Effect of oral intake of royal jelly on endothelium function in hemodialysis patients: study protocol for multicenter, double-blind, randomized control trial

Background Hemodialysis (HD) is a common renal replacement therapy for patients with renal failure. Cardiovascular and cerebrovascular diseases are known to shorten survival periods and worsen the quality of life of HD patients. Atherosclerosis is a major cause of vascular diseases, and various factors such as abnormality of lipid metabolism and increased macrophage activity, oxidative stress, and endothelial dysfunction are associated with its pathogenesis and progression. Further, endothelial stem cells (ESCs) have been reported to play important roles in endothelial functions. Royal jelly (RJ) affects atherosclerosis- and endothelial function-related factors. The main aim of this trial is to investigate whether oral intake of RJ can maintain endothelial function in HD patients. In addition, the effects of RJ intake on atherosclerosis, ESC count, inflammation, and oxidative stress will be analyzed. Methods This will be a multicenter, prospective, double-blind, randomized controlled trial. We will enroll 270 participants at Nagasaki Jin Hospital, Shinzato Clinic Urakami, and Maeda Clinic, Japan. The participants will be randomized into RJ and placebo groups. The trial will be conducted according to the principles of the Declaration of Helsinki, and all participants will be required to provide written informed consent. The RJ group will be treated with 3600 mg/day of RJ for 24 months, and the placebo group will be treated with starch for 24 months. The primary endpoint will be the change in flow-mediated dilation (FMD), a parameter of endothelium function, from the time before treatment initiation to 24 months after treatment initiation. The secondary and other endpoints will be changes in FMD; ESC count; serum levels of vascular endothelial cell growth factor, macrophage colony-stimulating factor, 8-hydroxydeoxyguanosine, and malondialdehyde; the incidence of cardiovascular diseases, cerebrovascular diseases, and stenosis of blood access; and safety. Discussion This trial will clarify whether oral intake of RJ can maintain endothelial function and suppress the progression of atherosclerosis in HD patients. In addition, it will clarify the effects of RJ on ESCs, oxidative stress, and angiogenic activity in blood samples. Trial registration The Japan Registry of Clinical Trials jRCTs071200031. Registered on 7 December 2020.

Modulation of endothelium function by fatty acids

The endothelium acts as the barrier that prevents circulating lipids such as lipoproteins and fatty acids into the arterial wall; it also regulates normal functioning in the circulatory system by balancing vasodilation and vasoconstriction, modulating the several responses and signals. Plasma lipids can interact with endothelium via different mechanisms and produce different phenotypes. Increased plasma-free fatty acids (FFAs) levels are associated with the pathogenesis of atherosclerosis and cardiovascular diseases (CVD). Because of the multi-dimensional roles of plasma FFAs in mediating endothelial dysfunction, increased FFA level is now considered an essential link in the onset of endothelial dysfunction in CVD. FFA-mediated endothelial dysfunction involves several mechanisms, including dysregulated production of nitric oxide and cytokines, metaflammation, oxidative stress, inflammation, activation of the renin-angiotensin system, and apoptosis. Therefore, modulation of FFA-mediated pathways involved in endothelial dysfunction may prevent the complications associated with CVD risk. This review presents details as to how endothelium is affected by FFAs involving several metabolic pathways.

THE VASCULAR ENDOTHELIUM FUNCTION INDICATORS IN ORAL LIQUID OF IQOS SMOKING ADOLESCENTS

Heated tobacco products (HTP) were introduced to the world market as an alternative to conventional tobacco cigarettes. Active advertising, readily available to purchase and the public's perception that HTP are a safer alternative to conventional tobacco cigarettes lead to increasing their consumption by young age group in Ukraine. Despite the claims by the tobacco corporations about reduction of adverse effects the HTP on the activity of cardiovascular system, the published studies of potential vascular endothelial consequences were not found. Therefore, the aim of our study is to assess the HTP effect on vascular endothelial cells by determination of the nitrate, nitrite, S-nitrosothiols, and endothelin-1 levels in saliva of smoking adolescents. The object and research methods. Thirty adolescents aged 14-17 years old were divided to three groups. Group I was introduced by ten healthy non-smoking adolescents (control group). Group II consists of ten smoking adolescents have smoked the IQOS for two years. Group III is formed by ten smoking adolescents who have smoked the IQOS for three years. The salivary nitrate and nitrite levels were measured using the Griess assay such as an indicator of NO production. The salivary S-nitrosothiols were measured spectrophotometrically. The salivary endothelin-1 level was measured with ELISA kit. Statistical analysis of the data was carried out using the STATISTICA 7.0 program. The data were presented as Median values (Me), lower and upper quartile, i.e. Me [Lq; Uq]. Statistical significance was accepted if p < 0.05. Results. The salivary nitrate concentrations in groups II (Me = 14.11 [13.98; 14.52] μmol/l) and III (Me = 12.06 [11.44; 12.31] μmol/l) were significantly decreased compared to group I (Me = 15.89 [14.98; 16.89] μmol/l, KW test: H = 23.59, p=0.000. The values of nitrite in groups II and III were the following: Me = 2.32 [1.47; 2.48] μmol/l and 1.37 [1.25; 1.44] μmol/l, respectively. The indices were lower in 1.41 and 2.36 times than in group I: Me = 3. 24 [3.05; 3.78] μmol/l, KW test: Н = 22.92, p = 0.000. The levels of salivary S-nitrosothiols in group II are: Me = 1.02 [0.84; 1.27] μmol/l and group III Me = 0.36 [0.25; 0.62] μmol/l were reduced in 1.75 and 4.97 times compared to group I: Me = 1.79 [1.67; 1.97] μmol/l, KW test: Н = 24.46, р = 0.000. We assume that the reduction of salivary nitrate and nitrite concentrations is associated with a low level of S-nitrosothiols which serve as deposited and released nitric oxide (NO). Probably, the decrease of nitrates and nitrites is associated with the inhibition of endothelial NO synthase. The salivary endothelin-1 level was significantly higher in group II: Ме=0.58 [0.53; 0.73] pmol/ml and in group III: Ме = 0.82 [0.79; 0.93] pmol/ml than in group I: Ме = 0.17 [0.14; 0.26] pmol/ml, KW test: Н = 23.94, р = 0.000. It should be noted, the significant differences between data of nitrate, nitrite, S-nitrosothiol and endothelin-1 content in groups II and III were found (Mann-Whitney U test, nitrates - Z = 3.62, p = 0.000; nitrites - Z = 2.91 , p = 0.003; S-nitrosothiols - Z = 3.74, p = 0.00; endothelin-1 - Z = 3.36, p = 0.000). These results showed interrelation between adverse IQOS effect on vascular endothelium of adolescents duration of IQOS smoke. Conclusions. The adverse effect of heated tobacco product (IQOS) on the biochemical indicators of the vascular endothelium function of adolescents was found in our experimental study. The salivary nitrate, nitrite and S-nitrosothiols levels were significantly decreased in IQOS smoking adolescents. The salivary endothelin-1 content was significantly elevated in IQOS smoking adolescents. The revealed changes indicate the endothelial dysfunction in young smokers. The development of pathological processes in the vascular endothelium depends on the smoking duration.

Prevention of Hypertensive Disorders of Pregnancy—Is There a Place for Metformin?

The possibility of prophylaxis of hypertensive disorders of pregnancy (HDPs) such as preeclampsia (PE) and pregnancy-induced hypertension is of interest due to the unpredictable course of these diseases and the risks they carry for both mother and fetus. It has been proven that their development is associated with the presence of the placenta, and the processes that initiate it begin at the time of the abnormal invasion of the trophoblast in early pregnancy. The ideal HDP prophylaxis should alleviate the influence of risk factors and, at the same time, promote physiological trophoblast invasion and maintain the physiologic endothelium function without any harm to both mother and fetus. So far, aspirin is the only effective and recommended pharmacological agent for the prevention of HDPs in high-risk groups. Metformin is a hypoglycemic drug with a proven protective effect on the cardiovascular system. Respecting the anti-inflammatory properties of metformin and its favorable impact on the endothelium, it seems to be an interesting option for HDP prophylaxis. The results of previous studies on such use of metformin are ambiguous, although they indicate that in a certain group of pregnant women, it might be effective in preventing hypertensive complications. The aim of this study is to present the possibility of metformin in the prevention of hypertensive disorders of pregnancy with respect to its impact on the pathogenic elements of development

Involvement of amylin B-H2S-connexin 43 signaling pathway in vascular dysfunction and enhanced ischemia–reperfusion-induced myocardial injury in diabetic rats

The present study was designed to investigate the role of amylin, H2S, and connexin 43 in vascular dysfunction and enhanced ischemia–reperfusion (I/R)-induced myocardial injury in diabetic rats. A single dose of streptozotocin (65 mg/kg) was employed to induce diabetes mellitus. After 8 weeks, there was a significant decrease in the plasma levels of amylin, an increase in I/R injury to isolated hearts (increase in CK-MB and cardiac troponin release) on the Langendorff apparatus. Moreover, there was a significant impairment in vascular endothelium function as assessed by quantifying acetylcholine-induced relaxation in norepinephrine-precontracted mesenteric arteries. There was also a marked decrease in the expression of H2S and connexin 43 in the hearts following I/R injury in diabetic rats. Treatment with amylin agonist, pramlintide (100 and 200 µg/kg), and H2S donor, NaHS (10 and 20 μmol/kg) for 2 weeks improved the vascular endothelium function, abolished enhanced myocardial injury and restored the levels of H2S along with connexin 43 in diabetic animals. However, pramlintide and NaHS failed to produce these effects the presence of gap junction blocker, carbenoxolone (20 and 40 mg/kg). Carbenoxolone also abolished the myocardial levels of connexin 43 without affecting the plasma levels of amylin and myocardial levels of H2S. The decrease in the amylin levels with a consequent reduction in H2S and connexin 43 may contribute to inducing vascular dysfunction and enhancing I/R-induced myocardial injury in diabetic rats.