The rumen microbiota contributed to the development of mastitis induced by subclinical ketosis

BACKGROUND

Mastitis is a serious disease which affects animal husbandry, particularly in cow breeding. The etiology of mastitis is complex and its pathological mechanism is not yet fully understood. Our previous research in clinical investigation has revealed that subclinical ketosis can increase the number of somatic cell counts (SCC) in milk, although the underlying mechanism remains unclear. Recent studies have further confirmed the significant role of mastitis.

RESULTS

In this study, we aimed to examine the SCC, rumen microbiota, and metabolites in the milkmen of cows with subclinical ketosis. Additionally, we conducted a rumen microbiota transplant into mice to investigate the potential association between rumen microbiota disturbance and mastitis induced by subclinical ketosis in dairy cows. The study has found that cows with subclinical ketosis have a higher SCC in their milk compared to healthy cows. Additionally, there were significant differences in the rumen microbiota and the level of volatile fatty acid (VFA) between cows with subclinical ketosis and healthy cows. Moreover, transplanting the rumen microbiota from subclinical ketosis and mastitis cows into mice can induce mammary inflammation and liver function damage than transplanting the rumen flora from healthy dairy cows.

CONCLUSIONS

In addition to the infection of mammary gland by pathogenic microorganisms, there is also an endogenous therapeutic pathway mediated by rumen microbiota. Targeted rumen microbiota modulation may be an effective way to prevent and control mastitis in dairy cows.

Gut/rumen-mammary gland axis in mastitis: Gut/rumen microbiota-mediated "gastroenterogenic mastitis"

BACKGROUND

Mastitis is an inflammatory response in the mammary gland that results in huge economic losses in the breeding industry. The aetiology of mastitis is complex, and the pathogenesis has not been fully elucidated. It is commonly believed that mastitis is induced by pathogen infection of the mammary gland and induces a local inflammatory response. However, in the clinic, mastitis is often comorbid or secondary to gastric disease, and local control effects targeting the mammary gland are limited. In addition, recent studies have found that the gut/rumen microbiota contributes to the development of mastitis and proposed the gut/rumen-mammary gland axis. Combined with studies indicating that gut/rumen microbiota disturbance can damage the gut mucosa barrier, gut/rumen bacteria and their metabolites can migrate to distal extraintestinal organs. It is believed that the occurrence of mastitis is related not only to the infection of the mammary gland by external pathogenic microorganisms but also to a gastroenterogennic pathogenic pathway.

AIM OF REVIEW

We propose the pathological concept of "gastroenterogennic mastitis" and believe that the gut/rumen-mammary gland axis-mediated pathway is the pathological mechanism of "gastroenterogennic mastitis".

KEY SCIENTIFIC CONCEPTS OF REVIEW

To clarify the concept of "gastroenterogennic mastitis" by summarizing reports on the effect of the gut/rumen microbiota on mastitis and the gut/rumen-mammary gland axis-mediated pathway to provide a research basis and direction for further understanding and solving the pathogenesis and difficulties encountered in the prevention of mastitis.

Patients with persistent symptoms after COVID-19 attending a multidisciplinary evaluation: Characteristics, medical conclusions, and satisfaction

OBJECTIVE

Among patients attending a multidisciplinary day-hospital program for persistent symptoms after COVID-19, we aimed i) to describe their characteristics ii) to present the medical conclusions (diagnoses and recommendations) and iii) to assess the patients' satisfaction and its correlates.

METHODS

For this retrospective chart review study, frequent symptoms were systematically assessed. Standardized questionnaires explored fatigue (Pichot scale), physical activity (Ricci & Gagnon scale), health-related quality of life (Short-Form Health Survey), anxiety and depressive symptoms (Hospital Anxiety and Depression scale) and associated psychological burden (Somatic-Symptom-Disorder B criteria Scale). Medical record conclusions were collected and a satisfaction survey was performed at 3-months follow-up.

RESULTS

Among 286 consecutive patients (median age: 44 years; 70% women), the most frequent symptoms were fatigue (86%), breathlessness (65%), joint/muscular pain (61%) and cognitive dysfunction (58%), with a median duration of 429 days (Inter-quartile range (IqR): 216-624). Questionnaires revealed low levels of physical activity and quality of life, and high levels of fatigue, anxiety, depression, and psychological burden, with 32% and 23% meeting the diagnostic criteria for a depressive or anxiety disorder, respectively. Positive arguments for a functional somatic disorder were found in 76% of patients, including 96% with no abnormal clinical or test findings that may explain the symptoms. Physical activity rehabilitation was recommended for 91% of patients. Patients' median satisfaction was 8/10 (IqR: 6-9).

CONCLUSION

Most patients attending this program presented with long-lasting symptoms and severe quality of life impairment, received a diagnosis of functional somatic disorder, and reported high levels of satisfaction regarding the program.

Gut dysbiosis induces the development of mastitis through a reduction in host anti-inflammatory enzyme activity by endotoxemia

BACKGROUND

Mounting experimental evidence has shown that the gut microbiota plays a significant role in the pathogenesis of mastitis, and clinical investigations have found that the occurrence of mastitis is correlated with ruminal dysbiosis. However, the underlying mechanism by which the ruminal microbiota participates in the development of mastitis remains unknown.

RESULTS

In the present study, we found that cows with clinical mastitis had marked systemic inflammation, which was associated with significant ruminal dysbiosis, especially enriched Proteobacteria in the rumen. Ruminal microbiota transplantation from mastitis cows (M-RMT) to mice induced mastitis symptoms in recipient mice along with increased mammary proinflammatory signature activation of the TLR4-cGAS-STING-NF-κB/NLRP3 pathways. M-RMT also induced mucosal inflammation and impaired intestinal barrier integrity, leading to increased endotoxemia and systemic inflammation. Moreover, we showed that M-RMT mirrored ruminal microbiota disruption in the gut of recipient mice, as evidenced by enriched Proteobacteria and similar bacterial functions, which were correlated with most proinflammatory parameters and serum lipopolysaccharide (LPS) levels in mice. Recurrent low-grade LPS treatment mirrored gut dysbiosis-induced endotoxemia and caused severe mastitis in mice. Furthermore, we found that gut dysbiosis-derived LPS reduced host alkaline phosphatase activity by activating neuraminidase (Neu), which facilitates low-grade LPS exposure and E. coli-induced mastitis in mice. Conversely, treatment with calf intestinal alkaline phosphatase or the Neu inhibitor zanamivir alleviated low-grade LPS exposure and E. coli-induced mastitis in mice.

CONCLUSIONS

Our results suggest that ruminal dysbiosis-derived low-grade endotoxemia can cause mastitis and aggravate pathogen-induced mastitis by impairing host anti-inflammatory enzymes, which implies that regulating the ruminal or gut microbiota to prevent low-grade systemic inflammation is a potential strategy for mastitis intervention. Video Abstract.

Changes in the rumen microbiota community in ketosis cows during propylene glycol treatment

Ketosis, a common metabolic disorder in dairy cattle, occurs during early lactation and leads to higher concentrations of non-esterified fatty acids (NEFAs) and β-hydroxybutyrate (BHBA), and is generally believed to be caused by excessive negative energy balance (NEB). Propylene glycol (PG), a gluconeogenic precursor, has been proved to promote gluconeogenesis and alleviate NEB. Oral administration of PG is widely considered one of the most effective therapeutic options for treating ketosis. Thus, in this study, we assessed the effects of PG on rumen microbiota via 16S rDNA analysis. The results show that one dose (500 mL) of PG treatment could rapidly reduce the blood BHBA level in ketosis cows by increasing the level and proportion of propionate in the rumen. Meanwhile, PG also had certain effects on the rumen bacterial community. Compared with before treatment, the relative abundances of Prevotella, Succinivibrionaceae_UCG-001 and Prevotellaceae_UCG-001 increased significantly, while those of Christensenellaceae_R-7_group, Butyrivibrio and Saccharofermentans significantly decreased. LEfSe analysis revealed that after PG treatment, only Rikenellaceae_RC9_gut_group was enriched in the rumen fluid at the genus level. In conclusion, the present study indicates that ketosis is accompanied by alterations in the rumen microbiota community. PG treatment changes the composition of rumen microbiota to a healthier state and contributes to rapid recovery from ketosis. These results support the usage of PG for treating such metabolic diseases that challenge high-yield cows due to their minimized cost and maximized safety without any adverse events.

Formononetin Protects LPS-Induced Mastitis Through Suppressing Inflammation and Enhancing Blood-Milk Barrier Integrity via AhR-Induced Src Inactivation

Formononetin (FOR), a natural flavonoid derived from Radix Astragali, has been reported to have anti-inflammatory and anti-oxidative effects. However, its protective mechanism against mastitis is still unknown. Nuclear factor kappa-B (NF-κB) signaling pathway plays an important role in inflammation, especially mastitis. Aryl hydrocarbon receptor (AhR) is involved in inflammatory regulation and defense against diseases. We investigated the protective effect of FOR on LPS-induced mastitis in mice and the effect of Ahr and NF-κB signaling pathways on the development of mastitis. In this study, mastitis model was induced by LPS injection through the nipple duct. Protective effect of FOR on LPS-induced mastitis was assessed by FOR pretreatment. The protective mechanism of FOR against mastitis was further investigated using LPS stimulation on mouse mammary epithelial cells EpH4-Ev. The results showed that LPS-induced mammary histological injury was inhibited by FOR. FOR significantly inhibited LPS-induced MPO activity. FOR administration enhanced the integrity of blood-milk barrier. In vitro and in vivo experiments showed that FOR inhibited LPS-induced NF-κB signaling pathway activation and the production of inflammatory factors TNF-α and IL-1ß. Moreover, FOR increased the expression of tight junction protein and enhanced blood-milk barrier integrity. LPS activated AhR and Src expression. But FOR induced significant increase in AhR inhibited Src phosphorylation to exert anti-inflammatory effects. In addition, AhR antagonist CH223191 reversed the inhibition of FOR on Src expression. And the inhibition of FOR on NF-κB activation and inflammatory cytokine production were reversed by AhR antagonist CH223191. In conclusion, FOR had protective effects against LPS-induced mastitis via suppressing inflammation and enhancing blood-milk barrier integrity via AhR-induced Src inactivation.

Development and validation of an individualized nomogram for predicting the high-volume (> 5) central lymph node metastasis in papillary thyroid microcarcinoma

PURPOSE

Papillary thyroid microcarcinoma (PTMC) frequently presents a favorable clinical outcome, while aggressive invasiveness can also be found in some of this population. Identifying the risk clinical factors of high-volume (> 5) central lymph node metastasis (CLNM) in PTMC patients could help oncologists make a better-individualized clinical decision.

METHODS

We retrospectively reviewed the clinical characteristics of adult patients with PTC in the Surveillance, Epidemiology, and End Results (SEER) database between Jan 2010 and Dec 2015 and in one medical center affiliated to Chongqing Medical University between Jan 2018 and Oct 2020. Univariate and multivariate logistic regression analyses were used to determine the risk factors for high volume of CLNM in PTMC patients.

RESULTS

The male gender (OR = 2.02, 95% CI 1.46-2.81), larger tumor size (> 5 mm, OR = 1.64, 95% CI 1.13-2.38), multifocality (OR = 1.87, 95% CI 1.40-2.51), and extrathyroidal invasion (OR = 3.67; 95% CI 2.64-5.10) were independent risk factors in promoting high-volume of CLNM in PTMC patients. By contrast, elderly age (≥ 55 years) at diagnosis (OR = 0.57, 95% CI 0.40-0.81) and PTMC-follicular variate (OR = 0.60, 95% CI 0.42-0.87) were determined as the protective factors. Based on these indicators, a nomogram was further constructed with a good concordance index (C-index) of 0.702, supported by an external validating cohort with a promising C-index of 0.811.

CONCLUSION

A nomogram was successfully established and validated with six clinical indicators. This model could help surgeons to make a better-individualized clinical decision on the management of PTMC patients, especially in terms of whether prophylactic central lymph node dissection and postoperative radiotherapy should be warranted.

Construction and validation of a nomogram for predicting cervical lymph node metastasis in classic papillary thyroid carcinoma

PURPOSE

Patients with papillary thyroid carcinoma (PTC) frequently present a relatively poor prognosis when they coexist with cervical lymph node metastasis (LNM). Moreover, it remains controversial whether prophylactic lymph node dissection (LND) should be performed for patients without clinically lymph node metastasis. Thus, we hereby develop a nomogram for predicting the cervical LNM (including central and lateral LNM) in patients with PTC.

METHODS

We retrospectively reviewed the clinical characteristics of adult patients with PTC in the surveillance, epidemiology, and end results (SEER) database between 2010 and 2015 and in our Department of Breast and Thyroid Surgery in the Second Affiliated Hospital of Chongqing Medical University between 2019 and 2020.

RESULT

A total of 21,972 patients in the SEER database and 747 patients in our department who met the inclusion criteria were enrolled in this study. Ultimately, six clinical features including age, gender, race, extrathyroidal invasion, multifocality, and tumor size were identified to be associated with cervical LNM in patients with PTC, which were screened to develop a nomogram. This model had satisfied discrimination with a concordance index (C-index) of 0.733, supported by both internal and external validation with a C-index of 0.731 and 0.716, respectively. A decision curve analysis was subsequently made to evaluate the feasibility of this nomogram for predicting cervical LNM. Besides, a positive correlation between nomogram score and the average number of lymph node metastases was observed in all groups.

CONCLUSION

This visualized multipopulational-based nomogram model was successfully established. We determined that various clinical characteristics were significantly associated with cervical LNM, which would be better helping clinicians make individualized clinical decisions for PTC patients.

P1021Comparative efficacy of microfidelity technology vs standard ablation for atrioventricular nodal ablation

Background

Microfidelity Cateter Technology has proven efficacy in ablating atrial arrhythmias in multiple pilot studies. Closely spaced radial microelectrodes render a focused near-field electrogram. Case series suggest that this catheter design facilitates accurate ablations with fewer radiofrequency (RF) lesions. Atrioventricular junction (AVJ) ablation is regarded as a straightforward procedure, but case records show wide variance in procedure times and number of RF lesions required.

Methods

Twenty-four patients scheduled for AVJ ablation were randomized to treatment with either the Microfidelity technology or standard 8mm/8 French ablation catheter. Both groups located the AVJ by fluoroscopic landmarks and His electrograms, and the MiFi group used electroanatomical mapping to create the location of his electrograms. The primary endpoints were development of Junctional Rhythm (JR) or Complete Heart Block (CHB), and time from first RF lesion until rhythm change. Secondary endpoints included number of RF applications.

Results

Patients were randomized one-to-one to the MiFi arm or standard ablation arm. JR or CHB was achieved in all patients. Time from first RF lesion until JR/CHB was: (Median/IQR) 325 sec/250–1270 sec. vs 287 sec/101–406 sec. Number of RF applications was 5/3–15 applications vs 4.5/1–5 applications. Total procedure time in the lab was 134 min/73.5–172.5 min vs 58 min/52–146 min.

Microfidelity Technology vs Standard

Conclusion

Analysis suggests that the MiFi catheter is efficacious in ablating the AVJ, but requires greater RF duration and number of lesions, with wider case-by-case variability to achieve JR or CHB. Microfidelity technology and electroanatomical mapping did not result in faster time to completion than using fluoroscopic landmarks and His electrograms alone. Preoperative choice of sheath for catheter stability and contact may also play a role in a more efficient timely successful ablation of the AV node.

Acknowledgement/Funding

Boston Scientific

Extended solid solutions and coherent transformations in nanoscale olivine cathodes

Nanoparticle LiFePO4, the basis for an entire class of high power Li-ion batteries, has recently been shown to exist in binary lithiated/delithiated states at intermediate states of charge. The Mn-bearing version, LiMn(y)Fe(1-y)PO4, exhibits even higher rate capability as a lithium battery cathode than LiFePO4 of comparable particle size. To gain insight into the cause(s) of this desirable performance, the electrochemically driven phase transformation during battery charge and discharge of nanoscale LiMn0.4Fe0.6PO4 of three different average particle sizes, 52, 106, and 152 nm, is investigated by operando synchrotron radiation powder X-ray diffraction. In stark contrast to the binary lithiation states of pure LiFePO4 revealed in recent investigations, the formations of metastable solid solutions covering a remarkable wide compositional range, including while in two-phase coexistence, are observed. Detailed analysis correlates this behavior with small elastic misfits between phases compared to either pure LiFePO4 or LiMnPO4. On the basis of time- and state-of-charge dependence of the olivine structure parameters, we propose a coherent transformation mechanism. These findings illustrate a second, completely different phase transformation mode for pure well-ordered nanoscale olivines compared to the well-studied case of LiFePO4.

Association between KCNQ1 genetic variants and QT interval in a Chinese population

AIM

There is a close link between electrocardiographic ventricular repolarization QT parameters and Type 2 diabetes. The aim of the present study was to assess the effects of QT-related and diabetes-related variants in KCNQ1 on QT interval in a Chinese population.

METHODS

We recruited 2415 patients with Type 2 diabetes and 1163 subjects with normal glucose regulation in the present study. QT interval was obtained and the heart rate-corrected QT interval (QTc) was calculated using Bazett's formula. Four single nucleotide polymorphisms in KCNQ1 were selected (rs12296050, rs12576239, rs2237892 and rs2237895) and genotyped.

RESULTS

In participants with normal glucose regulation, the minor allele T of rs12296050 was associated with a 3.46-ms QTc prolongation under an additive model (P = 0.0109, empirical P = 0.0498). In patients with Type 2 diabetes, we did not find any association for the single nucleotide polymorphisms.

CONCLUSIONS

Our findings indicate that KCNQ1 is associated with QT interval in a Chinese population with normal glucose regulation.

Genome-wide association study in a Chinese population identifies a susceptibility locus for type 2 diabetes at 7q32 near PAX4

AIMS/HYPOTHESIS

Most genetic variants identified for type 2 diabetes have been discovered in European populations. We performed genome-wide association studies (GWAS) in a Chinese population with the aim of identifying novel variants for type 2 diabetes in Asians.

METHODS

We performed a meta-analysis of three GWAS comprising 684 patients with type 2 diabetes and 955 controls of Southern Han Chinese descent. We followed up the top signals in two independent Southern Han Chinese cohorts (totalling 10,383 cases and 6,974 controls), and performed in silico replication in multiple populations.

RESULTS

We identified CDKN2A/B and four novel type 2 diabetes association signals with p < 1 × 10(-5) from the meta-analysis. Thirteen variants within these four loci were followed up in two independent Chinese cohorts, and rs10229583 at 7q32 was found to be associated with type 2 diabetes in a combined analysis of 11,067 cases and 7,929 controls (p meta = 2.6 × 10(-8); OR [95% CI] 1.18 [1.11, 1.25]). In silico replication revealed consistent associations across multiethnic groups, including five East Asian populations (p meta = 2.3 × 10(-10)) and a population of European descent (p = 8.6 × 10(-3)). The rs10229583 risk variant was associated with elevated fasting plasma glucose, impaired beta cell function in controls, and an earlier age at diagnosis for the cases. The novel variant lies within an islet-selective cluster of open regulatory elements. There was significant heterogeneity of effect between Han Chinese and individuals of European descent, Malaysians and Indians.

CONCLUSIONS/INTERPRETATION

Our study identifies rs10229583 near PAX4 as a novel locus for type 2 diabetes in Chinese and other populations and provides new insights into the pathogenesis of type 2 diabetes.

Genetic variants of LPIN1 indicate an association with Type 2 diabetes mellitus in a Chinese population

AIMS

Metabolic disorders are independent risk factors for the development of Type 2 diabetes. The aim of the study is to test the association of LPIN1 variants with Type 2 diabetes and clinical characteristics in large samples of the Chinese population.

METHODS

In the first stage, 15 single nucleotide polymorphisms within the LPIN1 region were selected and genotyped in 3700 Chinese Han participants. In the second stage, the single nucleotide polymorphisms showing significant association or trends towards association were genotyped in an additional 3122 samples for replication. Meta-analyses and genotype-phenotype association studies were performed after combining the data from the two stages.

RESULTS

In the first stage, we detected that rs16857876 was significantly associated with Type 2 diabetes with an odds ratio of 0.806 (95% CI 0.677-0.958, P = 0.015), while rs11695610 showed a trend with Type 2 diabetes (odds ratio 0.846, 95% CI 0.709-1.009, P = 0.062). In the second stage, a similar effect of rs11695610 on Type 2 diabetes was observed (odds ratio 0.849, 95% CI 0.700-1.030, P = 0.096). The meta-analyses combining the information from the two stages showed a significant effect of rs11695610 on Type 2 diabetes with an odds ratio of 0.847 (95% CI 0.744-0.965, P = 0.012). Finally, the phenotype-genotype association analyses showed that rs11695610 was associated with 2-h plasma glucose (P = 0.040) and triglyceride levels (P = 0.034).

CONCLUSIONS

Our data implied that common single nucleotide polymorphisms within the LPIN1 region were associated with Type 2 diabetes and metabolic traits in the Chinese population.

Functional analyses of the mutation nt-128 T→G in the hepatocyte nuclear factor-1α promoter region in Chinese diabetes pedigrees

AIMS

Hepatocyte nuclear factor-1α (HNF-1α) regulates the expression of genes encoding proteins involved in glucose metabolism and insulin secretion. Mutations in the HNF-1α gene cause maturity-onset diabetes of the young Type 3. However, the mechanism leading to this disease has not been completely ascertained. Previously, we found a novel mutation in the regulatory element of the human HNF-1α gene in two Chinese diabetes pedigrees. The nucleotide at position -128 T was substituted by G (nt-128 T→G). In this study, we analysed the functional defect of nt-128 T→G in HNF-1α transcription activity.

METHODS

Luciferase reporter gene assays were carried out to examine the functional characteristics of this mutant. Electrophoretic mobility shift assays and chromatin immunoprecipitation were performed to confirm the binding of nuclear proteins to oligonucleotides.

RESULTS

The variant construct (nt-128 T→G) had a 1.65-fold increase in promoter activity compared with that of the wild-type construct in HepG2 cells and a 1.33-fold increase in MIN6 cells, respectively. The variant resided at a FOXA/HNF-3 binding site identified by a series of competitive electrophoretic mobility shift assays and antibody supershift analyses. The assays showed a differential binding affinity in the wild-type and the nt-128 T→G mutant fragments by FOXA/HNF-3. Chromatin immunoprecipitation indicated that FOXA/HNF-3 bound to this region in vivo. One nucleotide substitution in the FOXA/HNF-3 site in the human HNF-1α regulatory element caused an increase of HNF-1α transcriptional activity.

CONCLUSIONS

Our data suggested that this substitution in the promoter region affects DNA-protein interaction and HNF-1α gene transcription. The mutant may contribute to the development of diabetes in these two nt-128 T→G pedigrees of Chinese.

Association between KCNQ1 genetic variants and obesity in Chinese patients with type 2 diabetes

AIMS/HYPOTHESIS

There is evidence of overlap between susceptibility loci for type 2 diabetes and obesity. The aim of this study is to explore the association between the established type 2 diabetes locus KCNQ1 and obesity in Han Chinese.

METHODS

We recruited 6,667 and 6,606 diabetic case-control samples from Shanghai and Hong Kong, respectively. Of the samples, 7.5% and 6.3% were excluded because of genotyping failure or data missing in the association analyses of rs2237892 and rs2237895 with obesity/BMI, respectively.

RESULTS

We found that rs2237892 was associated with lower BMI and lower incidence of overweight/obesity in diabetic patients from Hong Kong (BMI, β = -0.0060 per diabetes risk C allele for log(10)BMI [95% CI -0.0088, -0.0032; p = 2.83 × 10(-5)]; overweight/obesity, OR 0.880 for C allele [95% CI 0.807, 0.960; p = 0.004]) and in the meta-analysis of cases from the two regions (BMI, combined β = -0.0048 per C allele for log(10)BMI [95% CI -0.0070, -0.0026; p = 2.20 × 10(-5)]; overweight/obesity, combined OR 0.890 for C allele [95% CI 0.830, 0.955; p = 0.001]). rs2237895 was also related to decreased BMI (combined β = -0.0042 per diabetes risk C allele for log(10)BMI [95% CI -0.0062, -0.0022; p = 4.30 × 10(-5)]). A significant association with waist circumference was detected for rs2237892 in the pooled analyses (β = -0.0026 per C allele for log(10)[waist circumference] [95% CI -0.0045, -0.0007; p = 0.007]). However, neither an association with the risk of being overweight or obese nor associations with quantitive traits were detected for rs2237892 or rs2237895 in controls.

CONCLUSION

Our findings indicate that KCNQ1 is associated with obesity in Chinese patients with type 2 diabetes.

Increment of 30-min post-challenge plasma glucose is associated with urine albumin excretion in men with normal glucose regulation

AIMS

The overwhelming majority of subjects with normal glucose regulation have the highest plasma glucose concentration at 30 minutes during oral glucose tolerance. We aimed to examine the association between increment of 30-min post-challenge glucose and albuminuria in participants with normal glucose regulation.

METHODS

A population-based cross-sectional study was conducted in six communities in Shanghai between 2007 and 2008. A total of 3508 subjects with normal glucose regulation had complete data and were enrolled into the analysis. Among the selected subjects, only 1525 individuals (581 men, 944 women) were examined for their serum insulin levels. We assessed post-challenge blood glucose and insulin at 0, 30 and 120 min, urinary albumin and creatinine. The 30-min post-challenge glucose increment (Δ) was calculated as 30-min post-challenge glucose minus fasting plasma glucose, and albumin/creatinine ratio was used to reflect urinary albumin excretion.

RESULTS

Multivariable logistic regression analysis revealed that the Δ30-min post-challenge glucose was independently associated with increased albumin/creatinine ratio in men with normal glucose regulation (OR = 1.08, P = 0.025), but not in women. Furthermore, multivariable linear regression analysis revealed that early-phase glucose disposition index was the main factor responsible for Δ30-min post-challenge glucose and explained 14-20% of the variance of Δ30-min post-challenge glucose in the two subgroups (P < 0.05). Notably, men had higher Δ30-min post-challenge glucose and lower early-phase glucose disposition index than women (all P < 0.001).

CONCLUSIONS

The 30-min post-challenge plasma glucose increment is associated with urine albumin excretion in men with normal glucose regulation.

Effects of KCNQ1 polymorphisms on the therapeutic efficacy of oral antidiabetic drugs in Chinese patients with type 2 diabetes

The aim of this study was to explore the impact of KCNQ1 variants on the responses to oral antidiabetic drugs in a Chinese study population. A 48-week randomized pharmacogenetics study compared the effects of repaglinide and rosiglitazone in 209 newly diagnosed patients with type 2 diabetes. In the repaglinide cohort, individuals who were rs2237892 TT homozygotes exhibited lower 2-h glucose levels and significantly higher cumulative attainment rates of target 2-h glucose levels (P(log-rank) = 0.0383) than the C allele carriers; patients with a greater number of rs2237892 C alleles showed larger augmentations in both fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) (P = 0.0166 and 0.0026, respectively); moreover, the rs2237895 C allele was also associated with greater increments in both fasting insulin and HOMA-IR (P = 0.0274 and 0.0259, respectively). In contrast, only an association between rs2237897 and decrease in 2-h glucose levels was detected in the rosiglitazone cohort (P = 0.0321). Our results indicated that KCNQ1 polymorphisms are associated with repaglinide efficacy, and might also be associated with rosiglitazone response, in Chinese patients with type 2 diabetes.

A common variant of NOS1AP is associated with QT interval duration in a Chinese population with Type 2 diabetes

AIMS

Electrocardiographic ventricular repolarization QT parameters are independent risk factors for cardiovascular events and sudden cardiac death in diabetic patients. The aim of the study was to investigate the association of polymorphisms of the nitric oxide synthase 1 adaptor protein (NOS1AP) gene with QT interval in Chinese subjects with or without Type 2 diabetes.

METHODS

Three single nucleotide polymorphisms (SNPs) (rs10494366, rs12143842 and rs12029454) were genotyped in 1240 Type 2 diabetic patients (631 men and 609 women) and 1196 normal controls (433 men and 763 women). Individuals with overt diseases other than diabetes were excluded. Heart-rate corrected QT interval (QTc) was determined by standard 12-lead ECG and Bazett formula. Sex-pooled analysis and sex-specific analysis for genotype-phenotype association were both conducted.

RESULTS

In the diabetic group, the rs12143842 T allele was associated with a 3.87-ms (P = 0.014, empirical P = 0.039) increase in QTc duration for each additional allele copy, while rs10494366 and rs12029454 exhibited no significant association with QTc. We found no evidence of association for the three SNPs in subjects with normal glucose regulation. No significant SNP-gender and -diabetes affection interaction was observed.

CONCLUSIONS

The genetic variant rs12143842 in NOS1AP is associated with QT interval duration in a Chinese population with Type 2 diabetes. Future studies in different populations are needed to validate this finding and to evaluate the impact of NOS1AP variants on cardiovascular events and sudden cardiac death in diabetic patients.

Association of genetic variants of NOS1AP with type 2 diabetes in a Chinese population

AIMS/HYPOTHESIS

Chromosome 1q21-q24 has been shown to be linked to type 2 diabetes. The International Type 2 Diabetes 1q Consortium showed that one of the nominal associations was located in the NOS1AP gene. Although this association was not replicated in additional samples of European descent, it remains unknown whether NOS1AP plays a role in Chinese individuals.

METHODS

In stage 1 analyses, 79 single nucleotide polymorphisms (SNPs) of the NOS1AP gene were successfully genotyped in a group of Shanghai Chinese individuals, comprising 1,691 type 2 diabetes patients and 1,720 control participants. In stage 2 analyses, the SNP showing the strongest association was genotyped in additional Chinese individuals, including 1,663 type 2 diabetes patients and 1,408 control participants.

RESULTS

In stage 1 analyses, 20 SNPs were nominally associated with type 2 diabetes (p < 0.05), with SNP rs12742393 showing the strongest association (OR 1.24 [95% CI 1.11-1.38]; p = 0.0002, empirical p = 0.019). Haplotype analysis also confirmed the association between rs12742393 and type 2 diabetes. In stage 2 analyses, the difference in allele frequency distribution of rs12742393 did not reach statistical significance (p = 0.254). However, the meta-analysis showed a significant association between rs12742393 and type 2 diabetes with an OR of 1.17 (95% CI 1.07-1.26; p = 0.0005).

CONCLUSIONS/INTERPRETATION

Our data suggest that NOS1AP variants may not play a dominant role in susceptibility to type 2 diabetes, but a minor effect cannot be excluded.

Variations in KCNQ1 are associated with type 2 diabetes and beta cell function in a Chinese population

AIMS/HYPOTHESIS

Recent genome-wide association studies in East Asian populations reported that single nucleotide polymorphisms (SNPs) in KCNQ1 are associated with type 2 diabetes. The aim of this study was to validate this finding in a Chinese population.

METHODS

We genotyped four SNPs, rs2074196, rs2237892, rs2237895 and rs2237897, in a group of 3,503 Shanghai Chinese individuals, comprising 1,769 type 2 diabetic patients and 1,734 normoglycaemic controls. Both the cases and the controls were extensively phenotyped for anthropometric and biochemical traits related to glucose metabolism. Arginine stimulation tests under fasting conditions were performed in a subgroup of 466 cases.

RESULTS

All four of the SNPs were associated with type 2 diabetes, with rs2237892 showing strongest evidence for association (OR 1.532, 95% CI 1.381-1.698, p = 5.0 x 10(-16)). The SNP rs2237897 was associated with both acute insulin and C-peptide response after arginine stimulation in a subgroup of cases (p = 0.0471 and p = 0.0156, respectively). The SNP rs2237895 was associated with both first- and second-phase insulin secretion in the controls (p = 0.0334 and p = 0.0002, respectively).

CONCLUSIONS/INTERPRETATION

In this study we found that KCNQ1 was associated with type 2 diabetes susceptibility in a Chinese population, possibly through its effect on beta cell function.

A genetic variant of G6PC2 is associated with type 2 diabetes and fasting plasma glucose level in the Chinese population

AIMS/HYPOTHESIS

Single nucleotide polymorphisms (SNPs) in G6PC2 have been reported to be associated with fasting plasma glucose level in several populations of European descent. However, whether G6PC2 variants have a similar effect in other ethnic groups is unknown. The aim of this study was to investigate the effect of common variants of G6PC2 on type 2 diabetes and related clinical features in a Chinese population.

METHODS

We selected four SNPs, rs13387347, rs2232316, rs492594 and rs16856187, tagging all the common variants spanning the G6PC2 gene (r(2) >or= 0.8) based on HapMap Chinese data, and genotyped them in a group of 3,676 Shanghai Chinese individuals, comprising 1,876 cases and 1,800 controls.

RESULTS

Three SNPs were nominally associated with type 2 diabetes, with rs16856187 showing the strongest evidence for association (p = 0.0009, empirical p = 0.0047). Further conditional analysis revealed that the association signal arose from an individual SNP, rs16856187. This SNP was also associated with fasting plasma glucose level in participants with normal glucose regulation (p = 0.0002), with the fasting plasma glucose level observed to increase by 0.067 mmol/l with each copy of the rare C allele.

CONCLUSIONS/INTERPRETATION

In this study we identified a novel risk-conferring G6PC2 SNP for type 2 diabetes in a Chinese population and confirmed the previous finding that G6PC2 variants are associated with fasting plasma glucose concentration.

Chronic benzodiazepine-induced reduction in GABA(A) receptor-mediated synaptic currents in hippocampal CA1 pyramidal neurons prevented by prior nimodipine injection

One week oral flurazepam (FZP) administration in rats results in reduced GABA(A) receptor-mediated synaptic transmission in CA1 pyramidal neurons associated with benzodiazepine tolerance in vivo and in vitro. Since voltage-gated calcium channel (VGCC) current density is enhanced twofold during chronic FZP treatment, the role of L-type VGCCs in regulating benzodiazepine-induced changes in CA1 neuron GABA(A) receptor-mediated function was evaluated. Nimodipine (10 mg/kg, i.p.) or vehicle (0.5% Tween 80, 2 ml/kg) was injected 1 day after ending FZP treatment and 24 h prior to hippocampal slice preparation for measurement of mIPSC characteristics and in vitro tolerance to zolpidem. The reduction in GABA(A) receptor-mediated mIPSC amplitude and estimated unitary channel conductance measured 2 days after drug removal was no longer observed following prior nimodipine injection. However, the single nimodipine injection failed to prevent in vitro tolerance to zolpidem's ability to prolong mIPSC decay in FZP-treated neurons, suggesting multiple mechanisms may be involved in regulating GABA(A) receptor-mediated synaptic transmission following chronic FZP administration. As reported previously in recombinant receptors, nimodipine inhibited synaptic GABA(A) receptor currents only at high concentrations (>30 muM), significantly greater than attained in vivo (1 muM) 45 min after a single antagonist injection. Thus, the effects of nimodipine were unlikely to be related to direct effects on GABA(A) receptors. As with nimodipine injection, buffering intracellular free [Ca(2+)] with BAPTA similarly prevented the effects on GABA(A) receptor-mediated synaptic transmission, suggesting intracellular Ca(2+) homeostasis is important to maintain GABA(A) receptor function. The findings further support a role for activation of L-type VGCCs, and perhaps other Ca(2+)-mediated signaling pathways, in the modulation of GABA(A) receptor synaptic function following chronic benzodiazepine administration, independent of modulation of the allosteric interactions between benzodiazepine and GABA binding sites.

Effect of RBP4 gene variants on circulating RBP4 concentration and type 2 diabetes in a Chinese population

AIMS

Retinol binding protein 4 (RBP4) is a newly discovered adipokine, which plays a role in insulin resistance and obesity. The aim of this study was to determine the relationship between genetic variants of the RBP4 gene, circulating RBP4 concentrations and phenotypes related to glucose and lipid metabolism in the Chinese population.

METHODS

We sequenced exons and the putative promoter region to identify single nucleotide polymorphisms (SNPs) in the RBP4 gene in 32 Chinese subjects. Additional SNPs were selected from a public database to increase marker density. Taking account of the pairwise linkage disequilibrium and minor allele frequencies, a subset of SNPs was further genotyped in 255 Type 2 diabetic patients and 372 normal control subjects. Circulating RBP4 concentrations and phenotypes related to glucose and lipid metabolism were measured.

RESULTS

Ten SNPs were identified and five were further genotyped in the full sample. No individual SNP was significantly associated with Type 2 diabetes, but a rare haplotype CAA formed by +5388 C>T, +8201 T>A and +8204 T>A was more frequent in diabetic patients (P = 0.0343, empirical P = 0.0659 on 10 000 permutations). In both groups, non-coding SNPs were associated with circulating RBP4 concentrations (P < 0.05). In the normal control subjects, the SNP +5388 C>T was associated with serum C-peptide levels both fasting and 2 h after an oral glucose tolerance test (P = 0.0162 and P = 0.0075, respectively).

CONCLUSION

Our findings suggest that genetic variants in the RBP4 gene may be associated with circulating RBP4 concentration and phenotypes related to glucose metabolism.

The molecular genetics of diabetes mellitus

Diabetes mellitus is a clinically heterogeneous disorder which is characterized by hyperglycaemia due to an absolute or relative deficiency of insulin. Both genetic and non-genetic factors contribute to its development and, as such, it represents a multifactorial disorder. In addition, it may also be, in some instances, a polygenic disorder resulting from the cumulative effects of several genes with or without environmental factors. Serological and/or DNA markers for genes that confer susceptibility to the insulin-dependent form of the disorder (IDDM; type 1) have been identified in the HLA-D region of chromosome 6 and near the insulin gene on chromosome 11. Patients with non-insulin-dependent diabetes mellitus (NIDDM; type 2) make up a more heterogeneous group than those with IDDM and it is likely that in these patients similar clinical phenotypes may be produced by different genetic defects. The synthesis of either an abnormal insulin/proinsulin molecule or an abnormal insulin receptor can confer susceptibility to NIDDM. The genes encoding insulin and the insulin receptor are on chromosomes 11 and 19, respectively. In addition, studies of restriction fragment length polymorphism and disease associations suggest that two other genes may contribute to the development of NIDDM on chromosome 11, one near the insulin gene on the short arm of this chromosome and the other near the apolipoprotein A-I gene on the long arm. None of the susceptibility genes that have been identified to date causes diabetes in the absence of other genetic or non-genetic contributing factors, which is consistent with a multifactorial or polygenic origin for this disorder.

Peroxisome proliferator-activated receptor (PPAR) delta genetic polymorphism and its association with insulin resistance index and fasting plasma glucose concentrations in Chinese subjects

AIMS

Previous studies have shown that the peroxisome proliferator-activated receptor delta (PPARD) genetic polymorphism affects cholesterol metabolism in Whites. This association was not observed in a Korean population in a separate study, but this study showed a link between the PPARD polymorphism and body weight and fasting plasma glucose. The purpose of this study was to determine whether polymorphisms of PPARD influence glucose and cholesterol metabolism in Chinese subjects. We investigated the association between the polymorphism (-87T/C) of the human PPARD gene and phenotypes related to body weight, insulin sensitivity, glucose and lipid metabolism in Chinese subjects.

METHODS

Unrelated Chinese subjects (n = 663) in Shanghai were studied; 287 had newly diagnosed Type 2 diabetes mellitus and 376 were non-diabetic control subjects over 40 years old. Clinical parameters were collected and genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

In normal glucose tolerant (NGT) subjects, the C allele carriers had higher fasting plasma glucose concentrations (P = 0.0078) and a lower insulin sensitivity index (ISI) (P = 0.0365). The C allele carriers also showed higher concentrations of low-density lipoprotein cholesterol (P = 0.0261) and percentage of body fat (P = 0.0357). There was a trend towards higher visceral adiposity in C allele carriers, but the difference was not significant (P = 0.0830). In diabetes patients, similar results were detected for plasma glucose concentrations (fasting plasma glucose P < 0.0001, 2-h plasma glucose P = 0.0052) and insulin sensitivity (homeostasis model assessment of insulin resistance P = 0.0094; ISI P = 0.0058).

CONCLUSION

The PPARD-87T/C polymorphism is associated with higher fasting plasma glucose concentrations in both NGT and diabetic subjects, largely due to impaired insulin sensitivity.

Scanning for MODY5 gene mutations in Chinese early onset or multiple affected diabetes pedigrees

Mutation of HNF-1beta gene has been reported in early onset diabetes or MODY families and this gene has been defined as MODY5 gene. The aim of our study was to examine whether HNF-1beta mutation contribute to early onset or multiple affected diabetes pedigrees in Chinese. Molecular scanning of HNF-1beta gene promoter region, nine exons and flanking introns was performed in 154 unrelated probands from early onset and multiple affected diabetes Chinese pedigrees. The family members of probands with mutations or variants and 58 nondiabetics were also examined. Clinical examinations of renal morphology, renal function and beta-cell function were performed in the HNF-1beta gene mutation carriers and family members. Mutation of HNF-1beta gene causing the substitution S36F was found in two subjects of an early onset diabetic family. One carrier has early onset diabetes, renal function impairment and renal cyst, while the other has impaired glucose tolerance only. This is the first case of MODY5 gene mutation diabetes found in the Chinese. Three HNF-1beta variants were identified and no significant differences in allele frequencies for these variants were detected between the nondiabetic and diabetic groups. Nucleotide 66 of intron 8 of HNF-1beta gene was G in the Chinese population rather than A as noted in the GenBank sequence. These results suggest that HNF-1beta gene mutations may be associated with nondiabetic renal dysfunction and diabetes in Chinese, but they are responsible for only a small percentage of early onset or multiple affected diabetes pedigrees including MODY.

[The impact of calpain-10 gene combined-SNP variation on type 2 diabetes mellitus and its related metabolic traits]

OBJECTIVE

To investigate the impact of calpain-10 gene (CAPN-10) combined single nucleotide polymorphism (SNP) variation on type 2 diabetes mellitus (T2DM) and its related clinical metabolic traits in Chinese.

METHODS

The study population consisted of 268 Chinese residents in Shanghai. Among them, 144 were subjects with normal glucose tolerance (NGT) and 124, with T2DM. Plasma glucose (PG), insulin (INS), c-peptide (CP) and free fatty acids (FFA) levels were measured at fasting and 30, 60, 120, and 180 minutes after oral 75 g glucose challenge. The islet beta-cell insulin secretion and tissue insulin sensitivity were assessed. CAPN-10 UCSNP44,-43,-19 and -63 were genotyped.

RESULTS

(1) In Chinese NGT subjects, the major allele of UCSNP-44 was allele T (frequency=91%), of UCSNP43 was G(89%), of UCSNP-19 was I (3 repeats of a 32 bp sequence) (67%) and of UCSNP-63 was C allele (79%). Significant differences were observed in comparison of these allele frequencies in Chinese to those in other ethnic groups reported in the literature. (2) 14 genotype combinations of these four SNPs were observed in Chinese NGT subjects. 69% of the NGT population was composed of four genotype combinations, in the order of UCSNP44,-43,-19 and -63, i.e., combination A:TT-GG-DI-CC(haplotype combination was 1121/1111) (frequency=10%), combination B:TT-GA-II-CC(1121/1221)(10%), combination C:TT-GG-II-CC(1121/1121)(26%) and combination D:TT-GG-DI-CT(1121/1112)(22%).(3) The frequencies of the above mentioned SNP in single or in combinations were not different significantly between NGT and T2DM groups. (4) The variation of clinical metabolic parameter levels shifted from completely normal towards abnormal glucose intolerance among genotype combination subgroups. In comparison between combination A and combination D, subjects in the former subgroups had: higher PG levels with delayed peak after glucose challenge; less and lower decrement of FFA levels after challenge with no rising in late stage; higher insulin levels with delayed peak after challenge; and the tendency of decreased insulin sensitivity. More than half of the comparisons remained statistically significant after adjusted with age, gender, body mass index and waist circumference.

CONCLUSION

The variation of calpain-10 gene has impact on the variation of clinical metabolic parameter levels related to type 2 diabetes mellitus. Such impact depends upon the haplotypes as well as the haplotype combination of calpain-10 gene variations.

[Dyslipidaemia and insulin resistance in Chinese in Shanghai]

OBJECTIVE

To investigate the impact of dyslipidaemia on insulin resistance in Chinese individuals in Shanghai.

METHODS

830 individuals aged over 40 years (male 300, female 530) were divided into normal and dyslipidaemia groups. The latter included 7 subgroups as follows: low high density lipoprotein (L-HDL)-subgroup I, high triglycerides (H-TG)-subgroup II, high total cholesterol or high low density lipoprotein (H-TC/H-LDL)-subgroup III, low high density lipoprotein with high triglycerides (L-HDL + H-TG)-subgroup IV, low high density lipoprotein with high total cholesterol or high low density lipoprotein (L-HDL + H-TC/H-LDL)-subgroup V, high triglycerides with high total cholesterol or high low density lipoprotein(H-TG + H-TC/H-LDL)-subgroup VI, low high density lipoprotein with high triglycerides and high total cholesterol or high low density lipoprotein (L-HDL + H-TG + H-TC/H-LDL)-subgroup VII. Homeostasis model assessment (HOMA) was applied to estimate the degree of insulin resistance (IR).

RESULTS

(1) Adjusted with age, sex and body mass index (BMI), HOMA-IR was increased in the dyslipidaemia subgroups with high triglycerides. (2) Hypertriglyceridemia was more closely related to raised BMI and waist-hip ratio (WHR). (3) Both body fat (BMI, WHR) and triglycerides were independent risk factors accounting for HOMA-IR.

CONCLUSION

Hypertriglycerides could be regarded as an independent risk factor for insulin resistance.

Gene regulatory networks generating the phenomena of additivity, dominance and epistasis

We show how the phenomena of genetic dominance, overdominance, additivity, and epistasis are generic features of simple diploid gene regulatory networks. These regulatory network models are together sufficiently complex to catch most of the suggested molecular mechanisms responsible for generating dominant mutations. These include reduced gene dosage, expression or protein activity (haploinsufficiency), increased gene dosage, ectopic or temporarily altered mRNA expression, increased or constitutive protein activity, and dominant negative effects. As classical genetics regards the phenomenon of dominance to be generated by intralocus interactions, we have studied two one-locus models, one with a negative autoregulatory feedback loop, and one with a positive autoregulatory feedback loop. To include the phenomena of epistasis and downstream regulatory effects, a model of a three-locus signal transduction network is also analyzed. It is found that genetic dominance as well as overdominance may be an intra- as well as interlocus interaction phenomenon. In the latter case the dominance phenomenon is intimately connected to either feedback-mediated epistasis or downstream-mediated epistasis. It appears that in the intra- as well as the interlocus case there is considerable room for additive gene action, which may explain to some degree the predictive power of quantitative genetic theory, with its emphasis on this type of gene action. Furthermore, the results illuminate and reconcile the prevailing explanations of heterosis, and they support the old conjecture that the phenomenon of dominance may have an evolutionary explanation related to life history strategy.

Relationship between the renin-angiotensin system genes and diabetic nephropathy in the Chinese

OBJECTIVE

To clarify whether genetic variants of the renin-angiotensin system (RAS) contribute to the development of diabetic nephropathy (DN) in the Chinese.

METHODS

Totally 173 Chinese subjects of Han nationality from Shanghai were classified into! control, DN (-) and DN (+) groups. The latter was subdivided according to diabetic duration at the onset of DN and the stage of DN. Genotyping of five polymorphic sites in four key genes of the RAS: the AGT-T174M, AGT-M235T and AGTR1 genotypes were determined by PCR/restriction enzyme digestion. The insertion/deletion (I/D) and [ACAC] n-STR microsatellite polymorphic markers were used for ACE and REN genotyping, respectively. Statistical analysis showed comparisons of gene frequencies between any two groups were made with Fisher's exact test or Chi-square test. Logistic regression analysis was performed to identify predictors of DN.

RESULTS

The frequencies of ACE-DD genotype and ACE-D allele were much higher in DN(+) group than in DN (-) group (0.25 vs 0.05, 0.47 vs 0.29, respectively), so were the frequencies of TT genotype and T allele in AGT-M235T (0.73 vs 0.54, 0.85 vs 0.68, respectively). DN (+) DUR < 5 years group had greatly increased frequencies of AGT-M235T allele and ACE-DD genotype in comparison with DN(-) group (0.92 vs 0.68 and 0.28 vs 0.05, respectively). Logistic regression analysis further identified these two genes as contributing factors to DN. Although AGTR1 and AGT-T174M genotyping analysis revealed differences in frequency distribution between DN (+) and DN (-) or control groups, logistic regression analysis failed to implicate them in the development of DN.

CONCLUSIONS

Our study revealed RAS genes, ACE and AGT-M235T but not AGT-T174M, AGTR1 or REN genotypes, as contributing factors for DN in type 2 diabetes mellitus in Chinese.

[The association between A55V variant in UCP2 gene and body fat distribution, serum lipid profile in Chinese]

OBJECTIVE

Uncoupling protein 2(UCP2) could play an important role in energy metabolism and body weight regulation. The aim of this study was to investigate Ala55Val(A55V) variant in the UCP2 gene has effects on serum lipid profile, body fat and its distribution in Chinese.

METHODS

The genotypes of A55V variant in the UCP2 gene were determined by a PCR-RFLP assay in 359 unrelated Chinese [including 193 normal glucose tolerance(NGT) and 166 type 2 diabetic subjects by ADA 97' criteria]. The parameters for regional adipose tissue distribution were measured by magnetic resonance imaging(MRI).

RESULTS

In NGT group, an association between A55V variant in the UCP2 gene and body mass index(BMI) (P=0.0246), as well as femoral subcutaneous adipose tissue area (FA) (P=0.0017), was noted in females. A55V variant in the UCP2 gene was also associated with serum triglyceride (TG) level (P=0.0072) in males. However, in type 2 diabetes group, an association between A55V variant in the UCP2 gene and FA (P=0.0150) was replicated in females too. Those females who were homozygotes of AA in the UCP2 gene had decreased FA not only in NGT group but also in type 2 diabetes group. Furthermore, logistic regression analysis indicated that FA (P=0.0098 in NGT females, P=0.0071 in type 2 diabetic females) and BMI (P=0.0016 in NGT females), as well as TG level (P=0.0040 in NGT males) were associated with this variant in the UCP2 gene.

CONCLUSION

A55V variant in the UCP2 gene is associated not only with FA (in NGT females and type 2 diabetic females) but also with BMI (in NGT females). Therefore A55V variant in the UCP2 gene appears to play a role in body fat and its distribution in Chinese females.

[The mechanism of tumor necrosis factor-alpha (TNF-alpha) induced insulin resistance by variation in promoter region of TNF-alpha gene]

OBJECTIVE

To investigate the relationship between the G to A variant at the--308 bp of the promoter region of tumor necrosis factor-alpha gene (TNF-alpha-P) and the body adiposity, the insulin secretion and action, and the glucose and lipid levels in Chinese population.

METHOD

359 Chinese were genotyped for the TNF-alpha-P by using PCR/Nco I digestion. Fasting blood lipid profile and the levels of plasma glucose (PG), insulin (INS), c-peptide (CP) and the free fatty acids (FFA) at 0, 1/2, 1, 2 and 3 hours after glucose challenge were measured.

RESULTS

Genotype frequencies of TNF-alpha-P were not associated with diabetes and obesity. The genotype frequency of the G/A heterozygotes was significantly increased in non-diabetic subgroups with less decreased levels of 2 h-FFA and AUC-FFA after glucose challenge (Fisher exact P = 0.002 and 0.041 respectively). The FFA levels in non-diabetics with G/A heterozygotes were higher than those with G/G homozygotes, especially in the comparisons of the 2 h and 3 h FFA levels after glucose challenge (P = 0.029 and 0.030 respectively). Similar tendency was also observed in diabetics.

CONCLUSION

Circulation FFA level reflects the degree of lipolysis in adipose tissue. The difference in the degree of lipolysis led by the variant of the promoter region of TNF-alpha may be one of the mechanisms for the variation in the degree of insulin resistance in general population.

[Association of Gln223Arg variant in leptin receptor gene with metabolic abnormalities and hypertension in type II diabetes mellitus in Shanghai "Han" population]

OBJECTIVE

To investigate the association of Gln223Arg variant in leptin receptor gene with metabolic abnormalities and hypertension in type II diabetes mellitus.

METHODS

The genotypes of Gln223Arg variant in leptin receptor gene were determined by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) assay in 359 unrelated subjects of Shanghai "Han" population (including 193 subjects with normal glucose tolerance and 166 type II diabetic patients). The clinical data were also analyzed. The parameters for regional adipose tissue distribution were measured by magnetic resonance imaging (MRI).

RESULTS

Significant difference of genotype frequency of Gln223Arg variant in leptin receptor gene was observed between hypertensive and normotensive type II diabetic male patients (P = 0.008). "A" allele was associated with increased systolic blood pressure (P = 0.0026) and diastolic blood pressure (P = 0.0084) in type II diabetic male patients. Logistic regression analysis showed that this gene variant was an independent risk factor of type II diabetic male patients accompanied with hypertension (P = 0.0031), and it was associated with elevation of systolic blood pressure (P = 0.0054). The odds ratio of hypertension in type II diabetic male patients with "A" allele was 2.825 (95% CI 1.418, 5.627).

CONCLUSION

Gln223Arg variant in leptin receptor gene is associated with hypertension in type II diabetic male patients, especially with elevation of systolic blood pressure.

The impact of codon 54 variation in intestinal fatty acid binding protein gene on the pathogenesis of diabetes mellitus in Chinese

OBJECTIVE

To investigate whether or not the intestinal fatty acid binding protein gene (FABP2)-Ala54Thr variation is related to non-insulin dependent diabetes mellitus (NIDDM), obesity, dyslipidemia and glucose stimulated insulin secretion (GSIS) in Chinese.

METHODS

The FABP2-Ala54Thr variation was detected by PCR/Hhal digestion in 231 Chinese subjects (116 with normal glucose tolerance (NGT), 54 with impaired glucose tolerance (IGT) and 61 with NIDDM). Plasma glucose, insulin and C-peptide levels before and after 75 g glucose load as well as fasting lipid profile were determined.

RESULTS

(1) The Ala54 and Thr54 allele frequencies in Chinese were 0.71 and 0.29 respectively; (2) The FABP2-Ala54Thr variation was neither associated with fasting and post-challenged plasma glucose levels nor with NIDDM; (3) This variation was neither associated with fasting lipid profile nor with obesity; (4) The IGT subjects with genotype Thr54(+) (Thr54 homozygotes and heterozygotes) had lower fasting, 2-hour and total C-peptide levels and smaller AUC representing lesser C-peptide secretion after glucose challenge than those with genotype Thr54(-) (Ala54 homozygotes) (P = 0.04, 0.03, 0.01 and 0.01 respectively). The serum insulin levels changed in the same tendency.

CONCLUSIONS

The glucose stimulated insulin secretion (GSIS) reserve of islet beta-cells is more limited in subjects with FABP2-Thr54(+) genotype than in those with FABP2-Thr54(-) genotype. It suggests that FABP2-codon 54 variation might contribute to the insufficient insulin secretion in the development of NIDDM in Chinese.

[Effects of Trp64Arg mutation in the beta 3-adrenergic receptor gene on body fat, plasma glucose level, lipid profile, insulin secretion and action in Chinese]

OBJECTIVE

To ascertain the association of the Trp64Arg mutation in the beta 3-adrenergic receptor (ADRB3) gene with the total body fat and fat distribution, plasma glucose level, lipid profile, insulin secretion and action in Chinese.

METHODS

Genotyping of the Trp64Arg mutation in the ADRB3 gene as well as measurment of clinical variables body mass index(BMI), percent of desirable weight(PDW), area of regional adipose tissue depots, fasting lipid profile, and also, plasma glucose, insulin, C-peptide, free fatty acids levels before and after glucose challenge and blood pressure were performed in 308 Chinese, of whom, 161 were nondiabetics and 147, type 2 diabetic subjects.

RESULTS

(1) The frequency of Arg64 allele of ADRB3 gene in Chinese was similar to that in Japanese but slightly higher than that in Caucasians. (2) No association of any of the clinical varaibles with Trp64Arg mutation was observed in nondiabetics. (3) The Trp64Arg mutation in the ADRB3 gene was associated with BMI(P=0.019), PDW(P=0.001) and waist circumference (P=0.045) in type 2 diabetic subjects. In female diabetic subjects, more significant association with BMI(P=0.001), PDW(P=0.001), waist circumference(P=0.023), and also, association with abdominal and femoral subcutaneous fat area(P=0.032 and P=0.023) were observed. The frequencies of Arg64 allele were 21%, 14% and 4% in female diabetics with obesity, over-weight and normal-weight respectively (P=0.026). Logistic regression analysis showed that BMI was the only independent clinical variable related to the Trp64Arg mutation in the ADRB3 gene (P=0.0027).

CONCLUSION

The Trp64Arg mutation in ADRB3 gene contributes to the variation of total body fat in Chinese type 2 diabetic subjects.

[The impact of the missense mutation-ser20gly in islet amyloid polypeptide gene on NIDDM in Chinese]

OBJECTIVES

To ascertain the presence of the Ser 20Gly mutation of islet amyloid polypeptide (IAPP) gene and its impact on NIDDM in Chinese.

METHODS

In 896 Chinese, 825 were unrelated subjects (NIDDM in 609 and non-diabetics, 216) and 71 were family members of the pedigrees with IAPP gene-Ser 20Gly carrier probands detected from population screening. The mutation was examined by PCR-RFLP MspI digestion in population screening and the results was randomly checked by direct DNA sequencing. Data were analyzed through association as well as linkage approaches.

RESULTS

The Ser20Gly mutation of the IAPP gene was observed in Chinese. It was more prevalent in NIDDM (17 cases, 2.8%) than in non-diabetics (1 cases, 0.5%) (Fisher two-tailed exact P = 0.05). The mutation carrier detected by PCR-RFLP was confirmed to be the A to G point mutation in nucleotide 582 of IAPP gene cDNA encoding the amino acid codon 20. All the mutation carriers detected in population screening were heterozygotes. Analysis of the family members of the 12 NIDDM pedigrees with the IAPP gene Ser20Gly mutation showed that in two families, the mutation was not cosegregated with the affection status. The older was the age of Ser20Gly mutant carrier, the more prevalent was the diabetes in families (P = 0.0001). The highest total lod score of this 12 pedigree was 0.021(theta = 0) in parametric linkage analysis with the model of autosomal dominance with incomplete penetrance.

CONCLUSION

The Ser20Gly mutation of IAPP gene was present in Chinese. This mutation does not cause monogenic inheritance diabetes, but may be a pathogenetic factor for the development of NIDDM, the complex genetic disease.

[The relationship between angiotensin II type 1 receptor gene and coronary heart disease, hypertension and diabetes mellitus in Chinese]

OBJECTIVE

To ascertain whether the angiotensin II type 1 receptor (AGTR1) gene is associated with coronary heart disease (CHD), hypertension (HTN) and non-insulin-dependent diabetes mellitus (NIDDM) in Chinese and to observe the interaction of AGTR1 gene and angiotensin I converting enzyme(ACE) gene to the development of the associated disease in Chinese.

METHODS

270 cases of Chinese with CHD, HTN or NIDDM in single or in different combinations were genotyped for the A1166C variation at the 3'-untranslated region of AGTR1 gene by using PCR/Dde I restriction endonuclease digestion. And also, the insertion/deletion polymorphism at the intron 16 of ACE gene was typed by PCR.

RESULTS

(1) AGTR1 gene was associated with CHD (logistic regression analysis, P=0.02), but not with HTN and NIDDM; (2) The attributable risk of AGTR1 gene for CHD was 12.5% and the odds ratio was 4.55. Both AGTR1 gene and ACE gene were independent variation factors for CHD (P=0.032 and P=0.002 respectively); (3) The contribution of AGTR1 gene to the development of CHD was independent of total body adiposity, blood lipid profile and blood pressure; (4) The analysis of individual combined genotypes of AGTR1 gene and ACE gene showed significant difference in frequency distribution between patients with CHD and controls.

CONCLUSION

AGTR1 gene contributes to the development of CHD and is an independent risk factor for CHD in Chinese.

Mitochondrial tRNA(Leu(UUR)) gene mutation diabetes mellitus in Chinese

OBJECTIVE

To ascertain the prevalence and clinical features of mitochondrial tRNALeu(UUR) gene nucleotide (nt) 3243 A-->G mutation diabetes mellitus in Chinese and to establish the approaches for genetic diagnosis of this subtype of diabetes during routine daily clinical practice.

METHODS

Mitochondrial nt 3243 A-->G mutation was screened among 207 unrelated non-insulin-dependent diabetes mellitus (NIDDM) patients by using polymerase chain reaction (PCR)/Apa I restriction endonuclease digestion. Samples with positive result were confirmed by DNA sequence analysis. Genetic and clinical analysis were carried out in family members of the proband with positive genetic diagnosis.

RESULTS

Positive results were found in two subjects during screening of unrelated NIDDM patients, which account for 2.4%-11.1% of NIDDM subjects with uncommon clinical features (with early age-of-onset, with low body-mass-index and on insulin therapy) or with positive family history of diabetes consistent with or unable to exclude from maternal inheritance. Genetic diagnosis was positive in 10 out of 25 family members in the pedigrees of these two probands.

CONCLUSIONS

Mitochondrial tRNALeu(UUR) gene nt 3242 A-->G mutation should be considered in diabetic patients with the above-mentioned clinical features. The genetic diagnosis in daily clinical practice can be performed with allele specific priming amplification, or PCR/Hae III or Apa I digestion which are technically simple to perform and diagnostically easy to define.

[Relationship between angiotensin 1 converting enzyme gene polymorphism and diabetic nephropathy]

OBJECTIVE

To clarify if ACE gene I/D polymorphism attributes to the development of non-insulin dependent diabetes mellitus (NIDDM) and renal complication.

METHODS

A fragment of 287 bp Alu sequence in inron 16 of ACE gene was used as I/D polymorphic marker. After PCR amplification of DNA fragment, 12% non-denatured polyacrylamide gel electrophoresis was undertaken to analyze the PCR products.

RESULTS

Allele D was the prominent one (frequency 0.75) in the subgroup of DN which was complicated in the earliest stage of NIDDM without HTN, CHD and diabetic retinopathy. However, the frequency of allele D was low (0.39) in the subgroup of NIDDM without DN, HTN, CHD and diabetic retinopathy, in which the duration of each subject was over 5 years. It was significant to compare these two mentioned subgroups (P < 0.02, continuity-adjusted X2test, P < 0.05). The distribution of genotype in the whole NIDDM group without HTN and CHD (69 cases) was very similar to the normal control (110 subjects) (I 0.60 to 0.59, D 0.40 to 0.41).

CONCLUSION

The I/D polymorphism of ACE gene may be the factor of genetic predisposition of early-onset diabetic nephropathy in Chinese NIDDM.

Glucokinase gene variants in Chinese subjects with the common form of NIDDM

OBJECTIVE

To determine whether mutation of the coding or junction region of glucokinase gene (GCK) is also the pathogenic cause of the common form of non-insulin-dependent diabetes mellitus (NIDDM) in Chinese.

METHODS

Single strand conformation polymorphism (SSCP) analysis was performed after the 12 exons and junction regions of GCK of each subject studied were separately amplified with polymerase chain reaction (PCR). The molecular scanning was carried out in 30 Chinese subjects with common form NIDDM having the age of onset at or before 45 years, and/or with positive family history of diabetes mellitus (NIDDM-A group). Further screening of the mutation/variation found was conducted in 56 NIDDM subjects (NIDDM-B group) and 134 non-diabetes subjects (ND group) in order to define their frequencies.

RESULTS

No mutation was found by molecular scanning in coding or junction region of GCK in NIDDM-A group. A variant of intron I b was detected in GCK of NIDDM subjects, especially in those with early age of onset and/or with positive family history of diabetes. Significant difference in incidences was found between ND group and NIDDM-A+B group (0% vs 4.7%, Fisher exact P = 0.022).

CONCLUSIONS

(1) Mutation of coding and junction regions of GCK is not the main pathogenic factor of common form NIDDM in Chinese subjects. (2) A variant of GCK intron I b may be found in NIDDM in Chinese, especially in those with early age of onset and/or with positive family history of diabetes. Its role in the expression of GCK remain to be elucidated.

A genome-wide search for human non-insulin-dependent (type 2) diabetes genes reveals a major susceptibility locus on chromosome 2

Non-insulin-dependent (type 2) diabetes mellitus (NIDDM) is a common disorder of middle-aged individuals characterized by high blood glucose levels which, if untreated, can cause serious medical complications and lead to early death. Genetic factors play an important role in determining susceptibility to this disorder. However, the number of genes involved, their chromosomal location and the magnitude of their effect on NIDDM susceptibility are unknown. We have screened the human genome for susceptibility genes for NIDDM using non-and quasi-parametric linkage analysis methods in a group of Mexican American affected sib pairs. One marker, D2S125, showed significant evidence of linkage to NIDDM and appears to be a major factor affecting the development of diabetes mellitus in Mexican Americans. We propose that this locus be designated NIDDM1.

[Genetic diagnosis of a subtype diabetes mellitus with mitochondrial tRNA Leu(UUR) gene mutation]

The A-G point mutation of mitochondrial tRNALeu(UUR) gene at nucleotide 3243 caused clinical NIDDM in combination with or without deafness and was inherited through maternal transmission. An ApaI restriction site was resulted by this mutation, which could be detected by polymerase chain reaction (PCR) with ApaI digestion and be used in clinical genetic diagnosis. The first Chinese family with this mutation found through our screening of NIDDM patients was reported. Genetic diagnosis was done in 12 of 15 members in this three-generation pedigree. Positive results (present of ApaI restriction site) were observed in all 5 NIDDM patients (four with deafness). In 6 of 7 non-diabetic members, negative genetic diagnosis was obtained. The presymptomatic diagnosis of this disease was made in a 13-year old non-diabetic boy with positive genetic diagnosis in conjunction with the maternal segregation pattern of the mutation in this family. The finding of this disease in Chinese provides firm evidence of genetic heterogeneity in Chinese NIDDM. The techniques of the genetic diagnosis of this disease can be used in clinical laboratory, which indicates that in the diagnosis of NIDDN, the molecular etiologic level can be reached in daily clinical practice.

Relationship of LDLR gene polymorphism and NIDDM in Chinese

Genomic DNA was extracted from peripheral blood lymphocytes of 105 healthy and 75 NIDDM Chinese subjects. The fragment located in exon 13 of the low density lipoprotein receptor (LDLR) gene was amplified by polymerase chain reaction (PCR), and digested with restriction enzyme HincII. LDL, TC and TG levels were measured in all subjects. Investigations were conducted to explore the correlation between the HincII RFLP of LDLR gene and NIDDM in the Chinese population. The results showed that no significant correlation existed between this RFLP locus and NIDDM. Marked differences were found, however, between the genotype distribution of low LDL level subgroups of NIDDM patients and normal controls. It was inferred that the H1 allele might be associated with high blood cholesterol levels, and the H2 allele with low cholesterol levels. Disturbances of lipid metabolism occur frequently in diabetes mellitus. This study suggested that differences in LDLR genotypes may affect the phenotypes of lipid metabolism.

The population association of glucokinase gene with type 2 (noninsulin-dependent) diabetes mellitus in Chinese

The association of gluckinase (GCK) gene with type 2 (non-insulin-dependent) diabetes mellitus was investigated in 168 Chinese subjects (85 unrelated type 2 diabetics and 83 non-diabetic controls). The microsatellite polymorphism marker, GCK-5', was amplified with polymerase chain reaction. Four alleles were observed in Chinese population with length varying from 137bp to 143bp and the most common one being the 139bp allele 3. In comparison with non-diabetics, allele 4 was significantly increased in type 2 diabetes (10% versus 38, respectively; X2 = 6.773, P = 0.009); genotype 44 and 4X (X denotes any allele other than allele 4) were significantly increased in type 2 diabetes (16% versus 6% respectively; X2 = 6.439, P = 0.011). The frequency difference was also shown in overweight/obese subgroup comparison (X2 = 7.718, P = 0.021), but not in lean/normal-weight subgroup comparison. No differences of age of onset and frequency of positive family history were observed between type 2 diabetic patients with genotype 44 or 4X and those with XX. The risk for type 2 diabetes in Chinese with genotype 44 or 4X was about 3.5 times higher than in Chinese with genotype XX. Therefore, GCK gene was associated with Chinese type 2 diabetes.

Human hexokinase II: localization of the polymorphic gene to chromosome 2

Type 2 (non-insulin-dependent) diabetes mellitus is characterized by decreased levels of glucose 6-phosphate in skeletal muscle. It has been suggested that the lower concentrations of glucose 6-phosphate contribute to the defect in glucose metabolism noted in muscle tissue of subjects with Type 2 diabetes or subjects at increased risk of developing Type 2 diabetes. Lower levels of glucose 6-phosphate could be due to a defect in glucose uptake, or phosphorylation, or both. Hexokinase II is the isozyme of hexokinase that is expressed in skeletal muscle and is responsible for catalysing the phosphorylation of glucose in this tissue. The recent demonstration that mutations in another member of this family of glucose phosphorylating enzymes, glucokinase, can lead to the development of Type 2 diabetes prompted us to begin to examine the possible role of hexokinase II in the development of this genetically heterogeneous disorder. As a first step, we have cloned the human hexokinase II gene (HK2) and mapped it to human chromosome 2, band p13.1, by fluorescence in situ hybridization to metaphase chromosomes. In addition, we have identified and characterized a simple tandem repeat DNA polymorphism in HK2 and used this DNA polymorphism to localize this gene within the genetic linkage map of chromosome 2.