Relationship Between Angiopoietin-Like Protein 8 and Fasting Serum Triglyceride Level.

BACKGROUND: The aim of the study was to evaluate the correlation between angiopoietin-like protein 8 (ANGPTL8) and metabolic parameters in non-diabetic healthy humans. METHODS: We enrolled 30 healthy Japanese adults (25 men and five women). After 9 h of fasting, we collected blood samples and analyzed the ANGPTL8, lipoprotein lipase (LPL), plasma lipid and glucose metabolic parameters. In addition, we performed 75-g oral glucose tolerance test (OGTT) and measured adipokines (tumor necrosis factor-α, leptin and adiponectin). RESULTS: Median serum ANGPTL8 level was 224 (167 - 437) pg/mL, and serum ANGPTL8 level positively correlated with serum triglyceride level (r = 0.42, P = 0.021) and negatively correlated with LPL level (r = -0.44, P = 0.015). ANGPTL8 level showed no correlation with body mass index (BMI), waist-hip ratio, and homeostasis model assessment of insulin resistance (HOMA-IR) or with adipose tissue-derived adiponectin and leptin levels. Further, ANGPTL8 showed no association with glucose and insulin levels after 75-g OGTT. CONCLUSION: Serum ANGPTL8 level negatively correlated with LPL levels in healthy Japanese adults. Regulation of ANGPTL8 could be a promising therapeutic target for hypertriglyceridemia.

Daily variability in serum levels of calciprotein particles and their association with mineral metabolism parameters: A cross-sectional pilot study.

AIM: Calciprotein particles (CPPs), colloidal protein-mineral nanoparticles composed of solid-phase calcium phosphate and serum protein fetuin-A found in blood, are emerging as a novel component of chronic kidney disease-mineral and bone disorder (CKD-MBD). The relationship of CPPs with factors known to underlie the CKD-MBD pathophysiology is not well known.The aim of this study is to examine daily variations in CPPs as well as their association with mineral metabolism parameters in normal individuals and early-stage CKD patients. METHODS: Twenty subjects (10 healthy adults, 10 diabetic patients) were enrolled. Serum CPP Fetuin-A was measured and analyzed in relation to clinical parameters. RESULTS: Estimated glomerular filtration rates (eGFR) were 103 ± 11 and 75 ± 24 mL/min per 1.73 m2 in healthy adults and diabetic patients, respectively. Serum CPP Fetuin-A (g/L) were elevated at postprandial 2 h in diabetic patients. Furthermore, serum CPP Fetuin-A were inversely correlated with eGFR and serum 1,25-dihydroxyvitamin D3 and magnesium levels and were positively correlated with serum fibroblast growth factor-23. CONCLUSIONS: These findings indicated that serum CPP Fetuin-A were affected by food intake and may contribute to the pathophysiology of mineral metabolism in subjects with normal and moderately impaired renal function.

The Urinary Phosphate to Serum Fibroblast Growth Factor 23 Ratio Is a Useful Marker of Atherosclerosis in Early-Stage Chronic Kidney Disease.

BACKGROUND: Fibroblast growth factor 23 (FGF23) regulates mineral homeostasis. In developed renal dysfunction, FGF23 levels increase to maintain the phosphate excretion capacity. However, in diabetic patients with early-stage renal impairment, the FGF23 elevation is not very sensitive. We hypothesized that urinary phosphate (U-P)/serum FGF23 ratio would theoretically be an index that reflects the number of nephrons (nephron index). In this study, we determined whether the nephron index would be associated with renal function and vascular diseases in diabetic patients. METHODS: In total, 142 patients with diabetes mellitus were enrolled. The nephron index was calculated using the following formula: U-P (mg/day)/ serum FGF23 (pg/ml). RESULTS: The mean age was 63 ± 11 years and eGFR levels were 79.5 ± 25.4 ml/min/1.73 m2, respectively. Thirty patients had a medical history of macroangiopathy. The Nephron index was significantly decreased in subjects with macroangiopathy compared with those without macroangiopathy. A multivariate analysis of risk factors for macroangiopathy revealed that duration of diabetes, eGFR, and nephron index were significantly associated with a higher frequency of arteriosclerotic disease. CONCLUSION: These findings suggest that a decrease in nephron index reflects early-stage renal impairment and is an independent risk factor of macroangiopathy in diabetic patients.

Hypothalamic type of hypopituitarism and central diabetes insipidus probably linked to Rathke's cleft cyst.

A 73-year-old woman was admitted due to weight loss and generalized malaise. The basal levels of all the anterior pituitary hormones, except for prolactin, were reduced. However, they were all elevated in response to exogenous hypothalamic hormones. After starting hydrocortisone replacement, the patient had polyuria of >5,000 mL/day. T1-weighted MRI depicted a low signal of an oval mass in the sella turcica and an iso-intense signal of another mass at the pituitary stalk. These findings indicate a hypothalamic type of hypopituitarism and masked central diabetes insipidus which possibly derived from the atypical occupation of Rathke's cleft cyst at the pituitary stalk.

Circulating betatrophin is elevated in patients with type 1 and type 2 diabetes.

There is evidence that betatrophin, a hormone derived from adipose tissue and liver, affects the proliferation of pancreatic beta cells in mice. The aim of this study was to examine circulating betatrophin concentrations in Japanese healthy controls and patients with type 1 and type 2 diabetes. A total of 76 subjects (12 healthy controls, 34 type 1 diabetes, 30 type 2 diabetes) were enrolled in the study. Circulating betatrophin was measured with an ELISA kit and clinical parameters related to betatrophin were analyzed statistically. Circulating betatrophin (Log transformed) was significantly increased in patients with diabetes compared with healthy subjects (healthy controls, 2.29 ± 0.51; type 1 diabetes, 2.94 ± 0.44; type 2 diabetes, 3.17 ± 0.18; p<0.001, 4.1 to 5.4 times in pg/mL order). Age, HbA1c, fasting plasma glucose and Log triglyceride were strongly associated with Log betatrophin in all subjects (n=76) in correlation analysis. In type 1 diabetes, there was a correlation between Log betatrophin and Log CPR. These results provide the first evidence that circulating betatrophin is significantly elevated in Japanese patients with diabetes. The findings of this pilot study also suggest a possibility of association between the level of betatrophin and the levels of glucose and triglycerides.

Prompt efficacy of tolvaptan in treating hyponatremia of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) closely associated with rupture of a gastric artery aneurysm.

A 78-year-old man with abdominal pain was diagnosed with a rupture of a gastric artery aneurysm. The serum Na level promptly decreased from 135 to 110 mmol/L within several days. Brain magnetic resonance angiography revealed severe vasoconstriction of the cerebral basilar artery and anterior cerebral artery. There was neither dehydration nor edema. The plasma arginine vasopressin level was 3.3 pg/mL, despite hypoosmolality. These findings indicated a diagnosis of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) derived from severe vasoconstriction of the cerebral arteries. The administration of 7.5 mg of tolvaptan rapidly increased the serum Na level from 123 to 138 mmol/L within the first 24 hours, thereafter continuously maintaining a normal level. Treatment with tolvaptan corrected the patient's dilutional hyponatremia.

Combination therapy of angiotensin II receptor blocker and thiazide produces severe hyponatremia in elderly hypertensive subjects.

Thiazide diuretics are known to produce severe hyponatremia as well as hypokalemia. The present study demonstrated severe hyponatremia in three hypertensive patients who had received combination therapy consisting of an angiotensin II receptor blocker (ARB) and thiazide. The serum sodium (Na) levels in all three cases were markedly reduced to below 116 mmol/L, and the patients exhibited augmented urinary excretion of Na with a reduced circulatory blood volume. After withdrawing the ARB and thiazide treatment, the serum Na levels normalized within one to two weeks. Combination therapy with ARBs and thiazide may cause hyponatremia in elderly patients.

Index of glucose effectiveness derived from oral glucose tolerance test.

Aim of this study was to formulate an index for glucose effectiveness (Sg), SgIo, based on 3-point (0, 30 and 120 min) 75 g oral glucose tolerance test (OGTT). The equation for SgI(O) was developed in the Chikuma cohort (n = 502). Firstly, post-loading plasma glucose without insulin action and Sg (PPG-without insulin and Sg) was calculated as follows: fasting plasma glucose (mg/dl) + [0.75 × 75,000]/[0.19 × BW(kg) × 10]. Secondly, 'PPG-without insulin/with Sg' was obtained from inverse correlation between log(10)DI(O) and 2-h post-glucose plasma glucose at OGTT (2hPG) in each glucose tolerance category: DI(O) denotes oral disposition index, a product of the Matsuda Index and δIRI(0-30)/δPG(0-30). Thirdly, expected 2hPG (2hPG(E)) of a given subject was obtained from the regression, and the ratio of 2hPG to 2hPG(E) (2hPG/2hPG(E)) was determined as an adjustment factor. Lastly, SgI(O) ([mg/dl]/min) was calculated as [PPG-without insulin and Sg]-[PPG-without insulin / with Sg] x [(2hPG) / 2hPG(E)]. SgI(O) was validated against Sg obtained by frequently sampled intravenous glucose tolerance test in the Jichi cohort (n = 205). Also, the accuracy of prediction of Sg by SgIo was tested by the Bland-Altman plot. SgI(O) was 3.61 ± 0.73, 3.17 ± 0.74 and 2.15 ± 0.60 in subjects with normal glucose tolerance (NGT), non-diabetic hyperglycemia and diabetes, respectively, in the Chikuma cohort. In the Jichi cohort, SgI(O) was significantly correlated with Sg in the entire group (r = 0.322, P < 0.001) and in subjects with NGT (r = 0.286, P < 0.001), and SgIo accurately predicted Sg. In conclusion, SgI(O) could be a simple, quantitative index for Sg.

The lack of long-range negative correlations in glucose dynamics is associated with worse glucose control in patients with diabetes mellitus.

Glucose dynamics measured in ambulatory settings are fluid in nature and exhibit substantial complexity. We recently showed that a long-range negative correlation of glucose dynamics, which is considered to reflect blood glucose controllability over a substantial period, is absent in patients with diabetes mellitus. This was demonstrated using detrended fluctuation analysis (DFA), a modified random-walk analysis method for the detection of long-range correlations. In the present study, we further assessed the relationships between the established clinical indices of glycemic or insulinogenic control of hemoglobin A(1c) (HbA(1c)), glycated albumin (GA), 1,5-anhydroglucitol, and urine C-peptide immunoreactivity and the recently proposed DFA-based indices obtained from continuous glucose monitoring in 104 Japanese diabetic patients. Significant correlations between the following parameters were observed: (1) HbA(1c) and the long-range scaling exponent α(2) (r = 0.236, P < .05), (2) GA and α(2) (r = 0.254, P < .05), (3) GA and the short-range scaling exponent α(1) (r = 0.233, P < .05), and (4) urine C-peptide immunoreactivity and the mean glucose fluctuations (r = -0.294, P < .01). Therefore, we concluded that increases in the long-range DFA scaling exponent, which are indicative of the lack of a long-range negative correlation in glucose dynamics, reflected abnormalities in average glycemic control as clinically determined using HbA(1c) and GA parameters.

Hepatic insulin sensitivity assessed by integrated model of hepatic and peripheral glucose regulation.

BACKGROUND: The integrated model of hepatic and peripheral glucose metabolism incorporates a model for liver glucose metabolism into the two-compartment minimal model framework to describe endogenous glucose kinetics during a labeled intravenous glucose tolerance test (IVGTT). This model also provides a parametric description of endogenous glucose production (EGP). The present study extended the theoretical potential of the model by defining hepatic glucose effectiveness (hS(G)(2)) as the ability of glucose per se to inhibit EGP and hepatic insulin sensitivity (hS(1)(2)) as the ability of insulin to enhance glucose suppression of EGP. METHODS: As a retrospective data base review of our previous study, we re-analyzed time courses of exogenous and endogenous glucose concentration during [6,6-(2)H(2)]glucose-labeled IVGTT (0.3 g/kg glucose), performed in 11 exercise-trained and 12 age-matched sedentary subjects. Model parameters of the two-compartment minimal model and of liver glucose metabolism were simultaneously identified to assess insulin sensitivity specific to stimulate glucose uptake (S(1)(2*)) and that specific to inhibit EGP (hS(1)(2)). The abilities of glucose per se to stimulate its own uptake (S(G)(2*)) and to inhibit EGP (hS(G)(2)) were also estimated. RESULTS: Parameters of the integrated model were identified in all the subjects. Hepatic insulin sensitivity consisted of about one-third of total insulin sensitivity (S(1)(2*) + hS(1)(2)). Compared with the sedentary subjects, S(1)(2*), hS(1)(2), hS(G)(2) of the trained subjects were greater. CONCLUSIONS: Because insulin resistance in liver and peripheral tissue may play a differential role in the pathogenesis of diabetes, this analysis can serve as a simple one-step approach to obtain metabolic indexes specific to EGP suppression and stimulating glucose uptake.

Long-range negative correlation of glucose dynamics in humans and its breakdown in diabetes mellitus.

Diurnal fluctuations in glucose levels continuously monitored during normal daily life are investigated using an extended random walk analysis, referred to as detrended fluctuation analysis (DFA), in 12 nondiabetic subjects and 15 diabetic patients. The DFA exponent alpha = 1.25 +/- 0.29 for healthy individuals in the "long-range" (>2 h) regime is shown to be significantly (P < 0.01) smaller than the reference "uncorrelated" value of alpha = 1.5, suggesting that the instantaneous net effects of the dynamical balance of glucose flux and reflux, causing temporal changes in glucose concentration, are long-range negatively correlated. By contrast, in diabetic patients, the DFA exponent alpha = 1.65 +/- 0.30 is significantly (P < 0.05) higher than that in nondiabetic subjects, evidencing a breakdown of the long-range negative correlation. It is suggested that the emergence of such positive long-range glucose correlations in diabetic patients-indicating that the net effects of the flux and reflux persist for many hours-likely reflects pathogenic mechanisms of diabetes, i.e., the lack of long-term stability of blood glucose and that the long-range negatively correlated glucose dynamics are functional in maintaining normal glucose homeostasis.

Increased RhoA translocation in aorta of diabetic rats.

AIM: To analyze RhoA expression and activation in the aorta of diabetic rats. METHODS: Male SD rats (n=70) were divided into 2 groups: the diabetic group and the control group. Diabetes was induced by intravenous injection of streptozotocin (55 mg/kg). The Rats were studied 3 weeks after the induction of diabetes. Western blotting was used to measure the expression and activation of Rho. RESULTS: Heart rate was measured 24 h/d; it decreased by 58+/-13 beats/min in the diabetic rats. Isometric tension showed that the contraction of diabetic aorta was significantly reduced compared with that of control aorta when stimulated by KCl and serotonin. The relaxation of the diabetic aorta was reduced when stimulated by acetylcholine. An enhanced RhoA translocation in the aortic tissues of diabetic rats was determined by a 90% increase in membrane-bound RhoA, indicating that the activation of RhoA is markedly increased in the diabetic aorta. CONCLUSION: Our data suggest that upregulated RhoA could be involved in the vascular dysfunction of diabetic rats.

Interleukin-12p40 gene (IL-12B) polymorphism and Type 1 diabetes mellitus in Japanese: possible role in subjects without having high-risk HLA haplotypes.

The present study was undertaken to clarify a role of interleukin-12p40 gene (IL-12B) polymorphism, located on chromosome 5q33-34 (IDDM 18), in Japanese subjects with Type 1 diabetes mellitus (T1DM) and autoimmune thyroid diseases (AITD). In 179 subjects with T1DM, 166 with AITD (128 with Graves' disease and 38 with Hashimoto's thyroiditis) and 115 healthy control subjects, the IL-12B 3'UTR A-C polymorphism was determined by PCR-RFLP method. In T1DM subjects, the genotype was also analyzed in relation to human leukocyte antigen (HLA)-DRB1-DQB1 haplotype status. There was a weak difference in the distribution of the genotype frequency between T1DM and control subjects, and the C allele frequency was higher in T1DM subjects (P<0.05). In 68 T1DM subjects without having high-risk HLA haplotypes to T1DM in this population, the genotype distribution and C allele frequency was significantly different from control subjects without high-risk HLA haplotypes (P<0.01), and from T1DM subjects with high-risk HLA haplotypes (n=111) (P<0.05). There was no difference in the genotype and allele frequencies between AITD and control subjects. In conclusion, the IL-12B 3'UTR A-C polymorphism did not seem to play a major role on genetic susceptibility to T1DM and AITD in Japanese, although the polymorphism conferred susceptibility in T1DM subjects without having high-risk HLA haplotypes. The IL-12B 3'UTR A-C polymorphism would be considered as a supplementary risk factor to T1DM in conjunction with HLA haplotypes.

Technical note: preliminary results in development of a novel intracisternal penicillin seizure model in the rat.

In order to develop an intracisternal penicillin rat model of epilepsy, eleven anesthetized male Wistar rats were studied. 5 underwent intracisternal injection of penicillin (doses 150,000-300,000 units) in the prone position, and another 5 underwent intraperitoneal penicillin injection; one died following intracisternal injection, prior to further study. Time between penicillin injection and seizure induction (determined by electroencephalography) was recorded. Each animal had a tracheostomy, and was mechanically ventilated and carefully monitored for adverse effects. Seizures were noted in an average of 13:42 minutes following penicillin injection (range 4:30-23:20) for the intracisternally (IC) injected group. Both episodic and continuous seizure activity was seen, and a dose-dependent effect was seen (quicker-onset, more continuous seizures with higher doses, in the IC group). Onset was significantly faster in the IC than for the intraperitoneally injected group (all >1 hour for the latter group in our study). 96 total separate seizure episodes were seen, ranging from 3 to 540 seconds. Epileptic activity could be seen in all IC-injected rats lasting over 1 hour into the study. The intracisternal penicillin injection rat model appears to provide a quick-onset, reliable method of inducing seizure activity in the rat model while leaving the cranial vault intact.

Electroconvulsive therapy for seizure control: preliminary data in a new seizure generation and control model.

Electroconvulsive therapy (ECT) effect upon seizure cessation was studied in five male Wistar rats using a penicillin intracisternal injection model (which did not damage the cranial vault). Animals were observed both clinically and electrographically for seizure development. ECT was applied at varying times following onset of seizure, at varying parameters (frequency, pulsewidth, and duration). ECT affected EEG seizure pattern in several different stimulation parameter-dependent ways: (1) modulation to different pattern; (2) increased interictal time; and (3) seizure cessation. Stimulation with higher, sustained current (50 mA) led to changes in seizure amplitude; stimulation at pulses of current led to seizure frequency dimunition, and at certain characteristic pulses "capture" was seen as the EEG activity mimicked the ECT-inducing stimulation pattern. Interictal time was usually increased by sustained, continuous (rather than pulsatile) stimulation. Seizure activity was completely stopped in several instances using parameters of 800 pulses at a frequency of 200 Hz, with 2.56 ms pulsewidth and 50 mA of current (in consecutive iterations for one specimen). No ECT-related adverse effects were noted. Analogous to the heart, pacing or defibrillating the brain using external scalp electrodes may have a role in the control of otherwise intractable seizures.

A single bout of exercise at higher intensity enhances glucose effectiveness in sedentary men.

OBJECTIVE: Previous studies have shown that glucose effectiveness and insulin sensitivity are acutely enhanced by exercise at various intensities. The aim of this study was to determine the effects of a single bout of exercise at intensities recommended by the American Diabetes Association (ADA) and the American College of Sports Medicine (ACSM) on glucose uptake-specific glucose effectiveness (S(G)(2)*) and insulin sensitivity (S(I)(2)*). S(G)(2)* and S(I)(2)* were estimated by a two-compartment minimal model. DESIGN: Six healthy men (age, 28.5 +/- 2.0 yr) performed a stable-labeled frequently sampled iv glucose tolerance test (FSIGT) under three separate conditions: without any prior exercise, and immediately after single 20-min bouts of cycle ergometer exercise at an intensity of 50% and 70% of maximal oxygen uptake (Vo(2max)). The exercise intensities were close to the lower and upper boundaries recommended by the ADA and ACSM. RESULTS: Glucose disappearance constant (K(G)), S(G)(2)*, and S(I)(2)* increased after exercise in an intensity-dependent manner. Increases in S(G)(2)* (+237.1 +/- 50.5%), S(I)(2)* (+225.6 +/- 51.9%), and K(G) (+151.7 +/- 16.5%) following exercise at 70% Vo(2max) were statistically significant (P < 0.05), whereas those at 50% Vo(2max) were not. CONCLUSIONS: In conclusion, a single bout of exercise acutely improves S(I)(2)* and S(G)(2)* in individuals with normal glucose tolerance in an intensity-dependent manner.

Role of AT1 receptors and NAD(P)H oxidase in diabetes-aggravated ischemic brain injury.

The objective of the present study was to examine the role of the angiotensin II type 1 receptor (AT(1)-R) in the diabetes-aggravated oxidative stress and brain injury observed in a rat model of combined diabetes and focal cerebral ischemia. Diabetes was induced by an injection of streptozotoxin (STZ; 55 mg/kg iv) at 8 wk of age. Two weeks after the induction of diabetes, some animals received continuous subcutaneous infusion of the AT(1)-R antagonist candesartan (0.5 mg.kg(-1).day(-1)) for 14 days. Focal cerebral ischemia, induced by middle cerebral artery occlusion/reperfusion (MCAO), was conducted at 4 wk after STZ injection. Male Sprague-Dawley rats (n = 189) were divided into five groups: normal control, diabetes, MCAO, diabetes + MCAO, and diabetes + MCAO + candesartan. The major observations were that 1) MCAO produced typical cerebral infarction and neurological deficits at 24 h that were accompanied by elevation of NAD(P)H oxidase gp91(phox) and p22(phox) mRNAs, and lipid hydroperoxide production in the ipsilateral hemisphere; 2) diabetes enhanced NAD(P)H oxidase gp91(phox) and p22(phox) mRNA expression, potentiated lipid peroxidation, aggravated neurological deficits, and enlarged cerebral infarction; and 3) candesartan reduced the expression of gp91(phox) and p22(phox), decreased lipid peroxidation, lessened cerebral infarction, and improved the neurological outcome. We conclude that diabetes exaggerates the oxidative stress, NAD(P)H oxidase induction, and brain injury induced by focal cerebral ischemia. The diabetes-aggravated brain injury involves AT(1)-Rs. We have shown for the first time that candesartan reduces brain injury in a combined model of diabetes and cerebral ischemia.

Effect of moderate exercise training on peripheral glucose effectiveness, insulin sensitivity, and endogenous glucose production in healthy humans estimated by a two-compartment-labeled minimal model.

For examining the effects of moderate exercise training on peripheral glucose effectiveness (S(g)(2)*), insulin sensitivity (S(i)(2)*), and endogenous glucose production (EGP), seven men and one woman (24.8 +/- 1.8 years) participated in cycle ergometer training at lactate threshold intensity for 60 min/day, 5 days/week for 12 weeks. Stable-labeled frequently sampled intravenous glucose tolerance tests were performed before and 16 h and 1 week after the last training session. S(g)(2)* (pre 0.71 +/- 0.03 x 10(-2), 16 h 0.85 +/- 0.02 x 10(-2) dl. kg(-1). min(-1)) and S(i)(2)* (pre 12.6 +/- 2.6 x 10(-4), 16 h 19.7 +/- 3.3 x 10(-4) dl. kg(-1). min(-1). [ micro U/ml](-1)), analyzed using the two-compartment minimal model, were significantly elevated 16 h after the last training session. The elevated S(g)(2)* remained higher despite the cessation of exercise training for 1 week (1.00 +/- 0.03 x 10(-2) dl. kg(-1). min(-1)). EGP was suppressed within 20 min after glucose bolus, and the suppression of EGP was followed by their overshoot. The time course of EGP during the intravenous glucose tolerance test remained similar after the training period. In conclusion, moderate exercise training at lactate threshold improves not only peripheral insulin sensitivity but also peripheral glucose effectiveness with no change in the effect of glucose and/or insulin to suppress EGP in healthy humans.