A missense variant in GLP1R gene is associated with the glycaemic response to treatment with gliptins.

Gliptins act by increasing endogenous incretin levels. Glucagon-like peptide-1 receptor (GLP1R) and glucose-dependent insulinotropic peptide receptor (GIPR) are their indirect drug targets. Variants of GLP1R and GIPR have previously been associated with the incretin effect. The aim of the present pilot study was to examine associations of the GLP1R and GIPR gene variants with the glycaemic response to gliptins. A total of 140 consecutive patients with type 2 diabetes were followed-up 6 months after initiation of gliptin treatment. GLP1R rs6923761 (Gly168Ser) and GIPR rs10423928 genotyping was performed using real-time PCR, with subsequent high-resolution melting analysis. The main study outcome was reduction in glycated haemoglobin (HbA1c) after treatment. GLP1R Gly168Ser variant was significantly associated with reduction in HbA1c in an additive model (ß = -0.33, p = 0.011). The mean reduction in HbA1c in Ser/Ser homozygotes was significantly lower compared with Gly-allele carriers [0.12 ± 0.23% vs. 0.80 ± 0.09% (1.3 ± 2.5 mmol/mol vs. 8.7 ± 1.0 mmol/mol); p = 0.008]. In conclusion, GLP1R missense variant was associated with a reduced response to gliptin treatment. The genotype-related effect size of ∼0.7% (8 mmol/mol) is equal to an average effect of gliptin treatment and makes this variant a candidate for use in precision medicine.

Pharmacogenomic association between a variant in SLC47A1 gene and therapeutic response to metformin in type 2 diabetes.

Pharmacogenetic studies revealed that variants in genes related to the pharmacokinetics of metformin were associated with glucose-lowering effect of metformin. The aim of this study was to investigate possible associations of the variants in genes encoding organic cationic transporters-solute carrier family 22, members A1, A2 (SLC22A1, SLC22A2) and solute carrier family 47, member A1 (SLC47A1) with response to metformin in type 2 diabetes. One hundred forty-eight drug-naive patients with type 2 diabetes were included in the study. Genotyping for SLC22A1 rs622342, SLC22A2 rs316019 and SLC47A1 rs2289669 variants was performed using real-time PCR with subsequent melting-curve analysis. SLC47A1 rs2289669 genotype was significantly associated with the reduction in haemoglobin A1c (HbA1c) after 6 months. Twenty percentage of patients with diabetes that are homozygous for A-allele of SLC47A1 had twofold reduction in HbA1c in comparison with the patients carrying G-allele (GG + GA: 0.55 ± 0.09% vs. AA: 1.10 ± 0.18%, p = 0.018). In conclusion, the results of this study might have in future practical implication in personalised treatment of patients with type 2 diabetes.

Effect of sulphonylurea treatment on glycaemic control is related to TCF7L2 genotype in patients with type 2 diabetes.

The aim of the present study was to analyse effects of sulphonylurea treatment on parameters of glycaemic control in relation to transcription factor 7-like 2 (TCF7L2) genotypes. In 87 patients with type 2 diabetes who failed to achieve glycaemic control on metformin monotherapy, effects of 6-month sulphonylurea in addition to metformin on reductions in haemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) levels were evaluated. Reduction in HbA1c and FPG in response to 6-month sulphonylurea treatment was significantly higher in patients with CC genotype compared to those with the CT+TT genotype (1.16 ± 0.07 vs. 0.86 ± 0.07%, p = 0.003; 1.57 ± 0.12 vs. 1.14 ± 0.14 mmol/l, p = 0.031, respectively). In the multivariate analysis, baseline HbA1c and the TCF7L2 genotype were the only significant predictors of HbA1c reduction. In conclusion, the magnitude of HbA1c and FPG reductions after 6-month sulphonylurea treatment in addition to metformin is related to the TCF7L2 gene polymorphism.

Pharmacogenetics of oral antidiabetic treatment.

In the majority of patients with type 2 diabetes (T2D), oral antidiabetic drug (OAD) treatment is the first line treatment after lifestyle measures fail. Two major groups of OAD are used in clinical practice--insulin secretagogues and insulin sensitisers. Sulphonyluea (SU) derivatives are insulin secretagogues and stimulate insulin secretion by inhibiting ATP-sensitive potassium channels. Genes KCNJ11 and ABCC8 encode potassium channel proteins. KCNJ11 gene Glu23Lys polymorphism was associated with an increased risk of SU secondary failure, while Ser1369Ala polymorphism of ABCC8 gene had influence antidiabetic efficacy of SU drug gliclazide. In addition, the polymorphism of TCF7L2 gene, which has the strongest association with T2D, also influenced secondary SU drug failure. Insulin sensitisers include both metformin and glitazones. Some drug-genotype associations were observed for metformin in patients with T2D. Several genes influenced the effect of glitazone treatment. Rosiglitazone was more effective in diabetes control in carriers of Prol2Ala polymorphism of PPARG gene encoding the PPARg-receptor--the target of this drug. Rosiglitazone treatment had less effect on glycemic control and adiponectin increase in T2D patients with GG-genotypes of adiponectin (APM1) polymorphism. Pioglitazone treatment had smaller effect on glycemic control in patients with LPL Ser447X polymorphism. Identification of drug-genotype interactions in pharmacogenetic studies of the OAD treatment might have clinical implications in the near future resulting in selection of more specific "patient-tailored therapy" in T2D (Tab. 1, Ref. 58).

Carotid intima-media thickness in patients with chronic obstructive pulmonary disease.

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is associated with increased cardiovascular morbidity and mortality. Several large population-based cohort studies identified an association between reduced lung function and increased intima-media thickness (IMT). Nevertheless, a vast majority of subjects in these studies did not suffer from COPD and thus it remains unclear whether IMT differs among various stages of COPD severity. The aim of the present pilot study was to evaluate IMT in central European patients with moderate, severe and very severe COPD. METHODS: In forty-nine patients (34 men, 15 women; mean age 66.1 +/- 10.9 years) with COPD, the combined thickness of intima and media layers of the common carotid arteries was measured using B-mode ultrasound imaging. RESULTS: Increased cardiovascular disease risk as evidenced by carotid IMT values greater or equal to 75th percentile were present in 14 (28.6%), whereas IMT hypertrophy (IMT values greater or equal 0.80 mm) was present in 24 (49.0%) of patients. Average IMT in the entire cohort was 0.85 +/- 0.21 mm, with no significant differences from stage II to stages III and IV of COPD. CONCLUSION: Present results indicate a high prevalence of IMT hypertrophy and increased cardiovascular disease risk as assessed by carotid ultrasonography in COPD patients with a broad spectrum of airway obstruction severity. The lack of differences in carotid IMT between various stages of lung impairment severity suggests that atherosclerosis starts early in the course of COPD. Therefore, the need to screen patients for the presence of concomitant atherosclerosis in early stages of COPD severity may be warranted (Tab. 2, Ref. 33).

[Relationship of the CDKAL1 and KCNQ1 gene polymorphisms to the age at diagnosis of type 2 diabetes in the Slovakian population]. / Vzt'ah polymorfizmov génov CDKAL1 a KCNQ1 k veku diagnózy diabetu 2. typu v populácii slovenska.

BACKGROUND/AIMS: The association of CDKAL1 and KCNQ1 genes with type 2 diabetes mellitus (DM2T) was confirmed by several genome-wide association studies in both Caucasian and Asian populations. For both genes, it is supposed that the risk of DM2T development is related to impaired insulin secretion. Based on assumption that the presence of risk allele might predispose to an earlier onset of DM2T, the aim of the present study was to assess the frequency of risk alleles of CDKAL1 rs7756992 and KCNQ1 rs163184 polymorphisms and to analyze their association with the age at DM2T diagnosis in the Slovakian population. METHODS: CDKAL1 rs7756992 A/G and KCNQ1 rs163184 G/T polymorphisms were genotyped using asymmetric PCR with subsequent melting curve analysis in a group of 538 patients with DM2T. Anthropometric and laboratory parameters were determined by using standard methods. Since two genes were analysed, the required level for statistical significance was defined as p < 0.025. RESULTS: Risk homozygotes (CG) for KCNQ1 polymorphism had higher mean age of DM2T diagnosis by 2 years when compared to T-allele carriers (GT + TT) in a recessive model, but the difference did not reach the predefined level of statistical significance. No relationship of CDKAL1 polymorphism to the age at onset of DM2T diagnosis was observed. CONCLUSIONS: In the present study, no relationship of CDKAL1 and KCNQ1 polymorphisms to the earlier onset of type 2 diabetes was observed.

An association between rs7635818 polymorphism located on chromosome 3p12.3 and the presence of abdominal aortic aneurysm.

The association between gene variant rs7635818 located on chromosome 3p12.3 and abdominal aortic aneurysm (AAA) was not unambiguously determined by the results of genome-wide association studies. The aim of our study was to examine this possible association in the Slovak population, with respect to the presence and severity of AAA.A cross-sectional study was conducted between August 2016 and March 2020. The study included 329 participans, 166 AAA patients and a control group of 163 subjects without confirmed AAA with comparable distribution of genders. The anteroposterior diameter of the abdominal aorta was determined by duplex ultrasonography. AAA was defined as subrenal aortic diameter ≥ 30 mm. DNA samples were genotyped using real-time polymerase chain reaction and subsequent high-resolution melting analysis in presence of unlabelled probe. Genetic models studying the possible association were adjusted to age, sex, smoking, arterial hypertension, diabetes mellitus, creatinine and body mass index (BMI) in multivariate analysis. In the additive model, presence of each C-allele of rs7635818 polymorphism was associated with an almost 50 % increase in probability of developing AAA (OR 1.49; 95 % CI 1.06-2.08; p=0.020). Compared to GG homozygotes, CC homozygotes had more than two times higher risk of developing AAA (OR 2.23; 95 % CI 1.14-4.39; p=0.020). The risk of AAA was also in the recessive model higher for CC homozygotes compared to G-allele carriers (GC/GG) (OR 1.79; 95 % CI 1.01-3.19; p=0.047).The abdominal aortic diameter in CC homozygotes of the rs7635818 polymorphism was 7.66 mm greater compared to GG homozygotes (42.5±22.0 mm vs 34.8±21.3 mm; p=0.022) and 5.88 mm greater compared to G-allele carriers (GC/GG) (42.5±22.0 mm vs 36.6±21.0 mm; p=0.04) in univariate analysis. C-allele variant in rs7635818 G>C polymorphism is associated with a higher probability of developing AAA in the Slovak population.

Relationship of five type 2 diabetes candidate gene polymorphisms to the age at diagnosis of diabetes in the Slovakian population.

OBJECTIVES: To examine the relationship between polymorphisms of five candidate genes for type 2 diabetes mellitus (T2DM) and the age at diagnosis of T2DM. METHODS: 538 Slovakian patients with T2DM were included and their age at diagnosis of T2DM retrieved from their medical records. Polymorphisms of genes encoding peroxisome proliferator activated receptor gamma (PPARG), PPARG-coactivator-1 (PGC1), insulin-receptor substrate 1 (IRS1), the subunit Kir 6.2 of the ATP-dependent potassium-channel (KCNJ11) and transcription factor 7-like 2 (TCF7L2) were detected by PCR-RFLP methods. RESULTS: No significant relationship between the risk alleles of the examined gene polymorphisms to the lower mean age at diagnosis of T2DM was observed. The carriers of the TT-genotype of TCF7L2 rs7903146 polymorphism had significantly increased odds ratio for diagnosis of diabetes before the age of 40 years [OR 3.02 (1.34, 6.81), p = 0.008], in comparison with the CC/CT genotype carriers. CONCLUSION: No significant association of PPARG, PGC1, IRS1, KCNJ11 and TCF7L2 gene polymorphisms and the age at diagnosis of T2DM was observed in the present study. Homozygotes for the risk allele of TCF7L2 had more frequently early onset of T2DM, before age of 40 years (Tab. 4, Ref. 15).

Gene polymorphisms of renin angiotensin system and serotonin transporter gene in patients with vasovagal syncope.

UNLABELLED: Objective of this study was to compare the distribution frequencies of gene polymorphisms of renin-angiotensin and serotonin system in patients with positive and negative head- up tilt test (HUT). METHODS: DNA from 191 patients (mean age 44+ 18 years, 61 men) was collected. HUT was positive in 117 and negative in 74 patients. Following gene polymorphisms were determined by the PCR method: ACE insertion/deletion (I/D ACE), angiotensinogen (AGT) (M 235), angiotensin II receptor (ATR1) (A 1166C) and serotonin transporter (SERT) polymorphism (5HTTLPR). RESULTS: No significant differences in the distribution of gene polymorphisms between syncopal patients with positive and negative HUT were dectected. Distribution of polymorphisms included: I/D ACE: II 19 vs 20%, ID 55 vs 52%, DD 26 vs 28%. Angiotensinogen gene polymorphism MM 27% vs 30%, MT 48% vs 46%, TT 25% vs 24%. ATR1 polymorphism AA 44 vs 32%, AC50 vs 60%, CC 6 vs 8%, 5HTTLPR serotonin transporter gene polymorphism LL 42 vs 43%, SL 41 vs 39%, SS 17 vs 18%. CONCLUSIONS: An association between polymorphisms of ACE, AGT, ATR1 and SERT gene, and predisposition to VVS was not proven by the present study (Tab. 2, Ref. 22). Full Text (Free, PDF) www.bmj.sk.

Monitoring antioxidant enzymes in red cells during allergen immunotherapy.

The aim of this report was to answer the question how specific immunotherapy influences the antioxidant enzyme system in patients with respiratory allergy and in longer perspective to find markers suitable to assess the efficacy of treatment. In open prospective randomised study 28 patients (18 females and 10 males, age 14-48 years) with seasonal respiratory allergy were treated with allergen immunotherapy. Subjects received subcutaneous therapy with allergens absorbed on calcium phoshate or aluminium hydroxide and were analyzed by the established protocol at the beginning, after three and 12 month of the treatment. In all treatment group red cell superoxide dismutase and glutathione peroxidase activities were in the normal range in allergic patients both before and during the treatment. Catalase activity in the allergic patients was lower as compared with controls and a significant increase of the enzyme activity occurred during and at the end of the treatment. In patients treated with calcium phosphate adsorbed allergen there was a continous increase of catalase activity from beginning up to the end of observation. In the case of the aluminium hydroxide treatment there was an increase from the baseline values up in the third month of the treatment and a decrease on the 12th month. In summary, the present results open the question that allergen immunotherapy may cause imbalance of oxidants and antioxidants. To support our findings larger controlled field studies are needed.

An intravenous immunoglobulin therapy of serious autoimmune rheumatic diseases.

Intravenous immunoglobulins (IVIg) have been widely used in clinical practice for more than 35 years. Their efficacy has been established in many clinical trials for the treatment of autoimmune rheumatic diseases including systemic lupus erythematosus, ANCA positive vasculitis and dermatomyositis, but these indications are classified as the "off label" treatment. For the diseases mentioned above there are no generally accepted therapeutic guidelines. The case reports (one patient with lupus erythematosus chorea, two patients with dermatomyositis and one with the Wegener's granulomatosis) present a treatment of systemic connective tissue diseases with IVIg following the failure of standard therapeutic regimens. A successful therapy has been realized using different doses of IVIg, which raises a question on an appropriate dose. Based on our experience, we conclude that intravenous immunoglobulins are effective in the treatment of many "off label" indications in rheumatology, particularly in cases when standard immunosuppressive therapy could be harmful. Despite the evidence of efficacy, the dosage and timing of IVIg therapy, and questions of costs/benefits ratio still remain insufficiently documented and multicentric controlled clinical trials with consecutive development of guidelines are necessary (Ref. 27).

Variants in Pharmacokinetic Transporters and Glycemic Response to Metformin: A Metgen Meta-Analysis.

Therapeutic response to metformin, a first-line drug for type 2 diabetes (T2D), is highly variable, in part likely due to genetic factors. To date, metformin pharmacogenetic studies have mainly focused on the impact of variants in metformin transporter genes, with inconsistent results. To clarify the significance of these variants in glycemic response to metformin in T2D, we performed a large-scale meta-analysis across the cohorts of the Metformin Genetics Consortium (MetGen). Nine candidate polymorphisms in five transporter genes (organic cation transporter [OCT]1, OCT2, multidrug and toxin extrusion transporter [MATE]1, MATE2-K, and OCTN1) were analyzed in up to 7,968 individuals. None of the variants showed a significant effect on metformin response in the primary analysis, or in the exploratory secondary analyses, when patients were stratified according to possible confounding genotypes or prescribed a daily dose of metformin. Our results suggest that candidate transporter gene variants have little contribution to variability in glycemic response to metformin in T2D.

Relationship among urinary albumin excretion rate, lipoprotein lipase PvuII polymorphism and plasma fibrinogen in type 2 diabetic patients.

Plasma fibrinogen level represents a strong cardiovascular risk factor and is regulated by an interplay of genetic and environmental factors. Hyperfibrinogenemia frequently occurs in cluster with dyslipidemia within the frame of insulin resistance syndrome (IRS) and type 2 diabetes mellitus. Genetic variants with a pleiotropic effect have been proposed to cause IRS features including hyperfibrinogenemia. We studied the influence of polymorphisms in lipoprotein lipase (LPL) gene, beta-fibrinogen gene (FIBB) and environmental factors on plasma fibrinogen levels in type 2 diabetes patients. 131 type 2 diabetes patients (mean age 62+/-10 years, 33% male) were genotyped for polymorphisms in LPL gene (intron 6 PvuII, intron 8 HindIII) and FIBB gene (-148C/T, -455G/A) by PCR-RFLP method. Fibrinogen was measured by thrombin coagulation method, albuminuria by immunoturbidimetric assay. Polymorphism LPL PvuII showed a gene-dose effect on fibrinogen levels, with the highest fibrinogen in P-P- homozygotes (p = 0.05, analysis of variance). P-carriers (P-P- and P+P- combined) had significantly higher fibrinogen levels compared with P+P+ homozygotes (3.74+/-1.40 g/l vs 3.06+/-1.20 g/l, p=0.03). Other studied polymorphisms were not significantly related to fibrinogen levels. Age- and sex-adjusted fibrinogenemia correlated significantly with albuminuria (r = 0.48, p=0.001), serum uric acid (r = 0.42, p=0.006) and serum creatinine (r = 0.32, p=0.04). Multiple stepwise linear regression identified interaction term of LPL PvuII and albuminuria as an independent predictor of fibrinogen level, explaining 18% of fibrinogen variance. Albuminuria thus appears to be the best predictor of fibrinogen plasma levels in type 2 diabetic patients. Relationship between albuminuria and fibrinogenemia may be modified by the genotype LPL PvuII, which also shows a weak association with plasma fibrinogen level in type 2 diabetes patients.

Effect of gene polymorphisms on lipoprotein levels in patients with dyslipidemia of metabolic syndrome.

Dyslipidemia in the metabolic syndrome (MS) is considered to be one of the most important risk factors for atherosclerosis. It is characterized by hypertriglyceridemia, low concentration of plasma HDL-cholesterol, predominance of small dense LDL particles and an increased concentration of plasma apolipoprotein B (apoB). The pathogenesis of this type of dyslipidemia is partially explained, but its genetic background is still unknown. To evaluate the influence of cholesterol ester transfer protein (CETP) TaqIB polymorphism, lipoprotein lipase (LPL) PvuII and HindIII polymorphisms, hepatic lipase (LIPC) G-250A polymorphism and apolipoprotein C-III (APOC3) SstI gene polymorphism on lipid levels in dyslipidemia of the metabolic syndrome, 150 patients with dyslipidemia of metabolic syndrome were included. 96 % of patients had type 2 diabetes. The patients did not take any lipid lowering treatment. The exclusion criterion was the presence of any disease that could affect lipid levels, such as thyroid disorder, liver disease, proteinuria or renal failure. Gene polymorphisms were determined using the polymerase chain reaction and restriction fragment length polymorphisms. The genotype subgroups of patients divided according to examined polymorphisms did not differ in plasma lipid levels with the exception of apoB. The apoB level was significantly higher in patients with S1S1 genotype of APOC3 SstI polymorphism when compared with S1S2 group (1.10+/-0.26 vs. 0.98+/-0.21 g/l, p=0.02). Similarly, patients with H-H- genotype of LPL HindIII polymorphism had significantly higher mean apoB, compared with H+H- and H+H+ group (1.35+/-0.30 vs. 1.10+/-0.26 g/l, p=0.02). In the multiple stepwise linear regression analysis, apoB level seemed to be influenced by APOC3 SstI genotype, which explained 6 % of its variance. The present study has shown that the S1 allele of APOC3 SstI polymorphism and the H- allele of LPL HindIII polymorphism might have a small effect on apoB levels in the Central European Caucasian population with dyslipidemia of metabolic syndrome.

The effect of insulin on in vivo cerebral glucose concentrations and rates of glucose transport/metabolism in humans.

The continuous delivery of glucose to the brain is critically important to the maintenance of normal metabolic function. However, elucidation of the hormonal regulation of in vivo cerebral glucose metabolism in humans has been limited by the lack of direct, noninvasive methods with which to measure brain glucose. In this study, we sought to directly examine the effect of insulin on glucose concentrations and rates of glucose transport/metabolism in human brain using (1)H-magnetic resonance spectroscopy at 4 Tesla. Seven subjects participated in paired hyperglycemic (16.3 +/- 0.3 mmol/l) clamp studies performed with and without insulin. Brain glucose remained constant throughout (5.3 +/- 0.3 micromol/g wet wt when serum insulin = 16 +/- 7 pmol/l vs. 5.5 +/- 0.3 micromol/g wet wt when serum insulin = 668 +/- 81 pmol/l, P = NS). Glucose concentrations in gray matter-rich occipital cortex and white matter-rich periventricular tissue were then simultaneously measured in clamps, where plasma glucose ranged from 4.4 to 24.5 mmol/l and insulin was infused at 0.5 mU. kg(-1). min(-1). The relationship between plasma and brain glucose was linear in both regions. Reversible Michaelis-Menten kinetics fit these data best, and no differences were found in the kinetic constants calculated for each region. These data support the hypothesis that the majority of cerebral glucose uptake/metabolism is an insulin-independent process in humans.

Methodology of H NMR Spectroscopy of the Human Brain at Very High Magnetic Fields.

An ultrashort-echo-time stimulated echo-acquisition mode (STEAM) pulse sequence with interleaved outer volume suppression and VAPOR (variable power and optimized relaxation delays) water suppression was redesigned and optimized for human applications at 4 and 7 T, taking into account the specific requirements for spectroscopy at high magnetic fields and limitations of currently available hardware. In combination with automatic shimming, automated parameter adjustments and data processing, this method provided a user-friendly tool for routine (1)H nuclear magnetic resonance (NMR) spectroscopy of the human brain at very high magnetic fields. Effects of first- and second-order shimming, single-scan averaging, frequency and phase corrections, and eddy currents were described. LCModel analysis of an in vivo (1)H NMR spectrum measured from the human brain at 7 T allowed reliable quantification of more than fifteen metabolites noninvasively, illustrating the potential of high-field NMR spectroscopy. Examples of spectroscopic studies performed at 4 and 7 T demonstrated the high reproducibility of acquired spectra quality.

Glycemic control is related to the electrophysiologic severity of diabetic peripheral sensorimotor polyneuropathy.

OBJECTIVE: The aim of the present study was to examine risk factors for the electrophysiologic severity of diabetic peripheral sensorimotor polyneuropathy (DSP). RESEARCH DESIGN AND METHODS: A total of 97 patients with type 1 diabetes (25 patients) or type 2 diabetes (72 patients) were included in this cross-sectional study. Nerve conduction studies (NCS) were performed on median motor and sensory nerves, peroneal motor nerve, and both sural nerves. The severity of DSP was expressed as the sum of nerve conduction velocities (SNCV) and the score of distal amplitudes (SAMP) of the above-mentioned nerves. General linear models were used to assess the relationship between overall severity of DSP as well as the severity of lower extremity, upper extremity, motor nerve, or sensory nerve involvement and various risk factors. RESULTS: GHb was significantly related to both SNCV and SAMP in univariate and multivariate regression analyses. This relationship was present in models where GHb was handled either as a continuous variable or as a categorical variable with highest significance level, with a GHb cutoff level of 9%. The difference in NCV for individual nerves in patients with good-to-moderate glycemic control (GHb < or =9%) and those with poor glycemic control (GHb > or =9%) ranged from 1.8 to 3.6 m/s. SAMP was also significantly lower in patients with poor control. SNCV was also significantly related in multivariate analysis to duration of diabetes and height, while SAMP was related to duration of diabetes, age, and male sex. CONCLUSIONS: The severity of DSP expressed by electrophysiologic criteria was significantly related to glycemic control in a study including patients with type 1 or type 2 diabetes. Based on the results of the present study, it might be predicted that better diabetic control would decrease the severity of DSP.

Extracellular-intracellular distribution of glucose and lactate in the rat brain assessed noninvasively by diffusion-weighted 1H nuclear magnetic resonance spectroscopy in vivo.

To determine the distribution of cerebral glucose and lactate between the intracellular and the extracellular space of the rat brain in vivo, the diffusion characteristic of glucose and lactate was compared with that of metabolites known to be mainly intracellular (N-acetylaspartate, choline, creatine, glutamate, myo-inositol, and taurine) using a pulsed-field-gradient 1H nuclear magnetic resonance technique. The detection of a glucose signal at large diffusion weighting provided direct experimental evidence of intracellular glucose in the rat brain. At large diffusion weighting, the apparent diffusion coefficient (ADC) of glucose and lactate was similar to that of the intracellular metabolites such as N-acetylaspartate, creatine, and glutamate. At small diffusion weighting, the ADC of glucose and lactate was increased, which was explained by a decreased relative contribution of intracellular glucose to the total signal. The calculated extracellular volume fraction of glucose (0.19 +/- 0.05) and lactate (0.17 +/- 0.06) was consistent with a substantial fraction of glucose and lactate signals being intracellular. The findings were direct in vivo evidence that the largest concentration gradient of glucose is at the blood-brain barrier and that glucose is evenly distributed in the brain in vivo between the intracellular and extracellular space.

Important contribution of lipoprotein particle number to plasma triglyceride concentration in type 2 diabetes.

The aim of the present study was to determine the contributions of particle size versus number to differences in plasma triglyceride-rich lipoprotein concentrations in patients with type 2 diabetes. Fasting plasma was obtained from 174 consecutive eligible men and women with type 2 diabetes (with or without insulin treatment, mean age 57.0 + 6.3 years) who were undergoing coronary angiography. The triglyceride-rich (Sf 12-400) lipoproteins (TRL) were subfractionated into the Sf 12-60 and Sf 60-400 subfractions. Particle numbers, estimated by measuring apolipoprotein B by electroimmunoassay, in each of these lipoprotein fractions were related to enzymatically determined triglyceride levels in the triglyceride-rich lipoproteins. Approximately 87% of the triglyceride-rich lipoprotein particles were in the Sf 12-60 fraction and 13% in the Sf 60-400 fraction. Multiple linear regression indicated that 69% (i.e. r2=0.69) of the variance in the triglyceride levels could by explained by differences in TRL particle number and 17% (i. e. r2=0.17) by the differences in particle triglyceride content. These observations are similar in each gender and in those with or without insulin treatment. In conclusion, in type 2 diabetes, the vast majority of triglyceride-rich lipoproteins are smaller particles which are in the Sf 12-60 fraction. Differences in particle number, rather than triglyceride content, account for approximately 70% of the differences in triglyceride levels observed between individuals. Previous demonstrations, in those without diabetes, of an association between small triglyceride-rich lipoproteins with coronary artery disease suggest the importance of these findings to the increased atherosclerosis in diabetes.

Toward an in vivo neurochemical profile: quantification of 18 metabolites in short-echo-time (1)H NMR spectra of the rat brain.

Localized in vivo (1)H NMR spectroscopy was performed with 2-ms echo time in the rat brain at 9.4 T. Frequency domain analysis with LCModel showed that the in vivo spectra can be explained by 18 metabolite model solution spectra and a highly structured background, which was attributed to resonances with fivefold shorter in vivo T(1) than metabolites. The high spectral resolution (full width at half maximum approximately 0.025 ppm) and sensitivity (signal-to-noise ratio approximately 45 from a 63-microL volume, 512 scans) was used for the simultaneous measurement of the concentrations of metabolites previously difficult to quantify in (1)H spectra. The strongly represented signals of N-acetylaspartate, glutamate, taurine, myo-inositol, creatine, phosphocreatine, glutamine, and lactate were quantified with Cramér-Rao lower bounds below 4%. Choline groups, phosphorylethanolamine, glucose, glutathione, gamma-aminobutyric acid, N-acetylaspartylglutamate, and alanine were below 13%, whereas aspartate and scyllo-inositol were below 22%. Intra-assay variation was assessed from a time series of 3-min spectra, and the coefficient of variation was similar to the calculated Cramér-Rao lower bounds. Interassay variation was determined from 31 pooled spectra, and the coefficient of variation for total creatine was 7%. Tissue concentrations were found to be in very good agreement with neurochemical data from the literature.