SUMMARY: This review assesses the accumulated evidences on the mutual influence of monoamines, hormones and neuropeptides that are linked to obesity. A few anti-obesity drugs that exert their mechanisms of action through monoamines are briefly discussed to support the notion of monoamines being a critical target of drug discovery for new anti-obesity drugs. Subsequently, the review provides a comprehensive overview of central dopamine and serotonin changes that are associated with the use of khat or its alkaloids. Then, all the studies on khat that describe physical, biochemical and hormonal changes are summarised and discussed in depth.
CONCLUSION: The reviewed studies provide relatively acceptable evidence that different khat extracts or cathinone produces changes in terms of weight, fat mass, appetite, lipid biochemistry and hormonal levels. These changes are more pronounced at higher doses and long durations of intervention. The most suggested mechanism of these changes is the central action that produces changes in the physiology of dopamine and serotonin. Nonetheless, there are a number of variations in the study design, including species, doses and durations of intervention, which makes it difficult to arrive at a final conclusion about khat regarding obesity, and further studies are necessary in the future to overcome these limitations.
METHODS: Twenty healthy subjects were enrolled in a randomized, 3-way, blinded cross-over trial. The study was registered under ClinicalTrials.gov Identifier no. NCT00123456. At each test day, the subjects received one of three meals comprising 30 g of starch with 5 g of LD or UP or an energy-adjusted control meal containing pea protein. Fasting and postprandial blood glucose, insulin, C-peptide and glucagon-like peptide-1 (GLP-1) concentrations were measured. Subjective appetite sensations were scored using visual analogue scales (VAS).
RESULTS: Linear mixed model (LMM) analysis showed a lower blood glucose, insulin and C-peptide response following the intake of LD and UP, after correction for body weight. Participants weighing ≤ 63 kg had a reduced glucose response compared to control meal between 40 and 90 min both following LD and UP meals. Furthermore, LMM analysis for C-peptide showed a significantly lower response after intake of LD. Compared to the control meal, GLP-1 response was higher after the LD meal, both before and after the body weight adjustment. The VAS scores showed a decreased appetite sensation after intake of the seaweeds. Ad-libitum food intake was not different three hours after the seaweed meals compared to control.
CONCLUSIONS: Concomitant ingestion of brown seaweeds may help improving postprandial glycaemic and appetite control in healthy and normal weight adults, depending on the dose per body weight.
CLINICAL TRIAL REGISTRY NUMBER: Clinicaltrials.gov (ID# NCT02608372).
A 53-year-old woman presented with left-sided abdominal pain, nausea and vomiting for the past 3 months with associated loss of appetite and weight. On physical examination, there was a large, ill-defined, firm mass at the epigastrium. Ultrasonography showed heterogeneously hypoechoic filling defect within the dilated main portal vein. The filling defect showed florid signals on Doppler mode and it appeared to be an extension of a larger periportal mass. Contrast enhanced abdominal computed tomography confirmed a large distal gastric mass infiltrating into the periportal structures, including the main portal vein and the splenic vein. Esophagogastroduodenoscopy performed 2 days later showed an irregular, exophytic mass extending from the antrum into the first part of duodenum. The mass was deemed inoperable. Histopathological examination showed gastric adenocarcinoma. She was started on anticoagulant, chemotherapy and pain management. Follow-up computed tomography 4 months later showed liver metastases and formation of collateral blood vessels.