The impact of war on the development and progression of arterial hypertension and cardiovascular disease: protocol of a prospective study among Ukrainian female refugees

Background

Growing evidence supports the impact of psychological factors such as traumatic experiences and Post Traumatic Stress Disorder (PTSD) on the incidence of arterial hypertension (HTN) and cardiovascular diseases (CVD). The war in Ukraine is exposing million inhabitants to traumatic experiences and severe stress. Part of Ukrainians (mostly women and children) left the country to escape war. We report the protocol of a prospective study aiming at the assessment of the impact of war-induced stress on HTN and CVD in women Ukrainian refugees who moved to Poland.

Methods and design

The study will be conducted in 3 stages. Stage 1 will assess the prevalence of HTN and PTSD among Ukrainian refugees and will estimate the impact of war-related trauma exposure on these parameters. Data on office blood pressure (BP) will be compared to data already collected in STEPS data 2019 and May Measurement Month 2021 in Ukraine, matched for age and sex. Stage 2 will involve subjects diagnosed with HTN and/or PTSD referred for management and follow-up of these conditions. Psychologic targeted therapies will be offered to subjects with confirmed PTSD, with a periodical reassessment of the severity of PTSD-associated symptoms and of its impact on HTN and cardiovascular health. Clinical history and characteristics will be compared among three groups: subjects with HTN and PTSD, with HTN without PTSD, with PTSD but without HTN. Stage 3 will involve a subgroup among those screened in Stage 1, with the objective of investigating the biological mechanisms underlying the relation between HTN and trauma exposure, identifying early signs of subclinical target organ damage in subjects with HTN with/without PTSD.

Discussion

This study will test the hypothesis that trauma exposure and psychological stress contribute to BP elevation and progression of CVD in this population. It will provide new evidence on the effect of an integrated management, including psychological therapy, on BP and cardiovascular risk. Such approach may be further tested and extrapolated to other populations exposed to war and chronic violence, migrants and refugees around the world.

Research Study Registration

number 2022/45/P/NZ5/02812.

Perspectives on improving blood pressure control to reduce the clinical and economic burden of hypertension

The clinical and economic burden of hypertension is high and continues to increase globally. Uncontrolled hypertension has severe but avoidable long-term consequences, including cardiovascular diseases, which are among the most burdensome and most preventable conditions in Europe. Yet, despite clear guidelines on screening, diagnosis and management of hypertension, a large proportion of patients remain undiagnosed or undertreated. Low adherence and persistence are common, exacerbating the issue of poor blood pressure (BP) control. Although current guidelines provide clear direction, implementation is hampered by barriers at the patient-, physician- and healthcare system levels. Underestimation of the impact of uncontrolled hypertension and limited health literacy lead to low adherence and persistence among patients, treatment inertia among physicians and a lack of decisive healthcare system action. Many options to improve BP control are available or under investigation. Patients would benefit from targeted health education, improved BP measurement, individualized treatment or simplified treatment regimens through single-pill combinations. For physicians, increasing awareness of the burden of hypertension, as well as offering training on monitoring and optimal management and provision of the necessary time to collaboratively engage with patients would be useful. Healthcare systems should establish nationwide strategies for hypertension screening and management. Furthermore, there is an unmet need to implement more comprehensive BP measurements to optimize management. In conclusion, an integrative, patient-focused, multimodal multidisciplinary approach to the management of hypertension by clinicians, payers and policymakers, involving patients, is required to achieve long-term improvements in population health and cost-efficiency for healthcare systems.

Aortic invovement in fibromuscular dysplasia. 3-dimensional CT, case-control study. THE ARCADIA-POL BIS study

Background

Fibromuscular dysplasia (FMD) is a non-atherosclerotic arterial disease that manifests as the presence of beaded or focal lesions in medium or small-sized arteries and may also include arterial dissection, aneurysm, and tortuosity. FMD could be revealed in various manifestations, however limited data on the involvement of the thoracic aorta is reported.

Purpose

To measure and evaluate involvement of thoracic aorta in patients with FMD.

Methods

We analysed aortas of 144 consecutive patients (mean age 50.2±14.0, 116 women) with confirmed FMD in at least one vascular bed. The control group consisted of 144 (mean age 50.5±14.0, 116 women) age and sex matched individuals. All patients underwent detailed clinical evaluation including angio-CT scan including aortic valve, thoracic aorta and coronary arteries. We measured the aortic valve annulus, sinus of valsalva, sinotubular junction, the diameters of ascending and descending aorta, aortic unfolding, the height of ostium of RCA and LCA and diameter of right and left coronary artery ostia in patients with fibromuscular dysplasia and compared them to matched controls.

Results

The FMD group had significantly smaller dimensions of aortic valve annulus and sinus of Valsalva than control group (2.3 [2.1–2.6] vs 2.9 [2.7–3.1] p<0,0001; 2.9 [2.7–3.2] vs 3.1 [2.8–3.3] p=0,0011 respectively). In addition the FMD group had a significantly greater mean diameter of the ascending and the descending aorta than the control group (3.1 [2.7–3.3] vs 3 [2.9–3] p=0,0436; 2.4 [2.2–2.7] vs 2.3 [1.8–2.5] p<0,0001 respectively). The height of the ostium of the left and of the right coronary artery was smaller in FMD than in the control group (1.2 [1.1–1.4] vs 1.3 [1.2–1.4] p=0,0001; 1.1 [1–1.3] vs 1.3 [1.1–1.4] p<0,0001 respectively). There was no difference in the diameter of sinotubular junction and the right and the left coronary artery ostias between the FMD and control groups (2.7 [2.5–2.9] vs 2.7 [2.5–2.9]; 0.3 [0.2–0.3] vs 0.3 [0.2–0.3]; 0.3 [0.3–0.3] vs 0.3 [0.3–0.4] respectively).

Conclusions

Patients with fibromuscular dysplasia display smaller dimensions of aortic valve and larger diameter of ascending and descending aorta as compared to control subjects. Despite the predominant clinical significance of focal pathologies in FMD patients, the disease may display a specific, pan-vascular phenotype.

Funding Acknowledgement

Type of funding source: None

Spontaneous coronary artery dissection: insights from intravascular ultrasound

Introduction

Spontaneous Coronary Artery Dissection (SCAD) may be at the origin of up to 25% of acute coronary events in women <50 yo with no or few risk factors. The diagnosis of SCAD is challenging and in some cases it may be ascertained only by intracoronary imaging such as intravascular ultrasound (IVUS) or optical coherence tomography (OCT). IVUS is widely available and has a better depth penetration compared to OCT, showing the extent of the false lumen and the aspect of the adventitia but its lower resolution does not always allow the visualization of smaller structures such as fenestrations. In a previous study we investigated the role of OCT in understanding the pathophysiology of SCAD and we reported a number of OCT complications. It is not known if these also apply to IVUS but since IVUS does not require additional contrast injection, the risk of false lumen (FL) propagation should be lower.

Aim of the study

To analyze the value of IVUS in the assessment of key features of SCAD and to explore the feasibility of three-dimensional (3D) reconstruction using IVUS imaging.

Methods

We collated the imaging findings of 15 cases of SCAD for which IVUS was used as part of routine clinical care. Images were assessed to determine the visualisation of the true lumen, the false lumen extent and its contents, the intima-media membrane, the presence of fenestrations, the external elastic lamina and underlying adventitia. Furthermore, we performed a 3D reconstruction of a type 2a dissection of the right coronary artery. The IVUS images were exported in DICOM format. The segmentation of the true and false lumens in the regions of interest was manually done using the ImageJ software. Subsequent images were processed using 3D Slicer and Paraview in order to obtain the 3D reconstruction of the dissected segment.

Results

The false lumen was entirely visible in 13/15 cases (87%) and the external elastic lamina in 12/15 cases (80%). In 3/15 cases (20%) the dissection was circumferential. The false lumen content had lower echogenicity compared to the surrounding tissue in all 15 cases. There was no visible fenestration. The 3D reconstruction (Figure 1) showed that the false lumen was larger than the true lumen. The general cross-sectional appearance was that of a “horseshoe” dissection but there was also a short segment of circumferential dissection and the intima-media membrane looked thickened.

Conclusion

Despite its resolution being lower than OCT, IVUS has a deep penetration and provides adequate imaging of the key features of SCAD.

Perspectives

We plan to further expand these findings in a larger series, intending to better characterize the false lumen and the adventitia in SCAD.

IVUS findings in SCAD, 3D reconstruction

Funding Acknowledgement

Type of funding source: None

Adherence to Antihypertensive Treatment and the Blood Pressure–Lowering Effects of Renal Denervation in the Renal Denervation for Hypertension (DENERHTN) Trial

Background:

The DENERHTN trial (Renal Denervation for Hypertension) confirmed the blood pressure–lowering efficacy of renal denervation added to a standardized stepped-care antihypertensive treatment for resistant hypertension at 6 months. We report the influence of adherence to antihypertensive treatment on blood pressure control.

Methods:

One hundred six patients with hypertension resistant to 4 weeks of treatment with indapamide 1.5 mg/d, ramipril 10 mg/d (or irbesartan 300 mg/d), and amlodipine 10 mg/d were randomly assigned to renal denervation plus standardized stepped-care antihypertensive treatment, or the same antihypertensive treatment alone. For standardized stepped-care antihypertensive treatment, spironolactone 25 mg/d, bisoprolol 10 mg/d, prazosin 5 mg/d, and rilmenidine 1 mg/d were sequentially added at monthly visits if home blood pressure was ≥135/85 mm Hg after randomization. We assessed adherence to antihypertensive treatment at 6 months by drug screening in urine/plasma samples from 85 patients.

Results:

The numbers of fully adherent (20/40 versus 21/45), partially nonadherent (13/40 versus 20/45), or completely nonadherent patients (7/40 versus 4/45) to antihypertensive treatment were not different in the renal denervation and the control groups, respectively ( P =0.3605). The difference in the change in daytime ambulatory systolic blood pressure from baseline to 6 months between the 2 groups was –6.7 mm Hg ( P =0.0461) in fully adherent and –7.8 mm Hg ( P =0.0996) in nonadherent (partially nonadherent plus completely nonadherent) patients. The between-patient variability of daytime ambulatory systolic blood pressure was greater for nonadherent than for fully adherent patients.

Conclusions:

In the DENERHTN trial, the prevalence of nonadherence to antihypertensive drugs at 6 months was high (≈50%) but not different in the renal denervation and control groups. Regardless of adherence to treatment, renal denervation plus standardized stepped-care antihypertensive treatment resulted in a greater decrease in blood pressure than standardized stepped-care antihypertensive treatment alone.

Clinical Trial Registration:

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01570777.

Prevalence and spectrum of SDHx mutations in pheochromocytoma and paraganglioma in patients from Belgium: an update

Since the early 2000s, the prevalence and spectrum of mutations in genes encoding subunits of succinate dehydrogenase (SDHx) were reported in large cohorts of patients with pheochromocytoma (PC) and paraganglioma (PGL) from most Western countries. Unfortunately, in Belgium, no equivalent work was performed thus far. Therefore, the aim of the work was to look for mutations in SDHx genes and genotype-phenotype correlations in patients with PC and/or PGL from Belgium. Screening of the coding parts of SDHx genes and deletion search were performed in all patients with PC and/or PGL referred to the -Cliniques Universitaires Saint-Luc from 05/2003 to 05/2011. Genetic screening was performed in 59 unrelated head and neck (hn)PGLs (8 fami-lial) and 53 PCs (7 extra-adrenal; 3 metastatic). In hnPGLs, 10 different SDHD mutations (3 substitutions, 5 deletions, 2 splice site mutations) were detected in 16 patients, including 7 familial cases and 9 apparently sporadic cases. In the same subset, we found 8 different SDHB mutations (5 substitutions, 1 splice site mutation, 1 deletion, 1 duplication) in 10 patients with sporadic hnPGL without evidence of malignancy. No SDHx mutation was detected in patients harboring PCs and no SDHC mutation whatsoever. In conclusion, in our multicentric database of PC-PGLs from Belgium, (i) the prevalence of SDHx mutations was high in hnPGLs (44% in the whole subset, 37% of apparently sporadic cases); (ii) in sporadic cases, the prevalence of SDHB mutations was high (20%), similar to that of SDHD (18%); and (iii) no SDHx mutation was found in a subset of mostly adrenal, benign PCs.

Effect of endurance training on blood pressure regulation, biomarkers and the heart in subjects at a higher age

We reported previously that two otherwise identical training programs at lower (LI) and higher intensity (HI) similarly reduced resting systolic blood pressure (BP) by approximately 4-6 mmHg. Here, we determined the effects of both programs on BP-regulating mechanisms, on biomarkers of systemic inflammation and prothrombotic state and on the heart. In this cross-over study (3 × 10 weeks), healthy participants exercised three times 1 h/week at, respectively, 33% and 66% of the heart rate (HR) reserve, in a random order, with a sedentary period in between. Measurements, performed at baseline and at the end of each period, involved blood sampling, HR variability, systolic BP variability (SBPV) and cardiac magnetic resonance imaging. Thirty-nine participants (18 men; mean age 59 years) completed the study. Responses were not different between both programs (P>0.05). Pooled data from LI and HI showed a reduction in HR (-4.3 ± 8.1%) and an increase in stroke volume (+11 ± 23.1%). No significant effect was seen on SBPV, plasma renin activity, basal nitric oxide and left ventricular mass. Our results suggest that the BP reduction observed appears to be due to a decrease in systemic vascular resistance; training intensity does not significantly affect the results on mechanisms, biomarkers and the heart.

Are ACE-inhibitors or ARB's still needed for cardiovascular prevention in high risk patients? Insights from profess and transcend

The HOPE and EUROPA clinical studies have shown that treatment with the angiotensin-converting enzyme (ACE) inhibitors, ramipril and perindopril, may reduce the occurrence of major cardiovascular events in patients with proven atherosclerotic disease. The recently published results of the PRoFESS and TRANSCEND trials completed the much needed information concerning the use of an angiotensin receptor blocker for patients at high risk of cardiovascular events. PROFESS compared a therapy of telmisartan 80 mg daily with placebo in patients with a recent ischemic stroke. The difference in the primary outcome of first recurrent stroke was not statistically significant between telmisartan and placebo. The secondary outcome of major cardiovascular events showed a relative risk reduction (RRR) of 7% in favour of telmisartan. This tended to be significant (p = 0.06) despite a rather short follow-up period of only 28 months. In TRANSCEND 5926 patients at high risk for cardiovascular events were randomized to a treatment with telmisartan 80 mg daily or placebo for a mean duration of follow-up of 56 months. The primary composite outcome of cardiovascular death, myocardial infarction, stroke or hospitalization for heart failure showed a non-significant 8% RRR in favour of the telmisartan treated patients. The main secondary outcome of cardiovascular death and myocardial infarction or stroke as used in the HOPE trial showed a non-significant RRR of 13% in favour of telmisartan treated patients (p = 0.068 adjusted for multiplicity of comparisons). In comparing the Kaplan-Meier curves for the endpoint of major cardiovascular events used in HOPE, EUROPA, TRANSCEND and PRoFESS, the trends are similar. Results of most of the recently published trials have been neutral.This could partly be explained by major improvements in the optimal background therapy of the patients included. Nevertheless, the results of PRoFESS and TRANSCEND do not contradict the results from previous studies with theACE inhibitors ramipril and perindopril and the ARB telmisartan.

[The good use of home blood pressure monitoring. Consensus document]

Self or home blood pressure measurement (HBPM) is increasingly popular. Its prognostic value and clinical interest in the diagnosis and follow-up of hypertension are well established. In addition, experts widely agree on the fact that it improves hypertension management and therapeutic compliance. In particular, HBPM often allows to detect white coat hypertension (to be confirmed by 24-hour ambulatory blood pressure measurement). Unfortunately, a large part of HBPM devices in the European Union have not fulfilled independent validation criteria. Furthermore, many patients buy and use such devices without medical supervision. This consensus document summarizes the advantages and disadvantages of HBPM and the conditions of a proper use, in agreement with the recent European and American guidelines.

Lessons from ONTARGET

The recently published results of the ONTARGET trial shed a new light on the cardiovascular protection of patients at high risk of a cardiovascular event. Despite a number of trials looking at the efficacy of Angiotensin Converting Enzyme inhibitors (ACEis) or Angiotensin Receptor Blockers (ARBs) in the prevention of cardiovascular events in patients with specific high risk profiles, the question of the equivalence of ACEis and ARBs remained unanswered. The ONTARGET trial has shown that telmisartan 80 mg administered for a median duration of 4.5 years to patients at high risk of developing a major cardiovascular event, is equally effective to ramipril 10 mg. In addition, telmisartan was slightly better tolerated. The comparator ramipril has been chosen as it is currently the gold standard ACEi since the results of the HOPE study, in terms of the composite outcome of cardiovascular death, myocardial infarction and stroke. Moreover, ONTARGET is the first trial to test the hypothesis of superiority of adding an ARB (telmisartan 80 mg) to an ACEi (ramipril 10 mg) over the ACEi ramipril monotherapy in cardiovascular protection of the same broad range of high-risk patients. Surprisingly, despite a more pronounced blood pressure lowering, the combination of the two agents did not lead to an additional decrease in the number of events, but had significantly more side-effects compared to ramipril monotherapy. ONTARGET is a landmark study, performed according to the highest statistical and clinical standards, providing compelling evidence and clear answers to two important clinical questions.

Circulation of a type 1 recombinant vaccine-derived poliovirus strain in a limited area in Romania

After intensive immunisation campaigns with the oral polio vaccine (OPV) as part of the Global Polio Eradication Initiative, poliomyelitis due to wild viruses has disappeared from most parts of the world, including Europe. Here, we report the characterization of a serotype 1 vaccine-derived poliovirus (VDPV) isolated from one acute flaccid paralysis (AFP) case with tetraplegia and eight healthy contacts belonging to the same small socio-cultural group having a low vaccine coverage living in a small town in Romania. The genomes of the isolated strains appeared to be tripartite type 1/type 2/type 1 vaccine intertypic recombinant genomes derived from a common ancestor strain. The presence of 1.2% nucleotide substitutions in the VP1 capsid protein coding region of most of the strains indicated a circulation time of about 14 months. These VDPVs were thermoresistant and, in transgenic mice expressing the human poliovirus receptor, appeared to have lost the attenuated phenotype. These results suggest that small populations with low vaccine coverage living in globally well-vaccinated countries can be the origin of VDPV emergence and circulation. These results reaffirm the importance of active surveillance for acute flaccid paralysis and poliovirus in both polio-free and polio-endemic countries.

The molecular characterization of poliovirus strains by the RT-PCR-RFLP assay and its use in the active surveillance for acute flaccid paralysis cases in Romania between 2001-2006

Poliomyelitis, an acute disease of the the central nervous system can be controlled through the use of inactivated virus vaccine (IPV) or live attenuated vaccine (OPV). The goal of the Global Polio Eradication Initiative is to stop the global transmission of poliovirus. Our study is a retrospective and prospective study that was made because in 2002 was isolated from one acute flaccid paralysis AFP case and eight healthy contacts belonging to the same small socio-cultural group having a low vaccine coverage living in Babadag a town in Romania a serotype 1 vaccine-derived poliovirus (VDPV), recombinant S1/S2/S1. The 67 poliovirus strains isolated in Romania between 2001-2006 from acute flaccid paralysis cases (AFP) (n=20, age = 3 months - 10 years), facial paralysis cases (FP) (n=5, age = 3 months - 3.7 years) and healthy's AFP contacts (n=42, age = 2 months - 5.10 years) were molecular investigated to confirm the vaccine origin of these strains and for the detection of recombinant strains. The identification of these strains was achieved through reverse transcription (RT), polymerase chain reaction (PCR) and restriction fragment length polymorphisme assays (RFLP) applied to two sequences of the viral genome, which are located in VP1-2A (2870 nt - 3648 nt) and 3D (6086nt - 6516 nt) regions. For the strains investigated in VP1-2A region, the RFLP profils after digestion with 3 restriction enzymes (Rsal, Ddel, Hinf l) were Sabin-like only with one exception, VDPV strain. In 3D region after digestion with one, two or three enzymes the genomes of most poliovirus (PV) strains were found to be similar to the original vaccine Sabin strain. In 9 AFP cases the profils detected after RFLP in 3D region were S3/S1 (n=3); S3/52 (n=2); S2/S1 (n=2), S2/S1 + S2 (n=2). In 3 FP cases the profils were S3/S2 (n=2), 53/S1 (n=1). In 11 healthy contacts the RFLP profiles in 3D region were S3/S2 (n=6); S1/S1 +S3 (n=1); S3/S1 + S2 (n=1), S3/S2 + S3 (n=1), S2 + S3/S1 (n=1), S1/S2 (n=1).

[Guidelines for the management of arterial hypertension in general practice]

Guidelines for the management of arterial hypertension are regularly updated. This article summarizes the last international guidelines in this field published last year. The decision to initiate an antihypertensive treatment will not only depend on blood pressure levels, but also on global cardiovascular risk assessment.

Severe hypoplasia of the abdominal aorta and its branches in a patient and his daughter

We report the history of a patient and his daughter, both affected with hypoplasia of the abdominal aorta and its branches, leading to early and dramatic complications. In the index patient, renal ischaemia as a result of severe hypoplasia of the abdominal aorta and the origin of renal arteries led to progressive renal failure and end-stage renal disease at the age of 32 years. Other vascular abnormalities included hypoplasia of the celiac trunk (CT) and superior mesenteric artery (SMA). After a successful kidney transplantation at the age of 40 years, he eventually deceased following an episode of possibly ischaemic acute pancreatitis at 47 years. The patient's daughter suffered from an haemorrhagic stroke at the age of 7 years, which led to the discovery of severe hypertension caused by bilateral narrowing of renal arteries, as well as hypoplasia of CT, SMA, subclavian and pulmonary arteries. Biopsy of the narrowed renal artery of the daughter showed a particular form of fibrodysplasia characterized by an unusual fibrosis of the inner part of the media, just beneath the internal elastic lamina. To our knowledge, this is the first report of familial hypoplasia of the abdominal aorta. It might be the cardinal manifestation of a familial form of fibromuscular dysplasia (FMD). Interestingly, the histological lesions described in the daughter's renal artery differ from the classical form of medial FMD.

Modifier effect of ENOS in autosomal dominant polycystic kidney disease

A significant phenotypical variability is observed in autosomal dominant polycystic kidney disease (ADPKD). ADPKD is associated with altered endothelial-dependent vasodilation and decreased vascular production of nitric oxide (NO). Thus, ENOS, the gene coding for the endothelial nitric oxide synthase (eNOS), could have a modifier effect in ADPKD. In order to test this hypothesis, we genotyped 173 unrelated ADPKD patients from Belgium and the north of France for the Glu298Asp, intron 4 VNTR and T-786C polymorphisms of ENOS and looked for their influence on the age at end-stage renal disease (ESRD). In males (n = 93), the Glu298Asp polymorphism was associated with a lower age at ESRD (Glu/Asp + Asp/Asp: 49.0 +/- 1.2 years, n = 53; Glu/Glu: 53.5 +/- 1.5 years, n = 40; simple regression, P = 0.02; multiple regression, P = 0.006). This effect was confirmed in a subset of males linked to PKD1 and reaching ESRD before age 45, and by a cumulative renal survival analysis in PKD1-linked families. Further studies demonstrated that NO synthase (NOS) activity was decreased in renal artery samples from ADPKD males harbouring the Asp298 allele, in association with post-translational modifications and partial cleavage of eNOS. No significant effect of the other polymorphisms was found in males, and no polymorphism influenced the age at ESRD in females. In conclusion, the frequent Glu298Asp polymorphism of ENOS is associated with a 5 year lower mean age at ESRD in this subset of ADPKD males. This effect could be due to a decreased NOS activity and a partial cleavage of eNOS, leading to a further decrease in the vascular production of NO.

Natural genetic exchanges between vaccine and wild poliovirus strains in humans

In a previous study of poliovirus vaccine-derived strains isolated from patients with vaccine-associated paralytic poliomyelitis (VAPP) (9, 11), we reported that a high proportion (over 50%) of viruses had a recombinant genome. Most were intertypic vaccine/vaccine recombinants. However, some had restriction fragment length polymorphism (RFLP) profiles different from those of poliovirus vaccine strains. We demonstrate here that five such recombinants, of 88 VAPP strains examined, carried sequences of wild (nonvaccine) origin. To identify the parental wild donor of these sequences, we used RFLP profiles and nucleotide sequencing to look for similarity in the 3D polymerase-coding region of 61 wild, cocirculating poliovirus isolates (43 type 1, 16 type 2, and 2 type 3 isolates). In only one case was the donor identified, and it was a wild type 1 poliovirus. For the other four vaccine/wild recombinants, the wild parent could not be identified. The possibility that the wild sequences were of a non-poliovirus-enterovirus origin could not be excluded. Another vaccine/wild recombinant, isolated in Belarus from a VAPP case, indicated that the poliovirus vaccine/wild recombination is not an isolated phenomenon. We also found wild polioviruses (2 of 15) carrying vaccine-derived sequences in the 3' moiety of their genome. All these results suggest that genetic exchanges with wild poliovirus and perhaps with nonpoliovirus enteroviruses, are also a natural means of evolution for poliovirus vaccine strains.

Hereditary paraganglioma

Head and neck paraganglioma is a rare tumour, especially in its familial form. We report a case of a multifocal head and neck paraganglioma in a young man with a family history of cervical tumours. At the age of 24, exploration of a left cervical swelling disclosed jugulotympanic and carotid body paragangliomas. Surgical removal of both tumours was performed. Two years later, a right carotid body as well as vagal paragangliomas were discovered. Follow-up at age 30 demonstrated relapse of the bilateral cervical paragangliomas, but also aortopulmonary and mesogastric paragangliomas. Cervical paragangliomas were also detected in the patient's sister and daughter, but not in his father. Furthermore, the proband's paternal grandmother and a maternal great-uncle had a history of 'neck scar'. This family history is suggestive of an autosomal dominant pattern of inheritance with maternal genomic imprinting. Genetic analysis of paraganglioma kindreds showed linkage with two different loci: 11q13.1 and 11q22.3-q23. Further knowledge of the genes involved could provide early diagnosis and accurate genetic counselling in affected families. Thorough familial investigation is consequently mandatory in all head and neck paragangliomas, especially in younger patients with multiple localizations, as surgical removal is safer at an early stage.

Seven lessons from two candidate genes in human essential hypertension: angiotensinogen and epithelial sodium channel

The candidate gene approach to understanding the genetics of human essential hypertension is discussed by analyzing the contribution of 2 genes, angiotensinogen (AGT) and epithelial amiloride-sensitive sodium channel (ENaC). From a large series of studies conducted in humans and animals, it appears that the AGT gene plays a significant but modest role in human blood pressure variance. Mutations of the beta- and gamma-ENaC subunits are responsible for Liddle's syndrome, but the implication of the 3 ENaC subunits in essential hypertension is still questionable. Several lessons can be learned from these studies and applied to other candidate genes in essential hypertension: (1) Many linkage or association studies have a limited statistical power; (2) The genetic findings may vary greatly according to the populations studied; (3) There is a need for better phenotyping of the hypertensive population; (4) The causal relationship between molecular variants and hypertension is and will be difficult to establish firmly; (5) The contribution of genetic studied in rodents to the molecular genetics of human hypertension must be re-examined; (6) Most molecular variants lead to a low attributable risk in the population or a low individual effect at the individual level; and (7) It is too early to propose dietary recommendations and specific drug treatment according to patients' genotypes.

Polymorphisms of the gamma subunit of the epithelial Na+ channel in essential hypertension

OBJECTIVE

The gamma subunit of the epithelial Na channel (gammaENaC) has been implicated in Liddle's syndrome. The objective of this study was to examine its status in essential hypertension.

DESIGN AND METHODS

The search for molecular variants was performed using the SSCP technique after determination of the intron-exon boundaries of the transcribed sequence. We found an additional 205 bp intron splitting the published exon 10 in two. The last exon of gammaENaC was tested with samples from a series of 245 normotensive patients and 453 hypertensive subjects (383 Caucasians, 70 Afro-Caribbeans), all probands of hypertensive families in the HYPERGENE data set. The search was extended to the other 11 transcribed exons in a subset of 65 patients with low-renin profile.

RESULTS

Four neutral polymorphisms were detected, three in the third exon of the gene (T387C, T474C, C549T) and one in the last exon (C1990G). These four variants were found with similar frequencies in hypertensive and normotensive Caucasian subjects as well as in patients with low-renin profile. Hypertensive Caucasians and hypertensive subjects of African ancestry also had similar frequencies. Lastly, we found two rare mutations, one the insertion of a proline residue at position 594 of the mature protein (594insP), the other an Arg-to-His substitution at position 631 (R631H). Compared to wild-type (1.00 +/- 0.42, n = 26), expression of the 594insP (1.10 +/- 0.43, n = 26) and R631H (0.97 +/- 0.43, n = 26) variants in Xenopus oocytes produced no significant increase in Na+ current.

CONCLUSIONS

Screening of the entire coding sequence of gammaENaC does not suggest that this subunit is frequently involved in essential hypertension.

Genetic analysis of the beta subunit of the epithelial Na+ channel in essential hypertension

Mutations of the last exon of the beta subunit of the amiloride-sensitive epithelial Na+ channel (betaENaC) can lead to Liddle's syndrome, a rare monogenic form of hypertension. The objective of this study was to test whether more subtle changes of betaENaC could be implicated in essential hypertension. After determination of the betaENaC coding gene organization (12 exons spanning 23.5 kb), a systematic screening of the last exon of the gene was performed in 525 subjects (475 whites, 50 Afro-Caribbeans), all probands of hypertensive families. This search was extended to the remaining 11 exons in a subset of 101 probands with low-renin hypertension. Seven amino acid changes were detected: G589S, T594M, R597H, R624C, E632G (last exon), G442V, and V434M (exon 8). These genetic variants were more frequent in subjects of African origin (44%) than in whites (1%). The functional properties of the variants were analyzed in Xenopus oocytes by two independent techniques, ie, electrophysiology and 22Na+ uptake. Small but not significant differences were observed between the variants and wild type. The clinical evaluation of the family bearing the G589S variant, which provided the highest relative ENaC activity, did not show a cosegregation between the mutation and hypertension. The present study illustrates the difficulty in establishing a relation of causality between a susceptibility gene and hypertension. Furthermore, it does not favor a substantial role of the betaENaC gene in essential hypertension.

Abnormalities of nasal potential difference measurement in Liddle's syndrome

In Liddle's syndrome, a rare inherited form of hypertension, epithelial sodium channel mutations appear to cause high blood pressure by increasing sodium reabsorption through sodium channels in the renal distal tubule. This increase in channel activity has not been confirmed previously by in vivo measurement. We have made transnasal potential difference measurements (effective in detection of increased sodium channel activity in cystic fibrosis) in three brothers with genetically proven Liddle's syndrome, their unaffected sister, and 40 normotensive controls. Maximum potential difference after 2 wk off treatment in the affected brothers was -30.4+/-1.2 mV (values mean+/-SD, lumen-negative with respect to submucosa) and was significantly more lumen-negative than that of the control group (-18.6+/-6.8 mV, P = 0.0228) or the unaffected sister (-18.25 mV, P < 0.01). The change in potential difference after topical application of 10(-)4 M amiloride was greater in the Liddle's patients, 14.0+/-2.1 mV, than in controls (7.9+/-3.9 mV, P = 0.0126) or the unaffected sister (5.5 mV, P < 0.05). This is the first in vivo demonstration of increased sodium channel activity in Liddle's syndrome. If these results are confirmed in other kindreds with this condition, then nasal potential difference measurements could provide a simple clinical test for Liddle's syndrome.

Association of hypertension with T594M mutation in beta subunit of epithelial sodium channels in black people resident in London

BACKGROUND

Liddle's syndrome is a rare inherited form of hypertension in which mutations of the epithelial sodium channel result in increased renal sodium reabsorption. Essential hypertension in black patients also shows clinical features of sodium retention so we screened black people for the T594M mutation, the most commonly identified sodium-channel mutation.

METHODS

In a case-control study, 206 hypertensive (mean age 48.0 [SD 11.8] years, men:women 80:126) and 142 normotensive (48.7 [7.4] years; 61:81) black people who lived in London, UK, were screened for T594M. Part of the last exon of the epithelial sodium-channel beta subunit from genomic DNA was amplified by PCR. The T594M variant was detected by single-strand conformational polymorphism analysis of PCR products and confirmed by DNA sequencing.

FINDINGS

17 (8.3%) of 206 hypertensive participants compared with three (2.1%) of 142 normotensive participants possessed the T594M variant (odds ratio [OR]=4.17 [95% CI 1.12-18.25], p=0.029). A high proportion of participants with the T594M variant were women (15 of 17 hypertensive participants and all three normotensive participants), whereas women comprised a lower proportion of the individuals screened (61.2% hypertensive, 57.7% normotensive). However, the association between the T594M variant and hypertension persisted after adjustment for sex and body-mass index (Mantel-Haenszel OR=5.52 [1.40-30.61], p=0.012). Plasma renin activity was significantly lower in 13 hypertensive participants with the T594M variant (median=0.19 ng mL(-1) h(-1)) than in 39 untreated hypertensive individuals without the variant (median=0.45 ng mL(-1) h(-1), p=0.009).

INTERPRETATION

Among black London people the T594M sodium-channel beta subunit mutation occurs more frequently in people with hypertension than those without. The T594M variant may increase sodium-channel activity and could raise blood pressure in affected people by increasing renal tubular sodium reabsorption. These findings suggest that the T594M mutation could be the most common secondary cause of essential hypertension in black people identified to date.

[Renal fibromuscular dysplasia and cerebral aneurysm in a hypertensive patient with a familial history of cerebral vascular complications]

BACKGROUND

The possibility of an association between two vascular anomalies, renal artery dysplasia and cerebral artery aneurysm, merits recognition.

CASE REPORT

We report the case of a 63 year old woman who was found to have fibromuscular dysplasia affecting the right renal artery while being investigated for systemic hypertension. Given a family history of cerebrovascular accident occurring before the age of 50, a cerebral angiogram was performed which demonstrated a saccular aneurysm of the middle cerebral artery measuring 6 mm in diameter.

DISCUSSION

The association of these two anomalies could result from a familial arterial fibromuscular dysplasia. There are practical implications, notably the risk of aneurysm rupture and the role of hypertension.

Genotype-phenotype analysis of a newly discovered family with Liddle's syndrome

OBJECTIVE

To investigate the clinical, biologic, and molecular abnormalities in a family with Liddle's syndrome and analyze the short- and long-term efficacies of amiloride treatment.

PATIENTS

The pedigree consisted of one affected mother and four children, of whom three suffered from early-onset and moderate-to-severe hypertension.

METHODS

In addition to the biochemical and hormonal measurements, genetic analysis of the carboxy terminus of the beta subunit of the epithelial sodium channel (beta ENaC) was conducted through single-strand conformation analysis and direct sequencing. The functional properties of the mutation were analyzed using the Xenopus expression system and compared with one mutation affecting the proline-rich sequence of the beta ENaC.

RESULTS

Mild hypokalemia and suppressed levels of plasma renin and aldosterone were observed in all affected subjects. Administration of 10 mg/day amiloride for 2 months normalized the blood pressure and plasma potassium levels of all of the affected subjects, whereas their plasma and urinary aldosterone levels remained surprisingly low. A similar pattern was observed after 11 years of follow-up, but a fivefold increase in plasma aldosterone was observed under treatment with 20 mg/day amiloride for 2 weeks. Genetic analysis of the beta ENaC revealed a deletion of 32 nucleotides that had modified the open reading frame and introduced a stop codon at position 582. Expression of this beta 579del32 mutant caused a 3.7 +/- 0.3-fold increase in the amiloride-sensitive sodium current, without modification of the unitary properties of the channel. A similar increase was elicited by one mutation affecting the carboxy terminus of the beta ENaC.

CONCLUSIONS

This new mutation leading to Liddle's syndrome highlights the importance of the carboxy terminus of the beta ENaC in the activity of the epithelial sodium channel. Small doses of amiloride are able to control the blood pressure on a long-term basis in this monogenic form of hypertension.

Sequential and combined use of inactivated and oral poliovirus vaccines: Dolj District, Romania, 1992-1994

To determine the feasibility of a vaccination strategy that would reduce the risk of vaccine-associated paralysis while retaining a barrier against the spread of wild poliovirus, a 2-year project was undertaken using enhanced-potency inactivated poliovirus vaccine (IPV) administered at 2 and 3 months of age followed by doses of both IPV and oral poliovirus vaccine (OPV) administered at 4 and 9 months of age. Vaccination coverage by 12 months of age with three or more doses of IPV and two doses of OPV among 16,566 infants eligible for vaccination was > 95% and > 80%, respectively. Among 51 children from whom blood samples were obtained 45 days after their third dose of IPV and first dose of OPV, 100% had serum neutralizing antibodies (reciprocal titer > or = 10) to all three poliovirus types. No cases of paralytic poliomyelitis due to either wild or vaccine-related strains were reported. The project demonstrated the feasibility, safety, and high immunogenicity of sequential use of IPV followed by OPV in Romania.

Neutralization epitope patterns of poliovirus strains isolated from cases of acute spinal paralysis and from healthy vaccinated children

By using a battery of poliovirus neutralizing monoclonal antibodies received from the Pasteur Institute, Paris, we carried out the study of the patterns of neutralization epitopes of more than 300 poliovirus strains isolated from cases of acute spinal paralysis and from healthy vaccinated children. We tried to find out the utility of this test for establishing the origin (wild or Sabin) of a poliovirus strain and the possible evolution of the pattern of neutralization epitopes. The study of the neutralization epitopes was carried out by neutralization index assay (NI). The neutralization index represents the difference between the titers of poliovirus strain determined in parallel in the absence, as well as in the presence of constant concentration (predetermined) for each monoclonal antibody. An epitope was considered to be present for a NI > or = 2 and absent for a NI < or = 1.5. For types 1 and 3 polioviruses, Sabin-like epitopes have never been found to be present simultaneously with wild type epitopes on the same virus particle. Therefore, examination of the epitope pattern of these strains is very useful for intratypic differentiation. On the other hand, in type 2 poliovirus strains, Sabin and wild type epitopes sometimes coexist, in various combinations, thus rendering the interpretation of the results rather difficult.