Importance of maternal history of non-insulin dependent diabetic patients

Unmasking the silent epidemic: a comprehensive systematic review and meta-analysis of undiagnosed diabetes in Ethiopian adults

Background

Undiagnosed diabetes mellitus poses a significant global public health concern, exerting a substantial impact on the well-being of individuals, their families, and societies at large. Those individuals with undiagnosed diabetes miss opportunities to maintain quality of life and prevent diabetes-related complications. Even if there are ample primary studies on undiagnosed diabetes in Ethiopia, the results reveal conflicting results. Therefore, a comprehensive national picture of undiagnosed diabetes is essential for designing effective strategies at the national level.

Methods

This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for prevalence studies (PROSPERO ID: CRD42021266676). PubMed, Web of Science and the World Health Organization's Hinari portal were searched using a strategy developed in collaboration with Liberians. The inclusion criteria comprised studies reporting undiagnosed diabetes in Ethiopia. Two independent reviewers conducted a quality assessment using a 10-item appraisal tool. Meta-analysis and meta-regression were performed using a random-effects model.

Result

Twenty-five studies with 22,193 participants met the inclusion criteria. The pooled prevalence of undiagnosed diabetes among the Ethiopian adult population was 5.68% (95% CI: 4.53 - 6.83, I2 = 75.4). Factors significantly associated with undiagnosed diabetes include age, waist circumference, overweight, family history of diabetes, and a history of hypertension.

Conclusion

Our systematic review found a noteworthy prevalence of undiagnosed diabetes in Ethiopia. The majority of factors linked with undiagnosed diabetes in this review were modifiable. This underscores the importance of targeted factors and public health interventions to improve early detection and reduce the burden of undiagnosed diabetes and its complications in Ethiopia.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42021266676.

Mitochondrial ATP6 and ND3 genes are associated with type 2 diabetic peripheral neuropathy

BACKGROUND AND AIMS

The association of mitochondrial NADH dehydrogenase gene mutations with type 2 diabetes in the Karaikudi population was previously reported. This is a case report that demonstrated rare mutations are responsible for maternally inherited peripheral neuropathy of diabetes.

METHODS

We describe a 70-year-old male and his family (n = 25) with type 2 diabetic peripheral neuropathy having four rare mutations, 8597T > C, 8699T > C, 8966T > C, 10188A > G, and 9 bp deletion in various regions of the mitochondrial genes. Mutations were identified through direct sequencing of DNA isolated from the blood of the selected individuals. Blood samples were also analyzed for glucose, hemoglobin A1c, triglyceride, total cholesterol, oxidative stress markers, antioxidant status, cytochrome-C-oxidase and mitochondrial DNA content using appropriate methods.

RESULTS

Oxidative stress markers were found elevated while the antioxidant status, mitochondrial DNA content and the activity of cytochrome C-oxidase was reduced significantly. Analysis of mtDNA showed the presence of several mutations in various regions of mitochondrial genome. However, 8597T > C, 8699T > C, 8966T > C, 10188A > G, and 9 bp deletion were observed in the patient's family including his siblings.

CONCLUSION

This study shows that the mutations observed in the patient and his family is maternally inherited and suspected to be pathogenic in developing T2D associated peripheral neuropathy.

Heritability and Genetics of Type 2 Diabetes Mellitus in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

OBJECTIVES

Sub-Saharan Africa (SSA) is observing an accelerating prevalence rate of type 2 diabetes mellitus (T2DM) influenced by gene-environment interaction of modifiable and nonmodifiable factors. We conducted a systematic review and meta-analysis on the heritability and genetic risk of T2DM in SSA.

METHODS

We reviewed all published articles on T2DM in SSA between January 2000 and December 2019 and available in PubMed, Scopus, and Web of Science. Studies that reported on the genetics and/or heritability of T2DM or indicators of glycaemia were included. Data extracted included the study design, records of family history, pattern and characteristics of inheritance, genetic determinants, and effects estimates.

RESULTS

The pattern and characteristics of T2DM heritability in SSA are preference for maternal aggregation, higher among first degree compared to second-degree relatives; early age-onset (<50 years), and inherited abnormalities of beta-cell function/mass. The overall prevalence of T2DM was 28.2% for the population with a positive family history (PFH) and 11.2% for the population with negative family history (NFH). The pooled odds ratio of the impact of PFH on T2DM was 3.29 (95% CI: 2.40-4.52). Overall, 28 polymorphisms in 17 genes have been investigated in relation with T2DM in SSA. Almost all studies used the candidate gene approach with most (45.8%) of genetic studies published between 2011 and 2015. Polymorphisms in ABCC8, Haptoglobin, KCNJ11, ACDC, ENPP1, TNF-α, and TCF7L2 were found to be associated with T2DM, with overlapping effect on specific cardiometabolic traits. Genome-wide studies identified ancestry-specific signals (AGMO-rs73284431, VT11A-rs17746147, and ZRANB3) and TCF7L2-rs7903146 as the only transferable genetic risk variants to SSA population. TCF7L2-rs7903146 polymorphism was investigated in multiple studies with consistent effects and low-moderate statistical heterogeneity. Effect sizes were modestly strong [odds ratio = 6.17 (95% CI: 2.03-18.81), codominant model; 2.27 (95% CI: 1.50-3.44), additive model; 1.75 (95% CI: 1.18-2.59), recessive model]. Current evidence on the heritability and genetic markers of T2DM in SSA populations is limited and largely insufficient to reliably inform the genetic architecture of T2DM across SSA regions.

Maternal vs paternal diabetes: The parental history is different in younger onset versus older onset type 2 diabetes

BACKGROUND

A number of previous studies exploring family history of type 2 diabetes have reported a predominance of maternal diabetes. These studies have not explicitly compared parental history of diabetes across the spectrum of disease onset from youth to later adulthood.

METHODS

Family history data from 11,467 patients with type 2 diabetes were extracted from the RPA Diabetes Centre database. Parental histories of diabetes were compared across a range of age of diagnosis strata (15-<30, 30-<40, 40-<50, 50-<60 and 60-<70 years). For the young-onset group (diagnosed between 15 and 30 years of age), associations between parental history of diabetes and the presence of cardio-metabolic risk factors and diabetic complications were also explored.

RESULTS

For the total cohort and within each age of diagnosis strata, more individuals reported maternal history than paternal history of diabetes. The young-onset group demonstrated the highest prevalence of any parental history of diabetes (60.7%), the highest combined maternal and paternal history (15.8%) and the smallest differential between maternal (25.1%) and paternal (19.7%) history of diabetes. Within the young-onset group, no significant association between parental history and cardio-metabolic risk factors or diabetic complications were identified after a median of 15.0 years of diabetes exposure.

CONCLUSION

Overall, our results demonstrate a consistent maternal excess of diabetes which could be consistent with an underlying epigenetic effect. However, the differential between maternal and paternal history is significantly lower in the young-onset group. Earlier emergence of type 2 diabetes may therefore reflect a different interaction and impact of genetic and environmental factors.

Gestational Diabetes Mellitus: Mechanisms, Treatment, and Complications

Gestational diabetes mellitus (GDM) is the most common metabolic disturbance during pregnancy. The prevalence is rising and correlates with the increase in maternal obesity over recent decades. The etiology of GDM is complex, with genetic and environmental factors implicated in mechanistic and epidemiological studies. GDM begets important short- and long-term health risks for the mother, developing fetus, and offspring. This includes the high likelihood of subsequent maternal type 2 diabetes (T2DM), and possible adverse cardiometabolic phenotypes in the offspring. The most clinically and cost-effective methods of screening for GDM remain uncertain. Whilst treatments with lifestyle and pharmacological interventions have demonstrated short-term benefits, the long-term impact for the offspring of intrauterine exposure to antidiabetic medication remains unclear.

Prion-Like Protein Aggregates and Type 2 Diabetes

Type 2 diabetes (T2D) is a highly prevalent metabolic disease characterized by chronic insulin resistance and β-cell dysfunction and loss, leading to impaired insulin release and hyperglycemia. Although the mechanism responsible for β-cell dysfunction and death is not completely understood, recent findings suggest that the accumulation of misfolded aggregates of the islet amyloid polypeptide (IAPP) in the islets of Langerhans may play an important role in pancreatic damage. Misfolding and aggregation of diverse proteins and their accumulation as amyloid in different organs is the hallmark feature in a group of chronic, degenerative diseases termed protein misfolding disorders (PMDs). PMDs include highly prevalent human illnesses such as Alzheimer's and Parkinson's disease, as well as more than 25 rarer disorders. Among them, prion diseases are unique because the pathology can be transmitted by a proteinaceous infectious agent, termed a prion, which induces disease by propagating protein misfolding and aggregation. This phenomenon has a striking resemblance to the process of protein misfolding and aggregation in all of the PMDs, suggesting that misfolded aggregates have an intrinsic potential to be transmissible. Indeed, recent studies have shown that the pathological hallmarks of various PMDs can be induced in vivo under experimental conditions by inoculating tissue extracts containing protein aggregates into animal models. In this review, we describe our current understanding of the molecular mechanism underlying the prion-like transmission of protein aggregates and its possible role in T2D.

Early beta-cell dysfunction characterizes males with type 2 diabetes of Yemenite origin

AIMS

The aim of the current study was to characterize β-cell function, insulin sensitivity and line of inheritance in patients with recent-onset type 2 diabetes of Yemenite and non-Yemenite Jewish origin.

METHODS

A cohort study including 121 GAD negative diabetic patients, 59 of Yemenite and 62 of non-Yemenite origin, treated by diet ± oral antihyperglycemic monotherapy who underwent 180-min meal tolerance test (MMT). Based on MMT, indexes of insulin resistance and secretion were calculated.

RESULTS

There were no significant differences in age, sex, diabetes duration, BMI, HbA1c and lipid profile. A significant difference was found in family history of diabetes: 63 % of patients of Yemenite origin had maternal inheritance versus 35 % in the non-Yemenite origin (p < 0.001). Both indexes of β-cell function, the insulinogenic and the disposition indexes were significantly lower in patients of Yemenite origin compared with non-Yemenite origin (0.66 ± 0.4 vs. 0.93 ± 0.8, p = 0.04; 2.3 ± 1.8 vs. 3.3 ± 3.3, p = 0.04, respectively) with no difference in insulin sensitivity. When females and males were analyzed separately, the difference in maternal inheritance remained significant in both, but the difference in β-cell function indexes was observed only in males (p = 0.03, p = 0.01, respectively).

CONCLUSIONS

Males with recent-onset diabetes of Yemenite origin have a significant reduction of β-cell function and reduced ability to compensate for insulin resistance compared with diabetic males of non-Yemenite origin. Both males and females of Yemenite origin have a significantly higher maternal inheritance of diabetes. These data suggest different underlying mechanisms leading to early loss of β-cell in diabetic males of Yemenite origin.

The influence of family history of diabetes on disease prevalence and associated metabolic risk factors among Sri Lankan adults

AIMS

To describe the influence of family history on diabetes prevalence and associated metabolic risk factors in a nationally representative sample from Sri Lanka.

METHODS

A cross sectional national survey was conducted among 5000 adults in Sri Lanka. Family history was evaluated at three levels: (1) parents, (2) grandparents (paternal and maternal) and (3) siblings. A binary-logistic regression analysis controlling for confounders (age, gender, BMI and physical activity) was performed in all patients with 'presence of diabetes' as the dichotomous dependent variable and using family history in father, mother, maternal grandmother/grandfather, paternal grandmother/grandfather, siblings and children as binary independent variables.

RESULTS

The sample size was 4485, mean age was 46.1 ± 15.1 years and 39.5% were males. In all adults, the prevalence of diabetes was significantly higher in patients with a family history (23.0%) than those without (8.2%) (P < 0.001). When family history was present in both parents, the prevalence of diabetes was 32.9%. Presence of a family history significantly increased the risk of diabetes [odds ratio (OR): 3.35, 95% confidence interval (CI): 2.78-4.03], obesity (OR: 2.45, 95% CI: 1.99-2.99), hypertension (OR: 1.25, 95% CI: 1.08-1.45) and metabolic syndrome (OR: 2.28, 95% CI: 1.97-2.63). In all adults, the presence of a family history of diabetes in a father (OR: 1.29, 95% CI: 1.02-1.63), mother (OR: 1.23, 95% CI: 1.11-1.36), paternal grandfather (OR: 1.27, 95% CI: 1.14-1.41), siblings (OR: 4.18, 95% CI: 3.34-5.22) and children (OR: 5.47, 95% CI: 2.93-10.19) was associated with a significantly increased risk of developing diabetes.

CONCLUSIONS

Family history and diabetes had a graded association in the Sri Lankan population, because the prevalence increased with the increasing number of generations affected. Family history of diabetes was also associated with the prevalence of obesity, metabolic syndrome and hypertension. Individuals with a family history of diabetes form an easily identifiable group who may benefit from targeted interventions.

Maternal history of diabetes is associated with increased cardiometabolic risk in Chinese

OBJECTIVE

Positive family history is associated with increased type 2 diabetes (T2D) risk, and reflects both genetic and environmental risks. Several studies have suggested an excess maternal transmission of T2D, although the underlying mechanism is unknown. We aimed to examine the association between maternal diabetes and cardiometabolic risk in the offspring.

METHODS

Parental history of diabetes and clinical data including anthropometric traits, fasting plasma glucose and insulin (FPG, FPI), blood pressure and lipid profile were collected from 2581 unrelated Chinese offspring (2026 adolescents from a population-based school survey and 555 adults from a community-based health screening programme). A subset of subjects (n=834) underwent oral glucose tolerance test to measure the glucose and insulin concentrations at 0, 15, 30, 60 and 120 min for evaluation of the areas under the curve (AUC) of glucose and insulin at 0-120 min, homoeostasis model assessment of insulin resistance (HOMA-IR) and bell-cell function, insulinogenic index, insulin sensitivity index (ISI) and oral disposition index (DI).

RESULTS

A positive parental history of diabetes was associated with increased risk of obesity (odd ratios (OR) (95% confidence interval (CI))=1.48 (1.10-2.00)), central obesity (OR (95% CI)=1.67 (1.21-2.32)), higher FPI, HOMA-IR, 2-h insulin, AUC of glucose at 0-120 min, triglycerides, reduced ISI and DI. Compared with individuals without parental diabetes, offspring with diabetic mother had significantly increased risk of obesity (OR (95% CI)=1.59 (1.07-2.35)), central obesity (OR (95% CI)=1.88 (1.23-2.88)), higher glucose levels and BP, were more insulin resistant but also had impaired first-phase insulin response and worse lipid profile. However, paternal history of diabetes had no effect on any of the studied traits, except higher body mass index, waist circumference in females and FPG.

CONCLUSIONS

Our findings suggested that maternal history of diabetes conferred increased risk of cardiometabolic abnormalities, and was associated with both insulin resistance and impaired first-phase insulin secretion. Further investigation into the mechanism of transgenerational diabetes is warranted.

Characterization of mitochondrial haplogroups in a large population-based sample from the United States

Mitochondrial DNA (mtDNA) haplogroups are valuable for investigations in forensic science, molecular anthropology, and human genetics. In this study, we developed a custom panel of 61 mtDNA markers for high-throughput classification of European, African, and Native American/Asian mitochondrial haplogroup lineages. Using these mtDNA markers, we constructed a mitochondrial haplogroup classification tree and classified 18,832 participants from the National Health and Nutrition Examination Surveys (NHANES). To our knowledge, this is the largest study to date characterizing mitochondrial haplogroups in a population-based sample from the United States, and the first study characterizing mitochondrial haplogroup distributions in self-identified Mexican Americans separately from Hispanic Americans of other descent. We observed clear differences in the distribution of maternal genetic ancestry consistent with proposed admixture models for these subpopulations, underscoring the genetic heterogeneity of the United States Hispanic population. The mitochondrial haplogroup distributions in the other self-identified racial/ethnic groups within NHANES were largely comparable to previous studies. Mitochondrial haplogroup classification was highly concordant with self-identified race/ethnicity (SIRE) in non-Hispanic whites (94.8 %), but was considerably lower in admixed populations including non-Hispanic blacks (88.3 %), Mexican Americans (81.8 %), and other Hispanics (61.6 %), suggesting SIRE does not accurately reflect maternal genetic ancestry, particularly in populations with greater proportions of admixture. Thus, it is important to consider inconsistencies between SIRE and genetic ancestry when performing genetic association studies. The mitochondrial haplogroup data that we have generated, coupled with the epidemiologic variables in NHANES, is a valuable resource for future studies investigating the contribution of mtDNA variation to human health and disease.

Familial Clustering of Type 2 Diabetes among Omanis

OBJECTIVE

The aim of this study was to screen Omani individuals for the familial aggregation of type 2 diabetes mellitus.

METHODS

A random cohort of 1182 Omani individuals visiting the Family Medicine Clinic at Sultan Qaboos University Hospital (SQUH), Muscat, Oman, for regular medical checkup, aged ≥40 years, were sampled. Patients were categorized into three groups: (1) individuals who claim not to have diabetes and had no family history of diabetes; (2) individuals who claim not to have diabetes but had family history of diabetes; (3) individuals with diabetes. Only 16% of these Omani individuals had no diabetes and no family history of diabetes. Another separate random cohort of 234 Omani type 2 diabetes mellitus patients, from the Diabetes Clinic at SQUH, were interviewed and questioned about their family history of type 2 diabetes mellitus.

RESULTS

Ninety five percent of the patients had a family history of diabetes. Eighty percent had first degree relatives with diabetes and 46% had second degree relatives with diabetes. At least one parent with diabetes was reported among 55% of these diabetics, while maternal diabetes (55%) was found to be higher than paternal diabetes (47%). However, only 15% had both parents with diabetes. Furthermore, almost half of the 234 diabetics were having at least one of the following relatives with diabetes: brother, sister, aunt or an uncle.

CONCLUSION

The findings of this study confirm familial aggregation of diabetes among the Omani population. Compared to other populations, familial aggregation of type 2 diabetes mellitus among Omanis is relatively very high, and is perhaps due to the very high degree of consanguinity among Omanis. Since almost everyone seems to have a genetic predisposition to diabetes, the dramatic lifestyle changes over the past 25 years, could tip the population into an epidemic of type 2 diabetes mellitus.

Joint effect of family history of diabetes with obesity on prevalence of type 2 diabetes mellitus among Chinese and Finnish men and women

OBJECTIVE

To study joint effect of family history of diabetes (FHD) with obesity on prevalence of type 2 diabetes mellitus in the Chinese and in the Finns.

METHODS

A total of 1091 Chinese men and 1706 women, 1472 Finnish men and 1694 women, 45-74 years of age were studied. The probability and odds ratio (OR) of having diabetes were estimated using logistic regression analysis. The synergy index (SI) and relative excess risk due to interaction (RERI) of FHD with body mass index (BMI) or waist circumference (WC) was calculated.

RESULTS

Age-standardized prevalence of diabetes was higher in individuals with FHD than in those without in both the Chinese and Finns. Compared with individuals without FHD and with BMI <30 kg/m(2), ORs (95% confidence intervals [CI]) for diabetes were 2.7 (1.8, 4.0), 2.8 (1.9, 4.0), 9.1 (5.9, 13.9), respectively, in Finnish men with BMI ≥30 kg/m(2) alone, with FHD alone and with both (SI [95% CI] = 2.4 [1.4, 3.9], RERI = 4.6 [1.3, 8.0]); the corresponding figures were 1.7 (1.0, 2.9), 2.7 (1.8, 4.2) and 4.4 (1.9, 10.4) in Chinese men (SI = 1.4 [0.4, 4.9] RERI = 1.0 [-2.9, 5.0]). They were 3.5 (2.1, 5.8), 2.1 (1.3, 3.4) and 6.8 (4.1, 11.2) in Finnish women (SI = 1.6 [0.9, 2.8], RERI = 2.2 [-0.4, 4.9]), and 1.6 (1.1, 2.2), 2.1 (1.5, 3.0), 3.5 (1.9, 6.4) in Chinese women (SI = 1.5 [0.6, 3.8], RERI = 0.8 [-1.4, 3.0]). The pattern of synergistic effect of FHD with WC on diabetes was similar to that seen with BMI in the Finns but no effect was seen in the Chinese.

CONCLUSIONS

Both obesity and FHD are independent risk factors for diabetes, but their joint effect is significant only in Finnish men.

Parental transmission of type 2 diabetes mellitus in a highly endogamous population

AIM: To determine the parental transmission of diabetes mellitus (DM) and evaluate its influence on the clinical characteristics.

METHODS: This was a cross sectional study. The survey was carried out in urban and semi-urban primary health care centers. Of the 2400 registered with diagnosed diabetes, 1980 agreed and gave their consent to take part in this study, thus giving a response rate of 82.5%. Face to face interviews were conducted using a structured questionnaire followed by laboratory tests. DM was defined according to the World Health Organization expert group. A trained nurse performed physical examinations and measurements.

RESULTS: Of the study population, 72.9% reported a family history of DM. Family history of DM was significantly higher in females (54.2%; P = 0.04) and in the age group below 30 years (24%; P < 0.001). The prevalence of diabetes was higher among patients with a diabetic mother (25.4% vs 22.1%) and maternal aunts/uncles (31.2% vs 22.2%) compared to patients with a diabetic father and paternal aunts/uncles. Family history of DM was higher in patients of consanguineous parents (38.5%) than those of non-consanguineous parents (30.2%). The development of type 2 diabetes mellitus (T2DM) complications was higher in patients with either a paternal or maternal history of DM than in those without. No significant difference was observed in the metabolic characteristics of patients with/without family history of DM except for hypertension. Complications were higher in diabetic patients with a family history of DM.

CONCLUSION: The present study found a significant maternal effect in transmission of T2DM. Family history is associated with the increased incidence of diabetes.

Type 2 diabetes in Mauritania: prevalence of the undiagnosed diabetes, influence of family history and maternal effect

AIM

We estimated the prevalence of undiagnosed diabetes, analyzed the influence of family history on the occurrence of T2D and evaluated its aggregation pattern in the Mauritanian population.

METHODS

The prevalence of unknown diabetes was obtained using data compiled from 1278 Mauritanian adults applying a questionnaire and fasting serum glucose tests. Detailed family history of diabetes and clinical characteristics were gathered from 421 T2D patients.

RESULTS

The prevalence of undiagnosed diabetes was 4.7 ± 1.2% in the studied population (3.1% in men and 6.4% in women). 27% of T2D patients reported at least one relative with diabetes. Association between family history and diabetes was higher among first degree compared to second degree relatives (p=0.003). We observed more probands with an affected mother than those who have a father with diabetes (p = 0.002), suggesting a preferential maternal effect which did not extend to second degree relatives.

CONCLUSIONS

These results show that the prevalence of diabetes in the Mauritanian population could be higher than currently thought. Family history screening may be used in the management of this condition in Mauritania.

Acute effect of the transdermal administration of nicotine on insulin sensitivity in healthy individuals with and without a family history of type 2 diabetes mellitus in the first branch

The aim of this study was to evaluate the acute effect of the transdermal administration of nicotine on insulin sensitivity in healthy individuals with and without family histories of type 2 diabetes mellitus (DM2) in the first branch. A randomized, double-blind, cross-over, placebo-controlled clinical trial with two parallel groups was carried out in 12 healthy individuals, six with a family history of diabetes and six without such family history. The volunteers were randomly assigned to administration of a nicotine or placebo patch and were crossed-over with a difference of at least 3 days between each patch. The insulin sensitivity was estimated by means of the total glucose metabolism, which was obtained with the euglycemic- hyperinsulinemic clamp technique before the randomized assignment and on the following day for the corresponding patch. At the beginning of each clamp technique procedure, the metabolic and hepatic profiles were measured. We found that the total glucose metabolism value was not modified with the administration of nicotine, either in the group with a family history of DM2 (3.9 +/- 1.0 vs. 3.5 +/- 0.7 mg/kg/min; p = 0.60) or in the group without such a family history (5.4 +/- 2.0 vs. 5.1 +/- 1.6 mg/kg/min; p = 0.34). The administration of placebo did not modify the insulin sensitivity in either group. We conclude that acute transdermal administration of nicotine did not modify insulin sensitivity in healthy individuals with or without a family history of DM2 in the first branch.

[Long term outcome in children of mothers with gestational diabetes]

OBJECTIVES

To appreciate, in epidemiological studies, the impact of fetal exposure to gestational diabetes on the long term outcome of the offspring (type 2 diabetes, overweight and obesity, metabolic syndrome and neurological complications).

METHODS

A systematic search was conducted in Medline between January 1990 and April 2010. Prospective studies (follow-up of the offspring born of mothers with gestational diabetes) and retrospective studies (questionnaire about the parents'history of diabetes in diabetic patients) were searched and analysed.

RESULTS

The fetal exposure to maternal gestational diabetes is a moderate risk factor for metabolic syndrome in the offspring. But some other perinatal risk factors of metabolic syndrome carry a bigger influence. The influence of genetic factors and maternal overweight may not be easily distinguished from the impact of fetal exposure to gestational diabetes.

CONCLUSION

It remains uncertain if the control of maternal glycemia alone may be effective and sufficient to prevent the metabolic syndrome in the adult-aged offspring.

Sasang constitutional types can act as a risk factor for insulin resistance

The prevalence of insulin resistance (IR) was found to differ across different constitutional types defined by the Sasang constitutional medicine, a sub-division of the Korean traditional medicine, implying that the constitutional type of an individual is a trait that can act as an independent risk factor for IR.

An investigation into genetic contribution to the relationship between insulin resistance and birth weight

BACKGROUND

Insulin resistance has been proposed to be the most likely phenotypic trait that could represent a genetic link between low birth weight and type 2 diabetes, especially in Southeast Asia. Insulin resistance can persist for many years, even decades, before the manifestation of overt diabetes. There have been many studies suggesting a strong genetic basis in the etiology of type 2 diabetes mellitus. There is also ample evidence providing a link with low birth weight and type 2 diabetes in later life. Hence, parental insulin sensitivity could well serve as a representation of the offspring's future insulin resistance state. Association between maternal insulin sensitivity and the incidence of type 2 diabetes mellitus in low birth weight babies is confounded by many factors and hence, has limited value in the determination of any genetic origin of the disease. Therefore, the present study was done to investigate the relationship between paternal insulin sensitivity and the growth parameters of the foetus to determine a genetic link between poor early growth and the increased risk of type 2 diabetes mellitus in later life.

MATERIALS AND METHODS

The study was performed on 30 healthy fathers and their babies born from nondiabetic mothers. Each father underwent a low-dose short insulin tolerance test (ITT) as a measure of insulin sensitivity. Placental weight was recorded and a blood sample was collected from the placental side of the umbilical cord at birth for measurement of insulin. Measurement of birth weight, length, and head circumference were recorded and ponderal index was calculated from the formula: weight (kg)/ length (cm)(3). Individual parameters of insulin resistance syndrome were measured in the fathers.

RESULTS

The degree of insulin sensitivity, K(m) (constant for insulin tolerance test) did not correlate with the fetal growth parameters (Ponderal Index r = 0.031, P = 0.870; weight of baby r = 0.010, P = 0.959; length of baby r = 0.087, P = 0.464; head circumference r = 0.280, P = 0.142) or with the fathers' anthropometric measures: body mass index (BMI), blood pressure, fasting glucose, insulin, and lipid profiles.

CONCLUSION

The data suggest that the mechanism linking insulin resistance with low birth weight is not a genetically determined defect.

Mitochondrial DNA variants in the pathogenesis of type 2 diabetes - relevance of asian population studies

Mitochondrial dysfunction involves defective insulin secretion by pancreatic beta-cells, and insulin resistance in insulin-sensitive tissues such as muscle and adipose tissue. Mitochondria are recognized as the most important cellular source of energy, and the major generator of intracellular reactive oxygen species (ROS). Intracellular antioxidative systems have been developed to cope with increased oxidative damage. In case of minor oxidative stress, the cells may increase the number of mitochondria to produce more energy. A mechanism called mitochondrial biogenesis, involving several transcription factors and regulators, controls the quantity of mitochondria. When oxidative damage is advanced beyond the repair capacity of antioxidative systems, then oxidative stress can lead to cell death. Therefore, this organelle is central to cell life or death. Available evidence increasingly shows genetic linkage between mitochondrial DNA (mtDNA) alterations and type 2 diabetes (T2D). Based on previous studies, the mtDNA 16189 variant is associated with metabolic syndrome, higher fasting insulin concentration, insulin resistance index and lacunar cerebral infarction. These data support the involvement of mitochondrial genetic variation in the pathogenesis of T2D. Importantly, phylogeographic studies of the human mtDNAs have revealed that the human mtDNA tree is rooted in Africa and radiates into different geographic regions and can be grouped as haplogroups. The Asian populations carry very different mtDNA haplogroups as compared to European populations. Therefore, it is critically important to determine the role of mtDNA polymorphisms in T2D.

Familial history of diabetes and clinical characteristics in Greek subjects with type 2 diabetes

BACKGROUND

A lot of studies have showed an excess maternal transmission of type 2 diabetes (T2D). The aim, therefore, of the present study was to estimate the prevalence of familial history of T2D in Greek patients, and to evaluate its potential effect on the patient's metabolic control and the presence of diabetic complications.

METHODS

A total of 1,473 T2D patients were recruited. Those with diabetic mothers, diabetic fathers, diabetic relatives other than parents and no known diabetic relatives, were considered separately.

RESULTS

The prevalence of diabetes in the mother, the father and relatives other than parents, was 27.7, 11.0 and 10.7%, respectively. Patients with paternal diabetes had a higher prevalence of hypertension (64.8 vs. 57.1%, P = 0.05) and lower LDL-cholesterol levels (115.12 +/- 39.76 vs. 127.13 +/- 46.53 mg/dl, P = 0.006) than patients with diabetes in the mother. Patients with familial diabetes were significantly younger (P < 0.001), with lower age at diabetes diagnosis (P < 0.001) than those without diabetic relatives. Patients with a diabetic parent had higher body mass index (BMI) (31.22 +/- 5.87 vs. 30.67 +/- 5.35 Kg/m2, P = 0.08), higher prevalence of dyslipidemia (49.8 vs. 44.6%, P = 0.06) and retinopathy (17.9 vs. 14.5%, P = 0.08) compared with patients with no diabetic relatives. No difference in the degree of metabolic control and the prevalence of chronic complications were observed.

CONCLUSION

The present study showed an excess maternal transmission of T2D in a sample of Greek diabetic patients. However, no different influence was found between maternal and paternal diabetes on the clinical characteristics of diabetic patients except for LDL-cholesterol levels and presence of hypertension. The presence of a family history of diabetes resulted to an early onset of the disease to the offspring.

A family history of type 2 diabetes is associated with glucose intolerance and obesity-related traits with evidence of excess maternal transmission for obesity-related traits in a South East Asian population

AIM

To evaluate family history (FH) of type 2 diabetes (T2DM) as a risk factor for impaired fasting glucose (IFG), impaired glucose tolerance (IGT), T2DM and related metabolic traits in South East Asia and to compare the effects of a paternal versus maternal history.

METHODS

We studied 4717 men and women (68% Chinese, 18% Malays and 14% Asian Indians) living in Singapore. FH was considered positive if at least one first degree relative had T2DM. Obesity, fasting lipids, glucose and insulin levels were measured for all subjects. Insulin resistance (IR) was estimated by homeostasis model assessment (HOMA). An oral glucose tolerance test was carried for all subjects except those on diabetes medication.

RESULTS

A positive FH was associated with increased risk of IFG/IGT (OR=1.67, 95% CI=1.42-1.97) and T2DM (OR=2.95, 95% CI=2.36-3.70) as well as higher levels of obesity, HOMA-IR, fasting triglyceride (TG), and lower levels of high density lipoprotein (HDL) cholesterol and HOMA-beta. A maternal history of T2DM appeared to have a greater impact on obesity-related traits than a paternal history of T2DM. Compared to individuals with no FH of T2DM, a maternal history was associated with (i) greater body mass index (BMI) (24.15kg/m(2) vs. 23.42kg/m(2), p=0.016) and waist-to-hip ratio (WHR) (0.874 vs. 0.865, p=0.037) in men; and (ii) greater WHR (0.788 vs. 0.779, p=0.004), fasting triglyceride (1.23mmol/L vs. 1.09mmol/L, p<0.001), HOMA-IR (2.02 vs. 1.75, p<0.001), fasting plasma glucose (5.25mmol/L vs. 5.18mmol/L, p=0.005) and 2-h plasma glucose (6.01mmol/L vs. 5.78mmol/L, p=0.001) and lower HDL-C (1.41mmol/L vs. 1.47mmol/L, p=0.031) in women.

CONCLUSION

T2DM appears to be heritable in South East Asians with excess maternal transmission of obesity, IR and dyslipidemia.

Investigating parent of origin effects in studies of type 2 diabetes and obesity

The role of parent-of-origin effects (POE) in the etiology of complex diseases such as type 2 diabetes (T2DM) and obesity is currently of intense interest, but still largely unclear. POE are transmittable genetic effects whereby the expression of the phenotype in the offspring depends upon whether the transmission originated from the mother or father. In mammals, POE can be caused by genetic imprinting, intrauterine effects, or maternally inherited mitochondrial genes. In this paper, we describe the different mechanisms underlying POE, characterize known examples of POE in rare forms of diabetes, and review the evidence from linkage and association studies for POE in T2DM and obesity. Finally, we summarize some of the new and established statistical and experimental approaches commonly used to detect POE. Through this paper, we hope emphasizes the potentially significant importance of POE in the etiology of T2DM and obesity.

Parental diabetes in Taiwanese diabetic women with and without previous gestational diabetes

Background Gestational diabetes mellitus (GDM) is reported to be associated with maternal but not paternal diabetes. This study examined the relative contribution of maternal and paternal diabetes among type 2 diabetic women with and without a GDM history. Materials and methods A total of 48 502 type 2 diabetic women from a national sample were interviewed by telephone. Among them, 510 reported a GDM history. Parental diabetes was compared between patients with and without a GDM history considering the confounding effects of age, body mass index, smoking, hypertension, duration of diabetes and insulin use. Results Patients with a GDM history were younger in age, had younger age of onset, longer duration of diabetes, slightly lower body mass index, higher prevalence of insulin use and lower prevalence of hypertension, but smoking rates were similar. The percentages of parental diabetes of nil, mother only, father only and both father and mother for those without a GDM history were 76.2, 15.2, 5.8 and 2.8%, respectively; and were 47.8, 26.8, 17.5 and 7.9%, respectively, for those with a GDM history (P < 0.001). The adjusted odds ratios for patients with versus without a GDM history for parental diabetes of nil, mother only, father only, and both father and mother were 1.000, 1.210 (0.948-1.544), 1.783 (1.341-2.371) and 2.094 (1.440-3.045), respectively. Conclusions Although maternal diabetes is more commonly seen, the disproportionately higher paternal diabetes in patients with a GDM history suggests an important role for paternal diabetes on the development of GDM into type 2 diabetes mellitus.

Polymorphisms at the GLUT2 (β-cell/liver) glucose transporter gene and non-insulin-dependent diabetes mellitus (NIDDM): analysis in affected pedigree members

The precise genetic defects underlying the etiology of non-insulin-dependent diabetes mellitus (NIDDM) have yet to be identified. The beta-cell/liver glucose transporter gene GLUT2 represents a good candidate for the etiology of the disease, being involved in the glucose signalling for beta-cell insulin release. Population association studies of the GLUT2 gene in NIDDM have so far yielded controversial results. In order to determine the possible contribution of this gene to the inheritance of NIDDM, we have employed a new approach, where two polymorphic markers of the GLUT2 locus, detected with the restriction enzyme Taq-1, were examined for linkage with the disease in a group of 22 Italian pedigrees with affected members (n = 50). Departure from independent segregation between markers and disease was analyzed by the Affected-Pedigree-Members (APM) statistical method. Furthermore, association analysis between the Taq-1 RFLPs at the GLUT2 locus and NIDDM was performed in a group of diabetics with a strong family history, comprising the 22 probands and 23 other diabetics with an affected first-degree relative. The results indicate that there was no segregation distortion between the Taq-1 markers of the GLUT2 gene and the disease in the pedigrees examined. Also, no significant difference in genotype distribution, haplotype and allele frequencies was found between diabetics and controls for the two Taq-1 RFLPs. We conclude that genetic variation at the GLUT2 transporter gene is unlikely to contribute in a major way to the inheritance for NIDDM in this Italian population.

Familial history of type 2 diabetes in patients from Southern Brazil and its influence on the clinical characteristics of this disease

OBJECTIVE

To investigate the presence of maternal and paternal history of type 2 diabetes mellitus (DM) in relatives of 644 type 2 diabetic patients from Southern Brazil, and also to evaluate its influence on the clinical characteristics of this disease.

PATIENTS AND METHODS

Familial history of type 2 DM was investigated by a questionnaire. The maternal and paternal history was investigated over two generations. Complete data sets on familial history were obtained from 396 patients.

RESULTS

In general, 76.6% of the patients reported at least one first-degree affected relative. Besides, 31.6% of the patients reported a maternal history of type 2 DM and 12.6% reported a paternal history. Patients with maternal and/or paternal history presented a lower age at type 2 DM diagnosis when compared to patients without familial history. In addition, patients with only paternal history presented a higher frequency of hypertension than patients with no familial history.

CONCLUSIONS

This study suggests that there is a significant maternal effect in the transmission of type 2 DM in Southern Brazil, and that most of the clinical characteristics of this disease do not differ between patients with or without familial history of type 2 DM.

Linking mitochondrial function to diabetes mellitus: an animal's tale

Diabetes mellitus is one of the most common genetic diseases that afflicts humans. It is not a single disease but a collection of diseases having in common an abnormal glucose-insulin relationship and a dysfunctional regulation of glucose homeostasis. Of interest is the diabetic state that results when the mitochondrial genome mutates. Epidemiological studies have shown this to occur in humans. Detailed metabolic studies that are impossible to conduct in humans have been carried out in the BHE/Cdb rat. This rat has a mutated mitochondrial ATPase 6 gene. Strategies to ameliorate the consequences of this mutation have been explored and some of the mechanisms for the transcription and translation of the mitochondrial gene product have been elucidated.

Familial aggregation and excess maternal transmission of type 2 diabetes in Tunisia

AIM

To evaluate the degree of familial aggregation of type 2 diabetes mellitus in Tunisia and to investigate transmission patterns of the disease and their relationships with patients' clinical profiles.

METHODS

Family history of diabetes and clinical data were collected for 132 unrelated type 2 diabetic Tunisian patients. Diabetes status was recorded for first degree relatives (parents, siblings) and second degree relatives (aunts and uncles from both maternal and paternal sides). Information about family history of diabetes was gathered for a total of 1767 individuals.

RESULTS

Familial aggregation of type 2 diabetes was prominent and more important among first degree relatives than among second degree relatives (p = 0.01). Among studied subjects, 70% reported at least one relative with diabetes and 34% had at least one parent with diabetes. Diabetes was more frequent among mothers than fathers of probands (p = 0.03). This maternal effect extends to second degree relatives as diabetes was more common among maternal than paternal aunts and uncles (p = 0.01). There is no significant difference in clinical and metabolic profiles between patients according to transmission patterns of the disease.

CONCLUSION

These results suggest familial aggregation and excess maternal transmission of type 2 diabetes in the Tunisian studied population.

Mitochondrial haplogroup N9a confers resistance against type 2 diabetes in Asians

Because mitochondria play pivotal roles in both insulin secretion from the pancreatic beta cells and insulin resistance of skeletal muscles, we performed a large-scale association study to identify mitochondrial haplogroups that may confer resistance against or susceptibility to type 2 diabetes mellitus (T2DM). The study population comprised 2,906 unrelated Japanese individuals, including 1,289 patients with T2DM and 1,617 controls, and 1,365 unrelated Korean individuals, including 732 patients with T2DM and 633 controls. The genotypes for 25 polymorphisms in the coding region of the mitochondrial genome were determined, and the haplotypes were classified into 10 major haplogroups (i.e., F, B, A, N9a, M7a, M7b, G, D4a, D4b, and D5). Multivariate logistic-regression analysis with adjustment for age and sex revealed that the mitochondrial haplogroup N9a was significantly associated with resistance against T2DM (P=.0002) with an odds ratio of 0.55 (95% confidence interval 0.40-0.75). Even in the modern environment, which is often characterized by satiety and physical inactivity, this haplogroup might confer resistance against T2DM.

Mother to child transmission of diabetes mellitus: does gestational diabetes program Type 2 diabetes in the next generation?

AIM

Type 2 diabetes is frequently familial. Hyperglycaemia in pregnancy might act in addition to genetic factors to cause diabetes in the children of mothers with gestational diabetes mellitus (GDM). The first manifestation of this in female offspring is likely to be GDM in their own pregnancies. We compared the incidence of GDM in daughters of diabetic mothers and diabetic fathers to determine if in utero exposure to hyperglycaemia increased the risk of a diabetes-prone phenotype in offspring.

METHODS

We analysed the outcome of a GDM screening programme in women with a family history of diabetes in their mother (n = 535), father (n = 566), both parents (n = 77) or neither (n = 4672).

RESULTS

GDM was twice as common in the daughters of diabetic mothers (11%) than diabetic fathers (5%, P = 0.002). Women with two diabetic parents were no more likely to have GDM than women with only a diabetic mother.

CONCLUSIONS

Genetic predisposition to GDM should be equally shared by daughters of diabetic mothers and fathers. An excess of maternal transmission of diabetes is consistent with an epigenetic effect of hyperglycaemia in pregnancy acting in addition to genetic factors to produce diabetes in the next generation.

Consequences of fetal exposure to maternal diabetes in offspring

CONTEXT

Type 2 diabetes is the result of both genetic and environmental factors. Fetal exposure to maternal diabetes is associated with a higher risk of abnormal glucose homeostasis in offspring beyond that attributable to genetic factors, and therefore, may participate in the excess of maternal transmission of type 2 diabetes.

EVIDENCE ACQUISITION

A MEDLINE search covered the period from 1960-2005.

EVIDENCE SYNTHESIS

Human studies performed in children and adolescents suggest that offspring who had been exposed to maternal diabetes during fetal life exhibit higher prevalence of impaired glucose tolerance and markers of insulin resistance. Recent studies that directly measured insulin sensitivity and insulin secretion have shown an insulin secretory defect even in the absence of impaired glucose tolerance in adult offspring. In animal models, exposure to a hyperglycemic intrauterine environment also led to the impairment of glucose tolerance in the adult offspring. These metabolic abnormalities were transmitted to the next generations, suggesting that in utero exposure to maternal diabetes has an epigenetic impact. At the cellular level, some findings suggest an impaired pancreatic beta-cell mass and function. Several mechanisms such as defects in pancreatic angiogenesis and innervation, or modification of parental imprinting, may be implicated, acting either independently or in combination.

CONCLUSION

Thus, fetal exposure to maternal diabetes may contribute to the worldwide diabetes epidemic. Public health interventions targeting high-risk populations should focus on long-term follow-up of subjects who have been exposed in utero to a diabetic environment and on a better glycemic control during pregnancy.

The European-specific mitochondrial cluster J/T could confer an increased risk of insulin-resistance and type 2 diabetes: an analysis of the m.4216T > C and m.4917A > G variants

The aims of this study were to investigate the contributions of the mitochondrial DNA m.4216T > C and m.4917A > G variants, and also of the European-specific mitochondrial cluster J/T, to the development of type 2 diabetes mellitus in Caucasian-Brazilian patients from Southern Brazil. We analyzed 347 type 2 diabetes patients and 350 control subjects. Variant frequencies in patients and control subjects were compared using chi2 tests or odds ratio. We also compared clinical and laboratory characteristics among patients with and without the variants. We found that the frequencies of the m.4216T > C and m.4917A > G variants are higher in diabetic patients than in control subjects. Moreover, haplogroups J (partially defined by the presence of the m.4216T > C variant only) and T (partially defined by the presence of both m.4216T > C and m.4917A > G variants) are more frequent in the type 2 diabetic group than in the control group. Patients belonging to the cluster J/T are more insulin resistant than patients of other haplogroups. In conclusion, our results indicate the association of the cluster J/T (as suggested by analyses of the m.4216T > C and m.4917A > G variants) with insulin resistance and type 2 diabetes.

Maternally transmitted diabetes mellitus associated with the mitochondrial tRNA(Leu(UUR)) A3243G mutation in a four-generation Han Chinese family

We report here the characterization of a four-generation Han Chinese family with maternally transmitted diabetes mellitus. Six (two males/four females) of eight matrilineal relatives in this family exhibited diabetes. The age of onset in diabetes varies from 15 years to 33 years, with an average of 26 years. Two of affected matrilineal relatives also exhibited hearing impairment. Molecular analysis of mitochondrial DNA (mtDNA) showed the presence of heteroplasmic tRNA(Lue(UUR)) A3243G mutation, ranging from 35% to 58% of mutations in blood cells of matrilineal relatives. The levels of heteroplasmic A3243G mutation seem to be correlated with the severity and age-at-onset of diabetes in this family. Sequence analysis of the complete mitochondrial genome in this pedigree revealed the presence of the A3243G mutation and 38 other variants belonging to the Eastern Asian haplogroup M7C. However, none of other mtDNA variants are evolutionarily conserved and implicated to have significantly functional consequence. Thus, the A3243G mutation is the sole pathogenic mtDNA mutation associated with diabetes in this Chinese family.

Association between parental histories of hypertension, diabetes and dyslipidemia and the clustering of these disorders in offspring

BACKGROUND

Familial aggregation of hypertension, diabetes and dyslipidemia has been well reported. However, only a few studies have assessed to what extent parental histories were involved in the clustering of these diseases.

METHOD

In 2002, associations between parental histories of hypertension, diabetes and dyslipidemia and the clustering of high blood pressure, hyperglycemia and dyslipidemia in individuals were assessed on the basis of 5010 Japanese men and women aged 33-66 years. Risk factor clusters were defined as those having at least two of the three clinical disorders.

RESULTS

Compared with persons with no parental history of the three diseases, those who had 1, 2 and 3 or more parental histories had risk factor clusters, 1.25 (95% CI: 1.07, 1.47), 1.46 (95% CI: 1.16, 1.84) and 1.41 (95% CI: 0.95, 2.11) times higher, respectively, after adjusting for confounding factors. ORs by 1, 2 and 3 of maternal history were 1.33 (95% CI: 1.12, 1.58), 1.65 (95% CI: 1.16, 2.35) and 1.69 (95% CI: 0.64, 4.42), respectively (trend P < 0.001). However, the number of paternal history was not associated with risk factor clusters.

CONCLUSION

We conclude that familial history, particularly maternal history, is an important aid to prevention strategy and public health practice for metabolic disorders.

The G1888A variant in the mitochondrial 16S rRNA gene may be associated with Type 2 diabetes in Caucasian-Brazilian patients from southern Brazil

AIM

To compare the frequencies of the G1888A variant in the mitochondrial 16S rRNA gene between patients with Type 2 diabetes and non-diabetic control subjects from southern Brazil.

METHODS

We analysed 520 Type 2 diabetic patients (389 Caucasian- and 131 African-Brazilians) and 530 control subjects (400 Caucasian- and 130 African-Brazilians). DNA samples were amplified by polymerase chain reaction and digested with the RsaI enzyme. Variant frequency in patients and control subjects was compared using chi2 test, Fisher's exact test or odds ratio test. We also investigated the frequency of the G1888A variant in a subgroup of the patients with a maternal history of Type 2 diabetes plus two or more features of maternally inherited diabetes and deafness.

RESULTS

The 1888A allele does not seem to be associated with Type 2 diabetes in African-Brazilians (frequency of 3.8% in patients and 0.8% in control subjects; PFisher=0.213). However, in Caucasian-Brazilians, the 1888A allele was significantly associated with diabetes (12.3% in patients vs. 3.5% in control subjects; OR=3.881; 95% CI 2.106-7.164; P<0.001) and also with higher levels of insulin resistance. The majority of the patients carrying the 1888A allele did not have clinical features of maternally inherited diabetes and deafness.

CONCLUSION

The present study indicates the association of the mitochondrial G1888A variant with Type 2 diabetes and insulin resistance in Caucasian-Brazilian patients from southern Brazil. However, further studies are required to confirm its effects on mitochondrial function and the role of these effects on the pathogenesis of Type 2 diabetes.

Fetal erythrocyte membrane lipids modification: preliminary observation of an early sign of compromised insulin sensitivity in offspring of gestational diabetic women

AIMS

Intrauterine exposure to diabetes is a significant determinant of the development of obesity and early onset of Type 2 diabetes mellitus in the offspring. Both conditions are characterized by insulin resistance and the latter is associated with reduced membrane arachidonic and docosahexaenoic acids. Hence, we investigated if the membrane arachidonic and docosahexaenoic acids are depressed in the cord blood of babies born to women with gestational diabetes.

METHODS

Cord (fetal) and maternal blood were obtained at delivery from control subjects (n = 33) and women with gestational diabetes (n = 40) and analysed for plasma triglycerides and cholinephosphoglycerides, and erythrocyte choline- and ethanolaminephosphoglycerides fatty acids.

RESULTS

Babies of gestational diabetic mothers had reduced docosahexaenoic acid in the plasma (5.9 +/- 1.4 vs. 7.1 +/- 2.0, P < 0.01) and erythrocyte (4.0 +/- 2.2 vs. 5.4 +/- 2.9, P < 0.05) cholinephosphoglycerides. Moreover, the total omega-6 and omega-3 fatty acids of the erythrocyte cholinephosphoglycerides were significantly lower (P < 0.05) in these babies. A similar trend was observed in plasma triglycerides and erythrocyte ethanolaminephosphoglycerides. The maternal plasma triglycerides and erythrocyte ethanolaminephosphoglycerides fatty acids profile were not different between the two groups. However, there was a reduction in arachidonic acid and total omega-6 fatty acids in the erythrocyte cholinephosphoglycerides of the gestational diabetic women.

CONCLUSION

The altered plasma and erythrocyte fatty acids in the cord blood of babies born to women with gestational diabetes suggests a perturbation in the maternal-fetal nutrient transport and/or fetal lipid metabolism.

Associations of middle-aged mother's but not father's body mass index with 18-year-old son's waist circumferences, birth weight, and serum hepatic enzyme levels

Mitochondrial dysfunction has been reported to contribute to insulin resistance (IR) in the elderly and type 2 diabetes. To test this hypothesis, we examined relations of insulin resistance in young men to their mother's body mass index (BMI) and compared with those to their father's BMI, because as a rule, mitochondrial DNA is exclusively maternally inherited and because mitochondria are fundamental in mediating effects on energy dissipation. We measured heights, weights, waist circumference, systolic and diastolic blood pressure (BP), and biochemical variables in sera from 193 male college students aged 18 to 20 years after an overnight fast. Birth weight was available from 184 students. Self-reported heights and weights of their parents were obtained from 148 students. Insulin resistance and insulin secretion were estimated using homeostasis model assessment (HOMA-IR and HOMA-beta, respectively). Mother's BMI was associated with their son's birth weight (r=0.23, P=.008), BMI (r=0.37, P<.0001), waist circumference (r=0.42, P<.0001), fasting insulin (r=0.19, P=.02), and HOMA-IR (r=0.18, P=.03) but not with fasting glucose, HOMA-beta , and systolic and diastolic BP. In addition, high-density lipoprotein cholesterol and lipoprotein(a) [Lp(a)] were inversely associated with mother's BMI (r=-0.21, P=.01 and r=-0.17, P=.03, respectively). Furthermore, there were significant associations with aspartate (r=0.20, P=.01) and alanine (r=0.28, P=.0008) aminotransferase and gamma-glutamyl transpeptidase (r=0.30, P=.0003), all of which are associated with mitochondrial function. In contrast, none of those variables were associated with father's BMI, except for Lp(a), which showed a significant and inverse association (r=-0.17, P=.05). After adjustment for sons' BMI, waist circumference and 3 hepatic enzymes were associated with mother's BMI, whereas Lp(a) was associated with both mother's and father's BMI. In multiple regression analysis for HOMA-IR as a dependent variable, BMI of their own (beta=.10, P<.0001) and of their mothers (beta=.04, P=10) and birth weight (beta=-.27, P=.10) emerged as determinants of HOMA-IR of the students(R2=0.30). Our results are consistent with clinical observations of a greater risk of transmission of type 2 diabetes from the mother than the father and suggest that son's IR may be influenced by maternal effect as well as their adiposity.

Type 2 diabetes mellitus--genes or intrauterine environment? An embryo transfer paradigm in rats

AIMS/HYPOTHESIS

The familial predisposition to Type 2 diabetes mellitus is mediated by both genetic and intrauterine environmental factors. In the normal course of events, maternal genes always develop in the same uterus, thus restricting studies aimed at investigating the relative contribution of these factors. We have developed an embryo transfer paradigm in rats to overcome this difficulty.

METHODS

Euglycaemic female Wistar rats were superovulated and mated with male Wistar rats. The following day, fertilised eggs were transferred into pseudo-pregnant female Wistar rats or hyperglycaemic Goto Kakizaki (GK) rats. Pregnancies were allowed to go to term. Offspring were weighed at 6 weeks, 3 months and 6 months of age and an intravenous glucose tolerance test was carried out at 6 months of age.

RESULTS

Offspring from Wistar into Wistar embryo transfers (n=20) were not significantly hyperglycaemic compared to the non-manipulated Wistar stock colony (n=26). However, offspring from Wistar gametes reared in hyperglycaemic GK mothers (n=51) were significantly lighter at 6 weeks of age (156+/-4.1 g vs 180+/-6.1 g [mean +/- SEM], p<0.01) and significantly more hyperglycaemic at 6 months of age (fasting glucose 6.6+/-0.18 mmol/l vs 4.8+/-0.21 mmol/l, mean blood glucose during glucose tolerance test 14.3+/-0.31 mmol/l vs 11.1+/-0.28 mmol/l, p<0.01) than Wistar gametes transferred back into euglycaemic Wistar mothers. When GK rats were superovulated and mated together, transfer of 1-day-old embryos into pseudo-pregnant Wistar dams did not alleviate hyperglycaemia in adult offspring.

CONCLUSIONS/INTERPRETATION

In GK rats, a euglycaemic intrauterine environment cannot overcome the strong genetic predisposition to diabetes. However, in Wistar rats with a low genetic risk of diabetes, exposure to hyperglycaemia in utero significantly increases the risk of diabetes in adult life.

Lack of excess maternal transmission of type 2 diabetes in a Korean population

The purpose of this study was to assess the familial clustering of type 2 diabetes and to investigate the presence of excess maternal transmission of type 2 diabetes in Korea. The medical records of 56,492 subjects (31,680 men and 24,812 women), who attended the Health Promotion Center were examined. The subjects were questioned about their parents' diabetes status. All study subjects were classified into the three groups (normal fasting glucose (NFG), impaired fasting glucose (IFG), and diabetes). Offspring with paternal diabetes (odds ratio 2.54, 95% CI 2.22-2.91, P < 0.001) and those with maternal diabetes (odds ratio 3.10, 95% CI 2.76-3.49, P < 0.001) were at increased risk for diabetes when compared to subjects without parental diabetes and adjusted for other clinical and biochemical variables. Offspring with bilineal parental diabetes were at a greater risk for diabetes (odds ratio 6.09, 95% CI 4.55-8.16, P < 0.001) when compared to subjects without parental diabetes. In both genders, offspring with maternal diabetes showed no increased risk for diabetes (odds ratio 1.22, 95% CI 0.92-1.37, P + 0.266 in men; odds ratio 1.31, 95% CI 0.95-1.81, P = 0.104 in women) when compared with those with paternal diabetes. The data suggested that parental type 2 diabetes was an independent risk factor for offspring type 2 diabetes in this Korean population. Excess maternal transmission of type 2 diabetes was not observed.

Is human Type 2 diabetes maternally inherited? Insights from an animal model

AIMS

Patients with Type 2 diabetes mellitus more often report a history of an affected mother than father. However, in the few studies where both parents and offspring have been directly tested, this apparent maternal excess has not been confirmed. Rodent models of diabetes have the advantage that all parents and offspring can undergo glucose tolerance testing at a specific age in adult life. The aim of this study was to gain insights into the inheritance of human Type 2 diabetes by using a rat model.

METHODS

Goto Kakizaki (GK) rats (a model of Type 2 diabetes) were mated with non-diabetic Wistar rats. Offspring were produced from 20 GK female vs. Wistar male and 20 Wistar female vs. GK male crosses. Fasting blood glucose was measured at 6 weeks and 3 months of age and an intravenous glucose tolerance test (0.8 g/kg) performed at 6 months of age.

RESULTS

Wistar mothers produced litters with almost twice as many viable offspring as GK mothers (14.1 vs. 7.4, P < 0.001). Despite the larger litter size, offspring in the two groups were of comparable weight at 6 weeks and 6 months of age. At 3 months of age, male offspring of Wistar mothers were heavier than offspring of GK mothers (415.7 g vs. 379.5 g, P = 0.016) but this difference was not sustained at 6 months of age. Fasting blood glucose at all ages and average blood glucose during the glucose tolerance test were similar in both groups.

CONCLUSIONS

We therefore conclude that there is no evidence for maternal transmission of diabetes in the GK rat. Mothers were able to adjust their supply of milk so that offspring attained similar weights independent of litter size. The weight of the offspring remained independent of litter size into adult life.

Neurodegenerative disorders associated with diabetes mellitus

More than 20 syndromes among the significant and increasing number of degenerative diseases of neuronal tissues are known to be associated with diabetes mellitus, increased insulin resistance and obesity, disturbed insulin sensitivity, and excessive or impaired insulin secretion. This review briefly presents such syndromes, including Alzheimer disease, ataxia-telangiectasia, Down syndrome/trisomy 21, Friedreich ataxia, Huntington disease, several disorders of mitochondria, myotonic dystrophy, Parkinson disease, Prader-Willi syndrome, Werner syndrome, Wolfram syndrome, mitochondrial disorders affecting oxidative phosphorylation, and vitamin B(1) deficiency/inherited thiamine-responsive megaloblastic anemia syndrome as well as their respective relationship to malignancies, cancer, and aging and the nature of their inheritance (including triplet repeat expansions), genetic loci, and corresponding functional biochemistry. Discussed in further detail are disturbances of glucose metabolism including impaired glucose tolerance and both insulin-dependent and non-insulin-dependent diabetes caused by neurodegeneration in humans and mice, sometimes accompanied by degeneration of pancreatic beta-cells. Concordant mouse models obtained by targeted disruption (knock-out), knock-in, or transgenic overexpression of the respective transgene are also described. Preliminary conclusions suggest that many of the diabetogenic neurodegenerative disorders are related to alterations in oxidative phosphorylation (OXPHOS) and mitochondrial nutrient metabolism, which coincide with aberrant protein precipitation in the majority of affected individuals.

Metabolic and genetic influence on glucose metabolism in type 2 diabetic subjects--experiences from relatives and twin studies

Based on our investigations in first-degree relatives, in twins in general, and in monozygotic twins discordant for type 2 diabetes, we have studied the inheritance of glucose intolerance, insulin resistance and insulin secretion in order to evaluate the role of genes versus environment in the development of type 2 diabetes. Insulin resistance in type 2 diabetes is mainly linked to glucose disposal in skeletal muscle, i.e. reduced glycogen synthesis. In order to investigate the genetic component responsible for the reduced glycogen synthase activity and reduced glucose transport, we also investigated cultured myotubes based on in vivo skeletal muscle biopsies. The results obtained in our own studies are discussed in comparison with the international literature. We conclude that both genetic and environmental factors play a role in the development of type 2 diabetes (hyperglycaemia), and that only subjects who are genetically disposed to insulin resistance and who possess beta-cells which are unable to compensate for the degree of insulin resistance seem to develop type 2 diabetes. Variables of two gene alleles disposing to insulin resistance have been identified, and their role is discussed. The most important environmental factor seems to be obesity, but intrauterine malnutrition also plays a role. The cellular mechanism responsible for obesity/lipid-induced diabetes mellitus is discussed with specific emphasis on the role of accumulation of long-chain AcylCoA and triglycerides in liver, muscle and beta-cells.

Longitudinal changes in risk variables of insulin resistance syndrome from childhood to young adulthood in offspring of parents with type 2 diabetes: the Bogalusa Heart Study

The occurrence of metabolic abnormalities related to insulin resistance syndrome in nondiabetic offspring of type 2 diabetic parents is known. However, information is lacking on the timing and the course of development of the components of this syndrome from childhood to adulthood in the offspring of parents with diabetes. This aspect was examined in a community-based cohort with (n = 303) and without (n = 1,136) a parental history of type 2 diabetes followed longitudinally since childhood (ages 4 to 17 years; mean follow-up period, 15 years) by repeated surveys. Offspring with parental diabetes versus those without such history had significantly excess generalized and truncal adiposity as measured by body mass index (BMI) and subscapular skinfold beginning in childhood, higher levels of fasting insulin and glucose and homeostasis model assessment index of insulin resistance (HOMA-IR) from adolescence, and higher levels of low-density lipoprotein (LDL) cholesterol and triglycerides and lower levels of high-density lipoprotein (HDL) cholesterol in adulthood. Many of these risk variables changed adversely at an increased rate in offspring of diabetic parents. In a multivariate analysis, parental diabetes was an independent predictor of longitudinal changes in adiposity, glucose, insulin, HOM-IR, systolic and diastolic blood pressure, and LDL cholesterol in the offspring, regardless of race and gender. As young adults, the offspring of diabetic parents had a higher prevalence of generalized (BMI > 30, 36% v 16%, P =.0001) and visceral (waist > 100 cm, 15% v 6%, P =.0001) obesity, hyperinsulinemia indicative of insulin resistance (insulin > 18 microU/mL, 15% v 8%, P =.0001), hyperglycemia (>or=110 mg/dL, 2% v 0.5%, P =.02), high LDL cholesterol (>or=160 mg/dL, 11% v 7%, P =.02), low HDL cholesterol (<40 mg/dL for males and <50 mg/dL for females, 40% v 31%, P =.004), high triglycerides (>or=150 mg/dL, 23% v 15%, P =.0001), and hypertension (>140/90 mm Hg, 11% v 6%, P =.004). Thus, the offspring of diabetic parents displayed excess body fatness beginning in childhood and accelerated progression of adverse risk profile characteristics of insulin resistance syndrome from childhood to young adulthood. These observations have important implications for early prevention and intervention.