Advances in injectable hydrogels for radiation-induced heart disease.

Radiological heart damage (RIHD) is damage caused by unavoidable irradiation of the heart during chest radiotherapy, with a long latency period and a progressively increasing proportion of delayed cardiac damage due to conventional doses of chest radiotherapy. There is a risk of inducing diseases such as acute/chronic pericarditis, myocarditis, delayed myocardial fibrosis and damage to the cardiac conduction system in humans, which can lead to myocardial infarction or even death in severe cases. This paper details the pathogenesis of RIHD and gives potential targets for treatment at the molecular and cellular level, avoiding the drawbacks of high invasiveness and immune rejection due to drug therapy, medical device implantation and heart transplantation. Injectable hydrogel therapy has emerged as a minimally invasive tissue engineering therapy to provide necessary mechanical support to the infarcted myocardium and to act as a carrier for various bioactive factors and cells to improve the cellular microenvironment in the infarcted area and induce myocardial tissue regeneration. Therefore, this paper combines bioactive factors and cellular therapeutic mechanisms with injectable hydrogels, presents recent advances in the treatment of cardiac injury after RIHD with different injectable gels, and summarizes the therapeutic potential of various types of injectable hydrogels as a potential solution.

The Association Between Fecal Short-Chain Fatty Acids, Gut Microbiota, and Visceral Fat in Monozygotic Twin Pairs.

PURPOSE: To examine the association of short-chain fatty acids (SCFAs), gut microbiota and obesity in individual twins and to control for genetic and shared environmental effects by studying monozygotic intrapair differences. PATIENTS AND METHODS: The study recruited 20 pairs of monozygotic twins. Body composition measurements were performed by using the multi-frequency bioelectrical impedance technique. SCFAs were extracted from feces and quantified by gas chromatography-mass spectrometer. Gut microbiota was evaluated by 16S rRNA gene sequencing. RESULTS: Fecal SCFAs were negatively correlated with adiposity parameters including body mass index, visceral adipose tissue and waist circumference (all P < 0.05). Metastat analysis showed that the top 5 relatively abundant bacterial taxa of viscerally obese and non-obese groups were Bacteroides, Collinsella, Eubacterium rectale group, Lachnoclostridium, and Tyzzerella. Participants with visceral obesity had lower abundance of Bacteroides and Collinsella compared to non-obese patients (P < 0.05). Among them, the abundance of Collinsella was positively correlated with acetic acid concentrations (r = 0.63, P = 0.011). There were no significant intrapair differences in each SCFA concentrations between the twins in our study (P > 0.05). CONCLUSION: Low fecal concentrations of SCFAs were associated with visceral obesity, and the gut microbiota might be involved in the underlying mechanism.

Metabolites of gut microbiome are associated with glucose metabolism in non-diabetic obese adults: a Chinese monozygotic twin study.

BACKGROUND: Evidence suggests gut microbiome is associated with diabetes. However, it's unclear whether the association remains in non-diabetic participants. A Chinese monozygotic twin study, in which the participants are without diabetes, and are not taking any medications, was conducted to explore the potential association. METHODS: Nine pairs of adult monozygotic twins were enrolled and divided into two twin-pair groups (a and b). Clinical and laboratory measurements were conducted. Visceral adipose tissue (VAT) was assessed. Fecal samples were collected to analyze the microbiome composition by 16S rDNA gene amplicon sequencing. Liquid chromatography mass spectrometry was performed to detect the metabolites. RESULTS: The participants aged 53 years old averagely, with 8 (88.9%) pairs were women. All the participants were obese with VAT higher than 100 cm2 (152.2 ± 31.6). There was no significant difference of VAT between the twin groups (153.6 ± 30.4 cm2 vs. 150.8 ± 29.5 cm2, p = 0.54). Other clinical measurements, including BMI, lipid profiles, fasting insulin and blood glucose, were also not significantly different between groups (p ≥ 0.056), whereas HbA1c level of group a is significantly higher than group b (5.8 ± 0.3% vs. 5.6 ± 0.2%, p = 0.008). The number and richness of OTUs are relatively higher in group a, and 13 metabolites were significantly different between two groups. Furthermore, several of the 13 metabolites could be significantly linked to special taxons. The potential pathway involved drug metabolism-other enzymes, Tryptophan metabolism and Citrate cycle. CONCLUSIONS: Gut microbiome composition and their metabolites may modulate glucose metabolism in obese adults without diabetes, through Tryptophan metabolism, Citrate cycle and other pathways.