Anti-obesity and anti-hyperglycemic effects of cinnamaldehyde via altered ghrelin secretion and functional impact on food intake and gastric emptying

TRP Channels as Therapeutic Targets in Diabetes and Obesity

During the last three to four decades the prevalence of obesity and diabetes mellitus has greatly increased worldwide, including in the United States. Both the short- and long-term forecasts predict serious consequences for the near future, and encourage the development of solutions for the prevention and management of obesity and diabetes mellitus. Transient receptor potential (TRP) channels were identified in tissues and organs important for the control of whole body metabolism. A variety of TRP channels has been shown to play a role in the regulation of hormone release, energy expenditure, pancreatic function, and neurotransmitter release in control, obese and/or diabetic conditions. Moreover, dietary supplementation of natural ligands of TRP channels has been shown to have potential beneficial effects in obese and diabetic conditions. These findings raised the interest and likelihood for potential drug development. In this mini-review, we discuss possibilities for better management of obesity and diabetes mellitus based on TRP-dependent mechanisms.

Synthetic small molecule GLP-1 secretagogues prepared by means of a three-component indole annulation strategy

Rational assembly of small molecule libraries for purposes of drug discovery requires an efficient approach in which the synthesis of bioactive compounds is enabled so that numerous structurally related compounds of a similar basic formulation can be derived. Here, we describe (4 + 3) and (3 + 2) indole annulation strategies that quickly generate complex indole heterocycle libraries that contain novel cyclohepta- and cyclopenta[b]indoles, respectively. Screening of one such library comprised of these indoles identifies JWU-A021 to be an especially potent stimulator of glucagon-like peptide-1 (GLP-1) secretion in vitro. Surprisingly, JWU-A021 is also a potent stimulator of Ca²⁺ influx through TRPA1 cation channels (EC₅₀ca. 200 nM), thereby explaining its ability to stimulate GLP-1 release. Of additional importance, the available evidence indicates that JWU-A021 is one of the most potent non-electrophilic TRPA-1 channel agonists yet to be reported in the literature.

Cinnamaldehyde and allopurinol reduce fructose-induced cardiac inflammation and fibrosis by attenuating CD36-mediated TLR4/6-IRAK4/1 signaling to suppress NLRP3 inflammasome activation

Fructose consumption induces metabolic syndrome to increase cardiovascular disease risk. Cinnamaldehyde and allopurinol possess anti-oxidative and anti-inflammatory activity to relieve heart injury in metabolic syndrome. But the mechanisms of fructose-induced cardiac injury, and cardioprotective effects of cinnamaldehyde and allopurinol are not completely understood. In this study, fructose-fed rats displayed metabolic syndrome with elevated serum ox-LDL, cardiac oxidative stress, inflammation and fibrosis. Scavenger receptor CD36, Toll-like receptor 4 (TLR4), TLR6, IL-1R-associated kinase 4/1 (IRAK4/1), nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome, interleukin-1β, transforming growth factor-β (TGF-β), drosophila mothers against DPP homolog (Smad) 2/3 phosphorylation and Smad4 were increased in animal and H9c2 cell models. These pathological processes were further evaluated in ox-LDL or fructose-exposed H9c2 cells pretreated with ROS scavenger and CD36 specific inhibitor, or IRAK1/4 inhibitor, and transfected with CD36, NLRP3, or IRAK4/1 siRNA, demonstrating that NLPR3 inflammasome activation through CD36-mediated TLR4/6-IRAK4/1 signaling may promote cardiac inflammation and fibrosis. Cinnamaldehyde and allopurinol reduced cardiac oxidative stress to suppress NLPR3 inflammasome activation and TGF-β/Smads signaling by inhibiting CD36-mediated TLR4/6-IRAK4/1 signaling under fructose induction. These results suggest that the blockage of CD36-mediated TLR4/6-IRAK4/1 signaling to suppress NLRP3 inflammasome activation by cinnamaldehyde and allopurinol may protect against fructose-induced cardiac inflammation and fibrosis.

Potential therapeutic value of TRPV1 and TRPA1 in diabetes mellitus and obesity

Diabetes mellitus and obesity, which is a major risk factor in the development of type 2 diabetes mellitus, have reached epidemic proportions worldwide including the USA. The current statistics and forecasts, both short- and long-term, are alarming and predict severe problems in the near future. Therefore, there is a race for developing new compounds, discovering new receptors, or finding alternative solutions to prevent and/or treat the symptoms and complications related to obesity and diabetes mellitus. It is well demonstrated that members of the transient receptor potential (TRP) superfamily play a crucial role in a variety of biological functions both in health and disease. In the recent years, transient receptor potential vanilloid type 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1) were shown to have beneficial effects on whole body metabolism including glucose homeostasis. TRPV1 and TRPA1 have been associated with control of weight, pancreatic function, hormone secretion, thermogenesis, and neuronal function, which suggest a potential therapeutic value of these channels. This review summarizes recent findings regarding TRPV1 and TRPA1 in association with whole body metabolism with emphasis on obese and diabetic conditions.

GPR119 Agonist AS1269574 Activates TRPA1 Cation Channels to Stimulate GLP-1 Secretion

GPR119 is a G protein-coupled receptor expressed on intestinal L cells that synthesize and secrete the blood glucose-lowering hormone glucagon-like peptide-1 (GLP-1). GPR119 agonists stimulate the release of GLP-1 from L cells, and for this reason there is interest in their potential use as a new treatment for type 2 diabetes mellitus. AS1269574 is one such GPR119 agonist, and it is the prototype of a series of 2,4,6 trisubstituted pyrimidines that exert positive glucoregulatory actions in mice. Here we report the unexpected finding that AS1269574 stimulates GLP-1 release from the STC-1 intestinal cell line by directly promoting Ca(2+) influx through transient receptor potential ankyrin 1 (TRPA1) cation channels. These GPR119-independent actions of AS1269574 are inhibited by TRPA1 channel blockers (AP-18, A967079, HC030031) and are not secondary to intracellular Ca(2+) release or cAMP production. Patch clamp studies reveal that AS1269574 activates an outwardly rectifying membrane current with properties expected of TRPA1 channels. However, the TRPA1 channel-mediated action of AS1269574 to increase intracellular free calcium concentration is not replicated by GPR119 agonists (AR231453, oleoylethanolamide) unrelated in structure to AS1269574. Using human embryonic kidney-293 cells expressing recombinant rat TRPA1 channels but not GPR119, direct TRPA1 channel activating properties of AS1269574 are validated. Because we find that AS1269574 also acts in a conventional GPR119-mediated manner to stimulate proglucagon gene promoter activity in the GLUTag intestinal L cell line, new findings reported here reveal the surprising capacity of AS1269574 to act as a dual agonist at two molecular targets (GPR119/TRPA1) important to the control of L-cell function and type 2 diabetes mellitus drug discovery research.

Cinnamaldehyde supplementation prevents fasting-induced hyperphagia, lipid accumulation, and inflammation in high-fat diet-fed mice

Cinnamaldehyde, a bioactive component of cinnamon, is increasingly gaining interest for its preventive and therapeutic effects against metabolic complications like type-2 diabetes. This study is an attempt to understand the effect of cinnamaldehyde in high-fat diet (HFD)-associated increase in fasting-induced hyperphagia and related hormone levels, adipose tissue lipolysis and inflammation, and selected cecal microbial count in mice. Cinnamaldehyde, at 40 µM dose, prevented lipid accumulation and altered gene expression toward lipolytic phenotype in 3T3-L1 preadipocyte cell lines. In vivo, cinnamaldehyde coadministration prevented HFD-induced body weight gain, decreased fasting-induced hyperphagia, as well as circulating leptin and leptin/ghrelin ratio. In addition to that, cinnamaldehyde altered serum biochemical parameters related to lipolysis, that is, glycerol and free fatty acid levels. At transcriptional level, cinnamaldehyde increased anorectic gene expression in hypothalamus and lipolytic gene expression in visceral white adipose tissue. Furthermore, cinnamaldehyde also decreased serum IL-1β and inflammatory gene expression in visceral white adipose tissue. However, cinnamaldehyde did not modulate the population of selected gut microbial (Lactobacillus, Bifidibaceria, and Roseburia) count in cecal content. In conclusion, cinnamaldehyde increased adipose tissue lipolysis, decreased fasting-induced hyperphagia, normalized circulating levels of leptin/ghrelin ratio, and reduced inflammation in HFD-fed mice, which augurs well for its antiobesity role.

Effects of TRP channel agonist ingestion on metabolism and autonomic nervous system in a randomized clinical trial of healthy subjects

Various lines of published evidence have already demonstrated the impact of TRPV1 agonists on energetic metabolism through the stimulation of the sympathetic nervous system (SNS). This study presents a trial investigating if stimulation of the two related sensory receptors TRPA1 and TRPM8 could also stimulate the SNS and impact the energetic metabolism of healthy subjects. The trial was designed to be double-blinded, randomized, cross-over, placebo-controlled with healthy subjects and the impact on the energetic metabolism and the autonomic nervous system (ANS) of cinnamaldehyde, capsaicin and a cooling flavor was measured during the 90 min after ingestion. Energy expenditure and substrate oxidation were measured by indirect calorimetry. An exploratory method to measure ANS activity was by facial thermography and power spectral analysis of heart rate variability using ECG was also used. Following cinnamaldehyde ingestion, energy expenditure was increased as compared to placebo. Furthermore, postprandial fat oxidation was maintained higher compared to placebo after cinnamaldehyde and capsaicin ingestion. Similar peripheral thermoregulation was observed after capsaicin and cinnamaldehyde ingestion. Unlike capsaicin, the dose of cinnamaldehyde was not judged to be sensorially ‘too intense’ by participants suggesting that Cinnamaldehyde would be a more tolerable solution to improve thermogenesis via spicy ingredients as compared to capsaicin.

Ghrelin and gastroparesis as early predictors of clinical outcomes in acute pancreatitis

BACKGROUND

Impaired motor and hormonal gastrointestinal functions have been implicated in the pathogenesis of acute pancreatitis. The aim of the present study was to investigate the predictive value of the Gastroparesis Cardinal Symptom Index and serum ghrelin in the development of clinically meaningful outcomes in patients with acute pancreatitis.

METHODS

This was a prospective clinical study. The Gastroparesis Cardinal Symptom Index and serum ghrelin were measured for 48 h after hospitalization. Univariate and multivariate logistic regression analyses were conducted.

RESULTS

The Gastroparesis Cardinal Symptom Index total score alone on day 2 was a significant predictor of oral feeding intolerance in both unadjusted (odds ratio 1.21 (1.01-1.46), P = 0.04) and adjusted (odds ratio 1.30 (1.01-1.69), P = 0.05) analyses. Adding ghrelin to Gastroparesis Cardinal Symptom Index further improved prediction in both unadjusted (odds ratio 1.26 (1.02-1.56), P = 0.03) and adjusted (odds ratio 1.53 (1.00-2.35), P = 0.05) analyses.

CONCLUSION

This pilot study demonstrates that the Gastroparesis Cardinal Symptom Index has a potential to be used as a predictor of oral feeding intolerance. Ghrelin, when combined with the Gastroparesis Cardinal Symptom Index, may further improve the predictive accuracy. These findings need to be confirmed in larger studies.

Association of Ghrelin Gene Polymorphisms and Serum Ghrelin Levels with the Risk of Hepatitis B Virus-Related Liver Diseases in a Chinese Population

Background

The functions of ghrelin (GHRL) include anti-inflammatory effects, reduction of the fibrogenic response, protection of liver tissue, and regulation of cell proliferation. Genetic variations in the GHRL gene may play an important role in the development of chronic hepatitis B (CHB), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Therefore, we investigated whether GHRL gene polymorphisms and its serum levels are associated with hepatitis B virus (HBV)-related diseases risk in a Chinese population.

Methods

176 patients with CHB, 106 patients with HBV-related LC, 151 patients with HBV-related HCC, and 167 healthy controls were recruited in the study. Genotyping of GHRL rs26311, rs27647, rs696217, and rs34911341 polymorphisms were determined with the polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and DNA sequencing. The serum GHRL concentrations were determined using enzyme-linked immunosorbent assay (ELISA).

Results

Binary logistic regression analyses adjusting for gender and age revealed that a significant increased risk of LC was found in the GHRL rs26311 GC genotype and combined GC+CC genotypes when compared with the GG genotype (GC vs. GG: OR = 1.671, 95% CI = 1.013–2.757, P = 0.044; GC+CC vs. GG: OR = 1.674, 95% CI = 1.040–2.696, P = 0.034). In subgroup analysis by gender, binary logistic regression analyses adjusting for age showed that the GHRL rs26311 C allele and combined GC+CC genotypes were associated with a significantly increased risk to LC in males (C vs. G OR = 1.416, 95% CI = 1.017–1.972, P = 0.040; GC+CC vs. GG: OR = 1.729, 95% CI = 1.019–2.933, P = 0.042). In addition, we found significant decreased serum GHRL levels in LC patients compared with the healthy controls. However, there was no significant association of the GHRL rs26311 polymorphism with serum GHRL levels in LC patients.

Conclusions

These observations suggest that the GHRL rs26311 polymorphism is associated with an increased risk to HBV-related LC, especially in men. We also found an inverse association of serum GHRL levels with LC.

Comparative effect of cinnamon and Ibuprofen for treatment of primary dysmenorrhea: a randomized double-blind clinical trial

BACKGROUND AND AIMS

Primary dysmenorrheal has a negative impact on women's quality of life. The purpose of this study was to compare the effect of Cinnamon and Ibuprofen for treatment of primary dysmenorrheal in a sample of Iranian female college students from Ilam University of Medical Sciences (western Iran).

MATERIALS AND METHODS

In a randomized, double-blind trial, out of 114, control group received placebo (empty capsules contain starch, TDS, n= 38) a test group received Ibuprofen (capsule containing 400mg Ibuprofen, TDS, n=38), or another test group received Cinnamon (capsule containing 420 mg Cinnamon, TDS, n= 38) in 24 h. To determine severity of pain, we used the VAS scale. Pain intensity and duration of pain were monitored in the group during first 72 h of cycle.

RESULTS

The mean pain severity score and mean duration of pain in Ibuprofen and Cinnamon were less than placebo group respectively (p< 0.001). Of 4 hours after the intervention there were no statistically significant differences between the Cinnamon and placebo group (p> 0.05). Of eight hours after the intervention, the mean pain severity in the cinnamon group was significantly lower than placebo group (p< 0.001). At various time intervals the mean pain severity in the Ibuprofen group were significantly less than Cinnamon and placebo groups (p< 0.001).

CONCLUSION

Cinnamon compared with placebo significantly reduced the severity and duration of pain during menstruation, but this effect was lower compared with Ibuprofen. Cinnamon can be regarded as a safe and effective treatment for primary dysmenorrhea. More researches are recommended to study the efficacy of Cinnamon on reducing menstrual bleeding.