Jacek Sieradzki

Clinical risk factors and the role of VDR gene polymorphisms in diabetic retinopathy in Polish type 2 diabetes patients.

Evidence exists that some clinical, metabolic and genetic risk factors are associated with the development of diabetic retinopathy (DR). The aim of the study was: (1) to define the prevalence of DR in the examined group of 267 patients with type 2 diabetes mellitus (T2DM) from a Polish population; (2) to identify in crosssectional analysis, the clinical features associated with DR in the study group; and (3) to search for the association of 4 markers of vitamin D receptor (VDR), a candidate gene for vascular complications in diabetes, with DR. The examined group consisted of 146 female and 121 male T2DM patients (mean age at examination: 61.3±9.4 years; age at T2DM diagnosis: 50.0±9.2; T2DM duration: 11.3±7.8 years; body mass index (BMI): 30.5±5.5 kg/m2; HbA1c: 7.8±1.5%). In all patients, the clinical and metabolic profile was determined. Diagnosis of DR was determined by a trained ophthalmologist by ophthalmoscopy after pupillary dilatation. Colour photographic documentation was made. The examined T2DM patients were genotyped for FokI, ApaI, BsmI and TaqI frequent VDR polymorphisms based on the restriction fragment length polymorphism method. The statistical analysis was performed using univariate and multivariate logistic regression (SAS) and haplotype analysis (Haplostat). DR was detected in 85 (31.8%) patients with T2DM. The multivariate analysis revealed that significant predictors of this complication were: never-smoking status (odds ratio 2.2, 95% confidence interval 1.2–4), urea serum level (1.3, 1.1–1.5), HbA1c level (1.4, 1.1–1.8) and insulin treatment (2.7, 1.4–5.1). Other features such as age of T2DM diagnosis, T2DM duration prior to ophthalmic exam, obesity (BMI>30), serum creatinine level, albumin/creatinine ratio and arterial hypertension were univariate predictors of DR, however they lost significance as independent predictors in multivariate analysis. Similarly, the alleles, genotypes, haplotype and haplotype combination of VDR were not associated with the examined complication. However, there was a suggestion of a possible slight association between the fbaT haplotype and DR (p=0.11). In conclusion, our study showed that DR in T2DM patients remains a frequent complication in Polish T2DM patients. We were able to confirm the role of some clinical risk factors, surprisingly including not-smoking status, as was previously shown in the UK Prospective Diabetes Study (UKPDS). VDR gene polymorphisms did not constitute a risk factor for this size of study group.

Vitamin D binding protein gene and genetic susceptibility to type 2 diabetes mellitus in a Polish population.

Polymorphisms of the genes involved in the metabolism of vitamin D may predispose to type 2 diabetes mellitus (T2DM). For example, there is evidence suggesting that vitamin D binding protein (DBP) amino acid variants at codons 416 (aspartic acid-->glutamic acid) and 420 (threonine-->lysine) may affect genetic susceptibility to T2DM. The aims of this study are: (1) to determine the allele, genotype, haplotype and haplotype combination frequencies of those DBP amino acid variants in a Polish population and (2) to examine their role in the genetic susceptibility to T2DM in a Polish population. Overall 393 individuals were included in this study: 231 T2DM patients and 162 controls. The sequence of DBP exon 11, which contains both examined variants, was amplified by polymerase chain reaction (PCR). Alleles and genotypes were determined based on electrophoresis of the DNA digestion products by specific restriction enzymes HaeIII and StyI. Since variants of DBP were in very strong linkage disequilibrium, haplotypes could be assigned to phase-unknown individuals. Differences in distributions between the groups were examined by chi(2) test. At codon 416 the frequency of Asp/Glu alleles was 44.6/55.4% in T2DM patients and 40.7/59.3% in controls (chi(2)=2.1, d.f.=1, P=0.28). At codon 420 the frequency of Thr/Lys alleles were 69.4/30.6% and 71.6/28.4%, (chi(2)=0.41, d.f.=1, P=0.52), respectively. Distribution of genotypes, haplotypes and haplotype combinations were similar in both groups. In conclusion, the frequency of amino acid variants at codons 416 and 420 of vitamin D binding protein gene in a Polish population is similar to other Caucasian populations, but differs significantly from other races. No evidence was found for an association between DBP frequent polymorphisms and T2DM in this population.

Mutations in the ABCC8 (SUR1 subunit of the KATP channel) gene are associated with a variable clinical phenotype

Objectiveu2002 Mutations in the ABCC8 gene encoding the SUR1 subunits of the β‐cell K‐ATP channel cause neonatal diabetes (ND) mellitus. We aimed to determine the contribution of ABCC8 gene to ND in Poland, to describe the clinical phenotype associated with its mutations and to examine potential modifying factors.

Molecular background and clinical characteristics of HNF1A MODY in a Polish population

PURPOSEnKnowing the molecular background of monogenic diabetes in affected individuals influences the clinical practice. Mutations in the HNF1A gene are the most frequent cause of MODY. The aim of the present study was to identify the genetic and clinical characteristics of HNF1A MODY in a Polish population, and the prevalence of diabetic complications and renal malformations.nnnMETHODSnWe identified 47 families with the early-onset, autosomal-dominant form of diabetes that met the criteria of MODY. Mutation screening involved direct sequencing of the HNF1A gene. Patients characteristics included clinical data, anthropometric measurements and biochemical parameters. The search for renal malformations involved ultrasound examination of all HNF1A mutation carriers.nnnRESULTSnWe identified 13 HNF1A MODY families and examined 56 mutation carriers, including 46 diabetic patients. The average HbA(1c) level among the diabetics was 7.5%. We identified diabetic retinopathy in 47.7% of the MODY patients, while diabetic nephropathy was present in 25%. In five HNF1A mutation carriers from three families, renal developmental malformations were identified, including one functioning kidney in two (3.6%) of them.nnnCONCLUSIONnThis first systematic search for HNF1A mutations in a Polish population revealed that they are a frequent cause of MODY. In this population, HNF1A mutation carriers were characterized by a high prevalence of diabetic complications. In addition, renal developmental abnormalities were found in some mutation carriers.

Association study of the Vitamin D: 1alpha-hydroxylase (CYP1alpha) gene and type 2 diabetes mellitus in a Polish population

OBJECTIVESnType 2 diabetes mellitus (T2DM) is a complex disease. Genetic and environmental factors cooperate together to form its clinical picture. Polymorphisms in genes involved in the metabolism of vitamin D may influence susceptibility to T2DM. One of them is the vitamin D 1alpha-hydroxylase (CYP1alpha) gene. In this study we searched for the association of two markers, one in its intron 6 and the another one located upstream from the 5 end of CYP1alpha gene, with T2DM in a Polish population.nnnMETHODSnOverall 522 individuals were included in this study: 291 T2DM patients and 231 controls. The sequences, which contain both examined variants, were amplified by polymerase chain reaction (PCR). The T-->C polymorphism in intron 6 was assessed by the dot-blotting method using P(32). Genotyping of the other variant in the 5 end of CYP1alpha gene was carried out by restriction fragment length polymorphism (RFLP) method. Since variants of both SNPs were in very strong linkage disequilibrium, haplotypes could be assigned to phase-unknown individuals. The distribution of alleles, genotypes, haplotypes and haplotype combinations was compared between the groups by chi(2) test.nnnRESULTSnThe frequency of T/C alleles of the 5end variant was 81.7%/18.3% in T2DM patients and 82.8%/17.2% in the controls (chi(2)=0.2, 1.d.f., p=0.65). For a T-->C polymorphism in intron 6 the frequency of alleles was 65.1%/34.9% and 67.5%/32.5% in T2DM patients and controls, respectively (chi(2)=0.413, 1.d.f., p=0.669). Distribution of genotypes, haplotypes and haplotype combinations were similar in both groups. In stratified analysis, we observed that the T-C/T-T heterozygous haplotype combination was more prevalent in the subgroup of obese T2DM patients (BMI >=30) than in the controls (41.5% vs 28.6%, p=0.01).nnnCONCLUSIONSnVitamin D 1alpha-hydroxylase is not a major gene for T2DM in a Polish population. However, this gene may be associated with T2DM in subjects with obesity. Thus, to definitely determine the role of this gene in T2DM further studies are necessary in other populations using larger sample size.

The Ala45Thr polymorphism of BETA2/NeuroD1 gene and susceptibility to type 2 diabetes mellitus in a Polish population.

Abstract. The BETA2/NeuroD1 gene product is a transcription factor, a member of a helix-loop-helix (HLH) family that is specifically expressed in the endocrine pancreas. HLH and homeobox proteins are involved in the development and function of pancreatic islets cells. Mice homozygous for a targeted disruption of BETA2/NeuroD1 showed abnormal pancreatic islet morphogenesis and developed overt diabetes. Mutations in the NeuroD/BETA2 gene were linked to the development of type 2 diabetes (T2DM). The aims of the study were to determine the allele and genotype frequency of Ala45Thr polymorphism of BETA2/NeuroD1 in a Polish population and to examine the role of this amino acid variant in the genetic susceptibility to T2DM. We included 394 individuals into this study: 223 T2DM patients with the age at diagnosis above 35 years and 171 controls without a family history of T2DM. The fragment of the gene, corresponding to the Ala45Thr amino acid variant, was amplified by polymerase chain reaction. Alleles and genotypes were determined based on electrophoresis of the specific restriction enzyme EcoI57 DNA digestion products. Differences in distribution between the groups were examined by χ2 test. The frequencies of the Ala and Thr alleles in T2DM patients (62% and 37.9%) were similar to those in the controls (65.5% and 34.5%; p=0.32). Similarly, there was no difference between the groups when we analyzed the genotype distribution (p=0.24). The stratification analysis based on family history of T2DM, obesity, and age of diagnosis did not show any difference between the groups. In conclusion, the frequency of Ala45Thr polymorphism in this studied Polish population is similar to its frequency in other Caucasians. We did not find evidence that the Ala45Thr polymorphism of BETA2/NeuroD1 played a role in the risk of T2DM in the examined Polish population.

Diabetic retinopathy in permanent neonatal diabetes due to Kir6.2 gene mutations: the results of a minimum 2‐year follow‐up after the transfer from insulin to sulphonylurea

Permanent neonatal diabetes mellitus (PNDM) is a monogenic form of disease usually diagnosed within the first 6 months of life. Its most common form is associated with KCNJ11 gene mutations. This gene encodes the pore-forming Kir6.2 subunit of the pancreatic B-cell KATP-dependent potassium channel. Most children and adults with Kir6.2 mutations can be successfully transferred from insulin to sulphonylureas (SU) [1]. This transfer usually results in rapid and profound improvement in glycaemic control as measured by glucose and HbA1c. However, there are scant data on the influence of this change in therapy on the occurrence and progression of diabetic complications, e.g. diabetic retinopathy (DR). This could be a concern, particularly as transientprogressionof DRwas previously reported in various patients directly after intensification of glucose-lowering therapy [2,3]. The aim of this study was to assess the long-term effect of the switch from insulin to SU in diabetic patients with Kir6.2 mutations on the occurrence and progression of DR. We examined 11 Kir6.2 mutation carriers who after genetic testing wereswitchedfrominsulin toSUandinwhomthisnewtreatment was continued for at least 2 years (median 34 months, range 27– 51). The subjects underwent ophthalmological examinations at the time when diabetic therapy was changed and at least every 12 months during the follow-up period of a minimum of 2 years. The age of the 11 patients included ranged from 5 to 34 years. The mean HbA1c at baseline was 7.4% (range 6.6–10.2). Based on measurement before the transfer to SU and the first one after transfer (3–6 months), the initial dropinHbA1c was1.2%(range 0.3–3.7%). Excellent glycaemic control was maintained over the follow-up, and the mean HbA1c at the end of the observation was 6.0% (range 5.3–6.7%). Nine subjects were free of DR when SU treatment was started and no evidence of DR was found during follow-up. During the initial examination, one patient, a 21-year-old woman, showed evidence of mild non-proliferative DR. On follow-upevery12 months for the three subsequentyears, noDR progression was observed and there was no indication for laser treatment. However, in one 34-year-old female PNDM patient, a carrier of the R201H mutation, proliferative DR was present at the time when genetic testing was performed. She had undergone four episodes of laser photocoagulation during the 10 years prior to treatment intensification. Fundus eye examination and fluorescein angiography revealed the presence of proliferative DR. In addition, she also had microalbuminuria, moderate peripheral polyneuropathy, cardiovascular autonomic neuropathy and hypertension. This woman was diagnosed with diabetes at the age of 6 weeks and insulin therapy was startedat that time.Herdiabetes controlwasunsatisfactory,with most documented HbA1c measurements around 12.0–13.0%. She was transferred to an intensive insulin regimen (multiple daily injections) just 3 months before PNDM was diagnosed on genetic testing. This intensified insulin therapy resulted in a rapid and profound fall of HbA1c from 13.0 to 7.2%. Following identification of the R201H Kir6.2 mutation, she was, as previously described [4], transferred to glipizide gastrointestinal therapeutic system. Shortly thereafter, this patient became completely insulin independent. Six months later, her HbA1c level dropped further from to 7.2 to 5.9%. Over 28 months’ follow-up, progression of DR was observed with new areas of macular, iridal and optic disc neovascularization. After the switch the patient underwent laser therapy on 17 occasions (Fig. 1). During the most recent 10 months, however, stabilization in eye status was observed and further laser treatment was not required. At the same time, no other chronic complications of diabetes emerged or progressed. Thirty-four months after SU treatment was introduced she required 30 mg of glipizide daily. Glycaemic control was satisfactory (HbA1c 5.9%) and Continuous Glucose Monitoring System revealed normal glucose levels except for some rare episodes of moderate postprandial hyperglycaemia. The clinical characteristics of this patient in whom DR progressed are different from the other individuals. First, she had pre-existing proliferative DR at the switch from insulin to SU. In addition, she was the oldest of our patients and thus diabetes duration in her case was the longest. This patient not only had the highest recorded HbA1c values (> 13.0%), but had been exposed to those high values for many years. She also experienced the greatest initial drop in HbA1c (by 5.8% following intensification of insulin therapy and by another 1.3% following the start of SU), which could put the patient at higher risk of early development ⁄ progression of diabetic complications [2,3]. Finally, unlike the other patients, she had hypertension, a well-established risk factor for the development of DR [5]. In summary, the switch from insulin to SU in PNDM related to Kir6.2 mutations seems not to carry a risk of DR development andprogression in most patients. Nevertheless, subjects withpreexisting advanced DR and initial poor glycaemic control require special ophthalmological attention. DIABETICMedicine Letters

The dual-wave bolus feature in type 1 diabetes adult users of insulin pumps

One of the attributes of CSII (continuous subcutaneous insulin infusion) is its ability to tailor prandial insulin delivery to the composition of a meal and anticipated glycemic effects. The dual-wave bolus (DWB) is a tool implemented in contemporary insulin pumps that delivers a combination of an instant insulin bolus followed by a square bolus (SB) infused over several hours. We assessed the effectiveness of DWB in 56 adult patients with type 1 diabetes (T1DM) who were on continuous subcutaneous insulin infusion via insulin pump for at least 2xa0years. We divided patients into frequent (DWB+, nxa0=xa032) and infrequent (DWB−, nxa0=xa024) DWB users (>20% vs. <20% of daily bolus dose delivered as SB). CSII implementation resulted in a decrease of adjusted HbA1c level by 0.80% (95% CI 0.67–0.93, Pxa0<xa00.0001) and adjusted mean glycemia by 18.4xa0mg/dl (95% CI 15.3–21.4, Pxa0<xa00.0001) in the whole cohort within the first year of observation. It was sustained in the second year, but without further improvement. Frequent DWB use was associated with male sex (59% vs. 17%, pxa0=xa00.001) and shorter duration of T1DM (3.4 vs. 11.3 yrs, pxa0<xa00.0001), but not with patients’ age (25.7 vs. 27.0 years, Pxa0=xa00.6). DWB+ patients improved their HbA1c by 0.45% more (95% CI 0.20–0.71, Pxa0=xa00.0009) than DWB− individuals. In conclusion, DWB might be a tool potentially helping to improve glycemic control in T1DM adult users of insulin pumps. Male patients and those with a shorter duration of diabetes seem to use it more willingly.

Management and treatment goals in Polish patients with type 2 diabetes of more than ten years’ duration — results of ARETAEUS2-Grupa Study

INTRODUCTIONnPrevious studies have shown insufficient diabetes control in patients with type 2 diabetes (T2DM). Diabetes Poland changed the target HbA1c and blood pressure (BP) values in diabetic patients in their practice guidelines in 2011, that were further sustained. To assess the management and treatment choices in T2DM of more than ten years duration and the degree to which diabetic control criteria recommended by the Diabetes Poland clinical practice guidelines 2012 are being met.nnnMATERIAL AND METHODSnARETAEUS2-Grupa was a cross-sectional questionnaire-based study conducted in Poland in 2012 (April-June). It involved 1,740 patients of any age and both genders, with T2DM diagnosed more than ten years before the study, and recruited by randomly selected physicians.nnnRESULTSnAll patients received pharmacological treatment, most of them combination therapy or insulin in monotherapy. 40% of patients met the goal for HbA1c control (≤ 7%) and the median value of HbA1c was above the recommended threshold (7.2%). Only 8% of thetotal population met all three goals (HbA1c, BP and lipid levels), 26% - two goals, and 40% - only one goal. Over 25% of patients did not meet any of the treatment goals.nnnCONCLUSIONSnWe observed considerable deviations from treatment targets recommended by current clinical practice guidelines for patients with T2DM of more than ten years duration. The frequency of cardiovascular risk factors and late diabetes complications was high, while a relatively high percentage of patients was not examined for late diabetes complications.

Pancreatic exocrine insufficiency is not common in HNF-1α MODY

Aimsu2003 Exocrine pancreatic insufficiency has been described in Type 1 and Type 2 diabetes. The hepatocyte nuclear factor (HNF)‐1α gene associated with maturity‐onset diabetes of the young (MODY3) is expressed in several organs, including the exocrine pancreas. The aim of this study was to determine the prevalence of exocrine pancreas dysfunction in HNF‐1α MODY patients.