Chul Min Ahn

Abnormal left ventricular longitudinal functional reserve in patients with diabetes mellitus: implication for detecting subclinical myocardial dysfunction using exercise tissue Doppler echocardiography

Background: Sublinical myocardial dysfunction occurs in a significant number of patients with type 2 diabetes. Assessment of ventricular long-axis function by measuring mitral annular velocities using tissue Doppler echocardiography (TDE) is thought to provide a more sensitive index of systolic and diastolic function. We hypothesised that augmentation of left ventricular (LV) longitudinal contraction and relaxation during exercise would be blunted in patients with type 2 diabetes. Methods: Mitral annular systolic (S′) and early diastolic (E′) velocities were measured at rest and during supine bicycle exercise (25 W, 3 min increments) in 53 patients (27 male, mean age 53±14 years) with type 2 diabetes and 53 subjects with age and gender-matched control. None had echocardiographic evidence of resting or inducible myocardial ischaemia. Results: There were no significant differences in mitral inflow velocities at rest between the two groups. E′ and S′ at rest were also similar between the groups. However, S′ (7.1±1.3 vs 8.3±1.8 cm/s at 25 W, p = 0.0021; 8.1±1.5 vs 9.1±2.0 cm/s at 50 W, p = 0.026) and E′ (8.5±2.3 vs 9.9±3.1 cm/s at 25 W, p = 0.054; 9.1±2.1 vs 10.9±2.5 cm/s at 50 W, p = 0.0093) during exercise were significantly lower in patients with diabetes compared with controls. Longitudinal systolic and diastolic function reserve indices were significantly lower in patients with diabetes compared with that of controls (systolic index, 0.6±0.70 vs 1.2±1.5 cm/s at 25 W, p = 0.029; 1.2±1.2 vs 2.1±1.6 cm/s at 50 W, p = 0.009; diastolic index, 1.9±1.2 vs 2.5±2.2 cm/s at 25 W, p = 0.07; 2.3±1.3 vs 3.2±2.2 cm/s at 50 W, p = 0.031). Conclusion: In conclusion, unlike resting mitral inflow and annular velocities, changes of systolic and diastolic velocities of the mitral annulus during exercise were significantly reduced in patients with type 2 diabetes compared with the control group. The assessment of LV longitudinal functional reserve with exercise using TDE appears to be helpful in identifying early myocardial dysfunction in patients with type 2 diabetes.

Synergistic effect of peroxiredoxin II antisense on cisplatin-induced cell death

Peroxiredoxin II (Prx II) is known not only to protect cells from oxidative damage caused by hydrogen peroxide (H2O2), but also to endow cancer cells with resistance to both H2O2 and cisplatin and to grant them radioresistance. In this study, we examined whether Prx II antisense could enhance cisplatin-induced cell death. When gastric cancer cells were transfected with various concentrations of Prx II antisense plasmid, pPrxII/AS, and then treated with the same concentrations of cisplatin, Prx II antisense enhanced cisplatin-induced cell death. The combination index (CI) at all doses of the combination was below 1, indicating that Prx II antisense sensitized cisplatin-induced cell death. This synergism was also observed in the cells transfected with a Prx II antisense oligomer. Our present results, therefore, suggest that Prx II antisense would be a very good sensitizer for cisplatin, and that Prx II as a target for chemosensitizers constitutes a promising avenue for future research.

Clinical significance of insulin-like growth factor-1 receptor expression in stage I non-small-cell lung cancer: immunohistochemical analysis.

Background/Aims The insulin-like growth factor (IGF) system has been implicated in tumor growth, invasion, and metastasis. However, reports on the IGF-1 receptor (IGF-1R) based on radioimmunoassays are conflicting, and its prognostic implications in non-small-cell lung cancer (NSCLC) are still controversial. Methods Seventy-one paraffin-embedded tissue sections from stage I NSCLC patients were stained using a mouse monoclonal antibody against human IGF-1R. Results The intensity and frequency of IGF-1R expression on the membrane and cytoplasm of cancer cells was evaluated and scored using a semiquantitative system. IGF-1R expression was detected in nine of 71 (12.7%) cases. No significant relationship was found between clinical/histopathological parameters and IGF-1R expression. None of the patients whose tumor expressed IGF-1R had experienced distant metastasis or cancer-related death, although the difference did not reach statistical significance. Conclusions We conclude that IGF-1R expression may not be a major prognostic factor for stage I NSCLC.

Nanog regulates molecules involved in stemness and cell cycle-signaling pathway for maintenance of pluripotency of P19 embryonal carcinoma stem cells

To identify potential downstream targets of Nanog, a key transcription factor in the maintenance of pluripotency of embryonic stem (ES) and embryonal carcinoma (EC) cells, global gene expression profiles in Nanog small interfering RNA (siRNA)‐transfected P19 EC stem cells were performed using cDNA, 60‐mer, and 30‐mer microarray platforms. The putative Nanog target genes identified by Nanog silencing were verified using reverse transcription‐polymerase chain reaction after Nanog overexpression. Downregulation of Nanog in P19 cells resulted in reduction of pluripotency markers, such as Fgf4, Klf2, Mtf2, Oct‐4, Rex1, Sox1, Yes, and Zfp143, whereas overexpression of Nanog in P19 cells reversely upregulated their expression. However, expressions of pluripotency markers Cripto, germ cell nuclear factor, Sox2, and Zfp57 as well as leukemia inhibitory factor (LIF)/Stat3 pathway molecules LIF, IL6st, and Stat3 were not affected after 48 h transfection with Nanog siRNA or construct. Nanog silencing also downregulated expression of molecules involved in the p53‐ and cell cycle‐signaling pathway (Atf3, Jdp2, Cul3, Hist1hic, and Bcl6), whereas expression of E2f1, Tob1, Lyn, and Smarcc1 was upregulated by Nanog silencing. Expressions of cyclins D1, D2, D3, and E1 as well as cyclin‐dependent kinase (Cdk) 1 and Cdk6 were downregulated by Nanog silencing in P19 cells, whereas Nanog overexpression reversely increased their expressions. Taken together, examination of global transcriptional changes after Nanog silencing followed by verification by Nanog overexpression has revealed new molecules involved in the maintenance of self‐renewal and in the regulation of the p53‐ and cell cycle‐pathway of P19 cells. J. Cell. Physiol. 227: 3678–3692, 2012.

Cellular and Molecular Changes Associated With Inhibitory Effect of Pioglitazone on Neointimal Growth in Patients With Type 2 Diabetes After Zotarolimus-Eluting Stent Implantation

Objective—To investigate the mechanistic basis underlying antirestenosis and the antiatherogenic effect of pioglitazone in patients with type 2 diabetes mellitus who were undergoing zotarolimus-eluting stent implantation. Methods and Results—Recent studies highlight the beneficial effect of pioglitazone in attenuating neointimal growth after stent implantation. Patients with coronary artery diseases were randomly assigned to pioglitazone (n=47) or placebo (n=47) after stent implantation. Pioglitazone significantly reduced neointimal hyperplasia within the stented lesion and attenuated total plaque burden in the in-segment regions of the stent, as assessed by intravascular ultrasonography at the 8-month follow-up. These changes were preceded by reduced circulating natural killer (NK) cells, diminished interleukin 6 and monocyte chemoattractant protein-1 levels, and downregulation of chemokine receptor 2 at 2 days after stent implantation; and an elevated interleukin 10 level at 10 days after implantation. Furthermore, the proliferation and migration of vascular smooth muscle cells were inhibited in the presence of pioglitazone-treated patient serum, demonstrating that the antiproliferative effects of pioglitazone occurred concurrently with its antiinflammatory action. Conclusion—Our data present early cellular and immunologic changes by pioglitazone that might have been associated with antirestenotic and antiatherogenic effects in diabetic patients. Inhibiting proinflammatory responses while promoting antiinflammatory circuits, together with an antiproliferative action, may, in part, account for the antirestenotic effect of pioglitazone by altering vascular remodeling processes in the early phase.

Telmisartan reduces neointima volume and pulse wave velocity 8 months after zotarolimus-eluting stent implantation in hypertensive type 2 diabetic patients

Objective Telmisartan is a peroxisome proliferator-activated receptor-γ activator with potent anti-inflammatory and antiatherogenic effects. The authors compared the effects of telmisartan and valsartan on neointima volume, atherosclerosis progression and brachial-ankle pulse wave velocity (baPWV) after stenting in hypertensive type 2 diabetes. Design This was a prospective, randomised, 8-month follow-up study that included patients with significant coronary stenosis who received telmisartan (n=36) or valsartan (n=37). Setting University hospital. Main outcome measures Neointima volume and atherosclerosis progression 10 mm proximal and distal to the stented segment were analysed using repeat intravascular ultrasonography. baPWV and inflammatory markers such as interleukin 6, tumour necrosis factor α, C-reactive protein and adiponectin were compared. Results Neointima volume at 8 months was significantly lower in the telmisartan group than the valsartan group (1.9±1.0 vs 2.6±1.4 mm3/1 mm, p=0.007, respectively). Total plaque volumes 10 mm proximal (7.1±1.5 vs 7.8±1.6 mm3/1 mm, p=0.032, respectively) and distal (3.5±1.4 vs 4.1±1.3 mm3/1 mm, p=0.028, respectively) to the stent were significantly lower in the telmisartan group than the valsartan group at 8 months. The decrease from baseline in baPWV was significantly greater in the telmisartan group than the valsartan group (−52±104 vs 30±113 cm/s, p=0.002, respectively). The increase from baseline in adiponectin levels and the decreases from baseline in interleukin 6 and tumour necrosis factor α levels were significantly greater in the telmisartan group at 8 months. Retinol-binding protein-4, homeostasis model of assessment index, hemoglobin A1c and low-density lipoprotein cholesterol levels decreased significantly in both groups without differences in changes from baseline between the two groups. Conclusions Telmisartan reduced neointima volume; atherosclerosis progression 10 mm proximal and distal to the stented segment and baPWV independent of blood pressure, glucose and lipid control in hypertensive type 2 diabetes. Clinical trial no NCT00599885 (clinicaltrials.gov.)

Clinical Outcomes of Tigecycline in the Treatment of Multidrug-Resistant Acinetobacter baumannii Infection

PURPOSE Acinetobacter baumannii (A. baumannii) has emerged as a major cause of nosocomial pneumonia and sepsis in seriously ill patients. Multidrug-resistant A. baumannii (MDRAB) is increasing in frequency, and the management of its infections is consequently difficult. Therefore, tigecycline is considered to be the drug of choice for MDRAB treatment. The aim of our study was to evaluate the microbiological eradication and clinical effectiveness of tigecycline against MDRAB in seriously ill patients, including patients with ventilator-associated pneumonia (VAP). MATERIALS AND METHODS We conducted a retrospective study including patients with A. baumannii infections who were treated with tigecycline between April 1, 2009 and March 31, 2010. We treated 27 patients with tigecycline for MDRAB infections. RESULTS The mean age of patients was 66.2 years, and 20 (74.1%) patients were male. The median length of stay at hospital was 74.6 days. MDRAB was eradicated from the site of infection in 23 cases (85.2%), however, only 17 cases (63.0%) showed positive clinical responses. Overall, an in-hospital mortality rate of 51.9% was observed, and 4 cases of death were attributable to sepsis. The combination therapy showed better clinical and microbial success rates than the monotherapy without significant difference. CONCLUSION We observed the relatively low clinical success rate although the microbial eradication rate was high, probably due to superinfections in VAP and bacteremia. We suggest that clinicians should limit tigecycline monotherapy for MDRAB infection in critically ill patients, until large controlled clinical trials should be conducted.

Efficacy of Subintimal Angioplasty/Stent Implantation for Long, Multisegmental Lower Limb Occlusive Lesions in Patients Unsuitable for Surgery

Purpose: To investigate the feasibility and clinical outcomes of subintimal angioplasty combined with stent implantation in patients with long, multisegmental occlusive lesions unsuitable for surgical treatment. Methods: Between 2003 and 2005, 30 patients (23 men; mean age 68 years, range 49–82) with severe claudication (Rutherford category 3, n=12) or critical limb ischemia (CLI; Rutherford category 4 or 5, n=18) underwent subintimal angioplasty with primary stenting for long (mean 28±11 cm) total occlusion in the lower limb arteries. Bypass surgery was considered unsuitable owing to inappropriate anatomy or poor distal runoff in 14 (47%) patients, severe coronary artery disease 14 (47%), or poor general condition in 2 (6%). Results: Technical success was achieved in 27 (90%) of 30 cases. The 3 technical failures were due to inability to advance the wire, to re-enter the distal lumen, and vessel rupture, respectively. Three (10%) complications occurred (1 perforation, 2 hematomas) but did not require surgery. After a mean follow-up of 13±7 months (range 3–28), 10 (37%) cases of restenosis were found in 27 patients. At 12 months, the primary patency rate was 52%, and the limb salvage rate was 83%. Conclusion: Combined use of subintimal angioplasty and stent implantation was performed safely, with a relatively high success rate and acceptable intermediate-term clinical outcomes in patients with multisegmental, long occlusions of the lower limb arteries. Therefore, this strategy can be considered an option for symptomatic relief and limb salvage in patients unsuitable for bypass surgery due to various reasons.

Lipid raft modulation inhibits NSCLC cell migration through delocalization of the focal adhesion complex

Lipid raft, a specialized membrane structure enriched with cholesterol and glycosphingolipid, contains molecules that convey environmental stimuli to the intracellular systems. Authors investigated the effects of raft cholesterol depletion on non-small cell lung cancer (NSCLC) cell migration. Incubation of NSCLC cells in media containing lovastatin resulted in inhibition of cell migration by 63.1-83.3%, whereas raft cholesterol depletion with successive treatment using methyl-beta cyclodextrin (MbetaCD) followed by lovastatin further suppressed their migration by 35.0-57.8%. Raft cholesterol depletion partially inhibited EGF-induced phosphorylation of EGFR and FAK, however, no change was observed in other molecules comprising focal adhesion complex. It resulted in disappearance of filopodia, inhibition of EGF-induced pY397 FAK aggregation, and its destabilization. Cholesterol depletion inhibited phosphorylation of Src on Y416 in the detergent-insoluble fraction followed by decreased localization of total and pY397 FAK in the detergent-insoluble fraction. Minimal changes in these molecules were observed in the detergent-soluble fraction and interactions between FAK and other molecules of the focal adhesion complex were not influenced. Immunocytochemical analysis confirmed translocation of Src from the raft into cytoplasm and disappearance of EGF-induced membrane ruffling by raft cholesterol depletion. In cholesterol-depleted cells, EGF-induced phosphorylation of Src, Akt, and p44/42 in the detergent-insoluble fraction were inhibited whereas phosphorylation of GSK-3beta was unaffected. We conclude that raft cholesterol depletion inhibited NSCLC migration through inhibition of phosphorylation of raft associated Src and dislocation of molecules comprising focal adhesion complexes from raft rather than by inhibiting their recruitment to Src and interaction.

Red ginseng extract improves coronary flow reserve and increases absolute numbers of various circulating angiogenic cells in patients with first ST-segment elevation acute myocardial infarction.

The effects of red ginseng extract on circulating angiogenic cell mobilization and improvement of microvascular integrity were evaluated in ST‐elevation acute myocardial infarction (AMI) patients during 8‐month follow‐up. AMI patients (n = 50) were randomly assigned to the red ginseng group (3 g/day, n = 25) or the placebo group (n = 25) after coronary stenting. Coronary flow reserve (CFR) was measured at baseline and at 8 months with an intracoronary Doppler wire. Serial changes in the absolute numbers of circulating angiogenic cells such as CD34+, CXCR4+, CD117+, CD133+ and C‐met+ were measured at baseline, 1 day, 5 days and at 8 months.