|Year : 2015 | Volume
| Issue : 3 | Page : 184-187
Relationship between PTEN and gestational diabetes in Asian Indians womens
Imran Ali Khan1, Parveen Jahan2, Qurratulain Hasan3, Pragna Rao4
1 Department of Genetics and Molecular Medicine, Kamineni Hospitals, LB Nagar; Department of Genetics and Biotechnology, Osmania University, Tarnaka; Department of Genetics, Vasavi medical and Research Center, Khairathabad, Hyderabad, India
2 Department of Genetics and Biotechnology, Osmania University, Tarnaka, India
3 Department of Genetics and Molecular Medicine, Kamineni Hospitals, LB Nagar, India
4 Department of Biochemistry, Kasturba Medical College, Manipal University, Manipal, Karnataka, India
|Date of Web Publication||2-Jul-2015|
Dr. Pragna Rao
Department of Biochemistry, Kasturba Medical College, Manipal University, Manipal, Karnataka
Gestational diabetes mellitus (GDM) is defined as glucose intolerance of variable severity with onset of first recognition during pregnancy. GDM occurs in at least 30% of women with a family history of T2DM/GDM, suggesting that some women are genetically predisposed to develop GDM. Phosphatase and tensin homolog (PTEN) on chromosome 10 is a tumor-suppressor gene. Studies have demonstrated that PTEN dysfunction affects the function of insulin. However, the relationship between GDM and PTEN has not been studied. The aim of the present study was to investigate the relationship between PTEN and GDM in Asian Indian women. The case-control study used PCR-RFLP analysis to assess the PTEN−9C/G polymorphism in 150 GDM cases and 150 controls (non-GDM). No alleles or genotypes were detected at statistically significant frequencies. All subjects were normal, and no variants were detected in any of the pregnant women. In conclusion, PTEN has no role in GDM, consistent with previous studies.
Keywords: 9C/G, Asian Indians, gestational diabetes mellitus, phosphatase and tensin homolog
|How to cite this article:|
Khan IA, Jahan P, Hasan Q, Rao P. Relationship between PTEN and gestational diabetes in Asian Indians womens. J Health Spec 2015;3:184-7
|How to cite this URL:|
Khan IA, Jahan P, Hasan Q, Rao P. Relationship between PTEN and gestational diabetes in Asian Indians womens. J Health Spec [serial online] 2015 [cited 2018 Aug 21];3:184-7. Available from: http://www.thejhs.org/text.asp?2015/3/3/184/159910
| Introduction|| |
Gestational diabetes mellitus (GDM) is a disease state in which underlying defects in maternal insulin sensitivity and secretion are unmasked by the metabolic stressors of pregnancy.  GDM is a growing health concern characterized by carbohydrate intolerance of variable severity. It usually presents during the latter half of pregnancy. Risk factors for GDM include obesity, advanced maternal age, a family history of type 2 diabetes mellitus (T2DM), a past history of GDM, previous adverse pregnancy outcomes, and high-risk ethnicity.  Increases in maternal age and the rate of obesity have led to a growing number of GDM cases.  GDM is associated with an increased rate of obstetric and neonatal complications such as preeclampsia, neonatal hypoglycemia, caesarean section and macrosomia.  It is thought that hormones produced during pregnancy reduce a women's receptivity to insulin, leading to high blood sugar levels in almost 10 - 16% of pregnancies. , This is important because GDM is classified as a prediabetic condition with increased maternal and perinatal risk to develop T2DM. , Currently, selective screening strategies for GDM are based on maternal and obstetric history, with recent guidelines advising to screen the subjects based on the risk factor exposures. However, there is no consensus on how best to identify patients with GDM. 
Phosphatase and tensin homolog 10 (PTEN) (also known as mutated in multiple advanced cancers 1 or transforming growth factor-β-regulated and epithelial cell-enriched phosphatase 1) is a tumour suppressor gene located on chromosome 10q23.3.  PTEN contains nine exons and encodes a 403-amino acid protein, which contains a PIP2 binding site, a phosphatase domain, a C2 domain with phosphorylation sites, and a PDZ binding motif (PSD-95, Discs-large, ZO-1) from the N-terminal to C-terminal regions.  PTEN is associated with glucose and lipid metabolism, the association of its single nucleotide polymorphisms with metabolic diseases. Four PTEN polymorphisms have been identified in Caucasian patients with T2DM, but they were not associated with the disease. Three different PTEN variants have been identified in Japanese diabetic patients, and the substitution of C with G at position −9 (−9C → G) in the 5Ͳ-untranslated region of exon 1 is associated with T2DM.  The present study was taken up to investigate the association of PTEN (−9C/G) gene with gestational diabetes women in Asian Indians. Pregnant women from different districts of Telangana and Andhra Pradesh visited the Kamineni and Muslim maternity hospitals in Hyderabad. The disease pattern in the population of pregnant women included in this study is representative of the disease pattern in these regions.
| Materials and methods|| |
Three hundred pregnant women comprising of 150 GDM, and 150 non-GDM (control) were enrolled in this study. The study was approved by the ethical committee of the study hospitals. Qualified physicians screened and managed diabetes during pregnancy in accordance with the American Diabetes Association (ADA) guidelines. The inclusion and exclusion criteria are described in an earlier publications. ,,,
Assortment of gestational diabetes mellitus women
To identify women with GDM, a glucose challenge test (GCT) was administered at the 24th week of gestation. Glucose (50 g) was given after >12 hours of fasting; if the plasma glucose value exceeded 130 mg/dL after 1 h, a standard oral glucose tolerance test (OGTT) protocol was used for the pregnant (or gravid) women. After an overnight fast of 12h, venous plasma samples were collected fasting, and 100-g glucose. The diagnosis of GDM was based on the criteria of the ADA. The OGTT was performed routinely between 24 and 28 weeks of gestation and occasionally at other stages of gestation if clinically warranted. ,,,
Clinical and biochemical measurements
Clinical and anthropometric parameters, including body mass index (BMI), were calculated according to Quetelet's equation by using the weight in kilograms divided by the height in square meters (kg/m 2 ). Three milliliter of the plain serum sample was used to measure the glucose levels of fasting, postprandial, GCT and OGTT in GDM and non-GDM subjects.
DNA and polymerase chain reaction-restriction fragment length polymorphism exploration
Genomic DNA was isolated from the peripheral blood of the pregnant women (n = 300), collected in EDTA tube for the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The DNA samples were stored at −80°C. The genotyping was performed at Department of Genetics and Molecular Medicine (NABL accreditation laboratory), Kamineni Hospitals, Telangana, Hyderabad, India for the rs11202592 polymorphism in the exon 1 region of PTEN gene by PCR-RFLP, followed by agarose gel electrophoresis, using a pair of oligonucleotide primers: (Forward sequence) 5′-CTTCTGCCATCTCTCTCCTC-′3 and (reverse sequence) 5′-ACTACGGACATTTTCGCATC-′3 were used for PCR amplification. The primers were synthesized by Bioserve Biotechnology (Hyderabad, India) for PCR analysis. A three-step PCR was performed using Applied Biosystem thermal cycler (Invitrogen Foster city, United States). DNA was denatured at 95°C for 5 min, then amplified by 35 PCR cycles (95°C for 30 s, 60°C for 30 s, 72°C for 45 s) followed by final extension step at 72°C for 5 min. The reaction volume contained 100 pmol of each primer, 17.75 μL of sterile water, 6.25 μL of master mix (included MgCl 2 , 10x Taq buffer, 10 mM dNTPs and 10 unit of Taq DNA polymerase Bangalore Genie, India) and 1 μl template DNA. The amplified 212 bp PCR product was digested with AvaII restriction enzyme (Fermentas, fast digest) by incubating at 37°C for 5 min, followed by separation of the fragments on 2% agarose gel, [Figure 1].
|Figure 1: Electrophoresis on 2% agarose gel picture of PTEN gene. Lane 1: Polymerase chain reaction (PCR) product of 212 bp. Lane 2: Undigested PCR product CC genotype. Lane 3: Digested PCR product of CC genotype. Lane 4: No product. Lane 5: 100 bp DNA marker|
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Data were represented as mean ± standard deviation. Statistical analysis was carried out using Statistical Package for Social Sciences (SPSS) for Windows, version 19.0 (SPSS, Chicago, IL, USA). Chi-square test was used for comparison of expected and observed frequencies of categorical variables. Relative risk was calculated for the genotypes that showed a significant association with the disease. Values of P (two-tailed) < 0.05 were considered as statistically significant.
| Results and discussion|| |
The study included 150 women with GDM and 150 women without GDM. All pregnant women were from regions of South India (Telangana and Andhra Pradesh). The clinical characteristics of women with and without GDM are shown in [Table 1]. Of the GDM cases, 60% had a family history. Women with GDM had significantly higher levels of fasting blood glucose and postprandial blood glucose when GDM cases and controls were compared (P < 0.001). The genotypic distribution of PTEN−9C/G and the frequency of the C and G alleles in subjects with and without GDM are shown in [Table 2]. There was no statistically significant difference between cases and controls in the allele frequencies or in the genotypic distribution.
|Table 1: Clinical details of GDM and non-GDM women contributed in this study |
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|Table 2: Genotype and allele frequency of PTEN gene polymorphisms in GDM |
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This case-control study was carried out in Asian Indian women who developed diabetes during pregnancy. PTEN mutations in women with GDM (n = 150) were assessed with PCR-RFLP analysis. To our knowledge, this is the first study to assess the relationship between PTEN and GDM. The study demonstrated that the PTEN (-9C/G) polymorphism was not associated with GDM. A previous Japanese study with a different study design (case-control study) and smaller sample size (107 patients with T2DM and 100 control subjects) concluded that the PTEN−9C/G polymorphism was associated with T2DM because the allele frequency and the odds ratio for the frequency of the mutant genotype were significantly higher in the diabetic group than in the control group.  A study of the same polymorphism in a Chinese population with metabolic syndrome (530 cases and 202 controls) failed to find an association.  Our study is in agreement with the results of the latter study. In our population, T2DM was not associated with the PTEN −9C/G polymorphism (unpublished data).
The PTEN−9C/G polymorphism might increase PTEN expression. PTEN antagonizes PI3K, inhibits the PI3K/PI(3,5)P3/Akt pathway, and decreases insulin sensitivity. The PI3K/PI(3,5)P3/Akt pathway is crucial for the action of insulin in regulating feeding and energy homeostasis in the hypothalamus.  Inhibition of the PI3-kinase pathway as a result of enhanced PTEN lipid phosphatase activity results in increased food intake and a positive energy balance, leading to obesity in rats.  Further studies investigating the mechanism of correlation between GDM and the PTEN-9C/G polymorphism are necessary to fully elucidate this.
In this study, only the G allele and GG genotype were detected; the CG and GG genotypes were not detected in GDM cases or non-GDM subjects. Because mutations in PTEN were not detected, we could not compare genotypes with the clinical characteristics. Pregnancy BMI is a risk factor for GDM in women from Korea and Saudi Arabia. , Pregnancy is characterized by progressive insulin resistance. GDM develops in only a small proportion of pregnant women. The insulin resistance that develops during pregnancy might result from a combination of increased maternal adiposity and the insulin-desensitizing effects of placental products such as human placental lactogen, estrogen, and prolactin. Normally, an increase in insulin secretion by pancreatic islet β-cells compensates for the increase in insulin resistance during pregnancy. Consequently, the changes in circulating glucose levels throughout pregnancy are quite small, relative to the large changes in insulin sensitivity. GDM could develop when increased insulin resistance during pregnancy unmasks a genetic predisposition towards pancreatic β-cell impairment. 
| Conclusion|| |
Our aim was to identify a significant association with PTEN and GDM. From the results, we conclude that PTEN has no role in the pathogenesis and progression of the disease and that PTEN was not associated with GDM in Asian Indian population. To assess the PTEN -9C/G polymorphism in different ethnicities, additional studies with a large sample size are recommended.
| Acknowledgments|| |
The author would like to thank Kamineni Hospitals and Muslim Maternity Hospitals for helping with the samples. The author would like to thank ICMR for funding toward this research (No: 5-3-8-39-2007; RHN).
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[Table 1], [Table 2]