Association of Helicobacter pylori specific IgG antibody with serum magnesium levels in peritoneal dialysis patients

Introduction Helicobacter pylori infection is a major worldwide health issue, more than half of the world’s population are affected by H. pylori (1). H. pylori is the most common chronic bacterial infection of human gastrointestinal tract (2). It has been associated with various gastric and extra-gastric disorders. H. pylori infection is an important cause of gastritis, peptic ulcer and gastric cancers (3,4). H. pylori is also associated with various extra-gastric disorders such as iron deficiency anemia, idiopathic thrombocytopenic purpura (ITP) and also colonic, cardiovascular, hepatobiliary and pancreatic diseases (5,6). Hemodialysis and chronic renal failure (CRF) patients often complain of various gastrointestinal complications such as nausea, dyspepsia, appetite loss, epigastric discomfort, peptic ulcers and gastrointestinal bleeding. These symptoms decrease the quality of life. Additionally, gastrointestinal complications may alter patients’ nutrition status, effecting the morbidity and mortality rate (7). Around two million people (prevalence: 296 per million Amirhesam Alirezaei1, Shahryar Movassagh Koolankuh2, Ramin Talaie3, Saeed Azmoodeh1, Mahmood Bakhtiyari4,5*


Introduction
Helicobacter pylori infection is a major worldwide health issue, more than half of the world's population are affected by H. pylori (1).H. pylori is the most common chronic bacterial infection of human gastrointestinal tract (2).It has been associated with various gastric and extra-gastric disorders.H. pylori infection is an important cause of gastritis, peptic ulcer and gastric cancers (3,4).H. pylori is also associated with various extra-gastric disorders such as iron deficiency anemia, idiopathic thrombocytopenic purpura (ITP) and also colonic, cardiovascular, hepatobiliary and pancreatic diseases (5,6).Hemodialysis and chronic renal failure (CRF) patients often complain of various gastrointestinal complications such as nausea, dyspepsia, appetite loss, epigastric discomfort, peptic ulcers and gastrointestinal bleeding.These symptoms decrease the quality of life.Additionally, gastrointestinal complications may alter patients' nutrition status, effecting the morbidity and mortality rate (7).Around two million people (prevalence: 296 per million people) receive dialysis worldwide (8) and the proportion of the patients increase 7% annually (9).The prevalence of H. pylori infection in end-stage renal disease (ESRD) and dialysis patients have found conflicting results.The prevalence of H. pylori infection in CRF patients has been reported as high as 64% and significantly higher in dialysis patients compared to normal controls (10).However, other studies do not support the association of H. pylori infection with chronic kidney disease (CKD) or dialysis.Some studies have hypothesized a protective effect of long-term treatment with dialysis on infection by H. pylori (7,11).Helicobacter pylori is a gram-negative bacterium which can persistently colonize the human stomach.For successful colonization, the pathogenic bacteria sense subtle changes in their environment such as the low pH characteristic of the gastric niche, alterations in nutrient availability including divalent cations, fluctuations in osmolality, and the presence of the human immune system and rapidly respond with alterations in their transcriptional profile (12,13).Magnesium (Mg) is the fourth most abundant cation in human body.Mg is predominantly intracellular and about 1% of body Mg 2+ presents in the extracellular fluid.The normal serum level of Mg is usually in the range of 1.7-2.2mg/dL.Mg metabolism and excretion (which are predominantly renal) are impaired in kidney failure and dialysis patients.When glomerular filtration rate falls below 30 mL/min, Mg excretion decreases and serum Mg level increases subsequently (14).Parathyroid hormone (PTH) and vitamin D affect intestinal Mg absorption, and also its bone and renal re-absorption.Mg is an essential cofactor for several enzymes in human body and also an essential element for pathogens such as Helicobacter.Some recent studies have shown an association between H. pylori infection and serum Mg level in ESRD patients (15).

Objectives
In this study we have assessed the association between serum Mg level and H. pylori infection in ESRD patients receiving peritoneal dialysis.

Study population
This cross-sectional study was conducted on a group of ESRD patients undergoing peritoneal dialysis referred to Shafa peritoneal dialysis center.Patients on peritoneal dialysis for at least 6 months were enrolled in the study.Patients receiving antibiotics for H. pylori treatment, antacids, proton pump inhibitors and nonsteroidal antiinflammatory drugs (NSAIDs) during the past 2 months were excluded from the study.The results of examination drug administration and medical history of patients was recorded.Biochemical analysis was assessed including Mg, Ca, P, albumin, PTH, 25-hydroxyvitamin D [25(OH)D], serum urea and creatinine (Cr).Serum H. pylori specific IgG antibody was measured using ELISA method.A titer ≥5 U/mL was interpreted as positive according to the manufacturer's instructions.

Ethical issues
1) The research followed the tenets of the Declaration of Helsinki and its later amendments; 2) informed consent was obtained; and 3) This study was approved by the Ethics Committee of Shahid Beheshti University of Medical sciences.

Statistical analysis
Statistical analysis was performed by SPSS software (version 22); results were given as mean ± standard deviation (SD).Comparison between groups were evaluated by the independent sample t test and Mann-Whitney U test.Statistical significance was considered as P value of less than 0.05.

Results
In this cross-sectional study 40 peritoneal dialysis patients were included (18 male, 22 female).Patients' ages ranged between 16-80 years with the mean (SD) of 53.3 ± 14.5 years (Table 1).Serum H. pylori specific IgG antibody was positive in 18 patients (45%).Serum Mg level was in the range of 2.3 to 4.1 mg/dL with the mean (SD) of 3.00 ±0.36 mg/dL.The mean (SD) Mg level in H. pylori positive   (PKC), through the bacterial synthesis of the fatty acid MOA (21).Mg is also essential for eukaryotic cells.It is vital for numerous physiological functions.Particular Mg concentrations can modulate signaling processes and acid secretion function in parietal gastric cells (presumably by influencing the cellular calcium homeostasis) (22).

Conclusion
In the current study no association of serum Mg levels with H. pylori infection was detected.Serum Mg level reflects the circulating level of Mg 2+ and it is a poor indicator of the intracellular Mg availability (23,24).It is possible that Mg exchange rate between serum and cellular compartments does not allow reaching the steady state in a short period (21).Hence, more studies are recommended to assess the effect of serum Mg on H. pylori infection in renal failure patients receiving dialysis in order to offer a hypothesis for H. pylori eradication.

Figure 1 .
Figure 1.No significant correlation was found between serum H. pylori IgG and serum magnesium level.

Table 1 .
Demographic and biochemical data of patients

Table 2 .
Demographic and biochemical data of patients infected with Helicobacter pylori and patients negative for Helicobacter pylori