Lower Blood Pressure Increase Research Articles

Impact of Ultrafiltration Profiling Compared to Conventional Methods on Blood Pressure Regulation Among Hemodialysis Patients

Background: Standard hemodialysis sessions pose challenges for patients due to fluctuations in blood pressure. Alternative strategies, such as ultrafiltration profiling, have been proposed as potentially more effective treatments. Objectives: This study aimed to evaluate the effects of ultrafiltration profiling compared to the conventional method on blood pressure regulation among hemodialysis patients. Methods: This study employed a pre-test and post-test design, involving a single group of 30 hemodialysis patients undergoing treatment at Shahid Beheshti Hospital in Hamadan in 2022. The sampling method used was simple random sampling. The intervention consisted of three sessions using the routine method, followed by three sessions utilizing the ultrafiltration profile method, which employed an interval with a negative slope. Demographic and clinical information about the patients was recorded on a checklist. Systolic and diastolic blood pressure measurements were taken before the commencement of hemodialysis, at 1-, 2-, and 3-hour intervals post-treatment initiation, and again 15 minutes after completing hemodialysis. Results: The mean blood pressure changes observed during dialysis stages increased with both methods; however, there was a significant difference between the methods (P < 0.001). Specifically, patients receiving the ultrafiltration profile method experienced significantly lower increases in blood pressure compared to those receiving the routine method. Conclusions: Based on the research results, integrating ultrafiltration profiling into hemodialysis can be regarded as an effective and viable strategy for enhancing blood pressure regulation in patients undergoing hemodialysis treatment. Therefore, it is recommended that this approach be considered in hemodialysis programs as well.

Normotensive placental extracellular vesicles provide long-term protection against hypertension and cardiovascular disease

BackgroundWomen with normotensive pregnancy are at a reduced risk of developing cardiovascular disease postpartum compared to those who experience hypertensive conditions during pregnancy. However, the underlying mechanisms remain poorly understood. During normotensive pregnancy, vast numbers of placental extracellular vesicles are released into the maternal circulation, which protect endothelial cells from activation and alter maternal vascular tone. We hypothesized that placental extracellular vesicles play a mechanistic role in lowering risk of cardiovascular disease following normotensive pregnancy. ObjectiveThis study aimed to investigate the long-term effects of placental extracellular vesicles derived from normotensive term placentae on the cardiovascular system and explore the mechanisms underlying their biological effects. Study DesignSpontaneously hypertensive rats were injected with placental EVs from normotensive term pregnancies (2 mg /kg each time, n=8) or vehicle control (n=9) at 3 months of age. Blood pressure and cardiac function were regularly monitored from 3 months to 15 months of age. The response of mesenteric resistance arteries to vasoactive substances was investigated to evaluate vascular function. Cardiac remodelling, small artery remodelling, and renal function were investigated to comprehensively assess the impact of placental extracellular vesicles on cardiovascular and renal health. ResultsCompared to vehicle-treated control animals, rats treated with normotensive placental extracellular vesicles exhibited a significantly lower increase in blood pressure and improved cardiac function. Furthermore, the vasodilator response to the endothelium-dependent agonist acetylcholine was significantly enhanced in the normotensive placental extracellular vesicle-treated spontaneously hypertensive rats compared to the control. Moreover, treatment with placental extracellular vesicles reduced wall thickening of small renal vessels and attenuated renal fibrosis. ConclusionPlacental extracellular vesicles from normotensive term pregnancies have long-lasting protective effects reducing hypertension and mitigating cardiovascular damage in vivo.

Abstract 12772: Regulation of Blood Pressure by Smooth Muscle TRPV4 Channels Under Normal and Hypertensive Conditions

Introduction: Recent studies suggest that transient receptor potential vanilloid 4 (TRPV4) channel is a functionally important Ca 2+ influx pathway in arterial smooth muscle cells (SMCs). Hypothesis: We hypothesized that SMC TRPV4 (TRPV4 SMC ) channels regulate blood pressure under normal conditions and in hypertension. Results: Radiotelemetric recordings showed lower blood pressures in the SMC-specific TRPV4 -/- (TRPV4 SMC -/- ) mice than the control mice. Phenylephrine (PE, α1 adrenergic receptor or α1AR agonist)-induced constriction was blunted in small mesenteric arteries (MAs) from TRPV4 SMC -/- mice, whereas intraluminal pressure-induced constriction was increased. These data demonstrated that TRPV4 SMC channels contribute to α1AR-induced vasoconstriction but oppose pressure-induced vasoconstriction. Both PE and intraluminal pressure increased the activity of elementary Ca 2+ influx signals through TRPV4 SMC channels (TRPV4 SMC sparklets). TRPV4 agonist GSK1016790A (30 nM) activated the currents through large-conductance, Ca 2+ -sensitive K + (BK) channels in SMCs, whereas phenylephrine had no effect on BK channel currents. These data implied the presence of two functionally distinct pools of TRPV4 SMC channels: 1) α1AR-activated, constrictor TRPV4 SMC channels; and 2) pressure-activated, dilator TRPV4 SMC channels. Next, direct STORM imaging demonstrated that ~30% TRPV4 SMC channels co-localize with α1ARs and ~10% TRPV4 SMC channels co-localize with BK channels. Importantly, only ~3% TRPV4 SMC channels co-localized with both α1ARs and BK channels, supporting the concept of spatially distinct constrictor and dilator TRPV4 SMC channels. Angiotensin II (Ang II, 7-14 days) infusion resulted in a lower increase in blood pressure in TRPV4 SMC -/- mice than the control mice, demonstrating a crucial role of TRPV4 SMC channels in blood pressure elevation in hypertension. Moreover, Ang II infusion in C57BL6 mice increased α1AR-TRPV4 SMC signaling; reduced pressure-activation of TRPV4 SMC channels; and reduced TRPV4 SMC -BK channel signaling. Conclusions: Our results show that increased constrictor TRPV4 SMC channel activity and reduced dilator TRPV4 SMC channel activity combine to elevate blood pressure in hypertension.

Speed of Movement, Fatness, and the Change in Cardiometabolic Risk Factors in Children.

We aimed to examine speed of movement and its interactive association with fatness to changes in cardiometabolic risk factors over one year in children. The analysis included 8345 children aged 6-13 years. Cardiometabolic risk score was computed by summing Z-scores of waist circumference, the average of systolic and diastolic blood pressure, fasting glucose, high-density lipoprotein cholesterol (multiplied by -1), and triglycerides. Both high baseline and improvement in speed of movement were associated with favourable changes in percent body fat, lipids, and cardiometabolic risk score. Percentages of the association between baseline speed of movement and changes in cardiometabolic risk score, triglycerides, and high-density lipoprotein cholesterol explained by baseline BMI were 24.6% (19.6-29.1%), 26.2% (19.7-31.1%), and 12.5% (9.6-15.4%), respectively. The corresponding number for percent body fat was 47.0% (40.4-54.1%), 43.3% (36.7-51.7%), and 29.8% (25.0-34.6%), respectively. Speed of movement mediated the association between fatness and cardiometabolic risk factors. Improved speed of movement was associated with a lower increase in blood pressure in obese children only. Speed of movement is a strong predictor of changes in cardiometabolic risk factors. Fatness and speed of movement are interactively associated with cardiometabolic risk factors. Speed of movement may attenuate the positive association between fatness and blood pressure.

Increased α1-adrenoreceptor activity is required to sustain blood pressure in female rats under food restriction.

We evaluated the effect of food restriction (FR) on the various reflexes involved in short term cardiovascular regulation; we also evaluated the contribution of the sympathetic nervous systemand of the plasmatic nitric oxide (NO) in the development of the counterregulatory cardiovascular changes triggered by FR. Female rats were subjected to FR for 14 days, and after this period biochemical measurements of biochemical parameters were performed. For physiological tests, animals were anaesthetised, and a catheter was inserted into the femoral artery and vein for the acquisition of blood pressure and heart hate, and drug infusion, respectively.We then tested the Bezold–Jarisch reflex, the baroreflex and chemoreflex and the effect of the infusion of adrenergic receptor antagonists in control and food restricted animals. The rats subjected to severe FR presented biochemical changes characteristic of malnutrition with a great catabolic state. FR also led to hypotension and bradycardia besides reducing the plasmatic concentration of NO. Moreover, activation of the Bezold–Jarisch reflex induced a more pronounced hypotensive response in animals subjected to FR. Intravenous infusion of a α1-adrenoreceptor antagonist induced a greater hypotensive response and a more pronounced tachycardic response in animals under food restriction,while the infusion of β-adrenoreceptor antagonist induced lower increases in blood pressure in these animals. Our results suggest that an increased α1-adrenoreceptor activity in the resistance arteries coupled with a reduction of plasmatic NO contributes in a complementary manner to maintain the blood pressure levels in animals under FR.

Propofol and thiopental as anaesthetic agents in electroconvulsive therapy: A retrospective study in major depression

ObjectiveTo determine the influence of propofol and thiopental as anaesthetics in electroconvulsive therapy (ECT), as regards, seizure duration, electrical charge, clinical efficacy, cardiovascular profile, and presence of adverse cognitive effects. MethodsA retrospective design including 127 patients who received bilateral ECT for the treatment of a major depressive episode. ResultsThe mean seizure duration in the propofol group was significantly shorter than in the thiopental group (21.23±6.09 versus 28.24±6.67s, P<0.001). The mean stimulus charge was 348.22mC in the propofol group, and 238mC in the thiopental group (P<0.001). Propofol was associated with a lower increase in blood pressure. There were no differences between groups in treatment response or presence of adverse effects. ConclusionsThe anaesthetic agent used in ECT might determine differences in parameters such as seizure duration or electrical charge. However, this does not seem to be translated into differences in clinical efficacy or the pattern of adverse effects observed.

Propofol y pentotal como agentes anestésicos en la terapia electroconvulsiva: un estudio retrospectivo en el trastorno depresivo mayor

To determine the influence of propofol and thiopental as anesthetics in electroconvulsive therapy (ECT), as regards, seizure duration, electrical charge, clinical efficacy, cardiovascular profile, and presence of adverse cognitive effects.A retrospective design including 127 patients who received bilateral ECT for the treatment of a major depressive episode.The mean seizure duration in the propofol group was significantly shorter than in the thiopental group (21.23±6.09 versus 28.24±6.6 7s, P<.001). The mean stimulus charge was 348.22 mC in the propofol group, and 238 mC in the thiopental group (P<.001). Propofol was associated with a lower increase in blood pressure. There were no differences between groups in treatment response or presence of adverse effects.The anesthetic agent used in ECT might determine differences in parameters such as seizure duration or electrical charge. However, this does not seem to be translated into differences in clinical efficacy or the pattern of adverse effects observed.

Associations between Chronic Community Noise Exposure and Blood Pressure at Rest and during Acute Noise and Non-Noise Stressors among Urban School Children in India

The present study builds on prior research that has examined the association between children’s chronic exposure to community noise and resting blood pressure and blood pressure dysregulation during exposure to acute stressors. A novel contribution of the study is that it examines how chronic noise exposure relates to blood pressure responses during exposure to both noise and non-noise acute stressors. The acute noise stressor was recorded street noise and the non-noise stressor was mental arithmetic. The sample consisted of 189 3rd and 6th grade children (51.9% percent boys; 52.9% 3rd graders) from a noisy (n = 95) or relatively quiet (n = 94) public school in the city of Pune, India. There were no statistically significant differences between chronic noise levels and resting blood pressure levels. However, relative to quiet-school children, noisy-school children had significantly lower increases in blood pressure when exposed to either an acute noise or non-noise stressor. This finding suggests that chronic noise exposure may result in hypo-reactivity to a variety of stressors and not just habituation to noise stressors.

Dairy intake and changes in blood pressure over 9 years: the ARIC study

Dairy product intake could contribute to preventing hypertension, but information linking intake of these foods with changes in blood pressure over long periods of time, particularly in non-whites, is scarce. We analyzed the Atherosclerosis Risk in Communities study, a prospective cohort in the United States, to assess whether different types of dairy products were associated with changes in blood pressure over time. The analysis included 6912 white and 1296 African-American nonhypertensive men and women, aged 45-64 at baseline. After 9 years of follow-up, systolic blood pressure of whites consuming three or more daily servings of low-fat milk increased 2.7 mm Hg less than in those consuming less than one serving per week (P for trend=0.01). Among African Americans, dairy products intake was not associated with changes in blood pressure over time. In conclusion, higher low-fat milk intake was associated with lower increases in blood pressure in whites but not in African Americans.

Blutdrucksenkung durch Hydrotherapie: Eine randomisierte, kontrollierte Studie bei leichter bis mittelschwerer Hypertonie

Fragestellung: Beobachtungsstudien zeigten immer wieder, dass erhöhte Blutdruckwerte im Laufe einer Kur unter hydrotherapeutischen Maßnahmen nach Kneipp oder unter Balneotherapie abzusinken pflegen. Ob dies allein auch durch Milieuwechsel und Erholung zusammen mit einem gesundheitsbewussten Lebensstil erreicht werden kann, oder ob dies doch mehr den speziellen physikalischen Maßnahmen zuzuschreiben ist, sollte nun durch eine randomisierte, kontrollierte Studie an Hypertonikern, die sich wegen einer kardiovaskulären Grunderkrankung in einer 3–4-wöchigen stationären Rehabilitation befanden, geklärt werden.

Interleukin-1 receptor antagonist reduces the magnitude of the pressor response to acute stress

The purpose of the present study was to establish the effect of chronic central interleukin-1 receptors blockade and central chronic infusion of interleukin-1 beta (IL-1β) on cardiovascular response to an acute stressor. The experiments were performed on 12–14-week-old, male WKY rats, divided into three experimental groups. Each group was subjected to chronic intracerebroventricular (ICV) infusion of one of the following compounds: saline (control, group C), recombinant rat IL-1 receptor antagonist (IL-ANT group) or interleukin-1 beta (IL-1B group). After 5 days of the ICV infusions mean arterial blood pressure (MABP) and heart rate (HR) were recorded continuously under baseline conditions and after the application of an air jet stressor. The stressor was applied three times with 10-min intervals. There were no significant differences in MABP and HR between groups under baseline conditions and immediately before the application of the three consecutive air jets. After the first stressor the IL-ANT group responded with a significantly lower increase in blood pressure than the control and IL-1B group. After the application of the two following air jets only the trend for an intergroup difference was present. The results of the present study provide further evidence that cytokines play an important role in the regulation of the circulatory system. The most important new finding is that the magnitude of the pressor response to the alarming stress is strongly influenced by IL-1 receptors in the brain.

Genetic background in apolipoprotein A-I and cystathionine b-synthase deficiency

Double heterozygous mice lacking one allele of Cbs and Apoa1 develop hyperhomocysteinemia and hypoalphalipoproteinemia together with moderate hypertension. To study the influence of the genetic background into this specific phenotype, four groups of male mice were established: control and double heterozygous groups in C57BL/6J and in C57BL/6J x 129 backgrounds, respectively. Nitric oxide levels, systolic blood pressure, plasma lipid parameters, arylesterase activity and aorta histology were analyzed as well as oligonucleotide array hybridization of liver RNA. Results demonstrated that double heterozygous mice in C57BL/6J substrate had a milder phenotype showing lower increase in blood pressure compared to double heterozygous group in hybrid background. The severity of the phenotype in the latter group was associated with lower nitric oxide and arylesterase activity levels, and hyperplasia of the vascular media layer. Hepatic profiling of both genetic substrates showed profound differences in expression of contractile proteins that could explain these pathological findings. In summary, the phenotypic presentation of hypertension is associated with multiple processes from vascular bedside to liver as evidenced by nitric oxide production or paraoxonase levels.

Dietary patterns and blood pressure change over 5-y follow-up in the SU.VI.MAX cohort

Background:Although short-term effects of the Dietary Approaches to Stop Hypertension (DASH) diet on blood pressure have been shown in intervention studies, less is known about the long-term effects.Objective:The aim was to study the relation between dietary patterns based on DASH diet characteristics and blood pressure (BP) and BP change in a clinical trial of antioxidants conducted in France from 1994 to 2002.Design:Repeated 24-h dietary records were collected during the first year of follow-up. Dietary variables studied included fruit and vegetables, dairy products and fat (defined by Keys score), and two hypothesis-oriented scores based on the DASH diet. We performed a cross-sectional analysis of BP measured at the first clinical examination (1995–1996) in 4652 participants aged 35–63 y and a longitudinal analysis of BP change over a median follow-up of 5.4 y (n= 2341).Results:The mean increases in systolic (SBP) and diastolic (DBP) BPs were 9.3 and 4.5 mm Hg, respectively. After adjustment for potential confounders, higher fruit and vegetable consumption was associated with lower SBP and DBP at first clinical examination (Pfor trend < 0.02 for both) and a lower 5-y increase in SBP (−2.1 mm Hg in the 4th compared with the 1st quartile; Pfor trend < 0.004) and DBP (−0.7 mm Hg in the 4th compared with the 1st quartile; Pfor trend < 0.03). The 2 DASH scores also were significantly associated with a lower BP at the first clinical examination and a lower BP increase. No significant relations were observed with dairy products or Keys score in either analyses.Conclusion:These results suggest that high fruit and vegetable intakes may be associated with a lower increase in BP with aging.

The impact of different blood sampling methods on laboratory rats under different types of anaesthesia

Rats with implanted telemetry transponders were blood sampled by jugular puncture, periorbital puncture or tail vein puncture, or sampled by jugular puncture in carbon dioxide (CO2), isoflurane or without anaesthesia in a crossover design. Heart rate, blood pressure and body temperature were registered for three days after sampling. Initially blood pressure increased, but shortly after sampling it decreased, which led to increased heart rate. Sampling induced rapid fluctuations in body temperature, and an increase in body temperature. Generally, rats recovered from sampling within 2-3 h, except for rats sampled from the tail vein, which showed fluctuations in body temperature in excess of 30 h after sampling. Increases in heart rate and blood pressure within the first hours after sampling indicated that periorbital puncture was the method that had the largest acute impact on the rats and that it might take an extra hour to recover from it. CO2 anaesthesia seemed unable to prevent the increase in blood pressure and the fluctuations in body temperature induced by blood sampling, and up to 10 h after sampling, the rats were still affected by CO2 anaesthesia. Rats anaesthetized with isoflurane showed lower increases in blood pressure after, and fewer fluctuations in body temperature during sampling, and the post-anaesthetic effects of isoflurane, if any, seemed to disappear immediately after sampling. It is, therefore, concluded that blood sampling in rats by jugular puncture seems to be the method from which rats most rapidly recover when compared with periorbital puncture and tail vein puncture, and that for anaesthesia, isoflurane is recommended in preference to CO2.

Hair mercury (signature of fish consumption) and cardiovascular risk in Munduruku and Kayabi Indians of Amazonia

Fish is an important natural resource in the diet of inhabitants of the Amazon rain forest and a marker of its consumption (hair Hg) was used to compare selected cardiovascular risk parameters between tribes of Eastern Amazonia. Three Munduruku (Terra Preta, Kaburuá, Cururu) villages and one Kayabi village at the banks of head rivers (Tapajós, Tropas, Kabitutu, Cururu, Curuzinho, Teles Pires) of the Tapajós Basin were studied in relation to fish Hg concentrations, mercury in hair (fish consumption) and erythrocytes, body mass index (height/weight, kg/cm2), and blood pressure. The mean fish Hg concentrations were higher in predatory (578.6ng/g) than in nonpredatory species (52.8ng/g). Overall only 26% of fish Hg concentrations were above 500ng/g, and only 11% were above 1000ng/g. There was no systematic trend in fish Hg concentrations from rivers with a history of gold-mining activities. The biomarker of fish consumption (hair Hg) was significantly associated with erythrocyte-Hg (r=0.5181; P=0.0001) and was significantly higher in Kayabi (12.7μg/g) than in the Munduruku (3.4μg/g). Biomarker-assessed fish consumption rate was higher in the Kayabi (110g/day) than in the Munduruku villages (30g/day). Although no significant differences in body mass index (BMI) were observed between tribes, there was a trend of lower increase in blood pressure with age among the higher fish consumers (Kayabi). Summary clinical evaluation did not detect neurologic complaints compatible with Hg intoxication (paraparesis, numbness, tremor, balancing failure), but endemic tropical diseases such as clinical history of malaria showed a high prevalence (55.4%). Fish is an abundant natural resource, important in the Indian diet, that has been historically consumed without perceived problems and can easily be traced through hair Hg. The exposure to freshwater fish monomethyl mercury is less of an issue than endemic infectious diseases such as malaria and lack of basic medical services.

Effects of K+-Canrenoate on the Development of DOCA-salt Hypertension

The effects of K+-canrenoate, a digoxin antagonist, on the role of digoxin-like factor in the development of DOCA-salt hypertension has been examined. DOCA-salt rats treated with 66 mg kg-1 day-1 of K+-canrenoate (s.c.) presented a lower increase in blood pressure (P less than 0.01), less cardiac hypertrophy (P less than 0.05) and hypokalaemia (P less than 0.05) than non-treated DOCA-salt rats. K+-canrenoate treatment did not lead to significant changes in urinary volume, Na+ and K+ urinary excretion or suppression of plasma renin activity in DOCA-salt rats. None of the parameters were significantly different between uninephrectomized-salt rats treated or non-treated with K+-canrenoate. These data suggest a role for digoxin-like factor in DOCA-salt hypertension. However, the non-normalization of blood pressure observed in K+-canrenoate DOCA-salt treated rats indicates that other factors contribute to the initiating mechanisms in this type of hypertension. Moreover, these data suggest that digoxin-like factor plays no role in the suppression of plasma renin activity induced by DOCA and salt treatment.

Antibiotics attenuate experimental hypertension in rats.

Hypertension was produced in Sprague-Dawley rats by intramuscular injections of either corticosterone or ACTH. Lower increases in blood pressure to these challenges were observed in Sprague-Dawley rats pretreated with neomycin or vancomycin which alone had no effect on blood pressure or growth. The development of high blood pressure in spontaneously hypertensive rats of a stroke-prone substrain was also attenuated by oral administration of neomycin. These results suggest that experimental hypertension can be modulated by the administration of antibiotics.