H. pylori have been associated with coronary heart disease . Hyperhomocysteinemia secondary to folate and B12 deficiency might be the link between H. pylori infection and coronary heart disease. Reduced folate and B12 absorption can occur in an environment of increased gastric juice pH. This would result in a reduced folate status leading to decreased activity of methionine synthase and increased serum concentration of homocysteine. Homocysteine is toxic to endothelial cells and a risk factor for atherosclerosis . Since 199cuatro, several studies have been published on B12 and folate levels in H. pylori infected patients with conflicting results [6, 12, 13]. A review based upon more than two dozen studies dealing with H. pylori infection and vitamin B12 status and H. pylori infection and hyperhomocysteinemia or both citas universidad failed to show any clear relationship among H. pylori infection, B12 deficiency and hyperhomocysteinemia . Hence the objective of this study was to investigate the relationship between folate, vitamin B12 and homocysteine levels and the impact of H. pylori infection on this relationship in patients with FD.
One hundred and thirty-two consecutive adult males and non-pregnant females with symptoms of dyspepsia who were undergoing gastroscopy were enrolled in the study at the Aga Khan University Hospital (AKUH) from . Prior written informed consent was obtained from all the study patients. FD was defined as the presence of one or more symptoms of epigastric pain, postprandial bloating, epigastric burning and/or early satiety that are considered to originate from the gastroduodenal region in the absence of any organic, systemic or metabolic disease. Before inclusion in the study, patients were screened for thyroid dysfunction (by determining the serum levels of triiodothyronine, thyroxine and thyroid stimulating hormone), gall bladder disease (by ultrasound), diabetes mellitus (by determining fasting serum levels of glucose) and hepatitis B and C (by determination of serum antibodies). Moreover, patients currently using proton pump inhibitors, strict vegetarians, alcoholics, and other comorbids like chronic liver disease, chronic renal failure, and mal-absorption syndrome were excluded from the study. Patients with a recent history of H. pylori eradication therapy (during a period of six months prior to the study) were also excluded. Pregnant females were excluded due to their physiological state and contraindication of the urea breath test. Patients with a history of folic acid and B12 supplementations during the six months prior to the study were also excluded. A total number of 14 patients were excluded on the basis of above mentioned criteria. In the study, we did not include healthy Pakistani adults (as a negative control group) because 3 studies on healthy adults in Karachi over the past few years provided us with sufficient evidence about the prevalence estimates of vitamin B12 deficiency, folate deficiency and hyperhomocysteinemia [7–9]. The study was approved by the Ethics Review Committee of the Aga Khan University.
Prior to the gastroscopy, a fasting venous sample of 5 mL of blood was taken to check serum B12 and folate and homocysteine levels. Serum samples were analyzed for folate and vitamin B12 using radio-assays [15, 16].
Vitamin B12 (cobalamin) in serum sample was extracted by using one volume of serum, one volume of 0.06 M citrate-phosphate buffer, pH 2.6 and one volume of KCN (100 ?g/mL) in a bath of boiling water for 30 min. After centrifugation, the clear supernatant solution was neutralized with 0.2 M Na2HPO4, pH 9.0.
In this competitive ligand binding assay, [ 57 Co]cyanocobalamin [MP Biomedicals, LLC, USA] was used as the radiolabelled ligand and chicken serum as a binder of vitamin B12 in a dilution which approximately binds 50% of the radiolabelled cyanocobalamin. 2.5% hemoglobin-coated charcoal was used to in B12 (labelled as well as unlabelled) from the vitamin bound to the binder.