Non-dipping and arterial hypertension depend on clinical factors rather than on genetic variability of ACE and RGS2 genes in patients with type 1 diabetes

24-hour ambulatory blood pressure monitoring 9 years after pediatric cardiac surgery: a pilot and feasibility study

BACKGROUND

Children undergoing cardiac surgery are at risk of high blood pressure (BP), a risk factor for cardiovascular and kidney disease. Twenty-four-hour ambulatory BP monitoring (ABPM) is a reference standard hypertension (HTN) test. Little data exist on ABPM abnormalities in children several years post cardiac surgery. This study aimed to (a) determine ABPM feasibility; (b) describe and compare ABPM measures and abnormalities (percent load, masked HTN [MH]; non-dipping, mean systolic/diastolic BP > 95th percentile; pre-HTN (ABPM); white-coat HTN [WCH]) to casual BP; and (c) compare BP in patients with and without acute kidney injury (AKI).

METHODS

Prospective, follow-up pilot study of children (0-18 years) who underwent cardiac surgery from 2007 to 2009 at Montreal Children's Hospital. We recorded if participants had post-operative AKI and assessed the following outcomes at 9-year follow-up: casual BP classified by three single-visit measures (normal; elevated BP [eBPSingleVisit]; HTNSingleVisit); ABPM. Bivariable analyses were used to compare characteristics between groups.

RESULTS

Twenty-three patients (median [interquartile range], 8.6 [8.0, 9.0] years post cardiac surgery) were included; 16 (70%) male. Six participants (26%) had eBPSingleVisit or higher. On ABPM, 11 (48%) had ≥ 1 abnormality: 9 (39%) had non-dipping; 3 (13%) had pre-HTN; 3 (13%) had WCH; none had HTN or MH. There were no differences in ABPM according to AKI status.

CONCLUSION

Our pilot study determined that ABPM was feasible in children years after cardiac surgery and frequently identified ABPM abnormalities. Future research in larger populations is needed to define specific risk factors for HTN in children after cardiac surgery.

ACE2 and TMPRSS2 polymorphisms in various diseases with special reference to its impact on COVID-19 disease

Background

A carboxypeptidase protein called ACE2 is found in many organs. ACE2 protein can play a pivotal role to regulate the pathological changes of several diseases including COVID-19. TMPRSS2 gene is expressed in many human tissues and plays a critical role in spreading the infection of the viruses including coronavirus and progression of prostate cancer, and hence could be used as a potential drug target. There are limited reports on occurrence of genetic polymorphism of ACE2 and TMPRSS2 in general population, expressions in pathological conditions, and its impact on COVID-19 disease. Hence we comprehended the occurrence of ACE2, TMPRSS2 polymorphism in general population, expression in various diseases and its impact on COVID-19 disease.

Method

We utilized multiple databases, PubMed (Medline), EMBASE and Google Scholar for literature search.

Description

ACE2 polymorphisms have significant linkages with various diseases, including severity of SARS-CoV-2 infection. Genetic variations of these genes contribute to individual's genetic susceptibility to viral infection and its subsequent clearance. The diversity and variations in the population distribution of these genes, might greatly influence and in turn reflect into the observed population and gender differences of the severity and clinical outcomes of SARS-CoV-2 infection.

Conclusion

There are diversities in distribution of ACE2 and TMPRSS2 polymorphisms among different populations. Analyzing the genetic variants and expression of ACE2 and TMPRSS2 genes, in a population may provide the genetic marker for susceptibility or resistance against the coronavirus infection, which might be useful for identifying the susceptible population groups for targeted interventions and for making relevant public health policy decisions.

Pharmacogenetic analyses of variations of measures of cardiovascular risk in Alzheimer's dementia

Background & objectives:

Neurodegeneration affects blood pressure variations, while renal function and cerebral perfusion are impaired by vascular risk factors. This study was aimed to estimate variations of measures of cardiovascular risk in Alzheimer's dementia by pharmacogenetic analyses of the effects of angiotensin-converting enzyme (ACE) inhibitors and statins.

Methods:

Consecutive patients were prospectively followed to study variations of creatinine clearance and blood pressure for one year, estimated by correlating the effects of ACE inhibitors with the ACE Alu I/D polymorphism and genotypes or haplotypes of rs1800764 or rs4291, and the effects of statins with LDLR (low-density lipoprotein receptor) genotypes or haplotypes of rs11669576 (exon 8) or rs5930 (exon 10), or genotypes of rs2695121 (liver X receptor β gene). Variations of the coronary heart disease (CHD) risk according to these cardiovascular measures were also explored.

Results:

All polymorphisms of the 193 patients were in Hardy-Weinberg equilibrium. Genetic determinants of cardiovascular effects affected the individual variability of the response to ACE inhibitors and statins. ACE inhibitors, but not statins, reduced blood pressure for all patients. ACE inhibitors protected carriers of alleles that supposedly decrease serum ACE levels (rs1800764-T, rs4291-A, Alu II) regarding creatinine clearance variations (P<0.005), but carriers of Alu DD (P<0.02), rs1800764-C (P<0.05), or rs4291-AT (P<0.04) showed better blood pressure lowering effects. The presence of rs2695121-T (P=0.007) or rs5930-A (P=0.039) was associated with systolic blood pressure lowering, whereas rs5930-AA was protective against decrease in creatinine clearance (P=0.019). Statins lowered creatinine clearance for carriers of rs2695121-CT (P=0.026).

Interpretation & conclusions:

Pharmacological response of blood pressure and creatinine clearance to ACE inhibitors and statins may be genetically mediated.

Mice overexpressing chromogranin A display hypergranulogenic adrenal glands with attenuated ATP levels contributing to the hypertensive phenotype

OBJECTIVE

Elevated circulating chromogranin A (CHGA) is observed in human hypertension. CHGA is critical for granulogenesis and exocytosis of catecholamine stores from secretory large dense core vesicles (LDCV). This study aims to understand the morphological, molecular and phenotypic changes because of excess CHGA and the mechanistic link eventuating in hyper-adrenergic hypertension.

METHODS

Blood pressure and heart rate was monitored in mouse models expressing normal and elevated level of CHGA by telemetry. Catecholamine and oxidative stress radicals were measured. Adrenal ultrastructure, LDCV content and mitochondrial abundance were compared and respiration analyzed by Seahorse assay. Effect of CHGA dosage on adrenal ATP content, electron transport chain components and uncoupling protein 2 (UCP-2) were compared in vivo and in vitro.

RESULTS

Mice with excess-CHGA displayed hypertensive phenotype, higher heart rate and increased sympathetic tone. They had elevated plasma catecholamine and adrenal ROS levels. Excess-CHGA caused an increase in size and abundance of LDCV and adrenal mitochondria. Nonetheless, they had attenuated levels of ATP. Isolated adrenal mitochondria from mice with elevated CHGA showed higher maximal respiration rates in the presence of protonophore, which uncouples oxidative phosphorylation. Elevated CHGA resulted in overexpression of UCP2 and diminished ATP. In vitro in chromaffin cells overexpressing CHGA, concomitant increase in UCP2 protein and decreased ATP was detected.

CONCLUSION

Elevated CHGA expression resulted in underlying bioenergetic dysfunction in ATP production despite higher mitochondrial mass. The outcome was unregulated negative feedback of LDCV exocytosis and secretion, resulting in elevated levels of circulating catecholamine and consequently the hypertensive phenotype.

Association between ACE gene polymorphisms and Alzheimer's disease in Han population in Hebei Peninsula

PURPOSE

This study aimed to detect the association between angiotensin I converting enzyme (ACE) gene polymorphisms (rs4343 and rs1800764) and Alzheimer's disease (AD) in Han population in Hebei Peninsular.

METHODS

We recruited 113 AD patients and 142 healthy individuals in this case-control study. Differences of genotypes, alleles and haplotypes in two groups were analyzed by chi-square test. Besides, odds ratios (ORs) and 95% confidence intervals (CIs) were used to represent the relative risk of AD. At last, the analyses of linkage disequilibrium and haplotypes were done with HaploView software.

RESULTS

In the analyses of genotypes and alleles of ACE polymorphisms (rs4343 and rs1800764) in AD, no obvious association was found between genotypes and alleles of rs4343 with the susceptibility of AD. In rs1800764 polymorphism, only C allele had significant association with AD susceptibility (P=0.035, OR=1.473, 95% CI=1.027-2.111), which suggested that rs1800764 C allele is the susceptible allele of AD. Linkage disequilibrium analysis between rs4343 and rs1800764 polymorphisms indicated there existed 3 haplotypes (A-T, A-C and G-C). A-C haplotype might associate with the susceptibility of AD (P=0.023, OR=2.591, 95% CI=1.111-6.043).

CONCLUSION

Rs4343 polymorphism of ACE gene had no relationship with AD risk. C allele of rs1800764 could increase the susceptibility of AD. A-C haplotype of rs4343 and rs1800764 polymorphisms might increase the risk of AD, and the ORs was 2.591.

Angiotensin-converting enzyme insertion/deletion polymorphism, 24-h blood pressure profile and left ventricular hypertrophy in hypertensive individuals: a cross-sectional study

Background

The absence of nocturnal blood pressure dipping (ND) identified by 24-h ambulatory blood pressure monitoring (ABPM) correlates with a worse cardiovascular prognosis. The renin–angiotensin system influences blood pressure levels and the occurrence of target organ damage (TOD). Thus, the aim of this study was to correlate the angiotensin-converting enzyme gene (ACE) insertion/deletion (I/D) polymorphism with the 24-h blood pressure profile and TOD in hypertensive individuals.

Methods

155 non-diabetic hypertensive individuals on antihypertensive treatment underwent ABPM. Peripheral blood samples were drawn for biochemistry and genetic analysis of the ACE I/D polymorphism by polymerase chain reaction. ND was defined as ≥10 % differences in the mean systolic blood pressure (BP) during wakefulness and sleep.

Results

There were no differences in clinical or biochemical variables or TOD in respect to ND status, except for higher BP levels during sleep (p < 0.001) in non-dippers. There was significant difference in the prevalence of left ventricular hypertrophy (LVH) between ACE genotypes (II: 13.0 %; ID: 34.1 %; DD: 46.5 %; p value = 0.024) with an increased risk in carriers of the DD genotype (OR = 5.80; IC 95 % 1.50–22.44; p value = 0.011). Carriers of the D allele had higher systolic BP during wakefulness and by ABPM (p < 0.05), higher left ventricular mass (117.3 ± 50.0 vs. 100.3 ± 25.7; p value = 0.017) and higher prevalence of LVH (37.4 vs. 12.5 %; OR = 4.14; 95 % IC: 1.17–14.65; p value = 0.028), compared to the II genotype.

Conclusions

The DD genotype is associated with a higher prevalence of LVH. The presence of the D allele appears to be associated with higher mean 24-h and wake systolic BP measured by ABPM in hypertensive patients under antihypertensive treatment.

Regulators of G-protein-signaling proteins: negative modulators of G-protein-coupled receptor signaling

Regulators of G-protein-signaling (RGS) proteins are a category of intracellular proteins that have an inhibitory effect on the intracellular signaling produced by G-protein-coupled receptors (GPCRs). RGS along with RGS-like proteins switch on through direct contact G-alpha subunits providing a variety of intracellular functions through intracellular signaling. RGS proteins have a common RGS domain that binds to G alpha. RGS proteins accelerate GTPase and thus enhance guanosine triphosphate hydrolysis through the alpha subunit of heterotrimeric G proteins. As a result, they inactivate the G protein and quickly turn off GPCR signaling thus terminating the resulting downstream signals. Activity and subcellular localization of RGS proteins can be changed through covalent molecular changes to the enzyme, differential gene splicing, and processing of the protein. Other roles of RGS proteins have shown them to not be solely committed to being inhibitors but behave more as modulators and integrators of signaling. RGS proteins modulate the duration and kinetics of slow calcium oscillations and rapid phototransduction and ion signaling events. In other cases, RGS proteins integrate G proteins with signaling pathways linked to such diverse cellular responses as cell growth and differentiation, cell motility, and intracellular trafficking. Human and animal studies have revealed that RGS proteins play a vital role in physiology and can be ideal targets for diseases such as those related to addiction where receptor signaling seems continuously switched on.

Blood pressure disturbances and endothelial dysfunction markers in children and adolescents with type 1 diabetes

OBJECTIVE

Being the earliest step on the way to atherosclerosis, endothelial dysfunction is particularly escalated in diabetes. This study aimed at assessing endothelial dysfunction and blood pressure disturbances in young patients with type 1 diabetes mellitus (T1DM) and defining their interrelations.

METHODS

The study group comprised 52 children and adolescents aged 14.07 ± 3.03 years, with T1DM duration 5.13 ± 2.18 years. 20 healthy controls with similar age and sex distribution were included. Chosen serum biochemical markers of endothelial damage: intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), sE-selectin, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) as well as ambulatory blood pressure monitoring (ABPM) were performed in all subjects.

RESULTS

Patients with T1DM displayed significantly higher concentrations of chosen markers of endothelial dysfunction compared to controls (sVCAM-1 (ng/ml): 951.56 ± 330.68 vs. 710.35 ± 162.12, TNF-α (pg/ml): 16.63 ± 8.32 vs. 9.41 ± 4.23, IL-6 (pg/ml): 3.38 ± 1.31 vs. 2.45 ± 0.81; p < 0.05). Within the study group subjects with an abnormal ABPM reading had significantly higher concentrations of sE-selectin compared with subjects with normal ABPM (in ng/ml: 45.71 ± 15.63 vs. 32.42 ± 11.95; p < 0.01). The study revealed a significant positive correlation between sE-selectin and systolic as well as diastolic pressure loads during the day period (respectively: r = 0.46, r = 0.60; p < 0.01).

CONCLUSIONS

Endothelium dysfunction may be present early in the course of T1DM in children and adolescents. It seems to be related with blood pressure disturbances which highlights the need to intensify treatment in this group of patients.