Trends of HbA1c and BMI in People with Type 2 Diabetes: A Japanese Claims-Based Study

INTRODUCTION

Obesity prevalence has increased in Japan in recent years. Given the strong association of obesity with poor glycemic control, and increased risk of type 2 diabetes (T2D) with central obesity, this study describes the current trends and relationships between glycated hemoglobin (HbA1c), body mass index (BMI), and waist circumference in the Japanese people with T2D.

METHODS

This was a retrospective, cross-sectional study of people with T2D who had at least one recorded HbA1c and BMI (or waist circumference) value in the Japan Medical Data Center Claims database. Five annual cohorts of the study population were formed between January 2017 and December 2021. Annual trends of HbA1c across BMI categories (obesity class I [≥ 25 ~  < 30 kg/m2]-IV [≥ 40 kg/m2]) and in people with central obesity (waist circumference: ≥ 85 cm in men; ≥ 90 cm in women) were described by sex and age groups.

RESULTS

Overall, 106,089 people with T2D (HbA1c and BMI data: 106,079; HbA1c and waist circumference data: 105,424) were included, with the majority of people belonging to obesity class I (range: 39.7-40.6%) and obesity class II (range: 16.2-17.7%) categories across all annual cohorts. People in higher BMI categories had higher mean HbA1c, with > 50% of people with T2D in obesity class I-IV (54.8-56.5%) having HbA1c ≥ 7%. Between 2017 and 2021, BMI and waist circumference increased in the age group 18-44 years. More than 50% of people with T2D and central obesity in both sexes and people of age group 18-44 years across obesity class I-IV or with central obesity had HbA1c ≥ 7%.

CONCLUSION

More than half of the people with T2D belonging to obesity class I-IV or central obesity had poor glycemic control (HbA1c ≥ 7%), especially in the 18-44 age group. This highlights the need for body weight management for better glycemic control in relatively young Japanese people with T2D and obesity.

Prevalence of Metabolic Syndrome in Patients with Type 2 Diabetes in Japan: A Retrospective Cross-Sectional Study

INTRODUCTION

Recent data on the prevalence of metabolic syndrome in Japanese patients with type 2 diabetes (T2D) are limited.

METHODS

This retrospective, cross-sectional, observational study investigated the prevalence of metabolic syndrome in patients with T2D using a Japanese administrative claims database. Patients with a T2D diagnosis, prescription of a hypoglycemic agent, and one or more annual health checkups in 2020 were included. Trends in the prevalence of metabolic syndrome by sex and body mass index (BMI) subgroup were assessed.

RESULTS

The study cohort consisted of 155,653 patients (men, 81.6%; mean age 54.6 ± 8.5 years). Patients with metabolic syndrome had a higher mean BMI (29.1 ± 4.5 kg/m2 versus 25.2 ± 4.5 kg/m2) and mean waist circumference (98.3 ± 10.0 cm versus 87.9 ± 11.2 cm) compared to those without metabolic syndrome. Overall, the prevalence of metabolic syndrome was 43.0% in patients with T2D, with prevalence higher in men (46.6%) than women (27.0%). The prevalence increased across BMI subgroups from 17.3% in the < 25 kg/m2 subgroup, to 54.6% and 66.1% in the 25 to < 30 and ≥ 30 kg/m2 subgroups, respectively. A greater proportion of patients with metabolic syndrome had cardiovascular or renal comorbidities (BMI < 25, 0.3-2.0%; BMI 25 to < 30, 0.7-6.2%; BMI ≥ 30 kg/m2, 0.7-6.8%) and cardiovascular drug usage (BMI < 25, 1.3-9.0%; BMI 25 to < 30, 3.8-31.1%; BMI ≥ 30 kg/m2, 3.5-37.0%) in the higher BMI subgroups compared to the BMI < 25 kg/m2 subgroup.

CONCLUSION

The prevalence of metabolic syndrome in Japanese patients with T2D was 43.0% and increased with higher BMI. In patients with T2D and metabolic syndrome, cardiovascular drug usage and comorbidities increased in patients with a higher BMI. These data highlight the importance of managing metabolic parameters in addition to glycemic control in Japanese patients with T2D, particularly in patients with metabolic syndrome and BMI ≥ 25 kg/m2.

Glycaemic control, body weight, and safety of tirzepatide versus dulaglutide by baseline glycated haemoglobin level in Japanese patients with type 2 diabetes: A subgroup analysis of the SURPASS J-mono study

AIM

To evaluate glycaemic control, body weight, and safety outcomes following treatment with tirzepatide or dulaglutide in patients with type 2 diabetes (T2D) with a baseline haemoglobin (HbA1c) level of ≤8.5% (≤69 mmol/mol) versus >8.5% (>69 mmol/mol).

MATERIALS AND METHODS

SURPASS J-mono was a 52-week, multicentre, randomized, double-blind, parallel, active-controlled, phase 3 study conducted in Japan. In this exploratory subgroup analysis of SURPASS J-mono, we examined mean change in HbA1c and body weight and the incidence of adverse events (AEs) in patients with a baseline HbA1c of ≤8.5% versus >8.5% after treatment with tirzepatide (5, 10 or 15 mg) or dulaglutide 0.75 mg.

RESULTS

Of 636 randomized participants, 203 had a baseline HbA1c of >8.5% and 433 had a baseline HbA1c of ≤8.5% (range ≥7.0% to ≤10.0%). Both subgroups showed significantly greater reductions in HbA1c and body weight with any-dose tirzepatide versus dulaglutide 0.75 mg, with greater HbA1c reductions observed in patients with a baseline HbA1c of >8.5% treated with tirzepatide (least squares mean [LSM] differences of -3.13% to -3.86%) or dulaglutide (LSM -1.81%) compared with patients with a baseline HbA1c of ≤8.5% (LSM -2.00% to -2.32%) or dulaglutide (LSM -1.05%; treatment-by-baseline HbA1c subgroup interaction P ≤ 0.001). For the tirzepatide treatment arms, LSM change from baseline in body weight ranged from -6.7 to -10.7 kg for the baseline HbA1c ≤8.5% subgroup and from -4.0 to -10.6 kg for the baseline HbA1c >8.5% subgroup, compared with -0.6 kg and -0.4 kg, respectively, for the dulaglutide arm. The incidence of hypoglycaemia was low, with no substantial difference in hypoglycaemia or treatment-emergent AEs between subgroups.

CONCLUSIONS

Regardless of baseline HbA1c (≤8.5% or >8.5%), tirzepatide at doses of 5, 10 and 15 mg is effective in Japanese patients with T2D compared with dulaglutide 0.75 mg in terms of glycaemic control and body weight reduction, with an adequate safety profile consistent with previous reports.

Safety and efficacy analyses across age and body mass index subgroups in East Asian participants with type 2 diabetes in the phase 3 tirzepatide studies (SURPASS programme)

AIM

To assess the safety and efficacy of tirzepatide in people of East Asian descent based on age and body mass index (BMI).

MATERIALS AND METHODS

Data of participants enrolled in East Asian countries in the SURPASS-1, -3, -4, -5, J-mono and J-combo phase 3 clinical trials were included. Participants with type 2 diabetes with a baseline HbA1c of 7.0% up to 11.0% and a BMI of 23 kg/m² or greater or 25 kg/m² or greater were included. Participants treated with tirzepatide 5, 10 or 15 mg were evaluated to assess the safety and efficacy of tirzepatide in people of East Asian descent (94% from Japan) based on age (< 65 and ≥ 65 years) and BMI (< 25 and ≥ 25 kg/m² ). Key safety and efficacy outcomes were assessed.

RESULTS

At baseline, 73% of East Asian participants had a BMI of 25 kg/m² or greater and 74% were younger than 65 years. At week 52, tirzepatide induced a similar dose-dependent reduction in HbA1c, waist circumference and BMI across subgroups. Across all BMI and age subgroups, mean absolute HbA1c reductions across the three doses ranged from 2.3% to 3.0%, and mean waist circumference reductions ranged from 4.3 to 9.8 cm. Improvements in absolute insulin sensitivity, assessed by homeostatic model assessment for insulin resistance, were greater in those with a baseline BMI of ≥ 25 kg/m² . Improvements in lipid profiles were similar across subgroups. While the safety profile of tirzepatide was broadly similar across BMI and age subgroups, drug discontinuation because of adverse events was higher in participants with a baseline age of ≥ 65 years.

CONCLUSIONS

This post hoc analysis showed that once-weekly tirzepatide had a similar safety and efficacy profile across BMI and age subgroups in East Asian participants.

Cost-effectiveness analysis of empagliflozin in patients with heart failure with reduced ejection fraction in Japan based on the EMPEROR-Reduced trial

BACKGROUND

Several studies have reported the cost-effectiveness of sodium-glucose co-transporter 2 inhibitors in heart failure patients; however, their economic implications have not been sufficiently elucidated in Japan.

METHODS

A Markov cohort model was developed to evaluate the cost-effectiveness of empagliflozin plus standard of care (SoC) vs. SoC for patients with heart failure with reduced ejection fraction (HFrEF) in Japan. Model inputs, including risk of clinical events, costs, and utilities based on Kansas City Cardiomyopathy Questionnaire Clinical Summary Scores were derived from EMPEROR-Reduced trial data, published literature, and a claims database.

RESULTS

The model predicted lower lifetime hospitalizations for heart failure (HHFs) and additional quality-adjusted life-years (QALYs; 0.21) for empagliflozin plus SoC vs. SoC in the overall population. Increased costs of ¥100,495/patient ($772/patient), primarily driven by higher drug costs of ¥239,558/patient ($1,840/patient), were largely offset by reduced HHF management costs of -¥166,160/patient (-$1,276/patient), yielding an incremental cost-effectiveness ratio (ICER) of ¥469,672/QALY ($3,608/QALY). Results were consistent among subgroups and sensitivity analyses. In probabilistic sensitivity analysis, 82.5 % of runs were below the Japanese ICER reference value of ¥5,000,000/QALY ($38,408/QALY).

CONCLUSIONS

Empagliflozin was demonstrated to be cost-effective for HFrEF patients in Japan based on the EMPEROR-Reduced trial data.

Cost-Effectiveness Analysis of Linagliptin in Japan Based on Results from the Asian Subpopulation in the CARMELINA® Trial

INTRODUCTION

We evaluated the cost-effectiveness of linagliptin in Japan by estimating the lifetime outcome based on clinical event rates from the Asian subpopulation of the CARMELINA trial. In CARMELINA, linagliptin added to standard of care (SoC) versus SoC demonstrated noninferiority with regard to risk of composite cardiovascular (CV) outcome in patients with type 2 diabetes at high risk of CV and kidney events. Issues resulting from conducting a cost-effectiveness analysis using data from a clinical noninferiority study were also investigated.

METHODS

A microsimulation model was used to evaluate linagliptin/SoC versus SoC in terms of direct costs and quality-adjusted life years (QALYs) from a Japanese public healthcare payer's perspective. Cost data were obtained from recent Japanese publications. The time horizon was defined as lifetime, and the discount rate for costs and effectiveness was 2% per year. One-way and probabilistic sensitivity analyses were performed.

RESULTS

In the base case analysis, and taking medical history into account, the incremental effectiveness of linagliptin/SoC versus SoC was 1.34 QALYs, and the incremental cost for linagliptin was - 545,319 yen. In the one-way sensitivity analysis, the parameter which most affected the results was the hazard ratio for renal failure of linagliptin/SoC compared with SoC. The probabilistic sensitivity analysis showed that the probability of reduced costs and increased effectiveness (dominant) was 48%. Assuming an incremental cost-effectiveness ratio (ICER) threshold of 5 million yen, the probability that the ICER was below the threshold was 89% for linagliptin/SoC compared with SoC.

CONCLUSIONS

This evaluation, using Asian subpopulation data from the CARMELINA trial, suggested that the cost-effectiveness of linagliptin for a lifetime outcome was favourable in Japan. However, the results must be interpreted cautiously because of the noninferiority trial data source, which might cause ICER variations for each parameter.

Long-Term Safety and Effectiveness of Linagliptin in Japanese Patients with Type 2 Diabetes and Renal Dysfunction: a Post-Marketing Surveillance Study

INTRODUCTION

International clinical trials have shown that linagliptin significantly improves glycemic control and can be used at a single dose regardless of renal function in patients with type 2 diabetes (T2D). However, to date, no studies have evaluated the use of linagliptin in Japanese patients with T2D by renal function in routine clinical care.

METHODS

This was a subgroup analysis of data from a prospective observational post-marketing surveillance (PMS) study of linagliptin conducted in Japan that evaluated the safety and effectiveness of linagliptin in routine clinical care for 3 years in Japanese patients with T2D. The subgroup analysis examined the patient population of this PMS study according to renal function using estimated glomerular filtration rate (eGFR) data. The incidence of linagliptin-related adverse events (adverse drug reactions [ADRs]) was the primary endpoint, and the change in glycated hemoglobin (HbA1c) from baseline to last observation was the secondary endpoint.

RESULTS

Of the 2235 patients included in the safety analysis, eGFR was ≥ 90 mL/min/1.73 m² (defined as group G1) in 16.9% (n = 377), ≥ 60 to < 90 mL/min/1.73 m² (group G2) in 44.5% (n = 995), ≥  30 to < 60 mL/min/1.73 m² (group G3) in 21.7% (n = 486),  ≥ 15 to < 30 mL/min/1.73 m² (group G4) in 2.6% (n = 58) and < 15 mL/min/1.73 m² (group G5) in 1.7% (n = 37). No eGFR data were available for 12.6% (n = 282) of patients. In these GFR groups, the incidence of ADRs with linagliptin was 6.9% in group G1, 11.1% in group G2, 13.8% in group G3, 15.5% in group G4 and 16.2% in group G5; the change in HbA1c from baseline to the last observation was - 1.11, - 0.64, - 0.35, - 0.46 and - 0.54% in the respective subgroups.

CONCLUSIONS

Long-term linagliptin use showed sustained improvements in glycemic control with no new safety concerns regardless of renal function.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01650259).

FUNDING

This study was funded by Nippon Boehringer Ingelheim Co., Ltd. and Eli Lilly Japan K.K.

Carrier and spin dynamics of high-density exciton magnetic polarons in Cd0.8Mn0.2Te

We investigated the carrier and spin dynamics of high-density exciton magnetic polarons (HD-EMPs) in Cd_0.8Mn_0.2Te based on the measurement of their time-resolved photoluminescence (PL) spectra and polarization states, and the utilization of photo-induced Faraday rotation techniques. The PL from the HD-EMPs were collected in a forward scattering configuration, and was observed as a pulsed emission of a few picoseconds duration, exhibiting a blue-shift with time evolution. The blue shift originated from the refractive-index dispersion of the sample. By excluding the influence of the refractive-index dispersion on the time profile, it was revealed that the ultra-short pulsed emission with a time width smaller than 1 ps was initially radiated with a time delay of ~2.4 ps after photoexcitation. From the results of time evolution of the polarization states, it is concluded that the exciton-Mn spin interactions occurs immediately after the excitation, which causes the Mn ion spins to align to follow the spin states of photoexcited excitons. The alignment of the Mn ion spins through the formation of the HD-EMPs was significantly faster than that of the localized EMP. On the other hand, the time evolution of the photo-induced Faraday rotation showed two decay components attributed to spin relaxations of the excitons and Mn ions within the HD-EMP. The observation of the Faraday rotation signal due to the Mn ion spins further confirms that these spins were aligned by the photo-excited spin-aligned excitons. Our findings suggest a novel mechanism for the effective optical control of spins in a semimagnetic semiconductor, which is associated with a multi-exciton system and its localized state.

Empagliflozin Induces Transient Diuresis Without Changing Long-Term Overall Fluid Balance in Japanese Patients With Type 2 Diabetes

INTRODUCTION

Empagliflozin, a sodium glucose co-transporter 2 (SGLT2) inhibitor, ameliorates hyperglycemia in patients with type 2 diabetes (T2D) by inducing sustained glucosuria. Empagliflozin treatment was previously associated with a transient increase in 24-h urine volume in Caucasian patients with T2D, however comparable evidence in Japanese T2D individuals is scarce. We therefore assessed acute and chronic changes in 24-h urine volume and fluid intake with empagliflozin in Japanese patients with T2D.

METHODS

In this randomized, double-blind, placebo-controlled, parallel-group, multiple-dose, 4-week trial, 100 Japanese patients with T2D were randomized to receive either 1, 5, 10, or 25 mg empagliflozin or placebo once-daily. Changes from baseline in 24-h urine volume and fluid intake were assessed at days 1, 27, and 28 after the initiation of empagliflozin.

RESULTS

The 24-h urine volume and fluid intake were comparable across all treatment groups at baseline. Patients treated with either 10 or 25 mg empagliflozin (i.e., the licensed doses in Japan) showed a significant increase in 24-h urine volume compared to placebo at day 1 (mean change from baseline: + 0.83, + 1.08, and + 0.29 L/day in the empagliflozin 10 and 25 mg groups and the placebo group, respectively; both p < 0.001 vs. placebo). However, 24-h urine volume levels in the empagliflozin groups were comparable to placebo at day 27 and 28 (differences vs placebo < 0.1 L/day; p > 0.05). The 24-h fluid intake was comparable across all study groups throughout the entire study period. No events consistent with dehydration were reported during empagliflozin treatment.

CONCLUSION

Treatment initiation with empagliflozin in Japanese patients with T2D was associated with transient diuresis; however, overall urine volume returned towards baseline levels within 4 weeks of treatment. These findings are consistent with a physiological, adaptive mechanism of the kidney to maintain overall body fluid balance in response to treatment initiation with a SGLT2 inhibitor.

TRIAL REGISTRATION NUMBER

NCT00885118.

FUNDING

Nippon Boehringer Ingelheim Co., Ltd.

Stent-induced neutrophil activation is associated with an oxidative burst in the inflammatory process, leading to neointimal thickening

Activation of leukocytes plays an essential role in the mechanism of restenosis. Prior research has focused on monocytes and little is known about the role of neutrophils in this process. Neutrophils are known to contribute to tissue injury through oxygen-derived free radicals that nitrate tyrosine. This study was designed to elucidate clinically the role of neutrophil-mediated oxidative burst in the regulation of the post-stent inflammatory process. In 36 patients undergoing coronary stenting, we serially measured serum levels of glycosyl-phosphatidil-inositol-anchored protein (GPI)-80, a modulator of Mac-1 on the surface of neutrophils, in samples of coronary sinus as well as peripheral blood. We also simultaneously measured the serum 3-nitrotyrosine/tyrosine ratio as an index of oxidative stress. The GPI-80 level and the 3-nitrotyrosine/tyrosine ratio increased in the coronary sinus after coronary stenting in a time-dependent manner; with the maximum increase of GPI-80 level (3.1±2.9 to 8.6±4.3 ng/ml, P<0.01) at 48 hours, and 3-nitrotyrosine/tyrosine ratio at 24 hrs (5.2±4.8 to 28.4±13.2 ×10−4, P<0.01), more strikingly than in the peripheral blood. In the coronary sinus blood, the 3-nitrotyrosine/tyrosine ratio was correlated with GPI-80 levels at 24 hr (R=0.58, P<0. 001) and at 48 hr (R=0.41, P<0.01). Multiple regressions analysis showed that the maximum responses of GPI-80 level and 3-nitrotyrosine/tyrosine ratio were independent predictors of angiographic late lumen loss. Our results may supporta hypothesis that Mac-1-dependent activation of neutrophils causes oxidative burst in the post-stent inflammatory process, possibly leading to restenosis.

Role of AMPD2 in impaired glucose tolerance induced by high fructose diet

A high intake of products containing fructose is known to mediate insulin resistance. In the liver, AMPD2, an isoform of AMPD, has important glucose metabolic homeostasis functions including maintenance of AMP-activated protein kinase (AMPK). We speculated that AMPD2 induces impaired glucose tolerance in individuals who consume a high-fructose diet. We gave either a normal-chow (NCD) or high-fructose (HFrD) diet for 40 days to 8-week-old male wild-type (WT) and Ampd2 −/− homozygote (A2 −/−) C57BL/6 mice. A glucose tolerance test (GTT) and pyruvate tolerance test (PTT) were used to evaluate glucose metabolism. In addition, gluconeogenesis and glycolysis enzymes, and AMPK phosphorylation in the liver were investigated. With consumption of the HFrD, A2 −/− mice showed enhanced glucose tolerance in GTT and PTT results as compared to the WT mice, which were independent of changes in body weight. Also, the levels of phosphoenolpyruvate carboxy kinase and glucose-6-phosphatase (hepatic gluconeogenic enzymes) were significantly reduced in A2 −/− as compared to WT mice. The hepatic glycolytic enzymes glucokinase, phosphofructokinase, and pyruvate kinase were also examined, though there were no significant differences between genotypes in regard to both mRNA expression and protein expression under HFrD. Surprisingly, hepatic AMPK phosphorylation resulted in no changes in the A2 −/− as compared to WT mice under these conditions. Our results indicated that Ampd2–deficient mice are protected from high fructose diet-induced glycemic dysregulation, mainly because of gluconeogenesis inhibition, and indicate a novel therapeutic target for type 2 diabetes mellitus.

Pentraxin-3 regulates the inflammatory activity of macrophages

Background and aims

Pentraxin-3 (PTX3) reportedly has protective roles in atherosclerosis and myocardial infarction, and is a useful biomarker of vascular inflammation. However, the detailed functions of PTX3 in inflammation are yet to be elucidated. This study aimed to investigate the function of PTX3 in macrophages.

Methods

PMA-treated THP-1 cell line (THP-1 macrophage) and monocyte-derived human primary macrophages were treated with recombinant PTX3. Cytokine and chemokine levels in the THP-1 culture medium were measured as well as monocyte chemoattractant protein (MCP-1) concentrations in the Raw 264.7 cell culture medium. PTX3-silenced apoptotic macrophages (THP-1 cell line) were generated to investigate the roles of PTX3 in phagocytosis.

Results

In the presence of PTX3, macrophage interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α) and MCP-1 levels were reduced significantly (−39%, P=0.007; −21%, P=0.008; and −67%, P=0.0003, respectively), whilst activated transforming growth factor-β (TGF−β) was detected in the THP-1 macrophages (P=0.0004). Additionally, PTX3 induced Akt phosphorylation and reduced nuclear factor-kappa B (NF-κB) activation by 35% (P=0.002), which was induced by TNF-α in THP-1 macrophages. Furthermore, silencing of PTX3 in apoptotic cells resulted in increased macrophage binding, elevated expression rate of HLA-DR (+30%, P=0.015) and CD86 (+204%, P=0.004) positive cells, and induction of IL-1β (+36%, P=0.024) production. Conversely, adding recombinant PTX3 to macrophages reduced CD86 and HLA-DR expression in a dose-dependent manner.

Conclusions

We identified PTX3 as a novel regulator of macrophage activity, and this function suggests that PTX3 acts to resolve inflammation.

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PTX3 reduces pro-inflammatory cytokines from macrophages and induced active TGFβ.

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PTX3 upregulates Akt phosphorylation in macrophages.

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PTX3 reduces TNFα induced NFκ-B activation.

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Silencing PTX3 of apoptotic cells evokes phagocytic activity of macrophages.

AMPD1 regulates mTORC1-p70 S6 kinase axis in the control of insulin sensitivity in skeletal muscle

BACKGROUND

Insulin resistance triggered by excess fat is a key pathogenic factor that promotes type 2 diabetes. Understanding molecular mechanisms of insulin resistance may lead to the identification of a novel therapeutic target for type 2 diabetes. AMPD1, an isoform of AMP deaminase (AMPD), is suggested to play roles in the regulation of glucose metabolism through controlling AMP-activated protein kinase (AMPK) activation. We reported that the diet-induced insulin resistance was improved in AMPD1-deficient mice compared to wild type mice. To further delineate this observation, we studied changes of insulin signaling in skeletal muscle of wild type (WT) and AMPD1-deficient mice.

METHODS

Phosphorylation levels of kinases and expression levels of mTOR components were quantified by immunoblotting using protein extracts from tissues. The interaction between mTOR and Raptor was determined by immunoblotting of mTOR immunoprecipitates with anti-Raptor antibody. Gene expression was studied by quantitative PCR using RNA extracted from tissues.

RESULTS

Phosphorylation levels of AMPK, Akt and p70 S6 kinase in skeletal muscle were higher in AMPD1-deficient mice compared to WT mice after high fat diet challenge, while they did not show such difference in normal chow diet. Also, no significant changes in phosphorylation levels of AMPK, Akt or p70 S6 kinase were observed in liver and white adipose tissue between WT and AMPD1-deficient mice. The expression levels of mTOR, Raptor and Rictor tended to be increased by AMPD1 deficiency compared to WT after high fat diet challenge. AMPD1 deficiency increased Raptor-bound mTOR in skeletal muscle compared to WT after high fat diet challenge. Gene expression of peroxisome proliferator-activated receptor-γ coactivator 1α and β, downstream targets of p70 S6 kinase, in skeletal muscles was not changed significantly by AMPD1 deficiency compared to the wild type after high fat diet challenge.

CONCLUSION

These data suggest that AMPD1 deficiency activates AMPK/Akt/mTORC1/p70 S6 kinase axis in skeletal muscle after high fat diet challenge, but not in normal chow diet. These changes may contribute to improve insulin resistance.

Homodigital artery flap reconstruction for fingertip amputation: a comparative study of the oblique triangular neurovascular advancement flap and the reverse digital artery island flap

This fingertip reconstruction study retrospectively compared sensory recovery and active range of motion outcomes in neurovascular island advancement and reverse digital artery island flaps. Seventeen oblique triangular flaps and 14 reverse digital artery island flaps were performed for nail bed level fingertip amputations (Ishikawa subzone II). There was no significant difference between the two procedures in the Semmes-Weinstein monofilament test and range of motion results. For static and moving two-point discrimination tests, however, those with a reverse digital artery island flap required a longer period for sensory recovery compared to those with an oblique triangular advancement flap. This trend equilibrated at 12 months after surgery showing no significant difference in both static and moving two-point discrimination tests between the procedures.

AMPD1: a novel therapeutic target for reversing insulin resistance

BACKGROUND

Insulin resistance is one of the hallmark manifestations of obesity and Type II diabetes and reversal of this pathogenic abnormality is an attractive target for new therapies for Type II diabetes. A recent report that metformin, a drug known to reverse insulin resistance, demonstrated in vitro the metformin can inhibit AMP deaminase (AMPD) activity. Skeletal muscle is one of the primary organs contributing to insulin resistance and that the AMPD1 gene is selectively expressed at high levels in skeletal muscle.

METHODS

Recognizing the background above, we asked if genetic disruption of the AMPD1 gene might ameliorate the manifestations of insulin resistance. AMPD1 deficient homozygous mice and control mice fed normal chow diet or a high-fat diet, and blood analysis, glucose tolerance test and insulin tolerance test were performed. Also, skeletal muscle metabolism and gene expression including nucleotide levels and activation of AMP activated protein kinase (AMP kinase) were evaluated in both conditions.

RESULTS

Disruption of the AMPD1 gene leads to a less severe state of insulin resistance, improved glucose tolerance and enhanced insulin clearance in mice fed a high fat diet. Given the central role of AMP kinase in insulin action, and its response to changes in AMP concentrations in the cell, we examined the skeletal muscle of the AMPD1 deficient mice and found that they have greater AMP kinase activity as evidenced by higher levels of phosphorylated AMP kinase.

CONCLUSIONS

Taken together these data suggest that AMPD may be a new drug target for the reversal of insulin resistance and the treatment of Type II diabetes.

Interleukin 27 inhibits atherosclerosis via immunoregulation of macrophages in mice

Chronic inflammation in arterial wall that is driven by immune cells and cytokines plays pivotal roles in the development of atherosclerosis. Interleukin 27 (IL-27) is a member of the IL-12 family of cytokines that consists of IL-27p28 and Epstein-Barr virus induced gene 3 (EBI3) and has anti-inflammatory properties that regulate T cell polarization and cytokine production. IL-27-deficient (Ldlr-/-Ebi3-/-) and IL-27 receptor-deficient (Ldlr-/-WSX-1-/-) Ldlr-/- mice were generated and fed with a high-cholesterol diet to induce atherosclerosis. Roles of bone marrow-derived cells in vivo and macrophages in vitro were studied using bone marrow reconstitution by transplantation and cultured peritoneal macrophages, respectively. We demonstrate that mice lacking IL-27 or IL-27 receptor are more susceptible to atherosclerosis compared with wild type due to enhanced accumulation and activation of macrophages in arterial walls. The number of circulating proinflammatory Ly6C(hi) monocytes showed no significant difference between wild-type mice and mice lacking IL-27 or IL-27 receptor. Administration of IL-27 suppressed the development of atherosclerosis in vivo and macrophage activation in vitro that was indicated by increased uptake of modified low-density lipoprotein and augmented production of proinflammatory cytokines. These findings define a novel inhibitory role for IL-27 in atherosclerosis that regulates macrophage activation in mice.

The glucagon-like peptide 1 analog liraglutide reduces TNF-α-induced oxidative stress and inflammation in endothelial cells

OBJECTIVE

Glucagon-like peptide 1 (GLP-1), one of the incretin hormones, has been reported to increase positive inotropic activity in cardiac myocytes and protect against myocardial injury. However, the effects upon endothelial cells and the mechanisms involved are not fully understood. We assessed the hypothesis that GLP-1 has protective effects against inflammation and oxidative stress on human endothelial cells.

METHODS AND RESULTS

The effects of the GLP-1 analog liraglutide upon TNF-α-induced injury of the human umbilical vein endothelial cells (HUVECs) were evaluated. First, ROS induced by TNF-α was measured by staining with CM-H(2)DCFDA. Intracellular ROS production of HUVECs was significantly decreased in a dose-dependent manner until 30 nM while liraglutide inhibited the induction of gp91(phox) and p22(phox), subunit of NADPH oxidase, by TNF-α. In addition, protein levels of SOD-2, catalase and GPx were significantly increased by liraglutide. Second, rapid translocation of PKC-α into the membrane following TNF-α was evident. Liraglutide significantly inhibited this very rapid TNF-α-induced translocation of PKC-α into membrane at 2.5 min. Third, liraglutide significantly inhibited NF-κB activation and upregulated I-κB family while phosphorylation of IKK-α/β, which is upstream of NF-κB signaling, was also downregulated after 15 min of TNF-α treatment. Finally, liraglutide inhibited apoptosis of HUVEC and expression of Pentraxin-3 induced by TNF-α.

CONCLUSION

Liraglutide exerts marked anti-oxidative and anti-inflammatory effects on endothelial cells with inhibition of PKC-α, NADPH oxidase, NF-κB signaling and upregulation of protective anti-oxidative enzymes.

Endothelial dysfunction as a cellular mechanism for vascular failure

The regulation of vascular tone, vascular permeability, and thromboresistance is essential to maintain blood circulation and therefore tissue environments under physiological conditions. Atherogenic stimuli, including diabetes, dyslipidemia, and oxidative stress, induce vascular dysfunction, leading to atherosclerosis, which is a key pathological basis for cardiovascular diseases such as ischemic heart disease and stroke. We have proposed a novel concept termed "vascular failure" to comprehensively recognize the vascular dysfunction that contributes to the development of cardiovascular diseases. Vascular endothelial cells form the vascular endothelium as a monolayer that covers the vascular lumen and serves as an interface between circulating blood and immune cells. Endothelial cells regulate vascular function in collaboration with smooth muscle cells. Endothelial dysfunction under pathophysiological conditions contributes to the development of vascular dysfunction. Here, we address the barrier function and microtubule function of endothelial cells. Endothelial barrier function, mediated by cell-to-cell junctions between endothelial cells, is regulated by small GTPases and kinases. Microtubule function, regulated by the acetylation of tubulin, a component of the microtubules, is a target of atherogenic stimuli. The elucidation of the molecular mechanisms of endothelial dysfunction as a cellular mechanism for vascular failure could provide novel therapeutic targets of cardiovascular diseases.

IL-27 inhibits hyperglycemia and pancreatic islet inflammation induced by streptozotocin in mice

Inflammation driven by immune cells and pro-inflammatory cytokines is implicated in pancreatic β-cell injury, leading to the development of diabetes mellitus. IL-27, a cytokine consisting of IL-27p28 and Epstein-Barr virus-induced gene 3 (EBI3), binds a membrane-bound heterodimeric receptor consisting of the IL-27 receptor α chain (WSX-1) and gp130. IL-27 has anti-inflammatory properties that regulate T-cell polarization and cytokine production. We evaluated blood glucose and islet proinsulin concentrations, inflammatory cell infiltration in islets, and expression of IL-1β mRNA in pancreas in wild-type (WT), EBI3(-/-), and WSX-1(-/-) mice treated with streptozotocin (STZ). Hyperglycemia was augmented in EBI3(-/-) and WSX-1(-/-) mice compared with WT mice. Islet proinsulin levels after STZ treatment were lower in EBI3(-/-) and WSX-1(-/-) mice than in WT mice. The infiltration of islets by F4/80(+)CD11c(-)7/4(-) macrophages, CD4(+) T cells, and CD8(+) T cells was increased in EBI3(-/-) and WSX-1(-/-) mice compared with WT mice. The administration of recombinant IL-27, compared with control, decreased the blood glucose level, immune cell infiltration into islets, and IL-1β mRNA expression in the pancreas and increased islet proinsulin levels in WT and EBI3(-/-) mice. Thus, IL-27 inhibits STZ-induced hyperglycemia and pancreatic islet inflammation in mice and represents a potential novel therapeutic approach for β-cell protection in diabetes.

Rab5a-mediated localization of claudin-1 is regulated by proteasomes in endothelial cells

Tight junctions composed of transmembrane proteins, including claudin, occludin, and tricellulin, and peripheral membrane proteins are a major barrier to endothelial permeability, whereas the role of claudin in the regulation of tight junction permeability in nonneural endothelial cells is unclear. This study demonstrates that claudin-1 is dominantly expressed and depletion of claudin-1 using small interfering RNA (siRNA) increased tight junction permeability in EA hy.926 cells, indicating that claudin-1 is a crucial regulator of endothelial tight junction permeability. The ubiquitin-proteasome system has been implicated in the regulation of endocytotic trafficking of plasma membrane proteins. Therefore, the involvement of proteasomes in the localization of claudin-1 was investigated by pharmacological and genetic inhibition of proteasomes using a proteasome inhibitor, N-acetyl-Leu-Leu-Nle-CHO, and siRNA against the β₅-subunit of the 20S proteasome, respectively. Claudin-1 was localized at cell-cell contact sites in control cells. Claudin-1 was localized in the cytoplasm in association with Rab5a and EEA-1, a marker of early endosome, following inhibition of proteasomes. Depletion of Rab5a using siRNA reversed the localization of claudin-1 induced by inhibition of proteasomes. These data suggest that proteasomes regulate claudin-1 localization at the plasma membrane, which changes upon proteasomal inhibition to a Rab5a-mediated endosomal localization.

Angiotensin II increases expression of IP-10 and the renin-angiotensin system in endothelial cells

Angiotensin II promotes vascular inflammation, which plays important roles in vascular injury. In this study, we found that angiotensin II-stimulated human endothelial cells increased the release of a CXC chemokine, IP-10, according to an antibody array. IP-10 expression was higher in the endothelium of coronary blood vessels in mice infused with angiotensin II than in control. Quantitative real-time PCR analysis revealed that angiotensin II significantly increased IP-10 mRNA expression compared to control. Pretreatment with valsartan, but not with PD123319, blocked angiotensin II-induced IP-10 mRNA expression. IP-10 levels in conditioned media detected by ELISA increased in response to angiotensin II compared to control, which was blocked by the pretreatment with valsartan. These data indicate that angiotensin II stimulates IP-10 production from endothelial cells via angiotensin II type 1 receptors. In endothelial cells, IP-10 significantly increased mRNA expression of renin, angiotensin-converting enzyme, and angiotensinogen. IP-10 also increased angiotensin II levels in conditioned media compared to control. Angiotensin II significantly increased mRNA expression of renin, angiotensin converting enzyme and angiotensinogen, which was blocked by neutralization of IP-10 with antibody in endothelial cells. IP-10 neutralization with antibody blocked angiotensin II-induced apoptosis and cell senescence in endothelial cells. These data indicate that IP-10 is involved not only in leukocyte-endothelial interaction but also in the circuit of endothelial renin-angiotensin system activation that potentially promotes atherosclerosis.

Xenogenic macrophage immunization reduces atherosclerosis in apolipoprotein E knockout mice

Atherosclerosis is a complex chronic inflammatory disease in which macrophages play a critical role, and the intervention of the inflammatory process in atherogenesis could be a therapeutic strategy. In this study, we investigated the efficacy of xenogenic macrophage immunization on the atherosclerotic lesion formation in a model of murine atherosclerosis. Apolipoprotein E knockout (apoE-KO) mice were repeatedly immunized with formaldehyde-fixed cultured human macrophages (phorbol ester-stimulated THP-1 cells), using human serum albumin as a control protein or HepG2 cells as human control cells, once a week for four consecutive weeks. The vehicle phosphate-buffered saline was injected in the nonimmunized controls. THP-1 immunization induced antibodies that are immunoreactive with mouse macrophages. Although the plasma lipid levels were unchanged by the immunization, the atherosclerotic lesion area in the aortic root was significantly reduced by >50% in 16-wk-old THP-1-immunized apoE-KO mice compared with that in control mice. THP-1 immunization reduced in vivo macrophage infiltration, reduced in vitro macrophage adhesion, and changed cytokine production by macrophages to the antiatherogenic phenotype. Xenogenic macrophage immunization protects against the development of atherosclerosis in apoE-KO mice by modulating macrophage function in which antibodies induced by the immunization are likely to be involved. This method is a novel and potentially useful cell-mediated immune therapeutic technique against atherosclerosis.

Adenoviral transfer of rho family proteins to lung cancer cells ameliorates cell proliferation and motility and increases apoptotic change

Lung cancer is still a very severe disease which has a low survival rate due to local invasion and metastasis potentials in spite of many clinical challenges using anti-cancer drugs. Rho family small GTPases play pivotal roles in cell invasion and metastasis during carcinogenesis. In this study, we explored the inhibitory effect of adenoviral vector encoding dominant negative mutants of Rac, RhoA, and ROCK in human non-small cell lung carcinoma cell lines (A549 and SQ5) and mouse carcinoma cell line (Lewis lung carcinoma, LLC). These cells showed high expression of Rac, Rho, and ROCK, whereas only faint bands were detected in normal human lung epithelial cells, BET-1A. The efficiency of adenoviral vector transfer was stronger in A549 and SQ5 cells than LLC cells. Dominant negative forms of RhoA (Rho-DN) and Rac (Rac-DN) decreased cell proliferation in WST-8 assay and increased the number of apoptotic cells in both A549 and SQ5 cells by Hoechst 33258 and TUNEL staining. On the other hand, DN form of ROCK (ROCK-DN) did not show any apparent changes compared with the other proteins. Transwell chamber analysis showed that migration/invasion activity was significantly suppressed by gene transfection both in A549 and SQ5 cells and that ROCK-DN gene transfer required a higher multiplicity of infection to show effects similar to Rho and Rac. Although the effect of gene therapy is cell-dependent, these data suggest that adenoviral gene transfer with Rho family small GTPases is one good approach to lung cancer therapy.

Atorvastatin inhibits angiotensin II-induced T-type Ca2+ channel expression in endothelial cells

Ca2+ channels are involved in the regulation of vascular functions. Angiotensin II is implicated in the development of atherosclerosis and vascular remodeling. In this study, we demonstrated that angiotensin II preferentially increased the expression of alpha1G, a T-type Ca2+ channel subunit, via AT1 receptors in endothelial cells. Angiotensin II-induced expression of alpha1G was inhibited by pretreatment with atorvastatin and the MEK1/2 inhibitor, PD98059. The effect of atorvastatin was reversed by mevalonate and farnesyl pyrophosphate which implicates the activation of the small GTP-binding protein, Ras. Our data indicate that angiotensin II induces alpha1G expression in endothelial cells via AT1 receptors, Ras and MEK. Angiotensin II-induced migration of endothelial cells in a wound healing model was inhibited by incubation with mibefradil, a T-type Ca2+ channel blocker. Our data indicate that angiotensin II induces T-type Ca2+ channels in endothelial cells, which may play a role in the development of vascular disorders.

Stent-induced neutrophil activation is associated with an oxidative burst in the inflammatory process, leading to neointimal thickening

Activation of leukocytes plays an essential role in the mechanism of restenosis. Prior research has focused on monocytes and little is known about the role of neutrophils in this process. Neutrophils are known to contribute to tissue injury through oxygen-derived free radicals that nitrate tyrosine. This study was designed to elucidate clinically the role of neutrophil-mediated oxidative burst in the regulation of the post-stent inflammatory process. In 36 patients undergoing coronary stenting, we serially measured serum levels of glycosyl-phosphatidil-inositol-anchored protein (GPI)-80,a modulator of Mac-1 on the surface of neutrophils, in samples of coronary sinus as well as peripheral blood. We also simultaneously measured the serum 3-nitrotyrosine/tyrosine ratio as an index of oxidative stress. The GPI-80 level and the 3-nitrotyrosine/tyrosine ratio increased in the coronary sinus after coronary stenting in a time-dependent manner; with the maximum increase of GPI-80 level (3.1 +/- 2.9 to 8.6 +/- 4.3 ng/ml, P < 0.01) at 48 hours, and 3-nitrotyrosine/tyrosine ratio at 24 hrs (5.2 +/- 4.8 to 28.4 +/- 13.2 x 10(-4), P < 0.01), more strikingly than in the peripheral blood. In the coronary sinus blood, the 3-nitrotyrosine/tyrosine ratio was correlated with GPI-80 levels at 24 hr (R = 0.58, P < 0.001) and at 48 hr (R = 0.41, P < 0.01). Multiple regressions analysis showed that the maximum responses of GPI-80 level and 3-nitrotyrosine/tyrosine ratio were independent predictors of angiographic late lumen loss. Our results may support a hypothesis that Mac-1-dependent activation of neutrophils causes oxidative burst in the post-stent inflammatory process, possibly leading to restenosis.

Sphingosine 1-phosphate induces alpha-smooth muscle actin expression in lung fibroblasts via Rho-kinase

Transformation of fibroblasts into myofibroblasts is an important phenomenon that contributes to airway remodeling in bronchial asthma. Although several articles have recently indicated that a bioactive lysosphingolipid sphingosine 1-phosphate (S1P) plays roles in the pathogenesis of bronchial asthma, the role of S1P in the remodeling process is poorly understood. In the present study, we examined the effects of S1P on alpha-smooth muscle actin (SMA) expression and the morphology in lung fibroblasts. S1P stimulated the expression of alpha-SMA in a human lung fibroblast cell line WI38 that expresses EDG/S1P receptors. These processes were inhibited by Y-27632, but not by pertussis toxin. These results suggest that S1P induces a phenotypic change of lung fibroblasts via Rho-kinase that may lead to airway remodeling.

An anti-proliferative gene BTG1 regulates angiogenesis in vitro

B-cell translocation gene 1 (BTG1) is a member of the anti-proliferative gene family that regulates cell growth and differentiation. To clarify the role of BTG1 in angiogenesis, we examined the regulation of BTG1 expression in cultured endothelial cells and characterized its function in in vitro models of angiogenesis. BTG1 mRNA was abundantly expressed in quiescent endothelial cells. Addition of serum and angiogenic growth factors decreased BTG1 mRNA levels in endothelial cells. In contrast, BTG1 mRNA was up-regulated in tube-forming endothelial cells on Matrigel. This up-regulation was partially blocked by neutralizing antibody against transforming growth factor-beta (TGF-beta), and TGF-beta increased BTG1 mRNA levels. Inhibition of endogenous BTG1 by overexpression of antisense BTG1 resulted in inhibited network formation, and overexpression of sense BTG1 augmented tube formation in these cell lines. BTG1-overexpressing endothelial cells displayed increased cell migration. These findings suggest that BTG1 may play an important role in the process of angiogenesis.

Isoprenylcysteine Carboxyl Methyltransferase Modulates Endothelial Monolayer Permeability

RhoA and Rac1 regulate formation of stress fibers and intercellular junctions, thus modulating endothelial monolayer permeability. Posttranslational modifications of RhoA and Rac1 regulate enzyme activity and subcellular localization, resulting in altered cellular function. The role of RhoA and Rac1 carboxyl methylation in modulating endothelial monolayer permeability is not known. In this study, we found that inhibition of isoprenylcysteine-O-carboxyl methyltransferase (ICMT) with adenosine plus homocysteine or N-acetyl-S-geranylgeranyl-l-cysteine decreased RhoA carboxyl methylation, RhoA activity, and endothelial monolayer permeability, suggesting that RhoA carboxyl methylation may play a role in the ICMT-modulated monolayer permeability. Similar studies showed no effect of ICMT inhibition on Rac1 carboxyl methylation or localization. Bovine pulmonary artery endothelial cells (PAECs) stably overexpressing ICMT-GFP cDNA were established to determine if increased ICMT expression could alter RhoA or Rac1 carboxyl methylation, activation, and endothelial monolayer permeability. PAECs stably overexpressing ICMT demonstrated increased RhoA carboxyl methylation, membrane-bound RhoA, and RhoA activity. Additionally, PAECs stably overexpressing ICMT had diminished VE-cadherin and beta-catenin at intercellular junctions, with resultant intercellular gap formation, as well as enhanced monolayer permeability. These effects were blunted by adenosine plus homocysteine and by inhibition of RhoA, but not by inhibition of Rac1. These results indicate that ICMT modulates endothelial monolayer permeability by altering RhoA carboxyl methylation and activation, thus changing the organization of intercellular junctions. Therefore, carboxyl methylation of RhoA may modulate endothelial barrier function.

PI 3-kinase-Akt-p70 S6 kinase in hypertrophic responses to leukemia inhibitory factor in cardiac myocytes

Leukemia inhibitory factor (LIF) is a member of interleukin-6 related cytokines, which induces cardiac hypertrophy through glycoprotein (gp) 130. In this study, the role of phosphatidylinositol (PI) 3-kinase, Akt/protein kinase B (Akt/PKB), and p70 S6 kinase activation in LIF-induced hypertrophic responses such as stimulation of protein synthesis, atrial natriuretic peptide (ANP) gene expression, and reorganization of actin filaments into sarcomeric units was investigated in cultured cardiac myocytes. Treatment of cells with LIF resulted in sequential activation of PI 3-kinase, Akt/PKB, and p70 S6 kinase. Using inhibitors for PI 3-kinase and p70 S6 kinase activation, and adenovirus-mediated expression of dominant negative mutants of PI 3-kinase and Akt/PKB, we showed that PI 3-kinase activation was essential for stimulation of protein synthesis, ANP gene expression, and sarcomeric reorganization induced by LIF, while Akt/PKB activation was indispensable for ANP expression and stimulation of protein synthesis, but not for sarcomeric reorganization. Activation of p70 S6 kinase was necessary for stimulation of protein synthesis, but not for ANP gene expression or sarcomeric reorganization. These results indicated the essential role of PI 3-kinase-Akt/PKB-p70 S6 kinase pathway in the LIF-induced hypertrophic responses in cardiac myocytes.

HMG-CoA reductase inhibitor has protective effects against stroke events in stroke-prone spontaneously hypertensive rats

BACKGROUND AND PURPOSE

Recent clinical studies suggest that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) exert protective effects against nonhemorrhagic stroke. In a murine cerebral ischemia model produced by occlusion of the middle cerebral artery, statins were shown to reduce infarct size. However, the effect of statins on hypertension-based stroke is unknown. The purpose of this study is to clarify the effect of a statin on stroke in stroke-prone spontaneously hypertensive rats (SHR-SP), in which both cerebral hemorrhage and infarction occur.

METHODS

We treated SHR-SP chronically from 4 weeks of age with cerivastatin (2 mg/kg per day by gavage) or vehicle. The physiological parameters, the incidence of stroke-associated symptoms, and mortality were assessed.

RESULTS

At 14 weeks of age, the incidence (13+/-3% versus 37+/-8%; P<0.01) and the size of stroke (1.6+/-0.2 versus 2.2+/-0.1 arbitrary units; P<0.01) were significantly decreased by cerivastatin, although blood pressure and plasma cholesterol levels were not different. Moreover, stroke-associated symptoms and early mortality of SHR-SP were markedly reduced in the statin-treated group (mortality at the age of 15 weeks: 15% versus 50%; P<0.05). Statin treatment significantly reduced superoxide production from nonstroke parenchyma of brain and infiltration of inflammatory cells to the stroke lesions.

CONCLUSIONS

Our data show that a high dose of statin exerts protection against hypertension-based stroke and ameliorates the disease severity via inhibition of superoxide production and modulation of inflammation in brain.

A 3-hydroxy-3-methylglutaryl co-enzyme A reductase inhibitor reduces hypertensive nephrosclerosis in stroke-prone spontaneously hypertensive rats

BACKGROUND

Recent studies suggest that 3-hydroxy-3-methylglutaryl co-enzyme A reductase inhibitors (statins) exert their protective effects against cardiovascular diseases independently of their cholesterol-decreasing effects.

OBJECTIVE

To clarify the effect of a statin on hypertensive nephrosclerosis.

METHODS

We treated stroke-prone spontaneously hypertensive rats (spSHRs) chronically, starting at the age of 4 weeks, with cerivastatin (2 mg/kg per day by gavage) or vehicle. Physiological parameters, plasma chemistry and urine protein excretion were analysed. At 14 weeks of age, the rats had their kidneys removed for use in assays.

RESULTS

Compared with vehicle treatment, statin treatment reduced proteinuria and renal injury independently of blood pressure and cholesterol concentrations in spSHRs. Although expression of adhesion molecules and infiltration of inflammatory cells were not different whether or not cerivastatin treatment was used, renal fibrosis was significantly reduced in statin-treated spSHRs. We also found that expression of transforming growth factor-beta1 in kidneys was significantly inhibited in statin-treated spSHRs.

CONCLUSION

Cerivastatin prevents or retards hypertension-induced renal injury via inhibition of renal fibrosis and proteinuria. These results show the potential of statins as protective tools against proteinuric renal diseases, independent of their cholesterol-decreasing effects.

Overexpression of endothelial nitric oxide synthase attenuates cardiac hypertrophy induced by chronic isoproterenol infusion

Endogenous nitric oxide (NO) inhibits the contractile response to beta-adrenergic stimulation, but its effect on cardiac hypertrophy mediated by beta-adrenoceptors remains unclear. The present study was designed to determine whether overproduction of endothelial NO synthase (eNOS) could inhibit cardiac hypertrophy induced by chronic isoproterenol (ISO) infusion (30mg/kg per day) using eNOS overexpressing (eNOS-Tg) mice and wild-type (WT) mice. In a separate group, WT mice were treated with ISO and hydralazine to decrease blood pressure to the same levels in eNOS-Tg mice. The eNOS expression, NOS activity, and cGMP levels in the heart were remarkably higher in eNOS-Tg mice than in WT mice. ISO increased both heart weight and the heart/body weight ratio, which were significantly attenuated in eNOS-Tg mice compared with WT or hydralazine-treated WT mice. Histological examination revealed that the extent of fibrosis was not significantly different among the 3 groups, and that the increase in myocyte size was more than 10% lower in eNOS-Tg than in the other groups. In addition, up-regulated expression of atrial natriuretic peptide mRNA associated with cardiac hypertrophy was significantly inhibited in eNOS-Tg mice during ISO infusion. These results indicate that endogenous NO might act as a negative modulator for the hypertrophic response to beta-adrenergic stimulation.

Overexpression of endothelial nitric oxide synthase accelerates atherosclerotic lesion formation in apoE-deficient mice

Nitric oxide (NO) derived from endothelial NO synthase (eNOS) is regarded as a protective factor against atherosclerosis. Therefore, augmentation of eNOS expression or NO production by pharmacological intervention is postulated to inhibit atherosclerosis. We crossed eNOS-overexpressing (eNOS-Tg) mice with atherogenic apoE-deficient (apoE-KO) mice to determine whether eNOS overexpression in the endothelium could inhibit the development of atherosclerosis. After 8 weeks on a high-cholesterol diet, the atherosclerotic lesion areas in the aortic sinus were unexpectedly increased by more than twofold in apoE-KO/eNOS-Tg mice compared with apoE-KO mice. Also, aortic tree lesion areas were approximately 50% larger in apoE-KO/eNOS-Tg mice after 12 weeks on a high-cholesterol diet. Expression of eNOS and NO production in aortas from apoE-KO/eNOS-Tg mice were significantly higher than those in apoE-KO mice. However, eNOS dysfunction, demonstrated by lower NO production relative to eNOS expression and enhanced superoxide production in the endothelium, was observed in apoE-KO/eNOS-Tg mice. Supplementation with tetrahydrobiopterin, an NOS cofactor, reduced the atherosclerotic lesion size in apoE-KO/eNOS-Tg mice to the level comparable to apoE-KO mice, possibly through the improvement of eNOS dysfunction. These data demonstrate that chronic overexpression of eNOS does not inhibit, but accelerates, atherosclerosis under hypercholesterolemia and that eNOS dysfunction appears to play important roles in the progression of atherosclerosis in apoE-KO/eNOS-Tg mice.

Overexpression of endothelial nitric oxide synthase in endothelial cells is protective against ischemia-reperfusion injury in mouse skeletal muscle

Microvascular injury has been proposed to be a main cause of ischemia-reperfusion (I/R) injury. The roles of endothelial nitric oxide synthase (eNOS)-derived NO, a key regulator of vascular function, in I/R injury are incompletely understood. We used transgenic mice overexpressing eNOS in endothelial cells (eNOS-Tg) and their littermates wild-type mice (WT) to investigate the roles of eNOS in I/R injury in skeletal muscle. Superoxide levels in the affected muscles were reduced by approximately 50% in eNOS-Tg compared with WT during reperfusion. In WT, the disassembly of endothelial junctional proteins seen in the early period of reperfusion was recovered in the later phase. These findings were correlated with the increased vascular permeability in vivo. In contrast, eNOS-Tg maintained the endothelial junction assembly as well as vascular permeability during reperfusion. Leukocyte extravasation into tissue and up-regulated expression of adhesion molecules in the reperfused vessels were significantly inhibited in eNOS-Tg. Tissue viability of the affected muscle was decreased in WT time-dependently after reperfusion, whereas eNOS-Tg showed no significant reduction. NOS inhibition completely reversed these protective effects of eNOS overexpression in I/R injury. Thus, eNOS overexpression appears to prevent the I/R injury in skeletal muscle by maintaining vascular integrity.

Local overexpression of monocyte chemoattractant protein-1 at vessel wall induces infiltration of macrophages and formation of atherosclerotic lesion: synergism with hypercholesterolemia

Monocyte/macrophage infiltration to the arterial wall is an initial step in atherosclerosis, and monocyte chemoattractant protein-1 (MCP-1) is thought to play a central role in the recruitment of these cells. In the present study, we examined the role of local expression of MCP-1 at the vessel wall in the initiation and development of atherosclerosis. We transfected the cDNA encoding rat MCP-1 into the vessel wall of the rabbit carotid artery with the use of the hemagglutinating virus of Japan (HVJ)-liposome method. The rabbits were divided into the following groups: (1) those fed normal chow and transfected with MCP-1-HVJ, (2) those fed a high cholesterol diet (1% cholesterol) and transfected with MCP-1-HVJ, and (3) those fed a high cholesterol diet and transfected with control-HVJ. Prescribed diets were started 2 weeks before transfection and were continued for another 2 weeks. In group 1, vascular lesion formation was not found, and anti-rabbit monocyte/macrophage antibody (RAM-11) staining for monocytes/macrophages was negative, although anti-rat MCP-1 antibody (R-17) staining for rat MCP-1 was positive mainly in endothelial cells. Cholesterol feeding increased plasma cholesterol levels to 1801+/-444 mg/dL in group 2. In group 2, all rabbits displayed neointimal formation with infiltration of RAM-11-positive cells, and a part of the lesion was also positive for Sudan III lipid staining. In group 3, hypercholesterolemia did not induce the infiltration of monocytes/macrophages and subsequent lesion formation in the vessel wall despite definite upregulation of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 on the endothelium. To initiate atherosclerotic changes, local MCP-1 overexpression at the vessel is not sufficient, and activation of other factors induced by hypercholesterolemia is required.

Regulation of tight junction permeability and occludin phosphorylation by Rhoa-p160ROCK-dependent and -independent mechanisms

In epithelial and endothelial cells, tight junctions regulate the paracellular permeability of ions and proteins. Disruption of tight junctions by inflammation is often associated with tissue edema, but regulatory mechanisms are not fully understood. Using ECV304 cells as a model system, lysophosphatidic acid and histamine were found to increase the paracellular permeability of the tracer horseradish peroxidase. Cytoskeletal changes induced by these agents included stimulation of stress fiber formation and myosin light chain phosphorylation. Additionally, occludin, a tight junction protein, was a target for signaling events triggered by lysophosphatidic acid and histamine, events that resulted in its phosphorylation. A dominant-negative mutant of RhoA, RhoA T19N, or a specific inhibitor of Rho-activated kinases, Y-27632, prevented stress fiber formation, myosin light chain phosphorylation, occludin phosphorylation, and the increase in tracer flux in response to lysophosphatidic acid. In contrast, although RhoA T19N and Y-27632 blocked the cytoskeletal events induced by histamine, they had no effect on the stimulation of occludin phosphorylation or increased tracer flux, indicating that occludin phosphorylation may regulate tight junction permeability independently of cytoskeletal events. Thus, occludin is a target for receptor-initiated signaling events regulating its phosphorylation, and this phosphorylation may be a key regulator of tight junction permeability.

A calcium channel blocker, benidipine, inhibits intimal thickening in the carotid artery of mice by increasing nitric oxide production

OBJECTIVE

Recent studies suggest that several calcium channel blockers exert their protective effects against vascular disorders by increasing nitric oxide (NO) production from the endothelium. The purpose of this study was to clarify the effects of a long-lasting calcium channel blocker, benidipine, on vascular remodeling.

METHODS

The left common carotid arteries of mice were completely ligated just proximal to the carotid bifurcation. Treatment with benidipine (3 mg/kg per day) or vehicle was started 1 week before the carotid ligation, and continued throughout the experiments. Four weeks after the carotid ligation, these mice were killed and vascular remodeling was analyzed. Moreover, NO production and endothelial NO synthase (eNOS) expression were assessed.

RESULTS

At 4 weeks after ligation, the neointimal area in the vehicle-treated mice was 39,400 +/- 4,900 microm2 (n = 8), whereas that in the drug-treated mice was reduced to 18,300 +/- 3,800 microm2 (n = 10). Consequently, the luminal area was 35% larger in the drug-treated mice. Benidipine increased the basal as well as agonist-induced NO production from the endothelium, detected by Griess method or NOx analyzer. Endothelial NOS expression in vessels of the drug-treated mice was increased compared with that of the vehicle-treated mice.

CONCLUSION

Our data provide evidence that benidipine increases NO production via increment of eNOS protein in vessels and prevents intimal thickening in mice. These results show the possibility of benidipine as a protective tool against vascular remodeling independent of its effect on blood pressure.

Protein phosphorylation and the regulation of cell-cell junctions in brain endothelial cells

Endothelial cells lining the capillaries of the brain have two properties that distinguish them from their peripheral counterparts: (1) tight junctions of extremely low permeability; and (2) low rates of fluid-phase endocytosis. In combination, these features limit the nonspecific flux of ions, proteins, and other substances into the central nervous system environment, creating the blood-brain barrier. This barrier is not immutable. Tight junction permeability can be rapidly increased, which may play a role in the development of a variety of brain pathologies. We have therefore been interested in mechanisms regulating junctional permeability and strategies for interfering with this regulation. What is becoming increasingly apparent is that junctions are not passive mechanical entities; rather, they are targets for a variety of signaling pathways.

Occludin as a possible determinant of tight junction permeability in endothelial cells

Endothelial cells provide a crucial interface between blood and tissue environments. Free diffusion of substances across endothelia is prevented by the endothelial tight junction, the permeability of which varies enormously depending on tissue. Endothelial cells of the blood-brain barrier possess tight junctions of severely limited permeability, whereas those of non-neural tissue are considerably leakier, but the molecular basis for this difference is not clear. Occludin is a major transmembrane protein localizing at the tight junction. In this study, we show, by immunocytochemistry, that occludin is present at high levels and is distributed continuously at cell-cell contacts in brain endothelial cells. In contrast, endothelial cells of non-neural tissue have a much lower expression of occludin, which is distributed in a discontinuous fashion at cell-cell contacts. The apparent differences in occludin expression levels were directly confirmed by immunoblotting. The differences in occludin protein were reflected at the message level, suggesting transcriptional regulation of expression. We also show that occludin expression is developmentally regulated, being low in rat brain endothelial cells at postnatal day 8 but clearly detectable at post-natal day 70. Our data indicate that regulation of occludin expression may be a crucial determinant of the tight junction permeability properties of endothelial cells in different tissues.

A 155-kDa undercoat-constitutive protein of cell-to-cell adherens junctions

A fraction enriched in cell-to-cell adherens and tight junctions was isolated from the chick liver, and the undercoat-constitutive proteins were extracted from this isolated junctional fraction. Monoclonal antibodies (mAbs) were then obtained by injecting this extract into rats, and five antigens were identified to be concentrated in the isolated junctional fraction. We have characterized one mAb (E14 mAb) and its antigen (E14). By immunoblotting of the isolated junctional fraction the E14 mAb reacted strongly with a single band of approximately 155 kDa, and E14 was highly concentrated in the isolated junctional fraction. Immunofluorescence microscopy revealed that the E14 mAb exclusively stained the junctional complex region of the liver, renal epithelial cells, and the cell-cell border of endothelial cells in various tissues. The intercalated disc of the heart was also significantly stained. However, the E14 signal was hardly detected from intestinal epithelial cells. By immunoelectron microscopy using renal epithelial cells, E14 was mainly detected in the fibrous structures associated with the cell-to-cell adherens junction. We conclude that E14 is a novel undercoat-constitutive protein found in certain types of cell-to-cell adherens junctions.