Tikrit Journal of Pure Science

B ack ground: many researches about urinary tract infection has been conducted on adults but very little has been done on children. Therefore, this research is novel in Salahaddin city-Iraq. Urinary tract infection is a bacterial infection that affects part of the urinary tract. It affects the lower urinary tract as well as upper urinary tract. It is characterized by painful urination, urge to urinate or sometimes frequent urination. Other symptoms include fever in addition to flank pains. Bacteria infections cause a variety of changes in lipid profile concentrations by generating free radicals. Free radicals are reactive species generated by biochemical redox interactions that occur as a part of normal cell metabolism. These free radicals may cause lipid peroxidation and damage cellular structures of organism particularly erythrocytes and endothelium. Lipid peroxidation are free radicals mediated chain of reaction that, once initiated, results in oxidative deterioration of polyunsaturated lipids. The most common goal are components of biological membrane. When propagated in biological membranes, these reaction can be initiated or enhanced by a number of toxic products, including endoperoxides and aldehydes. Aim: The aims of this study were to evaluate the lipid profile of the children in acute


Introduction
Urinary tract infection are a bacterial infections that affects part of the urinary tract.It affects the upper urinary tract as well as lower urinary tract.It is characterized by painful urination, urge to urinate or sometimes frequent urination.Other symptoms include fever in addition to flank pains [1].Bacteria infections cause a variety of changes in lipid profile concentrations by generating free radicals.These free radicals may cause lipid peroxidation and damage cellular structures of organism particularly erythrocytes and endothelium [1].Lipid peroxidation is a free radical mediated chain of reaction that, once initiated, results in oxidative deterioration of polyunsaturated lipids [1].Patients with a variety of different infections (gram positive bacterial, gram negative bacterial, viral, tuberculosis) have similar alterations in plasma lipid levels.Specifically, total cholesterol, LDL cholesterol, and HDL cholesterol levels are decreased while plasma triglyceride levels are elevated or inappropriately normal for the poor nutritional status [2,3].As expected apolipoprotein A-I, A-II, and B levels are reduced [3,4].While LDL-c levels were decreased, the concentration of small dense LDL-c has been found to be increased during infections [5].That plasma cholesterol levels decrease during infection has been known for many years as it was described by Denis in 1919 in the Journal of Biological Chemistry (JBC 29: 93, 1919).The alterations in lipids correlate with the severity of the underlying infection i.e. the more severe the infection the more severe the alterations in lipid and lipoprotein levels [6,7].Of note studies have demonstrated that the degree of reduction in total cholesterol, HDL-c cholesterol, and apolipoprotein A-I are predictive of mortality in patients with severe sepsis [8,9].Moreover, epidemiologic studies have suggested that low cholesterol and HDL-c levels increase the chance of developing an infection [10].During recovery from the infection plasma lipid and lipoprotein abnormalities return towards normal.The changes in lipid and lipoproteins that occur during infection can be experimentally reproduced in humans and animals by the administration of endotoxin and lipoteichoic acid [11].Thus, in these different inflammatory disorders and infectious diseases, the alterations in plasma lipid and lipoprotein levels are very similar with decreases in plasma HDL-c being consistently observed.Also of note is the consistent increase in lipoprotein (a) levels and small dense LDL-c [12].There is also a tendency for plasma triglyceride levels to be elevated.The greater the severity of the underlying disease the more consistently these abnormalities in lipids are observed.Additionally, treatment of the underlying disease leading to a reduction in inflammation results in a return of the lipid profile towards normal.This is best illustrated in periodontal disease where intensive dental hygiene can reverse the abnormalities in the lipid profile [13,14].Inflammation and infections increase the production of a variety of cytokines, including TNF, IL-1, and IL-6, which have been shown to alter lipid metabolism [2].Many of the changes in plasma lipids and lipoproteins that are seen during chronic inflammation and infections are also observed following the acute administration of cytokines [2].Multiple cytokines increase serum triglyceride and VLDL levels (TNF, IL-1, IL-2, IL-6, etc.) [2].Following a single administration of a cytokine or LPS (a model of gram negative infections), which stimulates cytokine production, an increase in serum triglyceride and VLDL levels can be seen within 2 hours and this effect is sustained for at least 24 hours.The increase in serum triglycerides is due to both an increase in hepatic VLDL synthesis and secretion and a decrease in the clearance of triglyceride rich lipoproteins [2].The increase in VLDL production and secretion is a result of increased hepatic fatty acid synthesis, an increase in adipose tissue lipolysis with the increased transport of fatty acids to the liver, and a decrease in fatty acid oxidation in the liver.Together these changes provide an increased supply of fatty acids in the liver that stimulate an increase in hepatic triglyceride synthesis [2].The increased availability of triglycerides leads to the increased formation and secretion of VLDL.The decrease in the clearance of triglyceride rich lipoproteins is due to a decrease in lipoprotein lipase, the key enzyme that metabolizes triglycerides in the circulation [2].A variety of cytokines have been shown to decrease the synthesis of lipoprotein lipase in adipose and muscle tissue [2].In systemic lupus erythematosus, antibodies to lipoprotein lipase have been reported and are associated with increased triglyceride levels [15,16].

Objective
The objective of this study was to evaluation of lipid profile changes in pediatric patients with urinary tract infections.

Methodology
This case-control study was achieved in pediatric department, of Salahaddin teaching hospital from May 2017 till October 2017.It included 90 children with symptoms suggesting lower urinary tract infection, aged from (4 -14) years, and 40 clinically healthy control with same age.Inclusion criteria were dysuria, frequency, urgency, and abdominal flank pain with or without fever.Children with, underlying liver and renal diseases, malignancy, hypo-or hyperthyroidism, and patients treated with drugs affecting the serum lipid profile, were excluded from this study.Their consent was obtained as ethical approval from the ethical committee of the hospital.Total serum cholesterol was measured by using cholesterol enzymatic Biolabo kit (Maizy, France).Determination serum triglycerides was done by enzymatic colorimetric method using Biolabo kit (Maizy, France).Serum HDL-C concentration was determined by the precipitation method, using HDL-C Biolabo kit (Maizy, France).Serum LDL-c was calculated by using Friedewald equation [17].VLDL was calculated as TG/5.The age, gender and clinical manifestations of each children with lower urinary tract infection, were recorded in a checklist for each patient.According to the guidelines of United States National Cholesterol Education Program (NCEP), total cholesterol level less than 170 mg/dL, between 170-199 mg/dL and more than 200 mg/dL were considered as desirable, at moderate risk, and high risk, respectively [18].Also, LDL cholesterol levels less than 110 mg/dL, between 110-130 mg/dL, and more than 130 mg/dL were considered as desirable, moderate and high risk, respectively.Regarding to the patients' age and gender, a serum triglyceride level less than the 90th percentile was considered in normal range.Thus, in boys and girls aging 1-4 years the triglyceride levels less than 85 mg/dL and 95 mg/dL and in 5 -10 years, less than 70 mg/dL and 103 mg/dL were considered as normal, respectively [19].

Blood samples
Blood samples (2 ml) were drawn from each child by means of vein puncture and transferred to a plain vacutainer tubes for serum cholesterol, serum HDL, serum Triglycerides.

Statistical study
Data analysis was performed using statistical package of social science (SPSS) version 23.0 of windows.Numerical variables were reported in terms of mean and (T-Test) for comparison between categorical variables.The (p <0.05) was considered statistically significant for interpretation of result.

Table (1): Gender frequency and percentage of patients group.
Frequency

Discussion
The result of our study revealed that the female (59 female,65.6%)was more susceptible for urinary tract infection than male (31 male, 34.4%) as showed in table 1.These observation go with Mohammed A.Younis et al, that he was reported that the prevalence of UTI was common in females (64%) than males (36%) with 2:1 ratio (20) .[25].
During inflammation HDL particles tend to be larger with a decrease in cholesterol ester and an increase in free cholesterol, triglycerides, and free fatty acids.Furthermore, there are marked changes in HDL-c associated proteins and the enzymes and transfer proteins involved in HDL-c metabolism and function.
The precise mechanism by which inflammation and infection decrease HDL-c levels is uncertain and is likely to involve multiple mechanisms [2].Also current study shows that levels of TG were significantly (P<0.05)increase in children with UTI (118.03±18.66)compared with control (85.95±10.251).Multiple cytokines increase serum triglyceride and VLDL levels (TNF, IL-1, IL-2, IL-6, etc.).Following a single administration of a cytokine or lipoproteins lipase (a model of gram negative infections), which stimulates cytokine production, an increase in serum triglyceride and VLDL levels can be seen within 2 hours and this effect is sustained for at least 24 hours.The increase in serum triglycerides is due to both an increase in hepatic VLDL production and secretion and a decrease in the clearance of triglyceride rich lipoproteins [2].This is in line with the work of Gordon et al., 2001.Urinary tract infections produce alterations in the functions and compositions of lipoproteins [26].Conclusion: These observation shows that low levels of lipid, particularly total cholesterol, low density lipoprotein (LDL-c), high density lipoprotein (HDLc) and increased triglycerides (TG) probably be associated with urinary tract infections.Hence, the change in lipid profile could probably serve as indicators of urinary tract infection.Recommendations: we recommend that the children with UTI probably need measurement the levels of lipid peroxidation as a reflect of infection.

Table 3
Table 4 show the frequency and percent of healthy control group.The table 4 shows that the age of control group were the same age of patients group.
show that 90 children investigated in the study, urinary tract infection was more prevalence in age 6 years (19 children, 21.1%).

Table 5
show that the mean of serum cholesterol of children with UTI were 144.02± 17.687, while the mean of serum cholesterol of healthy children were 167.65±13.134.Table 5 also show that the cholesterol of children with UTI were significantly decrease P<0.05 compared with control.Table (6): Mean serum LDL-chol mg/dl of patients children and control.

Table 9
also show that VLDL were significantly increase (P<0.05) in children with UTI (23.56) compared with control (17.28).

Table 2
shows that the UTI were more prevalence in children with age 6 (19 children, 21.1%).In girls, the first UTI usually occurs by the age of 5 years old.In boys, most UTIs occur during the 1st year of life;