The role of transient receptor potential ankyrin 1 in age-related endothelial dysfunction

Advances in pharmacological effects and mechanism of action of cinnamaldehyde

Cinnamaldehyde is extracted from Cinnamomum cassia and other species, providing diverse sources for varying chemical properties and therapeutic effects. Besides natural extraction, synthetic production and biotechnological methods like microbial fermentation offer scalable and sustainable alternatives. Cinnamaldehyd demonstrates a broad pharmacological range, impacting various diseases through detailed mechanisms. This review aims to encapsulate the diverse therapeutic effects of cinnamaldehyde, its molecular interactions, and its potential in clinical applications. Drawing on recent scientific studies and databases like Web of Science, PubMed, and ScienceDirect, this review outlines cinnamaldehyde's efficacy in treating inflammatory conditions, bacterial infections, cancer, diabetes, and cardiovascular and kidney diseases. It primarily operates by inhibiting the NF-κB pathway and modulating pro-inflammatory mediators, alongside disrupting bacterial cells and inducing apoptosis in cancer cells. The compound enhances metabolic health by improving glucose uptake and insulin sensitivity and offers cardiovascular protection through its anti-inflammatory and lipid-lowering effects. Additionally, it promotes autophagy in kidney disease management. Preclinical and clinical research supports its therapeutic potential, underscoring the need for further investigation into its mechanisms and safety to develop new drugs based on cinnamaldehyde.

Involvement of nitric oxide synthase and reactive oxygen species in TRPA1-mediated cutaneous vasodilation in young and older adults

OBJECTIVE

To investigate the nitric oxide synthase (NOS) and reactive oxygen species (ROS) contributions of the cutaneous vasodilator response to transient receptor potential ankyrin-1 channel (TRPA1) activation in young and older adults.

MATERIALS AND METHODS

In sixteen young (20 ± 2 years, 8 females) and sixteen older adults (61 ± 5 years, 8 females), cutaneous vascular conductance normalized to maximum vasodilation (%CVC_max) was assessed at four dorsal forearm skin sites continuously perfused via microdialysis with: 1) vehicle solution (Control, 2 % dimethyl sulfoxide, 2 % Ringer, 96 % propylene glycol), 2) 10 mM Ascorbate (non-specific ROS inhibitor), 3) 10 mM L-NAME (non-specific NOS inhibitor), or 4) Ascorbate+L-NAME. The TRPA1 agonist cinnamaldehyde was co-administered at all sites [0 % (baseline), 2.9 %, 8.8 %, 26.4 %; ≥ 30 min per dose].

RESULTS

%CVC_max was not different between groups for Control, L-NAME, and Ascorbate (all p > 0.05). However, there were significant main dose effects for each site wherein %CVC_max was greater than baseline from 2.9 % to 26.4 % cinnamaldehyde for Control and Ascorbate, and at 26.4 % cinnamaldehyde for L-NAME and Ascorbate+L-NAME (all p < 0.05). For Ascorbate+L-NAME, there was a significant main group effect, wherein perfusion was 6 %CVC_max [95% CI: 2, 11, p < 0.05] greater in the older compared to the young group across all cinnamaldehyde doses. There was a significant main site effect for area under the curve wherein L-NAME and Ascorbate+L-NAME were lower than Control and Ascorbate across groups (all p < 0.05).

CONCLUSION

The NOS-dependent cutaneous vasodilator response to TRPA1 activation is maintained in older adults, with no detectable contribution of ascorbate-sensitive ROS in either age group.

The Therapeutic Roles of Cinnamaldehyde against Cardiovascular Diseases

Evidence from epidemiological studies has demonstrated that the incidence and mortality of cardiovascular diseases (CVDs) increase year by year, which pose a great threat on social economy and human health worldwide. Due to limited therapeutic benefits and associated adverse effects of current medications, there is an urgent need to uncover novel agents with favorable safety and efficacy. Cinnamaldehyde (CA) is a bioactive phytochemical isolated from the stem bark of Chinese herbal medicine Cinnamon and has been suggested to possess curative roles against the development of CVDs. This integrated review intends to summarize the physicochemical and pharmacokinetic features of CA and discuss the recent advances in underlying mechanisms and potential targets responsible for anti-CVD properties of CA. The CA-related cardiovascular protective mechanisms could be attributed to the inhibition of inflammation and oxidative stress, improvement of lipid and glucose metabolism, regulation of cell proliferation and apoptosis, suppression of cardiac fibrosis, and platelet aggregation and promotion of vasodilation and angiogenesis. Furthermore, CA is likely to inhibit CVD progression via affecting other possible processes including autophagy and ER stress regulation, gut microbiota and immune homeostasis, ion metabolism, ncRNA expression, and TRPA1 activation. Collectively, experiments reported previously highlight the therapeutic effects of CA and clinical trials are advocated to offer scientific basis for the compound future applied in clinical practice for CVD prophylaxis and treatment.

Knockout of Trpa1 accelerates age-related cardiac fibrosis and dysfunction

Age-related cardiac fibrosis contributes to the development of heart failure with preserved ejection fraction which lacks ideal treatment. Transient receptor potential ankyrin 1 (TRPA1) is an oxidative stress sensor and could attenuate age-related pathologies in invertebrates. The present study aimed to test whether TRPA1 plays a role in age-related cardiac remodeling and dysfunction. The cardiac function and pathology of 12-week-old (young) and 52-week-old (older) Trpa1^-/- mice and wild-type (WT) littermates were evaluated by echocardiography and histologic analyses. The expression levels of 84 fibrosis-related genes in the heart were measured by quantitative polymerase chain reaction array. Young Trpa1^-/- and WT mice had similar left ventricular wall thickness, volume, and systolic and diastolic function. Older Trpa1^-/- mice had significantly increased left ventricular internal diameter and volume and impaired systolic (lower left ventricular ejection fraction) and diastolic (higher E/A ratio and isovolumetric relaxation time) functions compared with older WT mice (P<0.05 or P<0.01). Importantly, older Trpa1^-/- mice had enhanced cardiac fibrosis than older WT mice (P<0.05) while the two strains had similar degree of cardiac hypertrophy. Among the 84 fibrosis-related genes, Acta2, Inhbe, Ifng, and Ccl11 were significantly upregulated, while Timp3, Stat6, and Ilk were significantly downregulated in the heart of older Trpa1^-/- mice compared with older WT mice. Taken together, we found that knocking out Trpa1 accelerated age-related myocardial fibrosis, ventricular dilation, and cardiac dysfunction. These findings suggest that TRPA1 may become a therapeutic target for preventing and/or treating cardiac fibrosis and heart failure with preserved ejection fraction in the elderly.

Capsaicin Prevents Contrast-Associated Acute Kidney Injury through Activation of Nrf2 in Mice

Capsaicin, a transient receptor potential vanilloid 1 channel agonist, possesses antioxidative properties through activating nuclear factor-erythroid 2-related factor 2 (Nrf2). As oxidative stress is a major contributor to the development of contrast-associated acute kidney injury (CA-AKI), we investigated the protective effect of capsaicin against CA-AKI via Nrf2. C57BL/6J mice were treated with dehydration and iodixanol to establish the model of CA-AKI. For pretreatment, capsaicin (0.3 mg/kg) was given via intraperitoneal injection one hour before iodixanol injection. Nrf2-specific siRNA was given through the tail vein to knock down Nrf2. The CA-AKI mouse model had remarkable mitochondrial fragmentation and dysfunction and apoptosis of tubular cells, overproduction of superoxide in renal tubules, increased renal malondialdehyde, tubular epithelial cell injury, and renal dysfunction. Importantly, pretreatment with capsaicin significantly ameliorated tubular cell injury and renal dysfunction with decreased superoxide, renal malondialdehyde, and apoptotic tubular cells and improved mitochondrial morphology and function in the CA-AKI mouse model. The expression of Nrf2 was increased in the kidney from the CA-AKI mouse model and was further enhanced by capsaicin. Administration of siRNA through the tail vein successfully decreased Nrf2 expression in the kidney, and knockdown of Nrf2 by siRNA abolished the beneficial effects of capsaicin on CA-AKI. The present study demonstrated a protective effect of capsaicin pretreatment against CA-AKI via Nrf2.