MTNR1A and MTNR1B Gene Variants of the Melatonin Receptor and Arterial Stiffness in Persons without Arterial Hypertension

A comparative analysis of vascular stiffness indices and the results of blood test was carried out in 85 healthy donors aged 19-64 years, carriers of polymorphic variants of type 1 and type 2 melatonin receptor genes. The associations of polymorphic markers of type 1 MTNR1A (rs34532313) and type 2 MTNR1B (rs10830963) melatonin receptor genes with parameters of vascular stiffness and blood parameters in healthy patients were studied. Genotyping was performed using allele-specific PCR. In all patients, 24-h BP monitoring with assessment of arterial stiffness was performed. Allele C homozygotes of MTNR1A differed significantly from carriers of the major T allele by elevated triglyceride, LDL, and fibrinogen levels. The major allele C of the rs10830963 polymorphic variant of the MTNR1B gene is associated with elevated LDL and triglycerides, as well as with individual differences in the elastic properties of the vascular wall in the examined subjects.

Analysis of Clinical and Biochemical Characteristics of Patients With Genetically Confirmed Familial Hypercholesterolemia in Russian North Western District Residents

Aim      To compare results of clinical, laboratory, and genetic examination of patients with familial hypercholesterolemia (FHC).

Material and methods  112 patients aged 40.2±17.9 years (49 men) were examined. The gene of low-density lipoprotein receptor (LDLR) was analyzed and evaluated using the Dutch Lipid Clinic Network (DLCN) criterion of lipid score ≥6. The LDLR gene mutation was searched for using the conformational polymorphism analysis followed by sequencing of the DNA of isolated LDLR gene exons.

Results Mean variables of the blood lipid profile were total cholesterol (C), 10.12±2.32 mmol/l, LDL-C, 7.72±2.3 mmol/l. Corneal arcus was observed in 15 % of patients, tendon xanthomas in 31.8 %, and xanthelasma palpebrarum in 5.3 %. The types of LDLR gene mutations included missense mutations (42.8 %), mutations causing a premature termination of protein synthesis (41.1 %), and frameshift mutations (16.1 %). In the presence of a mutation in exon 4, patients with IHD compared to patients with no IHD had significantly higher levels of total C (10.88±2.08 mmol/l vs. 8.74±1.57 mmol/l, respectively, р=0.001) and LDL-C (8.60±2.14 mmol/l vs. 6.62±1.79 mmol/l, respectively, р=0.005). Patients with IHD compared to patients with no IHD and a mutation in LDLR gene exon 9 had only a higher LDL-C level (8.96±1.53 mmol/l vs. 6.92±1.59 mmol/l, respectively, р=0.022). A differentiated comparison of IHD patients using a logistic regression depending on the identified type of LDLR gene mutation produced formulas for calculating the odds ratio of IHD and myocardial infarction (MI) with adjustments for the patient’s age and baseline LDL.

Conclusion      The detection rate of the LDLR gene mutations was 42.8 % for missense mutations, 41.1 % for mutations causing a premature termination of protein synthesis, and 16.1 % for frameshift mutations. Blood lipid profiles did not differ between patients from different cities and with different types of LDLR gene mutations. Blood lipid profiles were different in IHD patients depending on the mutation type.

The relationship of the carriership of allelic variations in rs2228145 (A > C) of the IL6R gene with the levels of VCAM1 and ICAM1 gene transcripts in patients with essential hypertension

The levels of plasma interleukin 6 and its soluble receptors were found to be elevated in subjects with cardiovascular diseases, which points to amplification of the IL-6-mediated trans-signaling pathway in cells and the development of chronic inflammation. The allelic variation in the rs2228145 IL6R gene is associated with a change in the contents of the soluble and membrane-bound receptor forms mediating the biological activity of IL-6. Cytokine IL-6 is involved in the development of endothelial dysfunction by regulating the expression of the VCAM1 and ICAM1 genes, encoding intercellular adhesion molecules. Prior to this work, no data on the association of essential arterial hypertension (EAH) with rs2228145 allelic variations of the IL6R gene have been reported. The aim of our work was to study the relationship of the carriership of rs2228145 (A > C) allelic variations with the development of EAH and the VCAM1 and ICAM1 transcript levels. We analyzed samples of DNA isolated from the whole blood of 148 healthy donors and 152 patients with EAH (stages I–II). The genotyping was performed by PCR-RFLP. The level of transcripts in peripheral blood leukocytes (PBL) was assessed by real-time PCR. Differences in the frequency distributions of rs2228145 (A > C) genotypes between the control group and the group of patients with EAH (χ2 = 9.303) were found. The frequency of the CC genotype in EAH patients was higher than in healthy people (0.191 and 0.095, respectively). The risk of EAH (I–II stages) development was shown to be 2.3 times higher in CC genotype carriers as compared to individuals with other genotypes (OR = 2.257, 95 % confidence interval 1.100–4.468). The levels of VCAM1 and ICAM1 gene transcripts in PBL of patients with EAH were significantly higher than in healthy people. The level of ICAM1 gene transcripts was almost 4 times higher in patients with CC genotype. The Kruskal–Wallis analysis of variance revealed an effect of rs2228145 (A > C) genotype on the transcriptional activity of ICAM1, which argues for its role in the pathogenesis of endothelial dysfunction and essential hypertension.

[Experience of the use of the PCSK9 inhibitor Alirocumab in patients with extremely high cardiovascular risk]

Aim To study the efficacy and safety of alirocumab in patients with high and very high cardiovascular risk in the Republic of Karelia and to evaluate their compliance with the alirocumab therapy.Materials and methods Study design: observational, noncomparative. The observation group consisted of 9 patients receiving alirocumab (Praluent®) (mean age, 48.6±4.7 years; 7 men). 7 patients had familial hypercholesterolemia of the type diagnosed by DLCN criteria; five patients had MI. Lipid profile, concentrations of transaminases, creatinine, glucose, and lipoprotein a (LP(a)) were measured at 3, 6, 12, and 18 months. Electrocardiography was performed, and the clinical picture (development of acute coronary syndrome, acute cerebrovascular disease, transient ischemic attacks, myocardial revascularization, and cardiovascular death) was evaluated. Efficacy criteria included the absence of these clinical conditions, the proportion of patients who achieved the LDL CS goal, and the decrease in LP(a). Safety was evaluated by clinical and laboratory data, such as levels of transaminases, total bilirubin, creatinine, and blood glucose. The observation lasted for 6 months to 1.5 years.Results LDL CS goals were achieved in 7 (77.8%) patients receiving alirocumab. The mean level of LP(a) decreased from 0.39 to 0.28 g/l; the degree of decrease ranged from 20 to 33 %. No cases of IHD instability (acute coronary syndrome) or new cases of acute cerebrovascular disease and transient ischemic attacks were observed. None of the patients had to stop the alirocumab treatment; adverse effects, including local ones, were not observed.Conclusion LDL CS goals were achieved in 7 (77.8%) patients. The level of LP(a) decreased by 20-33% in patients receiving the PCSK9 inhibitor. In real-life clinical practice, the alirocumab treatment was characterized with high compliance and good tolerability without side effects, including local ones.

[Lipid Lowering Therapy with Statins in Patients with Heterozygous Familial Hypercholesterolemia]

AIM

to analyze adherence of FH patients with familial hypercholesterolemia (FH) to the statin therapy and reveal factors, which influence it; to assess the degree of target level of low-density lipoprotein cholesterol (LDLCH) achievement by FH patients on statin therapy. Materials and methods. We included in this study 203 FH patients aged >18 years (mean age 50.0±1.1 years, 82 men). Definite FH was diagnosed in 96 persons, in the other patients FH was considered possible. For evaluating the adherence to therapy with statins we used the Morisky-Green questionnaire. Results. Among patients with definite FH 57 % were adherent to lipid-lowering therapy, 16 % were partially adherent, and 27 % - not adherent. Target LDLCH levels were achieved in 22.6 % and 12.5 % of patients with definite and possible FH, respectively. Smoking and gender were not associated with adherence to statin therapy. Factors associated with higher adherence were age (p=0.000003), arterial hypertension (odds ratio [OR] 1.90, 95 % confidence interval [CI] 1.02 to 3.55], p=0.044), ischemic heart disease (IHD) (OR=2.99, 95 %CI 1.50 to 5.97, p=0.002), history of myocardial infarction (MI) (OR 5.26, 95 %CI 2.03 to 13.60, p=0.0006), history of myocardial revascularization (OR 20.3, 95 %CI 2.64 to 156.11, p=0.004) and the fact of achieving target LDLCH level (OR 19.93, 95 %CI 7.03 to 56.50, p<0.0001). The main reason for the refuse from statin therapy in 87 % of patients was fear of side effects. Main reasons for stopping of ongoing therapy were: myalgia, an increase in transaminases, skin rashes, and high cost in 12, 35, 12, and 6 % of patients, respectively. The decision to withdraw therapy with statins was made by 29 % of patients by themselves.

CONCLUSION

In this study 57 % of patients with definite FH were adherent to statin therapy. Factors associated with increased adherence were age, hypertension, IHD, history of MI, history of myocardial revascularization, achievement of target LDLCH level. Target LDLCH levels were achieved by 22.6 and 12.5 %% of patients with definite and possible FH, respectively.

[Assessment of Vascular Stiffness in Normotensive Patients With Familial Hypercholesterolemia]

AIM

to analyze parameters of vascular stiffness and augmentation index in patients with familial hypercholesterolemia (FH).

MATERIALS AND METHODS

We compared parameters of vascular stiffness of 88 normotensive FH patients (mean age 41.95±1.43 years, 43 men [48.9 %]) and 68 subjects with normal blood lipid spectrum (mean age 37.58±1.02 years, 21 men [30.9 %]). FH was diagnosed according to the criteria of the Dutch Lipid Clinic Network. Examination included lipid profile, 24‑hour blood pressure (BP) monitoring with assessment of arterial stiffness.

RESULTS

Normotensive FH patients had higher pulse wave velocity (PWV) (7.99±0.17 m/s) in comparison with patients with normal lipid spectrum (6.87±0.10 m/s), p.

[The Familial Hypercholesterolemia Caused by a Novel Human Low Density Lipoprotein Receptor Gene Mutation c.1327 T>C (p.W433R)]

During investigation of molecular nature of familial hypercholesterolemia (FH) in Petrozavodsk (Russia) cohort of patients a novel low density lipoprotein (LDL) receptor gene mutation was found. This mutation designated c.1327 T>C (W443R [W422R]) was predicted to cause substitution of arginine for tryptophan residue in the very conservative -propeller domain of the LDL receptor. Inheritance of the new mutation was traced in four generations and its cosegregation with hypercholesterolemia phenotype was observed. Despite the predicted pathogenic effect of the mutation, ischemic heart disease in the pedigree was mild or absent. We consider identification of this mutation in the pedigree extremely helpful to start preventive medical treatment in affected patients.

Assessment of arterial wall stiffness by 24-hour blood pressure monitoring

Arterial wall stiffness is an early marker of cardiovascular diseases. The gold standard for assessment of the stiffness of large vessels is presently pulse wave velocity (PWV). Work is in progress on the study of the reference values of PWV in people of different genders and ages. 24-hour blood pressure (BP) monitoring is not only a procedure that can estimate diurnal BP variability, but also monitor the indicators of vascular wall stiffness in a number of cases over a 24-hour period. The given review highlights the pathophysiology of arterial stiffness, methods for its assessment, and the aspects of use in therapeutic practice.

[CONTRIBUTION OF LIPOPROTEIN(A) TO CARDIOVASCULAR RISK IN PATIENTS UNDER 40 YEARS OF AGE AFTER ACUTE MYOCARDIAL INFARCTION OR ACUTE CEREBRAL CIRCULATION DISORDER]

AIM

To evaluate the importance of lipoprotein(a) for the evaluation of cardiovascular risk in patient under 40 years of age after acute myocardial infarction or acute cerebral circulation disorder.

MATERIALS AND METHODS

We analysed the data from two departments of the Regional Vascular Centre for 2013-2015 including 90 case histories of patients of different age (mean 57.8 ± 3.4 yr) and studied standard risk factors, such as age, sex, smoking habits, dyslipidemia, aggravated heredity, arterial hypertension (AH), obesity. Standard examination of 7 patients under 40 years of age was supplemented by measuring lipoprotein(a) by the immunoturbodimetric method regarding the levels over 0.3 g/l as abnormally elevated.

RESULTS

The study group was dominated by young and middle-aged men (85.2 and 84% respectively). The key risk factors were increased LDLP level (88%) and smoking (70%) in patients under the age of 40 and AH in middle-aged men (100%, p < 0.004). Arterial hypertension was also diagnosed in 59% of the younger subjects. Increased LDLP levels most frequently occurred in senior patients (90%). The group of patients under 40 yr included 15% of those having a single risk factor. In this group, 22% of the patients were at high risk calculated prior to the development of vascular events, 58% at moderate and 20% at low risk. 42.8% of the patients had elevated lipoprotein(a) levels.

CONCLUSION

Based on the relative risk scoring scale, 22% of the patients under 40 years of age were at risk of myocardial infarction or cerebral circulation disorders prior to the development of vascular events. However, these patients like those of other age groups frequently had traditional risk factors, such as smoking (67.5%), AH and dyslipidemia (66.6% each). Total cholesterol was elevated only in 47.6% of the patients while LDLP and LP(a) in 92 and 42.8% respectively.

"Finnish" mutations in LDL receptor gene: a rare cause of familial hypercholesterolemia in St. Petersburg and Petrozavodsk

The search for two mutations, FH-Helsinki and FH-North Karelia, in LDL receptor gene was carried out in patients with familial hypercholesterolemia from St. Petersburg (80 families) and Petrozavodsk (80 families) using allele-specific PCR and analysis of single-stranded DNA fragment conformation polymorphism (SSCP analysis) with subsequent sequencing. The FH-North Karelia mutation was found in one family in St. Petersburg and in one family in Petrozavodsk, while FH-Helsinki mutation was not detected in any of the samples. Hence, the two "Finnish" mutations together responsible for 2/3 familial hypercholesterolemia cases in Finland were extremely rare in the Russian regions neighboring Finland.

Expression of circadian rhythm genes CLOCK, BMAL1, and PER1 in buccal epithelial cells of patients with essential arterial hypertension in dependence on polymorphic variants of CLOCK and BMAL1 genes

The transcript levels of circadian rhythm genes CLOCK, BMAL1, and PER1 in buccal epithelial cells of the patients with essential arterial hypertension was analyzed in relation to polymorphic variants of CLOCK and BMAL1 genes. These levels were assessed with realtime PCR method at daily hours 9, 13, and 17. The significant differences were revealed in transcript levels of the examined genes in patients with various genotypes at the polymorphic markers 3111TC and 257TG regulatory regions of CLOCK gene. The study detected no significant differences among the carriers of various genotypes at polymorphic markers 862TC and 2121GA of CLOCK gene and 56445TC of BMAL1 gene.

[Familial hypercholesterolemia due to a new mutation in the low density lipoprotein receptor gene]

Familial hypercholesterolemia (FHC) is a genetic disorder manifest as a rise in serum cholesterol level responsible for the development ofcardiovascular diseases.

AIM

To study genetic peculiarities of FHC in Kareliya.

MATERIALS AND METHODS

109 patients of the 196 ones with FHC (124 families) were subjected to genetic examination. Other parameters studied included the lipid spectrum, blood glucose level, ECG, 24 hr ECG monitoring, echocardiography, triplex scanning of brachiocephalic arteries and lower limb vessels, functional tests. Simon Broom criteria were used to diagnose FHC.

RESULTS

"Definitive" FHC was diagnosed in 136 (69.4%) patients, (probable) FHC in 30.6%. The total encoding region of the low density lipoprotein receptor gene was sequenced in 109 (55.6%) patients in parallel with the search for major mutations in the APOB and PCSK9 genes. A total of 13 mutations (p.G20R, c. 192del110/ins8, c.195-196insT, p.S206R, c925- 931del17, p.S447C, p.13981, p.L426P, L511S, c.1686del18/insT, p.L646I, p.N640N, c.2191delG) were identified in low density lipoprotein receptor gene; seven of them are reported for the first time in the world. No major mutations in the APOB and PCSK9 genes were found. The new c.2191delG (p.(Val73 1Serfs*6)) mutation is characterized and its segregation with familial dyslipidemia is shown. The present case is characterized by the absence of clinical picture of coronary heart disease and the family history complicated by cerebral basin lesion. Phenotypic manifestations of atherosclerosis in FHC with gene mutations need further studies.

[The clinical manifestations of atherosclerosis in familial hypercholesterolemia]

AIM

To study the specific features of manifestations of atherosclerosis in Karelia dwellers with familial hypercholesterolemia (FH).

SUBJECTS AND METHODS

The examination of 196 patients with FH involved laboratory tests, electrocardiography, echocardiography, triplex scanning of the arteries, exercise testing, and coronarography as indicated. Genetic examination was performed in 109 (55.6%) patients.

RESULTS

The examinees' mean age was 48 +/- 2.3 years; there was a female predominance (68.7%). All the patients were found to have significant hypercholesterolemia due to elevated low-density lipoprotein levels. There was arcus lipoides corneae in 26% of cases, tendinous xanthomas in 17%, and xanthelasma palpebrarum in 34.9%. Carotid stenosis and lower extremity atherosclerosis obliterans were detected in 26.3 and 4.6%, respectively. 27.5% of the patients were diagnosed with coronary heart disease (CHD) (mean age at onset 45 years): exertional angina pectoris (10.2%), acute myocardial infarction (AMI) (14.8%), and an arrhythmic form (5.6%). 65.5% of the patients who had developed the first AMI were aged younger than 55 years. The most common site of AMI was the anterior wall of the left ventricle (55%); 51.7% of cases had transmural AMI. 24.1% of the patients sustained recurrent AMI. Complicated AMI was noted in 13.8% of cases. One third of the patients could achieve target blood lipid levels.

CONCLUSION

The characteristics of the patients with FH in Karelia are a mean age of 48 years and a female predominance; the main criterion for the diagnosis of FH is significant dyslipidemia while its stigmas are rarely encountered. The specific features of CHD in the patients with FH are as follows: the age at onset is 45 years; AMI develops at the ages of less than 55 and 40 years in 65.5 and 26.3%, respectively; the rate of recurrent AMI is as high as 24%; transmural AMIs occur in 51.7% of the patients; 26.3% had signs of brachiocephalic artery stenotic lesion; 4.6% present with lower extremity atherosclerosis obliterans; one third of the patients could achieve target blood lipid levels.

[New mutations in low-density lipoprotein receptor gene in familial hypercholesterolemia patients from Petrozavodsk]

Using an automated fluorescent single-strand conformation polymorphism (SSCP) analysis of the entire coding region, promoter zone, and exon-intron junctions of the low-density lipoprotein (LDL) receptor gene, we examined 80 DNA samples of patients with familial hypercholesterolemia (FH) from Petrozavodsk. We revealed mutations that might cause FH in five probands, including FH-North Karelia (c.925-931del7) mutation and four previously unknown mutations. These novel mutations included a transversion (c.618T>G (p.S206R), one nucleotide insertion c.195_196insT (p.FsV66:D129X), a complex gene rearrangement c.192del10/ins8 (p.FsS65:D129X), and a single nucleotide deletion c.2191delG (p.FsV731:V736X). Three out of four novel mutations produce an open reading frame shift and the premature termination of translation. An analysis of the cDNA sequence of the LDL receptor showed that this might result in the formation of a transmembrane-domain-deficient receptor that is unable to bind and internalize the ligand. Our results suggest the absence of a strong founder effect associated with FH in the Petrozavodsk population.

[A case of familial hypercholesterolemia caused by a novel mutation p. FsS65:D129X of human low density lipoprotein receptor gene]

Novel mutation p. FsS65:D129X in human low density lipoprotein receptor gene in a female patient with typical clinical symptoms of familial hypercholesterolemia is described in this paper. Segregation of this mutation with hypercholesterolemia in the family of the patient from Petrozavodsk is demonstrated.

[Association of T3111C polymorphism in 3'-untranslated region of the CLOCK gene with the risk of essential arterial hypertension and coronary artery disease in the Russian population Karelia]

Allele and genotype distributions of the T3111C polymorphism in 3'-untranslated region of the CLOCKgene were examined in the groups of Russian patients with essential arterial hypertension (EAH) and coronary artery disease (CAD), and in control group of Russia residents of the Republic of Karelia. The genotype frequency distributions of the polymorphism examined in the EAH and CAD patients were statistically significantly different from that in the individuals without clinical signs of these diseases. The CC genotype frequency in EAH and CAD males was higher, and in the corresponding females it was lower than in males and females from the control group. Male CC carriers were characterized by a possible increased risk of EAH: OR (95% CI) = 1.42 (0.56; 3.58). Moreover, the presence of the CC genotype in males could increase the risk of CAD: OR (95% CI) = 1.58 (0.63; 3.93).

[Left ventricular myocardial geometry in arterial hypertension in patients with stenosing cerebral atherosclerosis]

The aim of the study was to define more exactly correlations between circulatory disturbances in the common carotid artery (CCA) basin, and hemodynamic disturbances and structural myocardial remodeling in patients suffering from arterial hypertension (AH) and cerebral atherosclerosis. The subjects were 83 patients evaluated by means of carotid arterial Doppler ultrasonography and echoCG; the variables of central homodynamic were measured as well. The study revealed that patients with AH and moderate CCA stenosis displayed hyperkinetic hemodynamic type more often than patients with severe CCA stenosis, of whom hypodynamic hemodynamic type was more typical. Left ventricular (LV) myocardial remodeling was more frequent in the latter group of patients; asymmetric LV hypertrophy prevailed. The study shows that the process of remodeling, caused by dissociation between central and regional hemodynamics, develops together with the progress of atherosclerotic arterial lesion.

[Specifics of lipid exchange in patients with atherosclerotic lesions of the coronary and cerebral arteries]

Atherogenic shift in blood lipid spectrum, which may manifest by the increase of serum levels of cholesterin, low-density lipoproteins (LDL), triglycerides, very-low-density proteins (VLDL) or the decrease of serum levels of antiatherogenic high-density lipoproteins (HDL), is one of the leading risk factors of atherosclerosis. Patients with atherosclerosis often have normal or subnormal level of cholesterin together with hypertriglyceridemia or no hyperlipidemia (HL) together with decreased serum level of HDL. Among coronary atherosclerosis (CorA), cerebral atherosclerosis (CA) and multifocal atherosclerosis the first condition has been explored more than the others, whose ethiopathogenic features has not been sufficiently studied yet. However, sufficient knowledge of ethiopathogenic features of atherosclerotic process in various blood vessel basins would allow revealing the so called predictors of multifocal lesions and carrying out their timely prophylaxis or inhibiting their progression. Investigation of lipid exchange showed that the most atherogenic alterations are characteristic of CorA and multifocal atherosclerosis. CA is characterized chiefly by HL type IV, while HP type II is more typical of CorA and multifocal atherosclerosis. Triglycerides have been demonstrated to influence mostly the progress of CA while LDL chiefly promote the dissemination of CorA.