Butyrate increases the formation of anti-angiogenic vascular endothelial growth factor variants in human lung microvascular endothelial cells

Management of Cardiovascular Diseases by Short-Chain Fatty Acid Postbiotics

PURPOSE OF REVIEW

Global health concerns persist in the realm of cardiovascular diseases (CVDs), necessitating innovative strategies for both prevention and treatment. This narrative review aims to explore the potential of short-chain fatty acids (SCFAs)-namely, acetate, propionate, and butyrate-as agents in the realm of postbiotics for the management of CVDs.

RECENT FINDINGS

We commence our discussion by elucidating the concept of postbiotics and their pivotal significance in mitigating various aspects of cardiovascular diseases. This review centers on a comprehensive examination of diverse SCFAs and their associated receptors, notably GPR41, GPR43, and GPR109a. In addition, we delve into the intricate cellular and pharmacological mechanisms through which these receptors operate, providing insights into their specific roles in managing cardiovascular conditions such as hypertension, atherosclerosis, heart failure, and stroke. The integration of current information in our analysis highlights the potential of both SCFAs and their receptors as a promising path for innovative therapeutic approaches in the field of cardiovascular health. The idea of postbiotics arises as an optimistic and inventive method, presenting new opportunities for preventing and treating cardiovascular diseases.

Glucoregulatory effect of butyrate is associated with elevated circulating VEGF and reduced cardiac lactate in high fructose fed rats

Background

High fructose diet has been linked with impaired body metabolism and cardiovascular diseases. Sodium butyrate (NaB) was documented to improve glucoregulation and cardiometabolic problems associated with high fructose diet (HFrD) but the mechanisms behind it are unclear. As a result, the purpose of this study was to look into the effects of NaB on VEGF and cardiac lactate in HFrD-induced dysmetabolism.

Methods

Twenty male Wistar rats of weight 130-140 g were assigned randomly after a week of acclimation into four groups: Control diet (CTR), High fructose drink (HFrD); 10 % (w/v), NaB (200 mg/kg bw), and HFrD + NaB (200 mg/kg bw). The animals were induced to be unconscious with 50 mg/kg of pentobarbital sodium intraperitoneally, blood samples were taken via cardiac puncture and cardiac tissue homogenates were obtained for Fasting Blood Sugar (FBS) and plasma insulin, cardiac glycogen, plasma and cardiac glycogen synthase, plasma and cardiac nitric oxide as well as vascular endothelial growth factor (VEGF).

Result

HFrD resulted in statistical elevation body and cardiac weight, plasma glucose, plasma insulin, cardiac lactate, glycogen and decreased nitric oxide level (NO) when compared with the control group. Administration of NaB reduced cardiac weight, blood glucose, plasma insulin, cardiac lactate while nitric oxide and glycogen increased (P < 0.05). NaB increased plasma glycogen synthase in normal rats, plasma and cardiac circulating VEGF in HFrD administered rats (P < 0.05) while no change was produced in plasma and cardiac glycogen synthase level of HFrD treated rats.

Conclusion

Sodium butyrate improves glucoregulation by reducing cardiac lactate and increasing circulating VEGF in HFrD-treated rats.

Role of Butyrate, a Gut Microbiota Derived Metabolite, in Cardiovascular Diseases: A comprehensive narrative review

Cardiovascular diseases (CVD) are major causes of death worldwide. Recently, new roles for intestinal microbiota in pathology and treatment of CVD have been proposed. Butyrate, a bacterial metabolite, is synthesized in the gut and performs most of its functions in there. However, researchers have discovered that butyrate could enter to portal vein and interact with various organs. Butyrate exhibits a broad range of pharmacological activities, including microbiome modulator, anti-inflammatory, anti-obesity, metabolic pathways regulator, anti-angiogenesis, and antioxidant. In this article we review evidence supporting a potentially therapeutic role for butyrate in CVD and the mechanisms and pathways involved in the cardio-protective effects of butyrate from the gut and circulation to the nervous system. In summary, although butyrate exhibits a wide variety of biological activities in different pathways including energy homeostasis, glucose and lipid metabolism, inflammation, oxidative stress, neural signaling, and epigenetic modulation in experimental settings, it remains unclear whether these findings are clinically relevant and whether the molecular pathways are activated by butyrate in humans.

Trimetazidine ameliorates hindlimb ischaemic damage in type 2 diabetic mice

BACKGROUND

Ischaemia caused by lower extremity artery stenosis is the main cause of peripheral artery disease (PAD) in patients with diabetes. Trimetazidine (TMZ) has traditionally been used as an anti-ischaemic drug for coronary artery disease. The effect of TMZ on PAD in a diabetic animal model and the underlying molecular mechanisms remain unclear.

METHODS

The db/db mice were challenged with femoral artery ligation (FAL), followed by TMZ treatment for 2 weeks. Scores on hindlimb ischaemia and function were evaluated. Histological and capillary density analyses of gastrocnemius were performed. The expression of vascular endothelial growth factor (VEGF) and myogenic regulators was also confirmed by Western blotting. We also detected serum intercellular adhesion molecule 1 (ICAM-1) level through ELISA.

RESULTS

Diabetic mice exhibited limb ulceration and motor dysfunction after FAL while TMZ-treated db/db mice exhibited milder ischaemic impairment. Furthermore, decreased capillary density in the gastrocnemius muscles of ischaemic hindlimb and reduced expressions of VEGF, myogenic markers, and serum ICAM-1 could be partially reversed by TMZ treatment.

CONCLUSION

TMZ may alleviate hindlimb ischaemic damage in db/db mice, at least partly, through enhancing angiogenesis and promoting myogenesis in ischaemia region.Key messagesTMZ intervention could alleviate hindlimb ischaemic damage in db/db mice.TMZ intervention could enhance angiogenesis and stimulate myogenesis in ischaemia region.

Effect of butyrate, a bacterial by-product, on the viability and ICAM-1 expression/production of human vascular endothelial cells: Role in infectious pulpal/periapical diseases

AIM

To investigate the effects of butyric acid (BA), a metabolic product generated by pulp and root canal pathogens, on the viability and intercellular adhesion molecule-1 (ICAM-1) production of endothelial cells, which are crucial to angiogenesis and pulpal/periapical wound healing.

METHODOLOGY

Endothelial cells were exposed to butyrate with/without inhibitors. Cell viability, apoptosis and reactive oxygen species (ROS) were evaluated using an MTT assay, PI/annexin V and DCF fluorescence flow cytometry respectively. RNA and protein expression was determined using a polymerase chain reaction assay and Western blotting or immunofluorescent staining. Soluble ICAM-1 (sICAM-1) was measured using an enzyme-linked immunosorbent assay. The quantitative results were expressed as mean ± standard error (SE) of the mean. The data were analysed using a paired Student's t-test where necessary. A p-value ≤0.05 was considered to indicate a statistically significant difference between groups.

RESULTS

Butyrate (>4 mM) inhibited cell viability and induced cellular apoptosis and necrosis. It inhibited cyclin B1 but stimulated p21 and p27 expression. Butyrate stimulated ROS production and hemeoxygenase-1 (HO-1) expression as well as activated the Ac-H3, p-ATM, p-ATR, p-Chk1, p-Chk2, p-p38 and p-Akt expression of endothelial cells. Butyrate stimulated ICAM-1 mRNA/protein expression and significant sICAM-1 production (p < .05). Superoxide dismutase, 5z-7oxozeaenol, SB203580 and compound C (p <  .05), but not ZnPP, CGK733, AZD7762 or LY294002, attenuated butyrate cytotoxicity to endothelial cells. Notably, little effect on butyrate-stimulated sICAM-1 secretion was found. Valproic acid, phenylbutyrate and trichostatin (three histone deacetylase inhibitors) significantly induced sICAM-1 production (p < .05).

CONCLUSION

Butyric acid inhibited proliferation, induced apoptosis, stimulated ROS and HO-1 production and increased ICAM-1 mRNA expression and protein synthesis in endothelial cells. Cell viability affected by BA was diminished by some inhibitors; however, the increased sICAM-1 secretion by BA was not affected by any of the tested inhibitors. These results facilitate understanding of the pathogenesis, prevention and treatment of pulpal/periapical diseases.

VEGF-A165b levels are reduced in breast cancer patients at primary diagnosis but increase after completion of cancer treatment

The antiangiogenic splice variant VEGF-A165b is downregulated in a variety of cancer entities, but little is known so far about circulating plasma levels. The present analysis addresses this question and examines circulating VEGF-A/VEGF-A165b levels in a collective of female high-risk breast cancer patients over the course of treatment. Within the SUCCES-A trial 205 patients were recruited after having received primary breast surgery. Using ELISA VEGF-A/VEGF-A165b concentrations were determined and correlated to clinical characteristics (1) before adjuvant chemotherapy, (2) four weeks and (3) two years after therapy and compared to healthy controls (n = 107). VEGF_165b levels were significantly elevated after completion of chemotherapy. Within the breast cancer cohort, VEGF-A165b levels increased two years after completion of chemotherapy. VEGF-A plasma concentrations were significantly elevated in the breast cancer cohort at all examined time points and decreased after treatment. VEGF-A levels two years after chemotherapy correlated with increased cancer related mortality, no such correlation could be found between VEGF-A165b and the examined clinical characteristics. Compared to controls, VEGF-A/VEGF-A165b ratios were decreased in patients before and after chemotherapy. Our data suggests that circulating VEGF-A165b is significantly reduced in women with primary breast cancer at time of diagnosis; furthermore, levels change during adjuvant treatment.

Sodium butyrate attenuates diabetes-induced aortic endothelial dysfunction via P300-mediated transcriptional activation of Nrf2

Oxidative stress and inflammation are major contributors to diabetes-induced endothelial dysfunction which is the critical first step to the development of diabetic macrovascular complications. Nuclear factor erythroid 2-related factor 2 (NRF2) plays a key role in combating diabetes-induced oxidative stress and inflammation. Sodium butyrate (NaB) is an inhibitor of histone deacetylase (HDAC) and an activator of NRF2. However, NaB's effect on diabetes-induced aortic injury was unknown. It was also not known whether or to what extent NRF2 is required for both self-defense and NaB's protection in the diabetic aorta. Additionally, the mechanism by which NaB activates NRF2 was unclear. Therefore, C57BL/6 Nrf2 knockout (KO) and wild type (WT) mice were induced to diabetes by streptozotocin, and were treated in the presence or absence of NaB, for 20 weeks. The KO diabetic mice developed more severe aortic endothelial oxidative stress, inflammation and dysfunction, as compared with the WT diabetic mice. NaB significantly attenuated these effects in the WT, but not the KO, mice. In high glucose-treated aortic endothelial cells, NaB elevated Nrf2 mRNA and protein without facilitating NRF2 nuclear translocation, an effect distinct from that of sulforaphane. NaB inhibited HDAC activity, and increased occupancy of the transcription factor aryl hydrocarbon receptor and the co-activator P300 at the Nrf2 gene promoter. Further, the P300 inhibitor C646 completely abolished NaB's efficacies. Thus, NRF2 is required for both self-defense and NaB's protection against diabetes-induced aortic endothelial dysfunction. Other findings suggest that P300 mediates the transcriptional activation of Nrf2 by NaB.

Alternative splicing regulated by butyrate in bovine epithelial cells

As a signaling molecule and an inhibitor of histone deacetylases (HDACs), butyrate exerts its impact on a broad range of biological processes, such as apoptosis and cell proliferation, in addition to its critical role in energy metabolism in ruminants. This study examined the effect of butyrate on alternative splicing in bovine epithelial cells using RNA-seq technology. Junction reads account for 11.28 and 12.32% of total mapped reads between the butyrate-treated (BT) and control (CT) groups. 201,326 potential splicing junctions detected were supported by ≥3 junction reads. Approximately 94% of these junctions conformed to the consensus sequence (GT/AG) while ∼3% were GC/AG junctions. No AT/AC junctions were observed. A total of 2,834 exon skipping events, supported by a minimum of 3 junction reads, were detected. At least 7 genes, their mRNA expression significantly affected by butyrate, also had exon skipping events differentially regulated by butyrate. Furthermore, COL5A3, which was induced 310-fold by butyrate (FDR <0.001) at the gene level, had a significantly higher number of junction reads mapped to Exon#8 (Donor) and Exon#11 (Acceptor) in BT. This event had the potential to result in the formation of a COL5A3 mRNA isoform with 2 of the 69 exons missing. In addition, 216 differentially expressed transcript isoforms regulated by butyrate were detected. For example, Isoform 1 of ORC1 was strongly repressed by butyrate while Isoform 2 remained unchanged. Butyrate physically binds to and inhibits all zinc-dependent HDACs except HDAC6 and HDAC10. Our results provided evidence that butyrate also regulated deacetylase activities of classical HDACs via its transcriptional control. Moreover, thirteen gene fusion events differentially affected by butyrate were identified. Our results provided a snapshot into complex transcriptome dynamics regulated by butyrate, which will facilitate our understanding of the biological effects of butyrate and other HDAC inhibitors.

VEGF spliced variants: possible role of anti-angiogenesis therapy

Angiogenesis has been targeted in retinopathies, psoriasis, and a variety of cancers (colon, breast, lung, and kidney). Among these tumour types, clear cell renal cell carcinomas (RCCs) are the most vascularized tumours due to mutations of the von Hippel Lindau gene resulting in HIF-1 alpha stabilisation and overexpression of Vascular Endothelial Growth Factor (VEGF). Surgical nephrectomy remains the most efficient curative treatment for patients with noninvasive disease, while VEGF targeting has resulted in varying degrees of success for treating metastatic disease. VEGF pre-mRNA undergoes alternative splicing generating pro-angiogenic isoforms. However, the recent identification of novel splice variants of VEGF with anti-angiogenic properties has provided some insight for the lack of current treatment efficacy. Here we discuss an explanation for the relapse to anti-angiogenesis treatment as being due to either an initial or acquired resistance to the therapy. We also discuss targeting angiogenesis via SR (serine/arginine-rich) proteins implicated in VEGF splicing.

Troglitazone-activated PPARγ inhibits LPS-induced lung alveolar type II epithelial cells injuries via TNF-α

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) are common syndromes characterized by diffuse, acute injury to the alveolar epithelium and pulmonary vascular endothelial cells, with high mortality rate for there are no effective pharmacological therapies. Peroxisome proliferators-activated receptor γ (PPARγ), a member of the nuclear hormone receptor superfamily of ligand-activated transcription factors, is ubiquitously expressed within the lung. Recent studies have indicated PPARγ can protect lung tissue and alleviate pulmonary inflammatory injury. But no studies examined whether PPARγ agonists can protect the alveolar epithelial cells cultured in vitro. We observed the protective effect of PPARγ in LPS-induced alveolar type II epithelial cells injury. The results showed troglitazone-activated PPARγ could inhibit the production of TNF-α, one of the most important inflammatory factors, and then increased the expression of surfactant-associated protein A (SP-A) and attenuate the apoptosis of alveolar type II epithelial cells. Our results suggest that PPARγ may have a potential therapeutic effect on ALI.