Homeostasis model assessment as a clinical index of insulin resistance in type 2 diabetic patients treated with sulfonylureas

OBJECTIVE

To investigate whether the insulin resistance index (IR) assessed by homeostasis model assessment (HOMA) is associated with the insulin resistance index assessed by euglycemic-hyperinsulinemic clamp (clamp IR) in type 2 diabetic patients who received sulfonylureas (SUs), as well as in those treated by diet alone.

RESEARCH DESIGN AND METHODS

Retrospectively, the association between HOMA IR and clamp IR was analyzed in 80 type 2 diabetic subjects (53 subjects treated with SUs and 27 subjects treated with diet alone). The 80 subjects, selected because they had not received insulin therapy, were among 111 diabetic participants in a clamp study for evaluation of insulin resistance from May 1993 to December 1997 in Osaka City University Hospital.

RESULTS

The HOMA IR showed a hyperbolic relationship with clamp IR. The log-transformed HOMA IR (all subjects, r = -0.725, P < 0.0001; SU group, r = -0.727, P < 0.0001; diet group, r = -0.747, P < 0.0001) correlated more strongly with clamp IR than did HOMA IR per se (all subjects, r = -0.594, P < 0.0001; SU group, r = -0.640, P < 0.0001; diet group, r = -0.632, P = 0.0004). The univariate regression line between log-transformed HOMA IR and clamp IR in the SU group did not differ from that in the diet group (slope, -6.866 vs. -5.120, P > 0.05; intercept, 6.566 vs. 5.478, P > 0.05). Stepwise multiple regression analyses demonstrated that the log-transformed HOMA IR was the strongest independent contributor to clamp IR (R2 = 0.640, P < 0.0001).

CONCLUSIONS

The HOMA IR strongly correlated with the clamp IR in type 2 diabetic patients treated with SUs as well as in those treated with diet alone.

High-resolution B-mode ultrasonography in evaluation of atherosclerosis in uremia

We sought to determine whether artherosclerosis may be accelerated in uremic patients on maintenance hemodialysis and investigated the risk factors for carotid and femoral atherosclerosis in such patients. High-resolution B-mode ultrasonography was used to determine the intima-media thickness (IMT) of the carotid and femoral arteries in 199 hemodialysis patients and 81 age-matched healthy controls subjects. The IMT values of the carotid and femoral arteries in the hemodialysis patients were significantly higher than in age-matched control subjects in most age groups. The IMT values of the carotid or femoral artery were significantly correlated with age in both the hemodialysis patients and the control subjects. There was a significant relationship between the IMT values of the two arteries in the hemodialysis patients (r = 0.418, P = 0.0001) and in the control subjects (r = 0.321, P = 0.0037). Multiple regression analysis showed that age, cigarette smoking, and uremic state were independent risk factors for atherosclerosis of both arteries in the patients and the control subjects (R2 = 0.174, P < 0.0001; R2 = 0.205, P < 0.0001, respectively). In the hemodialysis patients, the independent risk factors associated with the extent of the IMT of the carotid artery were age, cigarette smoking, and serum phosphorus level (R2 = 0.230, P < 0.0001), while those associated with the extent of the IMT of the femoral artery were age, cigarette-smoking, and serum m-PTH level (R2 = 0.230, P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation between the intima-media thickness of the carotid artery and aortic pulse-wave velocity in patients with type 2 diabetes. Vessel wall properties in type 2 diabetes

OBJECTIVE

The aim of this study was to assess the relationship between atherotic (structural) and sclerotic (functional) changes in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Aortic distensibility and carotid intimal-media thickness (IMT) were evaluated using carotid-femoral aortic pulse-wave velocity (a-PWV) and high-resolution B-mode ultrasonography in 271 patients with type 2 diabetes and 285 age-matched control subjects.

RESULTS

a-PWV and carotid IMT were significantly higher in the patients than in the control subjects in all age-groups (P < 0.0001, respectively). The carotid IMT and a-PWV were significantly correlated with age in both the patients with type 2 diabetes and control subjects. There was a significant positive relationship between the carotid IMT and a-PWV in both the patients (r = 0.482, P < 0.0001) and control subjects (r = 0.424, P < 0.0001). The slope of the regression line for the carotid IMT to the a-PWV was significantly steeper in the diabetic patients than in the control subjects (P < 0.05). Multiple regression analysis in all subjects showed that age, diabetic state, and cigarette smoking were independently common risk factors for the increase in carotid IMT and a-PWV. In the diabetic patients, the independent risk factors associated with the carotid IMT were age, hyperlipidemia, and duration of diabetes (R2 = 0.232, P < 0.0001), while those associated with a-PWV were age and duration of diabetes (R2 = 0.334, P < 0.0001).

CONCLUSIONS

The results indicated that diabetic patients showed more advanced changes in atherosis than that in sclerosis as compared with age- and sex-matched control subjects. Such atherotic changes in diabetic patients may be associated with hyperlipidemia.

Reactive oxygen in skeletal muscle. II. Extracellular release of free radicals

We have tested the hypothesis that diaphragm muscle fibers release superoxide anion radicals (O2-.) into the extracellular space. Fiber bundles were isolated from rat diaphragm and incubated in Krebs-Ringer solution containing cytochrome c (10(-5) M), a standard assay for O2-.. Bundles were either passive or active, i.e., directly stimulated to contract rhythmically. After 1 h, absorbance of reduced cytochrome c in the incubation medium was measured at 550 nm. Absorbance was greater in medium exposed to passive muscle than in medium without muscle (P < 0.01), indicating O2-. release by passive muscle. Absorbance was greater in medium exposed to active muscle than in that exposed to passive muscle (P < 0.01), an increase inhibited by superoxide dismutase (10(3) U/ml). Active bundles fatigued; bundles developing the lowest final stresses produced the greatest absorbance increases (P < 0.001), suggesting that the magnitude of fatigue was inversely related to O2-. release. We conclude that O2-. is released by diaphragm myocytes into the interstitium and surrounding medium, a process accelerated by fatiguing muscular contractions.

Neutrophil induced oxidative injury of cardiac myocytes. A compartmented system requiring CD11b/CD18-ICAM-1 adherence

We have previously shown that cytokines and postischemic cardiac lymph induce expression of intercellular adhesion molecule-1 (ICAM-1, CD54) on canine adult cardiac myocytes. ICAM-1 expression allows adherence of activated neutrophils to myocytes that is blocked by anti-CD18 mAb, R15.7, or anti-ICAM-1 mAb, CL18/6. Interleukin 1, tumor necrosis factor-alpha, or interleukin 6-stimulated cardiac myocytes were loaded with 2',7'-dichlorofluorescin, and oxidation to the fluorescent dichlorofluorescein was monitored. Fluorescence and neutrophil/myocyte adherence followed the same time course, and both were blocked by monoclonal antibodies to CD18, CD11b, and ICAM-1, but mAb R7.1, recognizing a functional epitope on CD11a, was not inhibitory. The iron chelator, desferroxamine, and the hydroxyl radical scavenger, dimethylthiourea, did not inhibit neutrophil adherence, but completely inhibited fluorescence. In contrast, the extracellular oxygen radical scavengers superoxide dismutase and catalase, and the extracellular iron chelator, starch-immobilized desferroxamine, did not affect either fluorescence or adherence. Under the experimental conditions used, no superoxide production could be detected in the extracellular medium. Fluorescence microscopy demonstrated that fluorescence began within 5 min after neutrophil adherence to an individual myocyte, and myocyte contracture followed rapidly. Fluorescent intensity was highest initially at the site of myocyte-neutrophil adherence. When only neutrophils were loaded with 2',7'-dichlorofluorescein, fluorescence was observed only in those neutrophils adhering to the cardiac myocytes. Thus, adherence dependent on Mac-1 (CD11b/CD18) and ICAM-1 (CD54) activates the neutrophil respiratory burst resulting in a highly compartmented iron-dependent myocyte oxidative injury.

Effect of a corticotropin releasing hormone receptor antagonist on colonic sensory and motor function in patients with irritable bowel syndrome

BACKGROUND AND AIMS

Corticotropin releasing hormone (CRH) is a major mediator of the stress response in the brain-gut axis. Irritable bowel syndrome (IBS) is presumed to be a disorder of the brain-gut link associated with an exaggerated response to stress. We hypothesised that peripheral administration of alpha-helical CRH (alphahCRH), a non-selective CRH receptor antagonist, would improve gastrointestinal motility, visceral perception, and negative mood in response to gut stimulation in IBS patients.

METHODS

Ten normal healthy subjects and 10 IBS patients, diagnosed according to the Rome II criteria, were studied. The tone of the descending colon and intraluminal pressure of the sigmoid colon were measured at baseline, during rectal electrical stimulation (ES), and at recovery after administration of saline. Visceral perception after colonic distension or rectal ES was evaluated as threshold values on an ordinate scale. The same measurements were repeated after administration of alphahCRH (10 micro g/kg).

RESULTS

ES induced significantly higher motility indices of the colon in IBS patients compared with controls. This response was significantly suppressed in IBS patients but not in controls after administration of alphahCRH. Administration of alphahCRH induced a significant increase in the barostat bag volume of controls but not in that of IBS patients. alphahCRH significantly reduced the ordinate scale of abdominal pain and anxiety evoked by ES in IBS patients. Plasma adrenocorticotropic hormone and serum cortisol levels were generally not suppressed by alphahCRH.

CONCLUSION

Peripheral administration of alphahCRH improves gastrointestinal motility, visceral perception, and negative mood in response to gut stimulation, without affecting the hypothalamo-pituitary-adrenal axis in IBS patients.

Identification of c-fos related genes and their induction by neural activation in rainbow trout brain

A number of studies have shown that the induction of c-fos gene is an indicator of the responses of cells and tissues to the environmental stimuli. In the present study, using RT-PCR-based strategy, we isolated, from the brain of the rainbow trout, two partial cDNA clones (RT-fos1 and RT-fos2) that code proteins homologous to c-Fos proteins of higher vertebrates. Sequence analysis of the two clones indicated that the two rainbow trout clones are very similar to each other over the entire cloned region (88% amino acid identity) and showed moderate similarity to c-Fos proteins of higher vertebrates (40% amino acid identity with human c-Fos). Two functionally important domains (i.e. the leucine zipper and zinc finger) are highly conserved among all the vertebrate species analyzed, although the region between the two domains was highly variable between different species. Intraperitoneal administration of kainic acid, a stable agonist of glutamate receptors, transiently induced the mRNAs for both RT-fos1 and RT-fos2 in the rainbow trout brain. These results indicate that the expression pattern of the two clones can be utilized as a suitable anatomical marker for the increased neural activities in salmonid fish brain to investigate the higher order behavior such as the learning and imprinting of odors of the home river.

Glycemic control is a predictor of survival for diabetic patients on hemodialysis

OBJECTIVE

To investigate the impact of glycemic control on the survival of diabetic subjects with end-stage renal disease (ESRD) starting hemodialysis treatment.

RESEARCH DESIGN AND METHODS

This single-center prospective observational study enrolled 150 diabetic ESRD subjects (109 men and 41 women; age at hemodialysis initiation, 60.5 +/- 10.2 years) at start of hemodialysis between January 1989 and December 1997. The subjects were divided into groups according to their glycemic control level at inclusion as follows: good HbA1c <7.5%, n = 93 (group G), and poor HbA1c > or = 7.5%, n = 57 (group P); and survival was followed until December 1999, with a mean follow-up period of 2.7 years.

RESULTS

Group G had better survival than group P (the control group) (P = 0.008). At inclusion, there was no significant difference in age, sex, systolic blood pressure (SBP), BMI, cardio-to-thoracic ratio (CTR) on chest X-ray, and serum creatinine (Cre) or hemoglobin (Hb) levels between the two groups. After adjustment for age and sex, HbA1c was a significant predictor of survival (hazard ratio 1. 133 per 1.0% increment of HbA1c, 95% CI 1.028-1.249, P = 0.012), as were Cre and CTR.

CONCLUSIONS

Good glycemic control (HbA1c <7.5%) predicts better survival of diabetic ESRD patients starting hemodialysis treatment.

Cardiovascular effect of normalizing the hematocrit level during erythropoietin therapy in predialysis patients with chronic renal failure

The optimal target hematocrit (Ht) level in recombinant human erythropoietin (rHuEPO) therapy remains controversial and has hardly been investigated in predialysis patients. We prospectively studied the regression of left ventricular hypertrophy (LVH) on echocardiography in nine predialysis patients with chronic renal failure after a partial correction (target Ht, 30%) and normalization (target Ht, 40%) of the Ht with rHuEPO treatment. Twenty-four-hour ambulatory blood pressure monitoring was also performed. The administration of rHuEPO significantly increased Ht to the target values. The rate of renal failure progression did not change during rHuEPO treatment for 12 months (Cr, from 6.2 +/- 2.0 to 5.5 +/- 2.1 mg/dL). The left ventricular mass index (LVMI) tended to decrease after a partial correction of anemia (Ht, 32.1% +/- 1.8%) at 4 months, whereas it tended to significantly decrease after normalization of Ht (Ht, 39.1% +/- 2.4%) at 12 months (baseline, 140.6 +/- 12.1 g/m2; partial correction, 126.9 +/- 10.0 g/m2; normalization, 111.2 +/- 8.3 g/m2). All patients had received antihypertensive medication before rHuEPO administration, and additional drugs were also required in four cases during the study. As a result, a good overall blood pressure control was obtained without any adverse effects on the circadian blood pressure rhythm. In conclusion, from the perspective of LVH regression, the normalization of Ht was found to be more effective than that associated with a partial correction of anemia during rHuEPO therapy.

Inverse relationship between circulating oxidized low density lipoprotein (oxLDL) and anti-oxLDL antibody levels in healthy subjects

Oxidized low density lipoprotein (oxLDL) has been implicated in the pathogenesis of atherosclerosis. Recent studies have shown that immunization of animals with oxLDL results in suppression of atherogenesis. Antibody against oxLDL (oxLDL Ab) is detectable in human sera, although its biological significance is not well established. We examined the relationship between oxLDL Ab titer and circulating oxLDL level in 130 healthy Japanese subjects. OxLDL was measured as apolipoprotein (apo) B-containing lipoproteins carrying oxidized phosphatidylcholines by a sensitive ELISA. IgG class oxLDL Ab titer was measured by ELISA. Plasma oxLDL concentration was very low and it corresponded on average to one to two out of 1000 apoB-containing lipoproteins in plasma. Plasma oxLDL correlated positively with LDL cholesterol and inversely with oxLDL Ab titer. These associations remained significant and independent in multiple regression analysis including age, gender, smoking, and high-density lipoprotein cholesterol. These data indicate that healthy subjects have a very low concentration of oxLDL in the circulation, and that oxLDL Ab titer is in an inverse relationship with plasma oxLDL concentration in this population. Although these results suggest that oxLDL Ab may play a role in maintaining the low level of plasma oxLDL, its role in atherogenesis awaits further studies.

Atrial activation during chronic atrial fibrillation in patients with isolated mitral valve disease

BACKGROUND

A computerized 32-channel mapping system has been developed to investigate the characteristics of the atrial activation sequence. The system is capable of displaying sequential atrial maps and provides a rapid and dynamic means of verifying the activation sequence of atrial fibrillation.

METHODS

Using this system, we performed intraoperative atrial activation mapping in 10 patients with chronic atrial fibrillation who were undergoing isolated mitral valve operations.

RESULTS

Regular and repetitive activation (cycle length ranged from 131 to 228 milliseconds) originated in the left atrium in all 10 patients. Two patterns of repetitive activation in 2 patients and three patterns in 1 patient appeared alternately during the observation period in the left atrium. In contrast to the repetitive activation in the left atrium, the activation sequence of the right atrium was extremely complex and chaotic. In 7 of the 10 patients, the same pattern of right atrial activation was never repeated during the observation period. In 2 patients, revolution of repetitive activation in the right atrium sporadically appeared, but the pattern of activation immediately deteriorated to a complex and chaotic pattern. In 1 patient, repetitive activation emerged from the low lateral portion of the right atrium. Because our mapping technique was limited by the number of available atrial electrodes, discrete reentrant circuits or ectopic foci could not be demonstrated in the present study. However, the activation sequences during chronic atrial fibrillation suggested that (1) the left atrium would act as an electrical driving chamber for atrial fibrillation in the majority of the patients and (2) atrial activation patterns are different in each case.

CONCLUSIONS

Computerized intraoperative mapping should guide surgeons in determining the appropriate surgical procedure and facilitate operation for chronic atrial fibrillation associated with mitral valve disease.

Intermediate-density lipoprotein as an independent risk factor for aortic atherosclerosis in hemodialysis patients

Patients with chronic renal failure often show accumulation of intermediate-density lipoprotein (IDL). Because recent studies have emphasized the atherogenicity of IDL in the general population, we evaluated the relationship between this lipoprotein and aortic atherosclerosis in uremic patients treated with hemodialysis. Aortic pulse wave velocity (PWV) was measured as a noninvasive index of sclerotic change of aorta in 205 hemodialysis patients and 184 age- and gender-matched healthy subjects. Fasting plasma lipoproteins were fractionated by ultracentrifugation into very low-density lipoprotein (VLDL), IDL, LDL, and HDL. Plasma lipoprotein (a) (Lp(a)) was measured by a latex immunoturbidimetric assay. Aortic PWV was significantly higher in the hemodialysis patients than in the control subjects. The hemodialysis group showed a significant increase in VLDL and IDL cholesterol, whereas their LDL and HDL cholesterol were lower than the control levels. Lp(a) levels did not differ between the two groups. In the hemodialysis population, VLDL, IDL, and LDL cholesterol correlated positively with aortic PWV adjusted for age, gender, smoking, and BP, whereas Lp(a) did not. Multiple regression analyses indicated that plasma triglycerides, independent of HDL cholesterol, had a significant association with aortic PWV in the hemodialysis patients but not in the control subjects. Further analyses revealed that aortic PWV in the hemodialysis patients had a significant and independent association with IDL cholesterol, whereas aortic PWV in the control subjects had significant and independent associations with HDL cholesterol and Lp(a). These results demonstrate that IDL is the lipoprotein fraction most closely associated with aortic PWV in the hemodialysis patients.

Body fat mass and lean mass as predictors of survival in hemodialysis patients

A higher body mass index (BMI) is a predictor of better survival in hemodialysis patients, although the relative importance of body fat and lean mass has not been examined in the dialysis population. We performed an observational cohort study in 808 patients with end-stage renal disease on maintenance hemodialysis. At baseline, fat mass was measured by dual-energy X-ray absorptiometry and expressed as fat mass index (FMI; kg/m2). Lean mass index (LMI) was defined as BMI minus FMI. During the mean follow-up period of 53 months, 147 deaths, including 62 cardiovascular (CV) and 85 non-CV fatal events, were recorded. In univariate analysis, LMI was not significantly associated with CV or non-CV death, whereas a higher FMI was predictive of lower risk for non-CV death. Analyses with multivariate Cox models, which took other confounding variables as covariates, indicated the independent associations between a higher LMI and a lower risk of CV death, as well as between a higher FMI and a lower risk of non-CV death. These results indicate that increased fat mass and lean mass were both conditions associated with better outcomes in the dialysis population.

Clarithromycin suppresses bronchial hyperresponsiveness associated with eosinophilic inflammation in patients with asthma

BACKGROUND

Although long-term administration of 14-membered macrolide antibiotics is a therapeutic alternative in asthma, both its pharmacologic mechanism of action and association with the pathogenesis of asthma remain obscure.

OBJECTIVE

This study investigated the suppressive effect of clarithromycin on airway responsiveness to methacholine provocation testing and examined whether chrarithromycin's antiasthmatic activity is associated with a reduction in eosinophilic inflammation.

METHODS

For 8 weeks, patients received 200 mg of clarithromycin or identical-appearing placebo twice daily. We assessed the effects of treatment with clarithromycin on bronchoconstriction precipitated by inhalation of methacholine in 17 adults with mild or moderate bronchial asthma who were in stable clinical condition. A double-blind, randomized, crossover design was used. Eosinophil counts and eosinophilic cationic protein (ECP) levels were determined in blood and sputum samples obtained on the morning of the methacholine provocation testing day.

RESULTS

After 8 weeks of treatment with clarithromycin, patients' symptoms, blood and sputum eosinophils counts and sputum ECP levels were significantly decreased compared with both placebo and baseline. Furthermore, values of PC20 methacholine improved in all patients after clarithromycin treatment.

CONCLUSIONS

Clarithromycin has a bronchial anti-inflammatory effect associated with decreased eosinophilic infiltration. This study suggests interesting therapeutic possibilities for bronchial asthma that warrant further trials.

Stiffness indexes beta of the common carotid and femoral arteries are associated with insulin resistance in NIDDM

OBJECTIVE

To investigate the association between arterial wall stiffness indexes beta of the common carotid artery (CCA) and the femoral artery (FA) and insulin resistance in NIDDM subjects in a cross-sectional study.

RESEARCH DESIGN AND METHODS

We evaluated the arterial stiffness indexes beta of CCA and FA using an ultrasonic phase-locked echo-tracking system in 60 NIDDM subjects attending the diabetes center in Osaka City University Hospital, compared with 120 age- and sex-matched control subjects. Insulin sensitivity indexes were evaluated using a euglycemic-hyperinsulinemic clamp.

RESULTS

Stiffness indexes beta of both CCA and FA were significantly higher in NIDDM subjects than in control subjects (CCA 18.1 +/- 0.9 vs. 11.7 +/- 0.3, respectively, P < 0.001; FA 35.7 +/- 2.3 vs. 23.7 +/- 0.8, respectively, P < 0.001). The mean insulin sensitivity index in NIDDM subjects was 4.69 +/- 0.29 mg.kg-1.min-1.mU-1.l. The stiffness indexes beta of both CCA and FA were inversely correlated with insulin sensitivity indexes (CCA r = -0.393, P = 0.002; FA r = -0.329, P = 0.010), as well as with age, duration of diabetes, and mean blood pressure. In stepwise multiple regression analyses, insulin sensitivity index and duration of diabetes were identified as significant independent variables for stiffness indexes beta in both CCA and FA (CCA R2 = 0.249, P = 0.0003; FA R2 = 0.336, P < 0.001).

CONCLUSIONS

Arterial stiffness indexes beta of CCA and FA were associated with insulin resistance in NIDDM subjects.

Jasmonate induction of putrescine N-methyltransferase genes in the root of Nicotiana sylvestris

Nicotine alkaloids are synthesized in the root of Nicotiana species, and their synthesis increases after insect attack, wounding and jasmonate treatment of the leaf. Putrescine N-methyltransferase (PMT) catalyzes the first committed step in nicotine biosynthesis. The expression patterns of the three Nicotiana sylvestris PMT genes (NsPMT1, NsPMT2, and NsPMT3) are reported in this study. Transcripts of the NsPMT genes were detected only in the root, and were up-regulated by methyl jasmonate treatment. When the 5'-flanking regions of NsPMT1, NsPMT2, and NsPMT3 were fused independently to beta-glucuronidase reporter gene and introduced into N. sylvestris by Agrobacterium-mediated transformation, all introduced transgenes were expressed in the cortex, endodermis, and xylem in the root, as well as upregulated by methyl jasmonate treatment. These qualitatively similar patterns of expression for the NsPMT genes are achieved with only 0.25 kb of their conserved 5'-flanking regions, which contained no known jasmonate-responsive elements.

Antibodies against oxidized LDL and carotid artery intima-media thickness in a healthy population

Oxidation of LDLs plays an important role in atherosclerosis, and immune response to oxidized LDL (oxLDL) may modulate atherogenesis. Although immunization with oxLDL is shown to suppress atherogenesis in animal models, the role of the immune response to oxLDL is not well established in humans. We investigated the relationship between the titer of anti-oxLDL antibody (oxLDL Ab) and arterial wall thickness in a healthy population with no clinical signs of atherosclerosis. Intima-media thickness of the carotid arteries (CA-IMT) was measured by high-resolution B-mode ultrasonography in 446 healthy subjects. The titer of IgG-class oxLDL Ab was measured by a solid-phase ELISA. In univariate analysis, CA-IMT correlated positively with age, systolic blood pressure, total cholesterol, triglyceride, LDL cholesterol, body mass index, and waist-to-hip ratio, whereas it correlated negatively with HDL cholesterol and oxLDL Ab titer. The inverse association between oxLDL Ab titer and CA-IMT remained significant in multiple regression analysis, which took other confounding variables into account. These results indicate an independent inverse relationship between oxLDL Ab titer and CA-IMT in healthy subjects, supporting the hypothesis that immune response to oxLDL may have a protective role at an early stage of human atherosclerosis.

Effect of cisplatin on the activities of enzymes which protect against lipid peroxidation

Increases in lipid peroxide in kidneys of rats treated with cisplatin were examined in relation to decreases in the activities of Cu,Zn-superoxide dismutase (Cu,Zn-SOD), Mn-SOD, glutathione peroxidase (GSHpx), glutathione S-transferase (GST) and catalase. The activities of catalase, GSHpx and GST in the kidney and the liver were significantly decreased after cisplatin administration. The decrease of GST activity in the kidney was 87.3%, this was the largest decrease among these enzymes in the tissues examined. Cu,Zn-SOD activity significantly decreased only in the kidney. In contrast, the activities of these enzymes in the heart and the lung, which showed no increase in lipid peroxide in our previous study, were not significantly decreased. Cisplatin does not directly increase lipid peroxidation in vitro; therefore, the increase of lipid peroxide in the kidneys of these rats treated with cisplatin can be attributed to a decrease in the activities of lipid peroxide-protecting enzymes.

Impaired metabolism of high density lipoprotein in uremic patients

We measured lipoproteins, apolipoproteins, lipoprotein lipase (LPL), hepatic triglyceride lipase (HTGL), lecithin: cholesterol acyltransferase (LCAT) and parameters of calcium metabolism to evaluate the roles of these enzymes and hypertriglyceridemia for impaired high-density lipoprotein (HDL) metabolism in chronic renal failure, and to examine the impact of altered calcium homeostasis on the lipoprotein-regulating enzymes. The subjects were 25 healthy volunteers and 66 uremic patients, 24 treated with hemodialysis (HD) and 42 with continuous ambulatory peritoneal dialysis (CAPD). Lipoprotein analysis revealed: (1) reduction in HDL cholesterol especially in HDL2 subfraction; (2) increase in HDL triglyceride; and (3) decreased ratio of HDL2 cholesterol to HDL3 cholesterol in both HD and CAPD patients. Simple regression analysis showed: (1) a positive correlation between VLDL triglyceride and triglyceride/cholesterol ratio of HDL; (2) positive correlations of LPL level in post-heparin plasma to cholesterol concentrations in HDL2, HDL3 and total HDL, and to apolipoproteins A-I and A-II; and (3) inverse correlations of HTGL to HDL2 cholesterol and to the ratio of HDL2 cholesterol/HDL3 cholesterol. Multiple regression analysis of HDL cholesterol indicated positive association with LPL and inverse correlation with VLDL triglyceride. Four variables including LPL, HTGL, LCAT and VLDL triglyceride explained 51.5% of the variation of HDL cholesterol. HDL2 cholesterol was associated positively with LPL and negatively with VLDL triglyceride in the model. HDL3 cholesterol was associated positively with LPL, HTGL and LCAT and inversely with VLDL triglyceride. Stepwise multiple regression analysis indicated that independent predictors of HTGL were gender, parathyroid hormone levels by a mid-portion assay, ionized calcium and age, and that those of LCAT were ionized calcium and age.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered Expression of Angiopoietins and Tie2 Endothelium Receptor in Psoriasis

Psoriasis is a chronic inflammatory skin disease in which epidermal proliferation is closely associated with excessive microvascular expansion within the papillary dermis. Angiopoietins have recently been identified as the major ligands of the endothelial- specific receptor Tie2. Angiopoietin 1 induces Tie2 signaling as a receptor activator and maintains blood vessel formation, whereas angiopoietin 2 destabilizes vessels by blocking Tie2 signaling as an antagonist of angiopoietin 1 and acts with vascular endothelial growth factor to initiate angiogenesis. In this study we examined the potential role of angiopoietins and the Tie2 receptor in vascular changes of psoriasis. Angiopoietin 1, angiopoietin 2, and Tie2 were upregulated in involved psoriasis skin compared to uninvolved psoriasis skin, healthy skin, and chronic spongiotic dermatitis skin. Angiopoietin 1 was expressed by stromal cells in the highly vascularized papillary dermis of involved psoriasis skin. Angiopoietin 2 was expressed by endothelial cells in the vicinity of the proliferating epidermis that abundantly expressed vascular endothelial growth factor. Vascular endothelial growth factor and basic fibroblast growth factor, which were overexpressed in involved psoriasis skin, enhanced angiopoietin 2 and Tie2 expression in dermal microvascular endothelial cell cultures. Thus, our findings suggest that upregulation of angiopoietin 1, angiopoietin 2, and Tie2 is closely associated with the development of microvascular proliferation in psoriasis, and that the angiopoietin-Tie2 system may act coordinately with vascular endothelial growth factor and basic fibroblast growth factor to promote neovascularization in psoriasis. Moreover, successful antipsoriatic treatment was accompanied by noticeable reduction of angiopoietin 2 expression, suggesting that alteration of angiopoietin 2 expression may be particularly important in controlling vascular proliferation in the treatment of psoriasis.

Early treatment with corticosteroids ameliorates proteinuria, proliferative lesions, and mesangial phenotypic modulation in adult diffuse proliferative IgA nephropathy

Diffuse proliferative immunoglobulin A (IgA) nephropathy has the potential risk for end-stage renal disease. However, treatment of IgA nephropathy has not been well established. To determine whether early treatment with corticosteroids ameliorates the proliferative lesions of diffuse proliferative IgA nephropathy, we conducted a prospective, randomized, controlled trial. Inclusion criteria were as follows: duration of abnormal urinalysis results less than 36 months, proteinuria less than 1.5 g/d of protein, serum creatinine level less than 1.5 mg/dL, and mesangial cell proliferation or matrix accumulation involving more than 50% of glomeruli. Twenty-one patients were randomly assigned to two groups: the corticosteroid group and the antiplatelet group. After 1 year of treatment, repeated renal biopsy was performed in 19 patients. We evaluated glomerular filtration rate, blood pressure, proteinuria, and histological parameters, including light microscopic findings and staining of alpha-smooth muscle actin (alphaSMA), as a marker of myofibroblast-like cells and fibronectin EDA (EDA-FN) as an indicator of renal fibrosis. After 1 year of treatment, proteinuria significantly decreased in the corticosteroid group. Histological findings, such as mesangial cell proliferation, mesangial matrix accumulation, and cellular crescents, showed significant improvement in the corticosteroid group but not in the antiplatelet group. Expression of alphaSMA in glomeruli significantly decreased in the corticosteroid group but not in the antiplatelet group. EDA-FN did not change in either group. We conclude that early treatment with corticosteroids for adult diffuse proliferative IgA nephropathy is effective in reducing renal injury.

The toxicology and safety of apple polyphenol extract

Apple polyphenol extract has strong antioxidant activity and various physiological functions, and is used in Japan as a food additive and nutritional supplements. Here, we tested the consumption safety of Applephenon, which is a polyphenol extract produced from unripe apples. The Ames test without S9 mixture revealed that Applephenon, had slight mutagenicity at a high concentration of 2500 microg/plate; however, both chromosomal aberration test and the micronucleus test found no significant mutagenicity. Furthermore, an acute oral-toxicity test, and a 90-day subchronic-toxicity test showed no significant hematological, clinical, chemical, histopathological, or urinary effects at a dose of 2000 mg/kg. These results confirm that Applephenon is safe and no toxic at average dietary level.

Atherogenic lipoprotein changes in the absence of hyperlipidemia in patients with chronic renal failure treated by hemodialysis

We compared plasma lipid and lipoprotein parameters between 210 chronic renal failure patients treated by hemodialysis and 223 age- and sex-matched healthy control subjects to examine whether atherogenic lipoprotein changes were present in hemodialysis patients in the absence of hyperlipidemia. The hemodialysis group showed higher levels of plasma triglycerides, very low density lipoprotein (VLDL) cholesterol, and intermediate density lipoprotein (IDL) cholesterol and a lower level of high density lipoprotein (HDL) cholesterol. Low density lipoprotein (LDL) cholesterol of the hemodialysis group was not elevated but their LDL was significantly more triglyceride-enriched than that of controls. Subjects were then divided into five categories according to their plasma triglyceride levels at an interval of 50 mg/dl, and comparison was made between the two groups in the same range of plasma triglycerides. Hemodialysis patients again showed higher levels of VLDL- and IDL-cholesterol, and lower levels of HDL-cholesterol than the control group even in the plasma triglycerides-matched comparisons. Similarly, higher VLDL- and IDL-cholesterol levels in hemodialysis patients were significant in plasma total cholesterol-matched subgroup comparisons. Multiple regression analysis indicated that the relationship between plasma lipid concentrations and individual lipoprotein levels were substantially altered in uremic state. The 95th percentile level of IDL-cholesterol in the nonuremic controls was 15 mg/dl, and 45% of hemodialysis patients exceeded this level. Decreased HDL-cholesterol levels < or = 35 mg/dl were seen in 6% of the control and 38% of the hemodialysis group. Elevated IDL-cholesterol and decreased HDL-cholesterol were persistently found in hemodialysis patients with normal lipid levels. It is concluded that hemodialysis patients exhibited more atherogenic lipoprotein profile than nonuremic subjects with comparable levels of plasma triglycerides and total cholesterol. Especially, increased IDL- and decreased HDL-cholesterol levels in hemodialysis patients persisted even at very low levels of plasma lipids. Since elevated IDL and decreased HDL-cholesterol are implicated in the progression of atherosclerosis, these findings are of clinical importance in the diagnosis of lipoprotein disorder in chronic renal failure.

Impact of insulin resistance and nephropathy on homocysteine in type 2 diabetes

OBJECTIVE

To assess the impacts of insulin resistance and renal function on plasma total homocysteine (tHcy) levels in patients with type 2 diabetes with a wide range of nephropathy.

RESEARCH DESIGN AND METHODS

Plasma tHcy levels were measured using the enzyme immunoassay method in 75 patients with type 2 diabetes and compared with those in 54 healthy control subjects. Insulin sensitivity indexes were assessed in patients with type 2 diabetes by hyperinsulinemic-euglycemic clamp using artificial pancreas.

RESULTS

Plasma tHcy levels and their log-translormed values (log tHcy) were significantly higher in all patients with diabetes than in control subjects (tHcy, 12.0 +/- 0.7 [SE] vs. 8.7 +/- 0.3 micromol/l, P < 0.0001; log tHcy, 1.040 +/- 0.021 vs. 0.920 +/- 0.016 micromol/l, P < 0.0001). Plasma tHcy levels in patients with diabetes were significantly increased according to degree of nephropathy (P < 0.0001). On simple regression analyses, log tHcy correlated with insulin sensitivity indexes (r = -0.319, P = 0.005) as well as creatinine clearance (r = 0.634, P < 0.0001) in all patients with diabetes. Multiple regression analyses showed that insulin sensitivity indexes (beta = -0.245) as well as creatinine clearance were independent contributors to log tHcy in all patients with diabetes (R2 = 0.750, P < 0.0001). For the 59 patients with diabetes with creatinine clearance >60 ml/min, insulin sensitivity indexes were also shown to be a significant contributor to log tHcy (beta = -0.438, R2 = 0.561, P < 0.001).

CONCLUSION

Insulin resistance and renal function are independent determinants of tHcy levels in patients with type 2 diabetes.