4 inhibitors in humans. We find that selective inactivation of any of the four PDE4 subtypes did not change the body temperature of mice, suggesting that PAN-PDE4 inhibitor-induced hypothermia (and hence nausea in humans) requires the simultaneous inhibition of multiple PDE4 subtypes. This finding contrasts with prior reports that proposed PDE4D as the subtype mediating these side effects of PDE4 inhibitors and suggests that subtype-selective inhibitors that target any individual PDE4 subtype, including PDE4D, may not cause nausea.

Abstract

Treatment with PAN-PDE4 inhibitors has been shown to produce hypothermia in multiple species. Given the growing body of evidence that links nausea and emesis to disturbances in thermoregulation in mammals, we explored PDE4 inhibitor-induced hypothermia as a novel correlate of nausea in mice. Using knockout mice for each of the four PDE4 subtypes, we show that selective inactivation of individual PDE4 subtypes per se does not produce hypothermia, which must instead require the concurrent inactivation of multiple (at least two) PDE4 subtypes. These findings contrast with the role of PDE4s in shortening the duration of α₂-adrenoceptor-dependent anesthesia, a behavioral surrogate previously used to assess the emetic potential of PDE4 inhibitors, which is exclusively affected by inactivation of PDE4D. These different outcomes are rooted in the distinct molecular mechanisms that drive these two paradigms; acting as a physiologic α₂-adrenoceptor antagonist produces the effect of PDE4/PDE4D inactivation on the duration of α₂-adrenoceptor-dependent anesthesia, but does not mediate the effect of PDE4 inhibitors on body temperature in mice. Taken together, our findings suggest that selective inhibition of any individual PDE4 subtype, including inhibition of PDE4D, may be free of nausea and emesis.

Cannabinoid Hyperemesis Syndrome Survey and Genomic Investigation

Background:

Cannabinoid hyperemesis syndrome (CHS) is a diagnosis of exclusion with intractable nausea, cyclic vomiting, abdominal pain, and hot bathing behavior associated with ongoing tetrahydrocannabinol (THC) exposure. Increasing cannabis use may elevate CHS prevalence, exacerbating a public health issue with attendant costs and morbidity.

Objective, Design, and Data Source:

This study, the largest contemporaneous database, investigated genetic mutations underlying CHS. Patients with CHS diagnosis and ongoing symptoms were compared with current cannabis users lacking symptoms.

Target Population:

A screening questionnaire was posted online. Of 585 respondents, 205 qualified as the CHS pool and 54 as controls; a reduced pool of 28 patients and 12 controls ultimately completed genomic testing.

Results:

Patients and controls were high-frequency users of cannabis flower or concentrates (93%), using multiple grams/day of THC-predominant material. Among patients, 15.6% carried diagnoses of cannabis dependency or addiction, and 56.6% experienced withdrawal symptoms. About 87.7% of patients improved after cannabis cessation, most suffering recurrence rapidly after resumption. Findings in patients included mutations in genes COMT {odds ratio, 12 (95% confidence limit [CL], 1.3–88.1) p=0.012}, transient receptor potential vanilloid receptor 1 (TRPV1) (odds ratio, 5.8 [95% CL, 1.2–28.4] p=0.015), CYP2C9 (odds ratio, 7.8 [95% CL, 1.1–70.1] p=0.043), gene coding dopamine-2 receptor (DRD2) (odds ratio, 6.2 [95% CL, 1.1–34.7] p=0.031), and ATP-binding cassette transporter gene (ABCA1) (odds ratio, 8.4 [95% CL, 1.5–48.1] p=0.012).

Limitations:

Some participants were reluctant to undergo genetic testing; only 28 of 99 CHS patients who agreed to testing ultimately returned a kit.

Conclusion:

This is the largest patient cohort of CHS examined to date, and first to note associated mutations in genes affecting neurotransmitters, the endocannabinoid system, and the cytochrome P450 complex associated with cannabinoid metabolism. Although the sample size was smaller than desired, these preliminary findings may contribute to the growing body of knowledge, stimulate additional investigation, help elucidate the pathophysiology of CHS, and, ultimately, direct future treatment.

Therapeutic Potential of Cannabidiol, Cannabidiolic Acid, and Cannabidiolic Acid Methyl Ester as Treatments for Nausea and Vomiting

Introduction: Nausea and vomiting are the most distressing symptoms reported by oncology patients undergoing anticancer treatment. With the currently available treatments, vomiting and especially nausea remain problematic, highlighting the need for alternative treatments. Discussion: Here we review in vitro and in vivo evidence for the effectiveness of the nonpsychoactive cannabinoid cannabidiol (CBD) in managing nausea and vomiting. In addition, we also review the evidence for CBD's acidic precursor, cannabidiolic acid (CBDA), and a methylated version of CBDA (CBDA-ME) in these phenomena. Finally, we explore the potential role of CBD in the treatment of cannabinoid hyperemesis syndrome. Conclusions: CBD has demonstrated efficacy in reducing nausea and vomiting, with CBDA and CBDA-ME being more potent. The data suggest a need for these compounds to be evaluated in clinical trials for their ability to reduce nausea and/or vomiting.

The HCN Channel Blocker ZD7288 Induces Emesis in the Least Shrew (Cryptotis parva)

Subtypes (1-4) of the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are widely expressed in the central and peripheral nervous systems, as well as the cells of smooth muscles in many organs. They mainly serve to regulate cellular excitability in these tissues. The HCN channel blocker ZD7288 has been shown to reduce apomorphine-induced conditioned taste aversion on saccharin preference in rats suggesting potential antinausea/antiemetic effects. Currently, in the least shew model of emesis we find that ZD7288 induces vomiting in a dose-dependent manner, with maximal efficacies of 100% at 1 mg/kg (i.p.) and 83.3% at 10 µg (i.c.v.). HCN channel subtype (1-4) expression was assessed using immunohistochemistry in the least shrew brainstem dorsal vagal complex (DVC) containing the emetic nuclei (area postrema (AP), nucleus tractus solitarius and dorsal motor nucleus of the vagus). Highly enriched HCN1 and HCN4 subtypes are present in the AP. A 1 mg/kg (i.p.) dose of ZD7288 strongly evoked c-Fos expression and ERK1/2 phosphorylation in the shrew brainstem DVC, but not in the in the enteric nervous system in the jejunum, suggesting a central contribution to the evoked vomiting. The ZD7288-evoked c-Fos expression exclusively occurred in tryptophan hydroxylase 2-positive serotonin neurons of the dorsal vagal complex, indicating activation of serotonin neurons may contribute to ZD7288-induced vomiting. To reveal its mechanism(s) of emetic action, we evaluated the efficacy of diverse antiemetics against ZD7288-evoked vomiting including the antagonists/inhibitors of: ERK1/2 (U0126), L-type Ca2+ channel (nifedipine); store-operated Ca2+ entry (MRS 1845); T-type Ca2+ channel (Z944), IP3R (2-APB), RyR receptor (dantrolene); the serotoninergic type 3 receptor (palonosetron); neurokinin 1 receptor (netupitant), dopamine type 2 receptor (sulpride), and the transient receptor potential vanilloid 1 receptor agonist, resiniferatoxin. All tested antiemetics except sulpride attenuated ZD7288-evoked vomiting to varying degrees. In sum, ZD7288 has emetic potential mainly via central mechanisms, a process which involves Ca2+ signaling and several emetic receptors. HCN channel blockers have been reported to have emetic potential in the clinic since they are currently used/investigated as therapeutic candidates for cancer therapy related- or unrelated-heart failure, pain, and cognitive impairment.

Topical capsaicin for the treatment of cannabinoid hyperemesis syndrome, a systematic review and meta-analysis

INTRODUCTION

Cannabinoid hyperemesis syndrome (CHS) is a condition that is being recognized and treated more frequently in emergency departments (EDs) across the United States. Currently, ED providers rely on antiemetics, antipsychotics and benzodiazepines to alleviate the symptoms. Topical capsaicin, a transient receptor potential vanilloid 1 (TRPV1) agonist, has been proposed in recent years as a low-cost and effective alternative to the traditional antiemetic regimen when treating CHS. The aim of this systematic review and meta-analysis is to demonstrate the reliability and the gaps of what is known about this treatment modality.

METHODS

Articles were extracted from PubMed, SCOPUS, and Google Scholar databases. Publication dates ranged from the inception of the databases to October 2020. Initial searches found 328 studies. After careful review and screening by two investigators, 7 studies met the inclusion criteria and were included for our meta-analysis. Variables that were evaluated included the prevalence of hospital admissions for patients treated with capsaicin, time to relief of symptoms after capsaicin administration, and ED length of stay (LOS). I-square and Q-statistic values were used to assess heterogeneity.

RESULTS

Among the 7 studies, there was a total of 106 patients. Two studies reported time to resolution of symptoms following capsaicin administration and ED LOS. Means for these outcomes were 325 (95% CI 234-787) and 379 (95% CI 10-747) minutes respectively. I-square was 44%, and Q-statistic was 11 with 6 degrees of freedom, with a p-value of 0.1.

DISCUSSION

With acceptable time to resolution of symptoms after topical administration and ED LOS, capsaicin appears to be an effective treatment option for symptomatic relief of CHS. Further randomized controlled trials should be conducted to examine if it is the more efficacious and efficient treatment for CHS across various care settings.

The Brazilian version of the Health-Related Quality of Life Questionnaire for Nausea and Vomiting of Pregnancy: translation, cross-cultural adaptation and reliability - an observational cross-sectional study

BACKGROUND

The Health-Related Quality of Life Questionnaire for Nausea and Vomiting of Pregnancy (NVPQOL) is a validated questionnaire assessing quality of life among pregnant women with nausea and vomiting.

OBJECTIVE

To translate, cross-culturally adapt and evaluate the reliability of the NVPQOL.

DESIGN AND SETTING

Observational cross-sectional study developed in a public university in Brazil.

METHODS

The translation, synthesis of translations, back-translation, expert committee, pre-testing and validation were carried out, resulting in a Portuguese-language version. The internal consistency, intra-rater and test-retest reliability and correlation between the total score of the Portuguese-language version of the NVPQOL and the domains of the World Health Organization Quality of Life-bref questionnaire were considered in the data analysis.

RESULTS

The instrument went through the process with testing on 104 pregnant women. Strong internal consistency (Cronbach's α: 0.95), strong intra-rater and test-retest reliability (P < 0.0; intraclass correlation coefficient: 0.89; confidence interval: 0.791-0.945) and strong correlation between the total score of the Portuguese-language version of the NVPQOL and the physical health domain of the World Health Organization Quality of Life-bref questionnaire (P < 0.01; R = -0.8) were observed.

CONCLUSION

The NVPQOL was translated, cross-culturally adapted and validated for the Portuguese language with satisfactory psychometric properties for assessing quality of life, especially in relation to physical health, among pregnant women with symptoms of nausea and vomiting in the first trimester of pregnancy.

Cannabis in Gastroenterology: Watch Your Head! A Review of Use in Inflammatory Bowel Disease, Functional Gut Disorders, and Gut-Related Adverse Effects

Purpose of review

To review recent clinical evidence surrounding the use of cannabinoids and cannabis in gastrointestinal diseases, particularly inflammatory bowel disease (IBD) and functional gut disorders. A second aim is to evaluate the current status of gastrointestinal related adverse effects which have been linked to cannabis use, specifically cannabis hyperemesis syndrome (CHS) and acute pancreatitis.

Recent findings

Observational and prospective studies suggest that cannabinoids improve IBD symptoms. Small prospective clinical trials have not shown any effects on objective inflammatory findings, other than one recent paper in ulcerative colitis, in abstract form only, which suggests endoscopic improvement. Short duration mechanistic studies in functional gut disorders suggest cannabinoids may attenuate gastric emptying and slow colonic motility but appear to have less effect on sensory thresholds in the gut.

Summary

In general, while mostly uncontrolled data suggests cannabis may improve symptoms in IBD (and to a lesser degree functional gut disorders), this is not likely due to any substantial anti-inflammatory effect. Much remains unknown about CHS etiology and complete abstinence from cannabinoids remains the generally accepted treatment strategy. Population-based studies do not suggest that cannabis use is related to acute pancreatitis. Further research is certainly warranted.

Ultra-low doses of the transient receptor potential vanilloid 1 agonist, resiniferatoxin, prevents vomiting evoked by diverse emetogens in the least shrew (Cryptotis parva)

Published studies have shown that the transient receptor potential vanilloid 1 (TRPV1) receptor agonist, resiniferatoxin (RTX), has pro and antiemetic effects. RTX can suppress vomiting evoked by a variety of nonselective emetogens such as copper sulfate and cisplatin in several vomit-competent species. In the least shrew, we have already demonstrated that combinations of ultra-low doses of RTX and low doses of the cannabinoid CB1/2 receptor agonist delta-9-tetrahydrocannabinol (Δ-THC) produce additive antiemetic effects against cisplatin-evoked vomiting. In the current study, we investigated the broad-spectrum antiemetic potential of very low nonemetic doses of RTX against a diverse group of specific emetogens including selective and nonselective agonists of serotonergic 5-hydroxytrptamine (5-HT3) receptor (5-HT and 2-Me-5-HT), dopaminergic D2 receptor (apomorphine and quinpirole), cholinergic M1 receptor (pilocarpine and McN-A-343), as well as the selective substance P neurokinin NK1 receptor agonist GR73632, the selective L-Type calcium channel agonist FPL64176, and the sarcoplasmic endoplasmic reticulum calcium ATPase (SERCA) inhibitor thapsigargin. When administered subcutaneously, ultra-low (0.01 µg/kg) to low (5.0 µg/kg) doses of RTX suppressed vomiting induced by the aforementioned emetogens in a dose-dependent fashion with 50% inhibitory dose values ranging from 0.01 to 1.26 µg/kg. This study is the first to demonstrate that low nanomolar nonemetic doses of RTX have the capacity to completely abolish vomiting caused by diverse receptor specific emetogens in the least shrew model of emesis.

Cannabinoid Hyperemesis Syndrome: A Review of Potential Mechanisms

Introduction: Cannabinoids have long been known for their ability to treat nausea and vomiting. Recent reports, however, have highlighted the paradoxical proemetic effects of cannabinoids. Cannabinoid hyperemesis syndrome (CHS) is characterized by cyclical episodes of nausea and vomiting, accompanied by abdominal pain following prolonged, high-dose cannabis use, which is alleviated by hot baths and showers. Little is known about the cause of this syndrome. Discussion: Cannabinoids produce a biphasic effect on nausea and vomiting, with low doses having an antiemetic effect and high doses producing emesis. Presentation and treatment of CHS are similar to cyclical vomiting syndrome as well as chemotherapy-related anticipatory nausea and vomiting, suggesting that these phenomena may share mechanisms. The prevalence of CHS is not known because of the symptomatic overlap with other disorders and the lack of knowledge of the syndrome by the public and physicians. Treatment with typical antiemetic drugs is ineffective for CHS, but anxiolytic and sedative drugs, along with hot showers, seem to be consistently effective at reducing symptoms. The only known way to permanently end CHS, however, is abstinence from cannabinoids. Case studies and limited pre-clinical data on CHS indicate that prolonged high doses of the main psychotropic compound in cannabis, Δ9-tetrahydrocannabinol (THC), result in changes to the endocannabinoid system by acting on the cannabinoid 1 (CB1) receptor. These endocannabinoid system changes can dysregulate stress and anxiety responses, thermoregulation, the transient receptor potential vanilloid system, and several neurotransmitters systems, and are thus potential candidates for mediating the pathophysiology of CHS. Conclusions: Excessive cannabinoid administration disrupts the normal functioning of the endocannabinoid system, which may cause CHS. More clinical and pre-clinical research is needed to fully understand the underlying pathophysiology of this disorder and the negative consequences of prolonged high-dose cannabis use.

Efficacy and safety of topical capsaicin for cannabinoid hyperemesis syndrome in the emergency department

Introduction: Cannabinoid hyperemesis syndrome (CHS) is a disorder of cyclic and recurrent nausea, vomiting, and abdominal pain associated with high-frequency and extended-duration marijuana use. Standard antiemetic therapy is often ineffective; however, capsaicin, an agonist of transient receptor potential vanilloid 1 (TRPV1), has shown promise in treating CHS.Methods: This retrospective cohort analysis evaluated the safety and efficacy of topical capsaicin for patients presenting with CHS. The primary outcome was to assess if utilization of capsaicin for ED management of CHS decreased ED length of stay (LOS) as compared to a visit without capsaicin. Secondary outcomes included a cost analysis, use of rescue therapies, and adverse events.Results: Forty-three patients met the inclusion criteria within the study period. ED LOS was reduced with capsaicin by a median of 22 minutes (201 vs. 179 min, p = 0.33). Patients received fewer additional medications if capsaicin was utilized (4 vs. 3 doses, p = 0.015), and 67% of visits where capsaicin was utilized required no further treatment prior to discharge. Additionally, opioid usage was less when utilizing capsaicin (166.5 vs. 69 mg OME). Forty-two percent of patients did not have a repeat CHS presentation to the ED after receiving capsaicin for an additional three months after the study period ended. Total medication cost was minimally more expensive (median difference of $3.26) in the capsaicin group. There were no significant adverse events reported with capsaicin.Conclusion: There was no significant difference in ED LOS when capsaicin was utilized for CHS. However, there was a decrease in total medications administered and a reduction in opioid requirements. While medication costs for capsaicin visits were minimally more expensive, the utility of capsaicin as an over-the-counter (OTC) product may empower at home therapy with OTC products, decreasing potentially unnecessary healthcare encounters and costs.

Efficacy of Capsaicin for the Treatment of Cannabinoid Hyperemesis Syndrome: A Systematic Review

Objective: Cannabinoid hyperemesis syndrome (CHS) is characterized by cyclic vomiting, abdominal pain, and alleviation of symptoms via hot showers in chronic cannabinoid users. Capsaicin is recommended as a reasonable first-line treatment approach for CHS despite limited clinical evidence regarding its use. The objective of this study is to systematically review the efficacy data for capsaicin in CHS. Data Sources: A literature search using keywords related to cannabinoids, emesis, and capsaicin was performed in MEDLINE, CINAHL, and EMBASE from inception through March 31, 2019. Study Selection and Data Extraction: Studies and published abstracts in which capsaicin was used for CHS and clinical outcomes were reported were eligible for inclusion. Data Synthesis: A total of 241 articles were screened, of which 5 full-text articles and 6 conference abstracts were included. Full-text case reports (n = 3) and case series (n = 2) found capsaicin to be effective in a total of 18 patients. Published abstracts were in the form of case reports (n = 1), case series (n = 3), and retrospective cohort studies (n = 2). Relevance to Patient Care and Clinical Practice: Capsaicin use was described as beneficial in all case series and case reports; however, both retrospective cohort studies were unable to find a significant benefit for capsaicin on primary outcomes (emergency department length of stay). Conclusion: Current data for capsaicin efficacy in CHS is of low methodological quality. However, the limited data on alternative antiemetic therapies and capsaicin’s favorable risk-benefit profile make it a reasonable adjunctive treatment option.

Cannabinoid Hyperemesis

Cannabinoid hyperemesis syndrome (CHS) is a paradoxical condition in which a long-term cannabis user suffers an episode of intractable vomiting that may last days separated by longer asymptomatic periods of weeks or months. Cannabinoids are often utilized for their antiemetic properties, so CHS can be a puzzling condition, and the diagnosis of CHS may be disputed by patients. Unlike other cyclic vomiting syndromes, CHS can be relieved by hot showers or topical capsaicin. Abstinence from cannabinoids causes CHS to resolve, sometimes in a matter of days or hours. Marijuana users as well as many clinicians are not aware of CHS, and patients may undergo unnecessary tests, scans, and other procedures to get an accurate diagnosis. Symptoms may be severe enough to require hospitalization. With liberalization of marijuana laws and favorable public opinion about the healing properties of cannabis, CHS may be more frequently observed in clinical practice.

Targeting TRPV1 to relieve motion sickness symptoms in mice by electroacupuncture and gene deletion

Motion sickness (MS) is an acute disorder that occurs in healthy individuals worldwide regardless of gender, age, or ethnicity. Our study used a mouse model to rule out the effects of any psychological factors related to MS and EA. Subjects were randomly separated into four groups, namely the control group (Con), motion sickness inducing group (MS), mentioning sickness inducing with electroacupuncture treatment group (EA) and motion sickness inducing only in TRPV1 knockout mice group (TRPV1-/-). The consumption of kaolin, a non-nutrient substance, was measured as a behavior observed response of an emetic reflex in a murine model. This behavior is referred to as pica behavior. Our results showed that pica behavior was observed in the MS group. Moreover, kaolin consumption in the EA group decreased to the average baseline of the control group. A similar result was observed in TRPV1 null mice. We also observed an increase of TRPV1 and related molecules in the thalamus, hypothalamic and brain stem after MS stimulation and a significant decrease in the EA and TRPV1 null groups. This is the first study to demonstrate that TRPV1 pathways are possibly associated with mechanisms of MS, and can be attended through EA or TRPV1 genetic manipulation.

Successful Treatment of Cannabinoid Hyperemesis Syndrome with Topical Capsaicin

Cannabinoid hyperemesis syndrome (CHS) is a clinical entity in which marijuana users develop nausea, vomiting, and abdominal pain that improves with hot water bathing or cannabis cessation. Previous models suggest that CHS arises solely from the derangement of cannabinoid receptor type 1 signaling. However, involvement of transient receptor potential vanilloid subtype 1 (TRPV1) receptor, which is activated by marijuana, capsaicin, and heat, could fill gaps in existing models, including the enigmatic role of hot water bathing. We propose that chronic cannabis use decreases TRPV1 signaling and alters gastric motility, and we report the case of a CHS patient whose symptoms improved after topical capsaicin.

Chemical warfare agents. Classes and targets

Synthetic toxic chemicals (toxicants) and biological poisons (toxins) have been developed as chemical warfare agents in the last century. At the time of their initial consideration as chemical weapon, only restricted knowledge existed about their mechanisms of action. There exist two different types of acute toxic action: nonspecific cytotoxic mechanisms with multiple chemo-biological interactions versus specific mechanisms that tend to have just a single or a few target biomolecules. TRPV1- and TRPA-receptors are often involved as chemosensors that induce neurogenic inflammation. The present work briefly surveys classes and toxicologically relevant features of chemical warfare agents and describes mechanisms of toxic action.

Resolution of cannabis hyperemesis syndrome with topical capsaicin in the emergency department: a case series

BACKGROUND

Cannabinoid hyperemesis syndrome (CHS) is characterized by symptoms of cyclic abdominal pain, nausea, and vomiting in the setting of prolonged cannabis use. The transient receptor potential vanilloid 1 (TRPV1) receptor may be involved in this syndrome. Topical capsaicin is a proposed treatment for CHS; it binds TRPV1 with high specificity, impairing substance P signaling in the area postrema and nucleus tractus solitarius via overstimulation of TRPV1. This may explain its apparent antiemetic effect in this syndrome.

PURPOSE

We describe a series of thirteen cases of suspected cannabis hyperemesis syndrome treated with capsaicin in the emergency departments of two academic medical centers.

METHODS

A query of the electronic health record at both centers identified thirteen patients with documented daily cannabis use and symptoms consistent with CHS who were administered topical capsaicin cream for symptom management.

RESULTS

All 13 patients experienced symptom relief after administration of capsaicin cream.

CONCLUSION

Topical capsaicin was associated with improvement in symptoms of CHS after other treatments failed.

Monoclonal Suncus Antibodies: Generation of Fusion Partners to Produce Suncus-Suncus Hybridomas

We used suncus (Suncus murinus; house musk shrew) to generate partner cells for cell fusion to produce suncus monoclonal antibodies. Suncus are insectivores that are genetically distant to rodents, and recognize antigens and epitopes that are not immunogenic in mice and rats, which are the animals most commonly used in basic life science research and from which monoclonal antibodies are usually produced. To date, monoclonal antibodies from suncus have not been generated due to the lack of a plasmacytoma fusion partner. To obtain suncus plasmacytoma cell lines suitable as a cell fusion partner, we injected suncus at both sides of the tail base with antigen emulsion, collected the lymph nodes and spleens, and cultured the cells to obtain immortalized lymphoid cell lines visually resembling mouse SP2/0-Ag14 myeloma cells. Three suncus immunized with the antigen provided 4 cell lines of suncus plasmacytoma, but they did not secrete immunoglobulins. Antibody-producing hybrid cells were generated from these cell lines using a cell fusion technique. Using one of the cell lines as a fusion partner, we obtained six lines of immunoglobulin-producing hybrid cells which secreted an unidentified monoclonal IgG. When these 6 lines were used as new fusion partners, we obtained several hybrid cell lines which secreted immunogen-specific monoclonal antibodies. These hybrid cells can be cloned and cryopreserved. We also obtained another good fusion partner which initially secreted antibody but later stopped doing so. These suncus-suncus hybrid cell lines will be useful for the production of suncus monoclonal antibodies.

The importance of systematic approaches in the study of emesis

Nausea and vomiting are among the most basic of human experiences and unfortunately accompany a wide variety of clinical treatments as side effects. Despite decades of research, the neural mechanisms of nausea and vomiting (emesis) remain elusive. TRPV1 represents a possibly overlooked and understudied pharmacological target with anti-emetic potential.