AIM: The aim of study was to evaluate the relationship of β-adrenergic receptors gene polymorphisms with low triiodothyronine syndrome in patients with a heart failure.
MATERIALS AND METHODS: 354 patients with HF on a background of postinfarction cardiosclerosis were included to the study. At 89 (25.1%) patients LT3S was diagnosed. The course of HF was studied for 2 years. Mean levels of thyroid stimulating hormone (TSH), free T3f and T4f were evaluated. Genotyping of 4 single nucleotide polymorphisms (Gly389Arg of β1-AR gene, Ser49Gly of β1-AR gene, Gln27Glu of β2- AR gene and Ser275 of GNβ3 gene) was performed by polymerase chain reaction. Genetic and epidemiological analysis was performed using the SNPStats program.
RESULTS: The risk of LT3S in patients with HF increases with homozygous G/G variant of Gln27Glu polymorphism of the β2-AR gene (OR=2.21, p=0.037), described as a recessive model of inheritance. There was a tendency to increase the risk of LT3S development in the presence of the genotype C/T of the Ser275 polymorphism of the GNb3 gene (OR=1.75, p=0.054), described as an over-dominant model. The genotype C/G of the Gln27Glu polymorphism of the β2-AR gene was associated with a decreased risk of LT3S development (OR=0.54, p=0.037), described as over-dominant model. Patients with HF carriers the A allele (A/GA/A) of the Ser49Gly polymorphism of the β1-AR gene have a lower risk of repeated hospitalization due to HF decompensation (OR=0.50, p=0.032), described as a dominant model. There was a tendency to increase the risk of re-hospitalization in the G-allele (C/GG/ G) variant of the Gln27Glu polymorphism of the β2-AR gene (OR=1.68, p=0.057), described as a dominant heredity model. At patients with HF in combination with LT3S the risk of re-hospitalization increases at C/G variant of the Gln27Glu polymorphism of β2-AR gene (OR=1.25, p=0.025), described as an over-dominant model.
CONCLUSIONS: The results suggest that congenital genetic alterations in β-adrenergic pathways may be associated with the development of LT3S in patients with HF and the features of the HF course.
PATIENTS AND METHODS: Materials and Methods: The systematization of literature data on the role of cytokines in the progression of HF in patients with concomitant thyroid pathology (TP) was carried out. The results of our own research were presented.
CONCLUSION: Conclusions: The final chapter in the history of the role of cytokines in the progression of HF has not yet been written. Further studies, including genetic ones, are necessary. The patients with HF have higher levels of TNFβ and IL-6, and a lower concentration of IL-4, compared to the control group. Patients with a fatal outcome of the disease, in contrast to those who survived for two years, have an increased level of TNFβ. In patients with concomitant TP, who had repeated hospitalization, a lower level was registered, compared to that under conditions of a more favorable course of heart failure. Concentrations of cytokines in the blood of patients with HF are associated with gene polymorphisms of the β-adrenoreceptor system: the C-allele of the Gly389A polymorphism of the β1-adrenoceptor gene leads to a decrease in the risk of increasing TNFα; IL-1α increases in the presence of the A-allele of the Ser49Gly polymorphism of this gene. In patients with HF and concomitant thyroid pathology, the risk of IL-6 growth increases in homozygous (C) patients for the Ser275 polymorphism of the β3 subunit of the G-protein.
RESULTS: No significant difference in plasma propranolol (mean +/- SEM) levels was seen between races six hours after the last dose (Malays, 59.7 +/- 8.8 ng/ml, Indians, 67.6 +/- 19.3 ng/ml, Chinese, 58.4 +/- 7.9 ng/ml). Chinese were least sensitive to the bradycardic and hypotensive effects of propranolol at rest and exercise. Indians and Malays had significant reduction of supine systolic blood pressure with propranolol but not Chinese. Comparison of percentage reductions of systolic blood pressure at supine, sitting and exercise by repeated measure analysis showed the Malays to have significantly higher change compared to the Chinese (p = 0.022). Similarly, comparison of percentage reductions of heart rate at supine, sitting and exercise by repeated measure analysis showed the Malays to have significantly higher change compared to the Chinese (p = 0.040). Average change in potassium concentrations at peak exercise and recovery showed the Indians to have significantly higher increase in potassium levels with propranolol compared to the Malays (p = 0.038). However, no significant interethnic difference was seen in the reduction of glucose levels at rest, peak exercise or recovery. Also, no significant interethnic difference was seen in reduction of FEV1 values.
CONCLUSION: We, therefore, conclude that ethnic differences in response to blockade of beta-receptors exist among racial groups in Malaysia. These differences were seen at similar plasma drug levels between races suggesting ethnic differences in drug sensitivity, rather than differences in drug disposition.
METHODS: Human Müller cells were cultured in low and high glucose conditions. Cells were treated with xamoterol (selective agonist for β1-AR), salmeterol (selective agonist for β2-AR), isoproterenol (β-ARs agonist) and propranolol (β-ARs antagonist), at 20 µM concentration for 24 h. Western Blotting assay was performed for the gene expression analysis. DNA damage was evaluated by TUNEL assay. DCFH-DA assay was used to check the level of reactive oxygen species (ROS). Cytochrome C release was measured by ELISA.
RESULTS: Xamoterol, salmeterol and isoproterenol showed no effect on Caspase-8 but it reduced the apoptosis and increased the expression of BDNF in Müller cells. A significant change in the expression of caspase-3 was observed in cells treated with xamoterol and salmeterol as compared to isoproterenol. Xamoterol, salmeterol and isoproterenol significantly decreased the reactive oxygen species (ROS) when treated for 24 hours. Glucose-induced cytochrome c release was disrupted in Müller cells.
CONCLUSION: β-ARs, stimulated by agonist play a protective role in hyperglycemic Müller cells, with the suppression of glucose-induced caspase-3 and cytochrome c release. B-Ars may directly mediate the gene expression of BDNF.
METHODS: An initial study showed that PMX53, an antagonist of C5aR1 in normal C57BL6/J (wild type, WT) mice reduced heart rate (HR) and appeared to have a protective effect on the heart following induced sepsis. C5aR1 knockout (CD88-/-) mice had a lower HR than wild type mice, even during sham surgery. A model to assess heart rate variability (HRV) in anesthetized mice was developed to assess the effects of inhibiting the β1-adrenoreceptor (β1-AR) in a randomized crossover study design.
RESULTS: HR and LF Norm were constitutively lower and SDNN and HF Norm constitutively higher in the CD88-/- compared with WT mice (P< 0.001 for all outcomes). Administration of atenolol (2.5 mg/kg) reduced the HR and increased HRV (P< 0.05, respectively) in the wild type but not in the CD88-/- mice. There was no shift of the sympathovagal balance post-atenolol in either strains of mice (P> 0.05), except for the reduced LF/HF (Lower frequency/High frequency) ratio (P< 0.05) at 60 min post-atenolol, suggesting increased parasympathetic tone of the heart due to the effect of atenolol administration. The HR of the WT mice were lower post atenolol compared to the CD88-/- mice (P = 0.001) but the HRV of CD88-/- mice were significantly increased (P< 0.05), compared with WT mice.
CONCLUSION: Knockout of the C5aR1 attenuated the effect of β1-AR in the heart, suggesting an association between the β1-AR and C5aR1, although further investigation is required to determine if this is a direct or causal association.