The role of vascular endothelium in nitroglycerin-mediated vasodilation

The Efficacy of Heparin and Nitroglycerin in Managing Vascular Embolism Complications from Polycaprolactone (PCL) Fillers: A Clinical Study

BACKGROUND

The use of PCL fillers has increased due to their long-lasting effects and collagen stimulation properties. However, managing vascular embolisms caused by PCL fillers is challenging due to the inability to dissolve them quickly. This study builds upon our previous findings from animal studies, which provided valuable insights into the management of PCL-related vascular complications.

OBJECTIVES

To evaluate the efficacy of heparin and nitroglycerin in managing vascular embolism complications resulting from PCL fillers in a clinical setting.

METHODS

A retrospective clinical study involves 10 patients with vascular embolisms following PCL injections. Treatments included heparin and nitroglycerin administration, imaging for embolism assessment and follow-up ranging from 1 month to 1 year.

RESULTS

The study demonstrated a significant improvement in blood flow and reduction in ischemia with minimal adverse reactions.

CONCLUSIONS

Heparin and nitroglycerin are effective in managing PCL-related vascular embolisms, providing a viable alternative for clinicians.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The efficacy of preemptive multimodal analgesia in elderly patients undergoing laparoscopic colorectal surgery: a randomized controlled trial

Objective To evaluate the effectiveness of preemptive multimodal analgesiain elderly patients undergoing laparoscopic colorectal surgery. Methods A prospective randomized controlled study was conducted in the Department of Gastrointestinal Surgery of the Second Hospital of Hebei Medical University from January 2022 to December 2022. A total of 133 patients were included according to the criteria and randomly divided into preemptive analgesia (PRA) group (test group, 67patients) and postoperative analgesia (POA) group (control group, 66patients). Results The Visual Analog Scale (VAS)scores of PRA group 24 h, 48 h, and 72 h after operation were lower than those of POA group, and the difference was statistically significant, P < 0.001.The incidences of postoperative gastrointestinal dysfunction (POGD) and postoperative delirium (POD)in PRA group were 13.43% and 8.98%, respectively, which were significantly lower than those in POA group (31.82% and 24.24%), P < 0.05. The levels of IL-6 and IL-10 in PRA group after the operation were 17.54 ± 2.13 ng/L and 15.57 ± 1.71 ng/L respectively, which were lower than those in POA group (25.45 ± 2.95 ng/L and 23.45 ± 1.88 ng/L), P < 0.05. The level of acetylcholinesterase(AchE) was 56.34 ± 5.62 nmol/L in the POA group, which was significantly higher than that in the POA group (49.59 ± 5.52 nmol/L), P < 0.001. Conclusion Preemptive multimodal analgesia can reduce the incidence of POGD and POD in elderly patients undergoing laparoscopic gastrocolic surgery, improve the recovery process of postoperative gastrointestinal function, increase the concentrations of propionic acid and butyric acid in short chain fatty acids (SCFAs) and the number of beneficial intestinal bacteria.

Are all sugars equal? Role of the food source in physiological responses to sugars with an emphasis on fruit and fruit juice

High (free) sugar intakes can increase self-reported energy intake and are associated with unfavourable cardiometabolic health. However, sugar source may modulate the effects of sugars due to several mechanisms including the food matrix. The aim of this review was to assess the current state of evidence in relation to food source effects on the physiological responses to dietary sugars in humans relevant to cardiometabolic health. An additional aim was to review potential mechanisms by which food sources may influence such responses. Evidence from meta-analyses of controlled intervention trials was used to establish the balance of evidence relating to the addition of sugars to the diet from sugar-sweetened beverages, fruit juice, honey and whole fruit on cardiometabolic outcomes. Subsequently, studies which have directly compared whole fruit with fruit juices, or variants of fruit juices, were discussed. In summary, the sources of sugars can impact physiological responses, with differences in glycaemic control, blood pressure, inflammation, and acute appetite. Longer-term effects and mechanisms require further work, but initial evidence implicates physical structure, energy density, fibre, potassium and polyphenol content, as explanations for some of the observed responses.

Glyceryl trinitrate-induced blood pressure variability decrease during head-up tilt test predicts vasovagal response

PURPOSE

Glyceryl trinitrate (GTN) provoked cardioinhibitory syncope during the head-up tilt test is preceded by a period of disrupted blood pressure variability (BPV). Endogenous nitric oxide (NO) attenuates BPV independently of blood pressure (BP). We hypothesized that exogenous NO donor GTN might decrease BPV during the presyncope period. A decrease in BPV may predict the tilt outcome.

METHODS

We analyzed 29 tilt test recordings of subjects with GTN-induced cardioinhibitory syncope and 30 recordings of negative subjects. A recursive autoregressive model of BPV after GTN was performed; powers of the respiratory (0.15-0.45 Hz) and nonrespiratory frequency (0.01-0.15 Hz) bands were calculated for each of the 20 normalized time periods. The post-GTN relative changes in heart rate, BP, and BPV were calculated.

RESULTS

In the syncope group, spectral power of nonrespiratory frequency systolic and diastolic BPV progressively felt for 30% after GTN application and stabilized after 180 s. BP started to fall 240 s after the GTN application. Decrease in nonrespiratory frequency power of diastolic BPV 20 s after GTN administration predicted cardioinhibitory syncope (area under the curve 0.811; 77% sensitivity; 70% specificity; cutoff value > 7%).

CONCLUSION

GTN application during the tilt test attenuates systolic and diastolic nonrespiratory frequency BPV during the presyncope period, independent of BP. A decrease in nonrespiratory frequency diastolic BPV 20 s after GTN application predicts cardioinhibitory syncope with good sensitivity and moderate specificity.

The effect of vitamin C on nitroglycerin-mediated vasodilation in individuals with and without the aldehyde dehydrogenase 2 polymorphism

AIMS

To mediate its pharmacodynamic effects, glyceryl trinitrate (GTN) requires bioactivation, by which it releases nitric oxide or a nitric oxide moiety. The exact mechanism of GTN bioactivation remains uncertain. Mitochondrial aldehyde dehydrogenase (ALDH-2) has been proposed as the primary enzyme responsible for this bioactivation process. Evidence for the importance of ALDH-2 in GTN bioactivation has been inconsistent, particularly in human models. An alternative hypothesis suggests that decreased ALDH-2 activity leads to accumulation of reactive cytotoxic aldehydes, which either inhibit the vasoactive product(s) of GTN or impair other enzymatic pathways involved in the bioactivation of GTN. We investigated the effect of supplemental vitamin C on vascular responses to GTN in healthy volunteers of East Asian descent, of whom 12 with and 12 without the ALDH-2 polymorphism participated.

METHODS

Subjects underwent 2 sequential brachial artery infusions of GTN at rates of 5, 11 and 22 nmol/min, separated by a 30-min washout period. The GTN infusions were carried out in the presence and absence of vitamin C using a randomized, crossover design. Venous occlusion plethysmography was used to measure forearm blood flow responses to GTN.

RESULTS

Compared to subjects with functional ALDH-2, the variant group exhibited blunted hemodynamic responses to intra-arterial GTN infusions, although this reduction in response was not statically significant. Contrary to our hypothesis, vitamin C had an inhibitory effect on GTN mediated vasodilation as compared to GTN during saline in both groups.

CONCLUSION

We conclude that vitamin C did not augment the acute vascular response to GTN in those with the ALDH-2 polymorphism.

Preventive effect of tetramethylpyrazine on nitroglycerin-tolerance in rats by improving oxidative stress and ribosome homeostasis

Nitroglycerin (NTG) is recommended as the first-line drug in angina pectoris though its prolonged use impacts nitroglycerin tolerance. In this study, we investigated the preventive effect of Tetramethylpyrazine (TMP), a famous Chinese medicine used for cardiovascular diseases, on NTG-induced tolerance and further explained the underlying mechanism of its action. The results revealed that pretreatment of TMP improved NTG-induced tolerance in vitro thoracic aorta rings and in rats. Proteomic analysis showed oxidative stress and ribosome proteins dyshomeostasis in NTG-tolerance vessels. TMP attenuated the oxidative stress by enhancing the protein expression of ALDH2, Nrf2 and HO-1. In addition, TMP recovered the down-regulated expression of RpL10a induced by nitroglycerin. Therefore, TMP could prevent nitroglycerin tolerance in rats, which may be mediated by up-regulation of ALDH2 and Nrf2/HO-1 signaling pathway and involved in the restoration of ribosome homeostasis. These findings indicate the potential of TMP as a promising medicine for preventing the development of nitroglycerin-induced tolerance.

Impact of the Post-Thrombotic Syndrome on the Arterial Wall of the Lower Limbs

OBJECTIVE

Deep vein thrombosis of the lower limbs is a common disease in vascular surgery. Approximately 20-50% of deep vein thrombosis patients develop post-thrombotic syndrome, which can severely affect the patient's quality of life. However, the precise science of the pathophysiology of the progression of the post-thrombotic syndrome remains unclear. Studies have demonstrated that patients with post-thrombotic syndrome of the lower limbs have impaired arterial wall endothelial function. Nevertheless, there is little research on the different impacts of post-thrombotic syndrome on the arterial wall endothelial function between the affected limbs and the healthy limbs. This study aims to assess this difference.

METHODS

A total of 60 patients treated for the post-thrombotic syndrome of the lower limbs were included. The flow-mediated dilation (FMD%) and nitroglycerin-mediated dilation (NMD%) were measured to assess the different endothelial function alterations of the common femoral arterial wall between the affected limb and the healthy limb.

RESULTS

No significant differences in the common femoral artery diameter between the affected limbs and the healthy limbs were discovered (8.94  ±  0.92 mm vs 8.75  ±  1.0 mm, P = 0.710). The flow-mediated dilation of the common femoral artery of the affected limbs were significantly lower compared to the healthy limbs (FMD%: 3.21  ±  1.07% vs 5.19  ±  1.35%, P  =  0.001). However, there was no significant difference in the nitroglycerin-mediated dilation of the common femoral artery between the affected limbs and the healthy limbs（ NMD%: 13.37  ±  1.78% versus 14.45  ±  2.14%, P = 0.083).

CONCLUSIONS

Our results demonstrated the association between post-thrombotic syndrome and deteriorated endothelial functional properties of the arterial wall of the lower limbs. Endothelial dysfunction of the arteries wall was more severe in the affected lower limbs with the post-thrombotic syndrome than in the healthy limbs. The mentioned findings may partly explain the pathophysiology of the progression post-thrombotic syndrome of the lower limbs.

HIGHLIGHTS

tudies have demonstrated that patients with post-thrombotic syndrome of the lower limbs have impaired arterial wall endothelial function. Our results demonstrated the endothelial dysfunction of the arteries wall was more severe in the affected lower limbs with the post-thrombotic syndrome than in the healthy limbs. Our findings may partly explain the pathophysiology of the progression post-thrombotic syndrome of the lower limbs.

The impact of the 24-h movement spectrum on vascular remodeling in older men and women: a review

Aging is associated with increased risk of cardiovascular and cerebrovascular events, which are preceded by early, negative remodeling of the vasculature. Low physical activity is a well-established risk factor associated with the incidence and development of disease. However, recent physical activity literature indicates the importance of considering the 24-h movement spectrum. Therefore, the purpose of this review was to examine the impact of the 24-h movement spectrum, specifically physical activity (aerobic and resistance training), sedentary behavior, and sleep, on cardiovascular and cerebrovascular outcomes in older adults, with a focus on recent evidence (<10 yr) and sex-based considerations. The review identifies that both aerobic training and being physically active (compared with sedentary) are associated with improvements in endothelial function, arterial stiffness, and cerebrovascular function. Additionally, there is evidence of sex-based differences in endothelial function: a blunted improvement in aerobic training in postmenopausal women compared with men. While minimal research has been conducted in older adults, resistance training does not appear to influence arterial stiffness. Poor sleep quantity or quality are associated with both impaired endothelial function and increased arterial stiffness. Finally, the review highlights mechanistic pathways involved in the regulation of vascular and cerebrovascular function, specifically the balance between pro- and antiatherogenic factors, which mediate the relationship between the 24-h movement spectrum and vascular outcomes. Finally, this review proposes future research directions: examining the role of duration and intensity of training, combining aerobic and resistance training, and exploration of sex-based differences in cardiovascular and cerebrovascular outcomes.

Role of Mitochondrial Aldehyde Dehydrogenase in Nitroglycerin-Mediated Vasodilation: Observations Concerning the Dose-Response Relationship

The mechanism of the bioactivation of nitroglycerin has long been controversial, with a number of suggested enzymatic pathways. More recently, aldehyde dehydrogenase-2 (ALDH-2) has been reported as the important enzyme involved in the bioactivation of nitroglycerin at therapeutically relevant concentrations. Other previously described enzyme systems can also bioactivate nitroglycerin, but only at concentrations, which are significantly higher than achieved in clinical practice. This study investigated the vascular response to nitroglycerin given over a wide range of concentrations in subjects with and without the ALDH-2 Glu504Lys polymorphism, a common genetic variant that greatly reduces the activity of ALDH-2 (n = 10 in both groups). Forearm blood flow (FBF) responses to a brachial artery infusion of nitroglycerin were assessed using venous occlusion plethysmography. Intra-arterial infusion of nitroglycerin caused a significant increase in FBF beginning at 0.464 µg/min with increasing responses seen in both groups at all infusion rates. However, there were no differences in the FBF responses to nitroglycerin in those with and without the ALDH-2 polymorphism, suggesting that ALDH-2 is not solely responsible for the bioactivation of nitroglycerin at either low (therapeutically relevant) or high concentrations of nitroglycerin.

The role of vascular endothelium in nitroglycerin-mediated vasodilation

AIMS

Nitroglycerin (or glyceryl trinitrate, GTN) has been long considered an endothelium-independent vasodilator because GTN vasodilation is intact in the absence of the endothelium and in the presence of endothelial dysfunction. However, in animal and in vitro models, GTN has been shown to stimulate the release of certain endothelium-derived vasodilators such as nitric oxide (NO) and prostacyclin (PGI₂ ). In addition, chronic GTN therapy leads to endothelial dysfunction. In this series of experiments, we explored how GTN might interact with the vascular endothelium in normal humans, without cardiovascular disease or risk factors associated with abnormalities in vascular function.

METHODS

We examined the effect of inhibition of NO, PGI₂ , and epoxyeicosatrienoic acids (EETs, a class of endothelium-derived hyperpolarizing factor) on GTN-mediated vasodilation. We measured arterial blood flow responses to brachial artery infusions of GTN in the absence and presence of L-NMMA (n = 13), ketorolac (n = 14) and fluconazole (n = 16), which are inhibitors of endothelium-derived NO, PGI₂ and EETs, respectively, in healthy volunteers.

RESULTS

Our results demonstrate that inhibition of endothelium-dependent vasodilator mechanisms does not alter forearm resistance vessel responses to GTN.

CONCLUSION

We conclude that GTN-mediated dilation of forearm resistance vessels is largely independent of vascular endothelium.