Zaiats O. Correlation between indices of oxidative processes, L-arginine/arginase system, gas mediators (nitrogen oxide and hydrogen sulfide) of the oral fluid and thyroid and dental status of children with latent iron deficiency

Українська версія

Thesis for the degree of Doctor of Philosophy (PhD)

State registration number

0822U100375

Applicant for

Specialization

  • 221 - Стоматологія

12-01-2022

Specialized Academic Board

ДФ 20.601.022

Ivano-Frankivsk national medical university

Essay

The scientific work is devoted to the study of gender and age characteristics of nitro-oxidative processes, the content of gas mediators (nitrogen oxide – NO and hydrogen sulfide - H2S) in the oral fluid of children with latent iron deficiency (LID) and mild iodine deficiency (MID) and their effect on dental status. Practically 133 healthy children (6-11 and 12-18 years old) were examined. The study design included control (1st, children with proper iron and iodine metabolism) and the following research groups: children with MID (2nd), LID (3rd) and under conditions of combination of latent iron deficiency and mild iodine deficiency (4th). For the first time established that under conditions of LID in the oral fluid (OF) of schoolchildren the processes of peroxidation of proteins (POP) and lipids (LP) are activated: increases the content of POP products by 20.9-62.5% (p<0.01), diene conjugates (DC) by 40.7% - 10.2 times (p<0.05), products that react to thiobarbituric acid – by 91.2% - 2.3 times (p<0.01) relative to data of healthy peers. Such changes develop against the background of suppression of superoxide dismutase (SOD) activity only in girls, regardless of age. Under conditions of combination of LID and MID in the oral fluid the POP processes are activated more intensively (the concentration of POP products increases by 87.3% - 3.3 times, p<0.05) and LP (increases the level of DC by 62.7% - 12.4 times, p<0.001) against the background of anti-radical reserve imbalance of OF (suppression of SOD activity by 20.4-30.7%, p<0.05 and activation of glutathione peroxidase by 92.0-93.3%, p<0.05) according to the data in children of the control group. Indicators of L-arginine-arginase systems in OF of schoolchildren with LID (L-arginine content in boys decreases by 29.4%, p<0.05, in girls – increases by 60.5%, p<0.001), metabolism NO (nitrite ion level – NO2- increases in boys in 3.6 times, p<0.01 and in girls – in 2.8 times, p<0.05) change relative to control. The development of comorbid pathology is accompanied by an increase in the content of NO2- in 8.3 times (p<0.001), the sum of nitrites and nitrates – in 3.3 times (p<0.05) in OF of boys and an intensive increase in of the concentration of peroxynitrite in 2.5-11.4 times (p<0.05) in junior and senior students relative to control. Reliable changes of H2S concentration is found only in girls. The level of caries process prevalence in this group corresponds to “average” regardless of age and sex, and the level of intensity in younger students “very low” and “low”, in older – “medium”. Hygienic index by Green-Vermillion (HI) reflects “unsatisfactory” and “poor” oral hygiene. The papillary-marginal-alveolar index (PMA) corresponds to the “average” severity of gingivitis, and the pH index decreases. The development of iron deficiency under conditions of iodine deprivation potentiates the changes of bone metabolism: the concentration of total and ionized calcium decreases by 54.7-66.1% (p<0.001) and 11.3-18.0 (p<0.05), respectively, relative to control. In girls with LID and MID, regardless of age, the processes of bone demineralization are activated (the level of total decreases – by 54.7%, p<0.001 and the concentration of ionized increases – by 52.4%, p<0.05 of calcium on the background of APs activation and alkaline phosphatase in 11.2-4.0 times, p<0.05 relative to control). Under such conditions, the prevalence of caries corresponds to “high”, and the intensity – “medium” and “high” levels. HI reflects “poor” oral hygiene. The PMA index corresponds to “mild” (in boys) and “severe” (in girls) severity of gingivitis, and pH index shifts to the acidic side. Close correlations between OF arginase activity and thyroid-stimulating hormone (TSH) (r =-0.77, p<0.05) and free triiodothyronine (fT3) (r=0.78, p <0.05); concentration of L-arginine and serum iron (r=0.87, p<0.05) were found. The level of TSH significantly affects the concentration of NO2- in OF (r=-0.89, p<0.05). The sum of nitrites and nitrates of OF with a high probability depends on the total iron-binding capacity of blood serum (IBCB) (r = 0.80, p<0.05), serum ferritin (SF) (r=-0.73, p<0,05), free thyroxine (fT4)(r=0.84, p<0.05) and fT3 (r=0.72, p<0.05). A strong direct correlation between IBCB and peroxynitrite concentration in OF (r=0.77, p<0.05) was found. The intensity of caries is significantly affected by: the level of serum iron (r=-0.70, p <0.05), IBCB (r=-0.82, p<0.05), SF (r=-0, 81, p<0.05) and fT4 (r=-0.72, p<0.05). Iron depot indicators play the greatest role in lowering of pH index of OF. The risk group for dental pathology is formed by girls of senior school age and all children with minimal thyroid insufficiency, regardless of gender. Key words: dental status, latent iron deficiency, mild iodine deficiency, nitrooxidative processes, bone metabolism. Branch – medicine.

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