Mechanisms underlying the attenuation of chronic inflammatory diseases by aged garlic extract: Involvement of the activation of AMP-activated protein kinase

Overfeeding in the early postnatal period aggravates inflammation and hepatic insulin sensitivity in the 5α-dihydrotestosterone-induced animal model of PCOS

Background

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and is closely associated with chronic low-grade inflammation and insulin resistance. To clarify the contribution of prepubertal weight gain to the development of insulin resistance in PCOS, we investigated the effects of early postnatal overfeeding on inflammatory and energy-sensing pathways as well as on markers of insulin signaling in the liver of the PCOS rat model.

Methods

Obesity induced by overfeeding was achieved by reducing litter size, while the PCOS-like condition was developed by treatment with 5α-dihydrotestosterone (DHT). Western blot and qPCR were used to analyze the expression of pro-inflammatory transcription factors and cytokines, as well as markers of the energy sensing and insulin signaling pathways.

Results

The results showed that hepatic insulin sensitivity was impaired only in DHT-treated rats raised in small litters, as evidenced by increased phosphorylation of IRS1 on Ser307 and decreased expression of total IRS1. Postnatal overfeeding stimulated JNK1 activation independent of hyperandrogenemia; nevertheless, the synergistic effect of both factors triggered NLRP3 activation and increased IL1β expression in the small litter DHT-treated group. This pro-inflammatory state was accompanied by decreased activatory phosphorylation of AMPK and reduced levels of its protein targets.

Conclusions

Overfeeding in the early postnatal period leads to a decrease in hepatic insulin sensitivity in the rat model of PCOS, which is associated with decreased activation of AMPK and stimulation of the hepatic NLRP3-IL1β signaling pathway. Accordingly, the inhibition of NLRP3 activation could provide a basis for the development of new therapeutic strategies for the treatment of insulin resistance in women with PCOS.

Therapeutic effect of aged garlic extract on gingivitis in dogs

Periodontal disease is one of the most common dental health problems in dogs. Clinical studies in humans have shown that aged garlic extract (AGE), which contains stable and water-soluble sulfur-containing bioactive compounds, improves the symptoms of periodontal diseases. Our previous study demonstrated that oral administration of AGE in healthy Beagle dogs at 90 mg/kg/day for 12 weeks had no adverse effects such as hemolytic anemia, which is well known to occur as a result of ingestion of Allium species, including onions and garlic, in dogs. However, the therapeutic potential of AGE in canine periodontal disease remains unclear. Accordingly, we investigated the therapeutic effects of AGE in Beagle dogs with mild gingivitis. Feeding 18 mg/kg/day of AGE for 8 weeks resulted in the improvement of gingival index score, level of volatile sulfur compounds in exhaled air, and enzyme activity of periodontal pathogens without any adverse effects on clinical signs and hematological and serum biochemical parameters. Moreover, AGE increased the concentration of salivary cathelicidin, an antimicrobial peptide that contributes to the oral innate immune response. These results suggest that AGE could be a potential therapeutic agent for canine gingivitis.

CRP Involved in Nile Tilapia (Oreochromis niloticus) against Bacterial Infection

Simple Summary

C-reactive protein (CRP) is an acute-phase protein that can be used as an early diagnostic marker for inflammation. Few CRPs have been isolated from teleost, and the specific immunological functions and mechanism of fish CRP have not been well-studied. Therefore, in this research, a CRP gene from Nile tilapia was identified, and its roles during bacterial infection were investigated. The current results revealed that CRP participated in anti-bacterial immune response through agglutinating bacterial, regulating phagocytosis and inflammation. Hopefully, our data might be beneficial in further study to understand the protective mechanism of fish CRP against bacterial infection.

Abstract

C-reactive protein (CRP) is an acute-phase protein that can be used as an early diagnostic marker for inflammation, which is also an evolutionarily conserved protein and has been identified from arthropods to mammals. However, the roles of CRP during the immune response of Nile tilapia (Oreochromis niloticus) remain unclear. In this study, a CRP gene from Nile tilapia (On-CRP) was identified, and its roles in response to bacterial infection were investigated in vivo or in vitro. On-CRP was found to contain an open reading frame of 675 bp, encoding a polypeptide of 224 amino acids with the conservative pentraxin domain. On-CRP shares more than 50% of its identity with other fish species, and 30% of its identity with mammals. The transcriptional level of On-CRP was most abundant in the liver and its transcripts can be remarkably induced following Streptococcus agalactiae and Aeromonas hydrophila infection. Furthermore, in vitro analysis indicated that the recombinant protein of On-CRP improved phagocytic activity of monocytes/macrophages, and possessed a bacterial agglutination activity in a calcium-dependent manner. Both in vivo and in vitro experiments indicated that On-CRP could promote inflammation and activate the complement pathway. However, a direct relationship between CRP and several immune pathways could not be confirmed. The present data lays a theoretical foundation to further explore the mechanism of how CRP protects fish against bacterial infection.

Morphological and molecular characterization of garlic (Allium sativum L.) genotypes sampled from Turkey

Garlic is a vegetable widely used both in food and as a pharmaceutical raw material in the world due to its contents. Although morphological differences are observed in garlic, which is obligatory apomictically propagated, clonal propagation causes narrowing variation, a genetic bottleneck. This situation complicates breeding programs aiming improvements in preferred agronomic characteristics. For this reason, determining the morphological and molecular differences between garlic genotypes originating from Turkey is important for breeding studies. In this study, morphological and molecular characteristics of 39 garlic genotypes, which are widely cultivated in Turkey, were determined. Kahramanmaraş4 genotype was different from other genotypes in terms of some morphological features (fresh weight, dry weight, and bulb diameter). In the molecular characterization study, 10 Inter-Simple Sequence Repeats (ISSR) primers were used, and it was determined that the genotype TekDiş31 of Tunceli region was different from other garlic genotypes. Genetic similarity coefficient was found to be high (0.85-1.0) in genotypes except for TekDiş31 garlic genotype. In general, some garlic clones (Maraş3 and Kayseri30, Urfa33 and Topaklı35, Kastamonu22 and Kastamonu28, Urfa10 and Kastamonu14, Kastamonu29 and Bademci23) were completely similar to each other, while few differences were found among others. In conclusion, this study revealed that the garlic plant, despite its clonal propagation, consisted of some level of morphological and partially molecular variation. Due to its mode of reproduction (vegetative), this variation may largely be due to point or chromosomal mutation. Furthermore, the 10 identified ISSR primers can generate valuable information for genetic diversity for use by garlic breeders.

Aged Garlic Extract Reduces IL-6: A Double-Blind Placebo-Controlled Trial in Females with a Low Risk of Cardiovascular Disease

Background

Chronic inflammation is a risk factor for cardiovascular disease. The aim of the study was to evaluate whether a daily supplementation of aged garlic extract (AGE) could reduce inflammation in females with low risk for cardiovascular disease. The study was conducted at a single center, as a parallel randomized placebo-controlled trial.

Method

63 females with a Framingham risk score over 10 underwent cardiac computed tomography (CT) scan. Of those, patients with a coronary artery calcium (CAC) scores less than 5 (n = 31) met the inclusion criteria and were randomized, in a double-blind manner to an intake of placebo or AGE (2400 mg daily) for 1 year.

Results

Main outcome measure was changes in inflammatory biomarkers, blood pressure, fastening blood glucose, and blood lipids. A total of 29 patients (14 in the AGE group and 15 in the placebo group) completed the study and were analyzed. Females treated with AGE showed lower levels of inflammatory marker IL-6 after 12 months of treatment compared to females receiving placebo (p < 0.05). The blood lipids had a trend towards a lowering effect in females treated with AGE; however, this trend was not significant.

Conclusion

The present study concludes that AGE lowers IL-6 in females with a risk profile of cardiovascular disease. We could also conclude that risk prediction with cardiac CT  scan turned out to be superior in estimating the risk of cardiac disease compared to Framingham risk score. This trial is registered with NCT03860350.

The effects of allium sativum on immunity within the scope of COVID-19 infection

The severity of coronavirus disease 2019 (COVID-19) infection is quite variable and the manifestations varies from asymptomatic disease to severe acute respiratory infection. Fever, dry cough, dyspnea, myalgia, fatigue, loss of appetite, olfactory and gustatory dysfunctions are the most prevalent general symptoms. Decreased immune system cells such as suppressed regulatory T cells, cytotoxic and helper T cells, natural killer cells, monocytes/macrophages and increased proinflammatory cytokines are the characteristic features. Compounds derived from Allium sativum (garlic) have the potential to decrease the expression of proinflammatory cytokines and to reverse the immunological abnormalities to more acceptable levels. Allium sativum is suggested as a beneficial preventive measure before being infected with SARS-CoV-2 virus. Allium sativum is a functional food well-known for its immunomodulatory, antimicrobial, antiinflammatory, antimutagenic, antitumor properties. Its antiviral efficiency was also demonstrated. Some constituents of this plant were found to be active against protozoan parasites. Within this context, it appears to reverse most immune system dysfunctions observed in patients with COVID-19 infection. The relations among immune system parameters, leptin, leptin receptor, adenosin mono phosphate-activated protein kinase, peroxisome proliferator activated receptor-gamma have also been interpreted. Leptin's role in boosting proinflammatory cytokines and in appetite decreasing suggest the possible beneficial effect of decreasing the concentration of this proinflammatory adipose tissue hormone in relieving some symptoms detected during COVID-19 infection. In conclusion, Allium sativum may be an acceptable preventive measure against COVID-19 infection to boost immune system cells and to repress the production and secretion of proinflammatory cytokines as well as an adipose tissue derived hormone leptin having the proinflammatory nature.

-1-Propenylcysteine, a sulfur compound in aged garlic extract, alleviates cold-induced reduction in peripheral blood flow in rat via activation of the AMPK/eNOS/NO pathway

Aged garlic extract (AGE) has been shown to improve peripheral circulatory disturbances in both clinical trials and experimental animal models. To investigate the effect of S-1-propenylcysteine (S1PC), a characteristic sulfur compound in AGE, on cold-induced reduction in tail blood flow of rat, Wistar rats were individually placed in a restraint cage and given the treatment with cold water (15˚C) after the oral administration of AGE or its constituents S1PC, S-allylcysteine (SAC) and S-allylmercaptocysteine (SAMC). After the cold-treatment the tail blood flow of rats was measured at the indicated times. The pretreatment with AGE (2 g/kg BW) and S1PC (6.5 mg/kg BW) significantly alleviated the reduction of rat tail blood flow induced by cold treatment. The effect of S1PC was dose-dependent and maximal at the dose of 6.5 mg/kg BW, whereas SAC and SAMC were ineffective. To gain insight into the mechanism of S1PC action, the concentration of nitrogen oxide metabolites (NOx) in the plasma and the levels of phosphorylated endothelial nitric oxide synthase (eNOS) and 5'-AMP-activated protein kinase (AMPK) in the aorta were measured. The pretreatment with S1PC significantly increased the plasma concentration of NOx as well as the level of phosphorylated form of AMPK and eNOS in the aorta after cold-treatment. The present findings suggest that S1PC is a major constituent responsible for the effect of AGE to alleviate the cold-induced reduction of peripheral blood flow in rat by acting on the AMPK/eNOS/NO pathway in the aorta.