الفهرس 
Aim of the WorkOnly 14 pages are availabe for public view
 |  | from | 137 |  |  |
| | | from | 137 | | |
Abstract
Summary
100
Summary
Diabetes Mellitus is a chronic, metabolic disease characterized by elevated levels of blood glucose.
Over 90 % of DM cases are T2DM and are primarily caused by a combination of impaired insulin secretion by pancreatic β-cells and insufficient insulin action (insulin resistance).
Long-term chronic insulin resistance in T2DM leads to several consequences, including macro vascular complications such as atherosclerosis, as well as micro vascular complications such as nephropathy, neuropathy, and retinopathy.
The mechanism underlying DMC is extremely complex and not fully understood.
Several hypotheses have then been proposed to explain the process of developing microvascular complications. These include; generation of reactive oxygen species and oxidative stress, stimulation of polyol pathway, production of advanced glycation end products, initiation of flux through the hexosamine pathway, altered expression and action of growth factors as VEGF and triggering of PKC.
VEGF is a heparin-binding, homo-dimeric glycoprotein which modulates angiogenesis and vascular permeability under physiologic and pathologic conditions. VEGF plays a key role in the pathogenesis of diabetes and its complications, particularly those linked with poor vascularization and hypoxia.
The VEGFA gene encoding VEGF is located on chromosome 6 at cytogenetic band 6p21.3, consisting of seven introns and eight exons with a full molecular length of 14 kb.
VEGFA gene is highly polymorphic, with different near-gene variants at varied frequencies and some of which are linked with altered VEGF protein expression, T2DM susceptibility and associated complications, in particular microvascular complications.
The aim of this work was to evaluate the association of VEGF serum level with its genetic variants VEGFA (rs3025020 and rs3025039) and micro-vascular complications in type-2 diabetic patients.
This case control study included one hundred and thirty diabetic patients recruited from the Internal Medicine Outpatient Clinics, Inpatient Departments, and Dialysis Unit of Menoufia University Hospitals in addition to 26 apparently healthy individuals, age and gender matched with patients groups.
The one hundred and thirty diabetic patients were classified into 5 groups:
Diabetic kidney disease group: this group included 26 T2DM patients with diabetic nephropathy.
Diabetic neuropathy group: this group included 26 T2DM patients with diabetic neuropathy.
Diabetic retinopathy group: this group included 26 T2DM patients with diabetic retinopathy.
T2DM with mixed complications group: this group included 26 T2DM patients with mixed complications.
Summary
101
T2DM without complications group: this group included 26 T2DM patients without complications.
Five milliliters venous blood were withdrawn by venipuncture from all subjects and divided as follow: Three milliliters were collected in a plain vaccutainer, left for 10 minutes to clot and centrifuged at 3000 rpm for 10 minutes to separate the serum which was then used for VEGFA level assay and biochemical laboratory investigations; Two milliliters were collected in sterile vaccutainer containing ethylene diamine tetra acetate (EDTA), then aliquoted in two eppendorfs for Hb A1C assay and VEGFA genotyping. Random urine sample for urinary albumin/creatinine ratio assay.
All patients were subjected to the followings:
1. Detailed history taking: including duration of the disease and its age of onset.
2. Clinical examination: including neurological examination and fundus examination.
3. Laboratory investigations including: Fasting blood glucose (FBG).
Kidney function tests: Blood urea nitrogen (BUN), creatinine, uric acid and estimated glomerular filtration rate (eGFR) was calculated according to the Modification of Diet in Renal Disease (MDRD) formula.
Lipid profile: Triglycerides (TGs), Total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C). Urinary albumin/creatinine ratio.
Glycated Hemoglobin (Hb A1C).
Quantitative estimation of serum VEGF level by ELISA technique.
Analysis of SNPs rs3025020 and rs3025039 in the VEGFA gene by real time polymerase chain reaction (PCR) technique.
The study revealed that:
The studied groups were age and gender matched (statistical non-significant P value > 0.05).
There was a statistical significant difference between studied groups regarding age of onset and duration of T2DM.
FBG and HbA1c were higher in the whole diabetic patient groups than in controls.
There were statistical significant differences between the studied groups as regard different lipid profile parameters.
Albumin/creatinine ratio, creatinine, BUN and uric acid were significantly increased and eGFR was significantly decreased in DKD and mixed complications groups than in control group.
There was statistical significant difference between studied groups as regard VEGF serum level.
Regarding VEGF rs3025020 genotypes and alleles distribution among the studied groups in the current study; TT genotype had a significant high frequency in DN and
Summary
102
DR groups while its T allele had a significant high frequency in DN, DR and mixed complications groups compared to control group.
Regarding VEGF rs3025039 genotypes and alleles distribution among the studied groups, CT and TT genotypes and its T allele had a significant high frequency in DKD and mixed complications groups compared to both DM without complications and control groups.
Both VEGF rs3025020 and rs3025039 were not considered a genetic risk factor for the occurrence of DM.
VEGF rs3025039 was considered a genetic risk factor for the occurrence of DKD.
VEGF rs3025020 was considered a genetic risk factor for the occurrence of DN and DR.
VEGF rs3025039 and VEGF rs3025020 T allele were considered a genetic risk factor for the occurrence of mixed diabetic complications.
ROC curve analysis of VEGF serum level for detection of diabetic complications revealed maximal statistical significance in DKD detection. So, VEGF had a significant role for DKD detection.
Patients with DKD carrying CC and CT genotypes of VEGF rs3025020 and CT genotype of VEGF rs3025039, and diabetic neuropathy carrying CT genotype of VEGF rs3025039 had significant lower serum VEGF levels than DM without complications patients.
The carriage of minor alleles of VEGF rs3025039 was negatively correlated with albumin/creatinine ratio in uncomplicated DM group and was positively correlated with serum VEGF and serum triglycerides in the diabetic retinopathy group and with serum triglycerides in the diabetic neuropathy group. While carriage of minor alleles of VEGF rs3025020 was negatively correlated with serum VEGF in the diabetic kidney disease group and with age in mixed complications group.