Category Archives: Liver Disease

Therapeutic potential of cannabinoid medicines.

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Drug Testing and Analysis

“Cannabis was extensively used as a medicine throughout the developed world in the nineteenth century but went into decline early in the twentieth century ahead of its emergence as the most widely used illicit recreational drug later that century. Recent advances in cannabinoid pharmacology alongside the discovery of the endocannabinoid system (ECS) have re-ignited interest in cannabis-based medicines.

The ECS has emerged as an important physiological system and plausible target for new medicines. Its receptors and endogenous ligands play a vital modulatory role in diverse functions including immune response, food intake, cognition, emotion, perception, behavioural reinforcement, motor co-ordination, body temperature, wake/sleep cycle, bone formation and resorption, and various aspects of hormonal control. In disease it may act as part of the physiological response or as a component of the underlying pathology.

In the forefront of clinical research are the cannabinoids delta-9-tetrahydrocannabinol and cannabidiol, and their contrasting pharmacology will be briefly outlined. The therapeutic potential and possible risks of drugs that inhibit the ECS will also be considered. This paper will then go on to review clinical research exploring the potential of cannabinoid medicines in the following indications: symptomatic relief in multiple sclerosis, chronic neuropathic pain, intractable nausea and vomiting, loss of appetite and weight in the context of cancer or AIDS, psychosis, epilepsy, addiction, and metabolic disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/24006213

http://onlinelibrary.wiley.com/doi/10.1002/dta.1529/abstract

Peripherally restricted CB1 receptor blockers.

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“Antagonists (inverse agonists) of the cannabinoid-1 (CB1) receptor showed promise as new therapies for controlling obesity and related metabolic function/liver disease.

These agents, representing diverse chemical series, shared the property of brain penetration due to the initial belief that therapeutic benefit was mainly based on brain receptor interaction. However, undesirable CNS-based side effects of the only marketed agent in this class, rimonabant, led to its removal, and termination of the development of other clinical candidates soon followed. Re-evaluation of this approach has focused on neutral or peripherally restricted (PR) antagonists.

Supporting these strategies, pharmacological evidence indicates most if not all of the properties of globally acting agents may be captured by molecules with little brain presence. Methodology that can be used to eliminate BBB penetration and the means (in vitro assays, tissue distribution and receptor occupancy determinations, behavioral paradigms) to identify potential agents with little brain presence is discussed.

Focus will be on the pharmacology supporting the contention that reported agents are truly peripherally restricted. Notable examples of these types of compounds are: TM38837 (structure not disclosed); AM6545 (8); JD5037 (15b); RTI-12 (19).”

http://www.ncbi.nlm.nih.gov/pubmed/23902803

The endocannabinoid system in advanced liver cirrhosis: pathophysiological implication and future perspectives.

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“Endogenous cannabinoids (EC) are ubiquitous lipid signalling molecules providing different central and peripheral effects that are mediated mostly by the specific receptors CB1 and CB2. The EC system is highly upregulated during chronic liver disease and consistent experimental and clinical findings indicate that it plays a role in the pathogenesis of liver fibrosis and fatty liver disease associated with obesity, alcohol abuse and hepatitis C.

Furthermore, a considerable number of studies have shown that EC and their receptors contribute to the pathogenesis of the cardio-circulatory disturbances occurring in advanced cirrhosis, such as portal hypertension, hyperdynamic circulatory syndrome and cirrhotic cardiomyopathy.

More recently, the EC system has been implicated in the development of ascites, hepatic encephalopathy and the inflammatory response related to bacterial infection. Rimonabant, a selective CB1 antagonist, was the first drug acting on the EC system approved for the treatment of obesity. Unfortunately, it has been withdrawn from the market because of its neuropsychiatric side effects.

Compounds able to target selectively the peripheral CB1 receptors are under evaluation.

In addition, molecules stimulating CB2 receptor or modulating the activity of enzymes implicated in EC metabolism are promising areas of pharmacological research.

Liver cirrhosis and the related complications represent an important target for the clinical application of these compounds.”

http://www.ncbi.nlm.nih.gov/pubmed/23890208

[Marihuana and cannobinoids as medicaments].

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“Biological activity of cannabinoids is caused by binding to two cannabinoid receptors CB1 and CB2. Psychoactive is not only tetrahydrocannabinol (THC) but also: cannabidiol, cannabigerol or cannabichromen.

Formerly, the usefulness of hemp was assessed in the relation to temporary appeasement of the symptoms of some ailments as nausea or vomiting.

Present discoveries indicates that cannabis-based drugs has shown ability to alleviate of autoimmunological disorders such as: Multiple sclerosis (MS), Rheumatoid arthritis (RA) or inflammatory bowel disease.

Another studies indicates that cannabinoids play role in treatment of neurological disorders like Alzheimer disease or Amyotrophic lateral sclerosis (ALS) or even can reduce spreading of tumor cells.

Cannabinoids stand out high safety profile considering acute toxicity, it is low possibility of deadly overdosing and side-effects are comprise in range of tolerated side-effects of other medications.

In some countries marinol and nabilone are used as anti vomiting and nausea drug. First cannabis-based drug containg naturally occurring cannabinoids is Sativex. Sativex is delivered in an mucosal spray for patients suffering from spasticity in MS, pain relevant with cancer and neuropathic pain of various origin.

Cannabis side-effects varies and depend from several factors like administrated dose, rout of administration and present state of mind. After sudden break from long-lasting use, withdrawal symptoms can appear, although they entirely disappear after a week or two.”

http://www.ncbi.nlm.nih.gov/pubmed/23421098

Intractable nausea and vomiting due to gastrointestinal mucosal metastases relieved by tetrahydrocannabinol (dronabinol).

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“Four years following resection of a Clark’s level IV malignant melanoma, a 50-year-old man developed widespred metastatic disease involving the liver, bones, brain, gastrointestinal mucosa, and lungs. One week after whole brain radiation therapy, he was admitted to the hospital for nausea, vomiting, and pain.

He was treated with several antiemetic drugs, but it was not until dronabinol was added that the nausea and vomiting stopped.

Dronabinol was an effective antiemetic used in combination with prochlorperazine in nausea and vomiting unresponsive to conventional antiemetics.”

http://www.ncbi.nlm.nih.gov/pubmed/9392925

The endocannabinoid system and its therapeutic exploitation.

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“The term ‘endocannabinoid’ – originally coined in the mid-1990s after the discovery of membrane receptors for the psychoactive principle in Cannabis, Delta9-tetrahydrocannabinol and their endogenous ligands – now indicates a whole signalling system that comprises cannabinoid receptors, endogenous ligands and enzymes for ligand biosynthesis and inactivation. This system seems to be involved in an ever-increasing number of pathological conditions. With novel products already being aimed at the pharmaceutical market little more than a decade since the discovery of cannabinoid receptors, the endocannabinoid system seems to hold even more promise for the future development of therapeutic drugs. We explore the conditions under which the potential of targeting the endocannabinoid system might be realized in the years to come.”  http://www.ncbi.nlm.nih.gov/pubmed/15340387

http://www.nature.com/nrd/journal/v3/n9/full/nrd1495.html

Evaluation of anti-invasion effect of cannabinoids on human hepatocarcinoma cells.

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“Cancer is a disease characterized by abnormal growth of cells. One of the most common types of liver cancers is called hepatocellular carcinoma (HCC) which is highly metastatic. As most of cannabinoids have shown anticancer effect against different cell lines in a number of reports, a biological investigation of two cannabinoids, CB65 (CB2 receptor agonist) and ACEA (CB1 receptor agonist) was carried out in this study.

In an attempt to find natural products as a new solution of cancer, this study was designed to investigate the potential antitumoral and anti-invasive activity of cannabinoids…

The results revealed that both cannabinoids reduce cell viability, cell invasion as well as MMP-2 and MMP-9 expression in higher dose of 20 nM. Furthermore, higher concentrations of examined cannabinoids were more effective.

These data suggest ACEA and CB65 as an option for novel treatment of hepatocellular cancer.

Our findings may contribute to design of new therapeutic strategies for the management of HCC.”

http://www.ncbi.nlm.nih.gov/pubmed/22978792

From cannabis to the endocannabinoid system: refocussing attention on potential clinical benefits.

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“Cannabis sativa is one of the oldest herbal remedies known to man. Over the past four thousand years, it has been used for the treatment of numerous diseases but due to its psychoactive properties, its current medicinal usage is highly restricted. In this review, we seek to highlight advances made over the last forty years in the understanding of the mechanisms responsible for the effects of cannabis on the human body and how these can potentially be utilized in clinical practice. During this time, the primary active ingredients in cannabis have been isolated, specific cannabinoid receptors have been discovered and at least five endogenous cannabinoid neurotransmitters (endocannabinoids) have been identified. Together, these form the framework of a complex endocannabinoid signalling system that has widespread distribution in the body and plays a role in regulating numerous physiological processes within the body. Cannabinoid ligands are therefore thought to display considerable therapeutic potential and the drive to develop compounds that can be targeted to specific neuronal systems at low enough doses so as to eliminate cognitive side effects remains the ‘holy grail’ of endocannabinoid research.”

http://www.ncbi.nlm.nih.gov/pubmed/23155985

CB1 cannabinoid receptor antagonism: a new strategy for the treatment of liver fibrosis.

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“Hepatic fibrosis, the common response associated with chronic liver diseases, ultimately leads to cirrhosis, a major public health problem worldwide. We recently showed that activation of hepatic cannabinoid CB2 receptors limits progression of experimental liver fibrosis… In conclusion, our study shows that CB1 receptor antagonists hold promise for the treatment of liver fibrosis.”

http://www.ncbi.nlm.nih.gov/pubmed/16715087

Reversal of liver fibrosis by the antagonism of endocannabinoid CB1 receptor in a rat model of CCl(4)-induced advanced cirrhosis.

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Abstract

“The endocannabinoid system is involved in the pathogenesis of liver fibrosis. Although many substances have been proved to reduce fibrosis in experimental models of chronic liver injury, most of them appear to be effective only if given as a prophylactic or early treatment. This study aimed to explore the effect of pharmacological antagonism of the endocannabinoid cannabinoid type 1 (CB1) receptor started after the stage of full-blown cirrhosis had been reached. Wistar-Han rats with carbon tetrachloride (CCl(4))-induced cirrhosis were randomized to receive the CB1 receptor antagonist Rimonabant (10 mg/kg/day) or the vehicle for 2 weeks. Age-matched healthy rats served as controls. Liver fibrosis was assessed using Sirius red staining, hydroxyproline concentration and α-smooth muscle actin expression. Hepatic gene expression of mediators of fibrogenesis and inflammation were evaluated by real-time PCR. We also assessed the hepatic expression of CB1 and CB2 receptors and that of the enzymes implicated in the endocannabinoid metabolism. Fibrosis was significantly reduced in rats treated with Rimonabant compared with rats receiving the vehicle. CB1 receptor antagonism limited the gene upregulation of fibrogenic and inflammatory mediators occurring in untreated cirrhotic rats. CB1 and CB2 receptor expression was increased in cirrhotic animals. Interestingly, pharmacological CB1 receptor antagonism was associated with a further induction of the CB2 receptor expression. Regression of fibrosis can be achieved by pharmacological blockade of the CB1 receptor even when started in an advanced stage of the disease. This effect is associated with the suppression of pro-fibrogenic and inflammatory mediators and may have been indirectly favoured by the induction of CB2 receptor expression.”

http://www.ncbi.nlm.nih.gov/pubmed/22184091