Synergistic Renoprotective Effect of Melatonin and Zileuton by Inhibition of Ferroptosis via the AKT/mTOR/NRF2 Signaling in Kidney Injury and Fibrosis

According to recent evidence, ferroptosis is a major cell death mechanism in the pathogenesis of kidney injury and fibrosis. Despite the renoprotective effects of classical ferroptosis inhibitors, therapeutic approaches targeting kidney ferroptosis remain limited. In this study, we assessed the renoprotective effects of melatonin and zileuton as a novel therapeutic strategy against ferroptosis-mediated kidney injury and fibrosis. First, we identified RSL3-induced ferroptosis in renal tubular epithelial HK-2 and HKC-8 cells. Lipid peroxidation and cell death induced by RSL3 were synergistically mitigated by the combination of melatonin and zileuton. Combination treatment significantly downregulated the expression of ferroptosis-associated proteins, 4-HNE and HO-1, and upregulated the expression of GPX4. The expression levels of p-AKT and p-mTOR also increased, in addition to that of NRF2 in renal tubular epithelial cells. When melatonin (20 mg/kg) and zileuton (20 mg/kg) were administered to a unilateral ureteral obstruction (UUO) mouse model, the combination significantly reduced tubular injury and fibrosis by decreasing the expression of profibrotic markers, such as α-SMA and fibronectin. More importantly, the combination ameliorated the increase in 4-HNE levels and decreased GPX4 expression in UUO mice. Overall, the combination of melatonin and zileuton was found to effectively ameliorate ferroptosis-related kidney injury by upregulating the AKT/mTOR/ NRF2 signaling pathway, suggesting a promising therapeutic strategy for protection against ferroptosis-mediated kidney injury and fibrosis.

Vactosertib, TGF-β receptor I inhibitor, augments the sensitization of the anti-cancer activity of gemcitabine in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) exhibits a pronounced extracellular matrix (ECM)-rich response, which is produced by an excessive amount of transforming growth factor β (TGF-β), resulting in tumor progression and metastasis. In addition, TGF-β signaling contributes to rapidly acquired resistance and incomplete response to gemcitabine. Recently, selective inhibitors of the TGF-β signaling pathway have shown promise in PDAC treatment, particularly as an option for augmenting responses to chemotherapy. Here, we investigated the synergistic anticancer effects of a small-molecule TGF-β receptor I kinase inhibitor (vactosertib/EW-7197) in the presence of gemcitabine, and its mechanism of action in pancreatic cancer. Vactosertib sensitized pancreatic cancer cells to gemcitabine by synergistically inhibiting their viability. Importantly, the combination of vactosertib and gemcitabine significantly attenuated the expression of major ECM components, including collagens, fibronectin, and α-SMA, in pancreatic cancer compared with gemcitabine alone. This resulted in potent induction of mitochondrial-mediated apoptosis, gemcitabine-mediated cytotoxicity, and inhibition of tumor ECM by vactosertib. Additionally, the combination decreased metastasis through inhibition of migration and invasion, and exhibited synergistic anti-cancer activity by inhibiting the TGF-β/Smad2 pathway in pancreatic cancer cells. Furthermore, co-treatment significantly suppressed tumor growth in orthotopic models. Therefore, our findings demonstrate that vactosertib synergistically increased the antitumor activity of gemcitabine via inhibition of ECM component production by inhibiting the TGF-β/Smad2 signaling pathway. This suggests that the combination of vactosertib and gemcitabine may be a potential treatment option for patients with pancreatic cancer.

A novel DDR1 inhibitor enhances the anticancer activity of gemcitabine in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an extracellular matrix (ECM)-rich carcinoma, which promotes chemoresistance by inhibiting drug diffusion into the tumor. Discoidin domain receptor 1 (DDR1) increases tumor progression and drug resistance by binding to collagen, a major component of tumor ECM. Therefore, DDR1 inhibition may be helpful in cancer therapeutics by increasing drug delivery efficiency and improving drug sensitivity. In this study, we developed a novel DDR1 inhibitor, KI-301690 and investigated whether it could improve the anticancer activity of gemcitabine, a cytotoxic agent widely used for the treatment of pancreatic cancer. KI-301690 synergized with gemcitabine to suppress the growth of pancreatic cancer cells. Importantly, its combination significantly attenuated the expression of major tumor ECM components including collagen, fibronectin, and vimentin compared to gemcitabine alone. Additionally, this combination effectively decreased mitochondrial membrane potential (MMP), thereby inducing apoptosis. Further, the combination synergistically inhibited cell migration and invasion. The enhanced anticancer efficacy of the co-treatment could be explained by the inhibition of DDR1/PYK2/FAK signaling, which significantly reduced tumor growth in a pancreatic xenograft model. Our results demonstrate that KI-301690 can inhibit aberrant ECM expression by DDR1/PYK2/FAK signaling pathway blockade and attenuation of ECM-induced chemoresistance observed in desmoplastic pancreatic tumors, resulting in enhanced antitumor effect through effective induction of gemcitabine apoptosis.

Lidocaine enhances the efficacy of palbociclib in triple-negative breast cancer

The use of anesthetics in the surgical resection of tumors may influence the prognosis of cancer patients. Lidocaine, a local anesthetic, is known to act as a chemosensitizer and relieve pain in some cancers. In addition, palbociclib, a potent cyclin-dependent kinase (CDK) 4/6 inhibitor, has been approved for chemotherapy of advanced breast cancer. However, recent studies have revealed the acquired resistance of breast cancer cells to palbociclib. Therefore, the development of combination therapies that can extend the efficacy of palbociclib or delay resistance is crucial. This study investigated whether lidocaine would enhance the efficacy of palbociclib in breast cancer. Lidocaine synergistically suppressed the growth and proliferation of breast cancer cells by palbociclib. The combination treatment showed an increased cell cycle arrest in the G0/G1 phase by decreasing retinoblastoma protein (Rb) and E2F1 expression. In addition, it increased apoptosis by loss of mitochondrial membrane potential as observed by increases in cytochrome c release and inhibition of mitochondria-mediated protein expression. Additionally, it significantly reduced epithelial-mesenchymal transition and PI3K/AKT/GSK3β signaling. In orthotopic breast cancer models, this combination treatment significantly inhibited tumor growth and increased tumor cell apoptosis compared to those treated with a single drug. Taken together, this study demonstrates that the combination of palbociclib and lidocaine has a synergistic anti-cancer effect on breast cancer cells by the inhibition of the PI3K/AKT/GSK3β pathway, suggesting that this combination could potentially be an effective therapy for breast cancer.

Comparative analysis of mesenchymal stem cells cultivated in serum free media

Stem cells are attractive candidates for the regeneration of tissue and organ. Mesenchymal stem cells (MSCs) have been extensively investigated for their potential applications in regenerative medicine and cell therapy. For developing effective stem cell therapy, the mass production of consistent quality cells is required. The cell culture medium is the most critical aspect of the mass production of qualified stem cells. Classically, fetal bovine serum (FBS) has been used as a culture supplement for MSCs. Due to the undefined and heterologous composition of animal origin components in FBS, efforts to replace animal-derived components with non-animal-derived substances led to safe serum free media (SFM). Adipose derived mesenchymal stem cells (ADSCs) cultivated in SFM provided a more stable population doubling time (PDT) to later passage and more cells in a shorter time compared to FBS containing media. ADSCs cultivated in SFM had lower cellular senescence, lower immunogenicity, and higher genetic stability than ADSCs cultivated in FBS containing media. Differential expression analysis of mRNAs and proteins showed that the expression of genes related with apoptosis, immune response, and inflammatory response were significantly up-regulated in ADSCs cultivated in FBS containing media. ADSCs cultivated in SFM showed similar therapeutic efficacy in an acute pancreatitis mouse model to ADSCs cultivated in FBS containing media. Consideration of clinical trials, not only pre-clinical trial, suggests that cultivation of MSCs using SFM might offer more safe cell therapeutics as well as repeated administration due to low immunogenicity.

Combination Therapy of the Active KRAS-Targeting Antibody inRas37 and a PI3K Inhibitor in Pancreatic Cancer

KRAS activating mutations, which are present in more than 90% of pancreatic cancers, drive tumor dependency on the RAS/mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/AKT signaling pathways. Therefore, combined targeting of RAS/MAPK and PI3K/AKT signaling pathways may be required for optimal therapeutic effect in pancreatic cancer. However, the therapeutic efficacy of combined MAPK and PI3K/AKT signaling target inhibitors is unsatisfactory in pancreatic cancer treatment, because it is often accompanied by MAPK pathway reactivation by PI3K/AKT inhibitor. Therefore, we developed an inRas37 antibody, which directly targets the intra-cellularly activated GTP-bound form of oncogenic RAS mutation and investigated its synergistic effect in the presence of the PI3K inhibitor BEZ-235 in pancreatic cancer. In this study, inRas37 remarkably increased the drug response of BEZ-235 to pancreatic cancer cells by inhibiting MAPK reactivation. Moreover, the co-treatment synergistically inhibited cell proliferation, migration, and invasion and exhibited synergistic anticancer activity by inhibiting the MAPK and PI3K pathways. The combined administration of inRas37and BEZ-235 significantly inhibited tumor growth in mouse models. Our results demonstrated that inRas37 synergistically increased the antitumor activity of BEZ-235 by inhibiting MAPK reactivation, suggesting that inRas37 and BEZ-235 co-treatment could be a potential treatment approach for pancreatic cancer patients with KRAS mutations.

Intracellular KRAS-specific antibody enhances the anti-tumor efficacy of gemcitabine in pancreatic cancer by inducing endosomal escape

KRAS mutation is associated with the progression and growth of pancreatic cancer and contributes to chemo-resistance, which poses a significant clinical challenge in pancreatic cancer. Here, we developed a RT22-ep59 antibody (Ab) that directly targets the intracellularly activated GTP-bound form of oncogenic KRAS mutants after it is internalized into cytosol by endocytosis through tumor-associated receptor of extracellular epithelial cell adhesion molecule (EpCAM) and investigated its synergistic anticancer effects in the presence of gemcitabine in pancreatic cancer. We first observed that RT22-ep59 specifically recognized tumor-associated EpCAM and reached the cytosol by endosomal escape. In addition, the anticancer effect of RT22-ep59 was observed in the high-EpCAM-expressing pancreatic cancer cells and gemcitabine-resistant pancreatic cancer cells, but it had little effect on the low-EpCAM-expressing pancreatic cancer cells. Additionally, co-treatment with RT22-ep59 and gemcitabine synergistically inhibited cell viability, migration, and invasion in 3D-cultures and exhibited synergistic anticancer activity by inhibiting the RAF/ERK or PI3K/AKT pathways in cells with high-EpCAM expression. In an orthotopic mouse model, combined administration of RT22-ep59 and gemcitabine significantly inhibited tumor growth. Furthermore, the co-treatment suppressed cancer metastasis by blocking EMT signaling in vitro and in vivo. Our results demonstrated that RT22-ep59 synergistically increased the antitumor activity of gemcitabine by inhibiting RAS signaling by specifically targeting KRAS. This indicates that co-treatment with RT22-ep59 and gemcitabine might be considered a potential therapeutic strategy for pancreatic cancer patients harboring KRAS mutation.

Selonsertib Inhibits Liver Fibrosis via Downregulation of ASK1/ MAPK Pathway of Hepatic Stellate Cells

Liver fibrosis constitutes a significant health problem worldwide due to its rapidly increasing prevalence and the absence of specific and effective treatments. Growing evidence suggests that apoptosis-signal regulating kinase 1 (ASK1) is activated in oxidative stress, which causes hepatic inflammation and apoptosis, leading to liver fibrogenesis through a mitogen-activated protein kinase (MAPK) downstream signals. In this study, we investigated whether selonsertib, a selective inhibitor of ASK1, shows therapeutic efficacy for liver fibrosis, and elucidated its mechanism of action in vivo and in vitro. As a result, selonsertib strongly suppressed the growth and proliferation of hepatic stellate cells (HSCs) and induced apoptosis by increasing Annexin V and TUNEL-positive cells. We also observed that selonsertib inhibited the ASK1/MAPK pathway, including p38 and c-Jun N-terminal kinase (JNK) in HSCs. Interestingly, dimethylnitrosamine (DMN)-induced liver fibrosis was significantly alleviated by selonsertib treatment in rats. Furthermore, selonsertib reduced collagen deposition and the expression of extracellular components such as α-smooth muscle actin (α-SMA), fibronectin, and collagen type I in vitro and in vivo. Taken together, selonsertib suppressed fibrotic response such as HSC proliferation and extracellular matrix components by blocking the ASK1/MAPK pathway. Therefore, we suggest that selonsertib may be an effective therapeutic drug for ameliorating liver fibrosis.

Multiparametric approach with diffusion-weighted imaging and dynamic contrast-enhanced MRI: a comparison study for differentiating between benign and malignant bone lesions in adults

AIM

To evaluate and compare the diagnostic performance of quantitative parameters derived from diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in differentiating benign and malignant bone tumours.

MATERIALS AND METHODS

Fifty-five patients (age range, 21-82 years; mean age, 55 years) underwent pretreatment MRI. Apparent diffusion coefficient (ADC) values were calculated by DWI. The DCE-MRI data were analysed for the volume transfer constant (K^trans), extravascular extracellular volume fraction (V_e), and volume rate constant (K_ep), and K^trans/ADC ratio. Each parameter's performance was evaluated using the area under the receiver operating characteristic (ROC) curv (AUC), and their AUCs were compared. ROC curves were analysed and each parameter's optimal cut-off value was determined, from which each parameter was evaluated for sensitivity, specificity, accuracy, and positive and negative predictive values. The odds ratio (OR) with 95% confidence interval for detecting malignant bone lesions after adjusting the age factor of each parameter was estimated.

RESULTS

All parameter values (except V_e) were significantly different between benign and malignant bone tumours (p<0.05). The K^trans had a significantly greater AUC than V_e (p=0.03). The K^trans/ADC and K_ep had the best sensitivity (0.917) and specificity (0.632), respectively. The K_ep and K^trans/ADC had the best positive (0.811) and negative (0.769) predictive values, respectively. The OR was highest for K^trans/ADC (17.38; p=0.0013).

CONCLUSION

The K^trans, K_ep, ADC, and K^trans/ADC could help to detect malignant lesions from bone tumours and K^trans/ADC appears to be the superior variable among them.

Diagnostic performance of conventional MRI parameters and apparent diffusion coefficient values in differentiating between benign and malignant soft-tissue tumours

AIM

To compare the abilities of conventional magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) in differentiating between benign and malignant soft-tissue tumours (STT).

MATERIAL AND METHODS

A total of 123 patients with STT who underwent 3 T MRI, including diffusion-weighted imaging (DWI), were retrospectively analysed using variate conventional MRI parameters, ADC_mean and ADC_min.

RESULTS

For the all-STT group, the correlation between the malignant STT conventional MRI parameters, except deep compartment involvement, compared to those of benign STT were statistically significant with univariate analysis. Maximum diameter of the tumour (p=0.001; odds ratio [OR], 8.97) and ADC_mean (p=0.020; OR, 4.30) were independent factors with multivariate analysis. For the non-myxoid non-haemosiderin STT group, signal heterogeneity on axial T1-weighted imaging (T1WI; p=0.017), ADC_mean, and ADC_min (p=0.001, p=0.001), showed significant differences with univariate analysis between malignancy and benignity. Signal heterogeneity in axial T1WI (p=0.025; OR, 12.64) and ADC_mean (p=0.004; OR, 33.15) were independent factors with multivariate analysis.

CONCLUSION

ADC values as well as conventional MRI parameters were useful in differentiating between benign and malignant STT. The ADC_mean was the most powerful diagnostic parameter in non-myxoid non-haemosiderin STT.

Reuse of a previously transplanted kidney from a deceased donor using Luminex virtual crossmatching: a case report

Kidney transplantation is the most desired modality of renal replacement therapy for patients with end-stage renal disease (ESRD). We have attempted to expand the organ donor pool through several methods, including the use of expanded donor criteria. Although previously transplanted kidneys are rarely reused, they can be suitable for transplantation into patients in need. We report a case of successful reuse of a previously transplanted kidney from a deceased donor by means of Luminex virtual crossmatching with the first donor and actual crossmatching with the second donor.

Clinical relevance of the apparent diffusion coefficient value of metastatic bone tumours on diffusion-weighted MRI images: differences according to the types of primary tumour, the affected bones, and clinical factors

AIM

To evaluate whether the apparent diffusion coefficient (ADC) of metastatic bone tumours on diffusion-weighted magnetic resonance imaging (MRI) images differs according to the type of primary cancer, the affected bone, and clinical factors.

MATERIALS AND METHODS

For this retrospective study, two radiologists reviewed MRI images, including ADC maps, of 67 patients (M:F=38:29; median age, 48 years) who were diagnosed with bone metastasis by means of histological or clinical confirmation. The primary tumours included 29 lung adenocarcinomas, 15 invasive ductal adenocarcinomas of the breast, 13 hepatocellular carcinomas, six prostatic carcinomas, and four renal cell carcinomas. ADC values of the metastatic tumour were compared according to the type of primary malignancy, the affected bone, and the age and sex of the patient using Kruskal-Wallis and Mann-Whitney U-tests with Bonferroni correction. In addition, pre-contrast CT images were available in 38 of 67 patients; a subanalysis of the CT radiodensity and ADC values were performed with Spearman correlation.

RESULTS

The mean, standard deviation, and minimum and maximum values of the ADC of metastatic bone tumours did not differ significantly according to type of primary malignancy, the affected bone, or clinical variables (p>0.1). The ADC value was not significantly correlated with CT radiodensity (p=0.24). Intra- and interobserver agreements for the mean ADC values were excellent (intra-observer: p=0.98; interobserver: p=0.98).

CONCLUSIONS

Assessment of the ADC value of metastatic bone tumours is not reliable for differentiation of the type of primary cancer.

Reducing metallic artefacts in post-operative spinal imaging: slice encoding for metal artefact correction with dual-source parallel radiofrequency excitation MRI at 3.0 T

OBJECTIVE

To compare the effects of metal artefacts and acquisition time among slice encoding for metal artefact correction (SEMAC), SEMAC with dual-source parallel radiofrequency (SEMAC-DSPRF) transmission and fast spin echo (FSE) images using 3.0-T MRI.

METHODS

The signal-to-noise ratio (SNR) was calculated in a phantom study using a pedicle screw. A total of 16 patients who underwent spinal surgery using pedicle screws were included in the clinical study. T1 weighted FSE, SEMAC and SEMAC-DSPRF images were obtained. Four imaging findings (visibility of the dural sac, neural foramens, bone-implant interface and overall artefacts) were evaluated by using five-point scales independently by two observers. The mean scan time was recorded.

RESULTS

The mean SNR was 71.2, 25.7 and 28.4 for FSE, SEMAC and SEMAC-DSPRF images, respectively. FSE images were ranked lower than SEMAC and SEMAC-DSPRF images, and ranking of SEMAC and SEMAC-DSPRF images did not differ statistically for all four imaging findings. The mean scan time was 9 min 51 s and 6 min 31 s for SEMAC and SEMAC-DSPRF images, respectively.

CONCLUSION

SEMAC can reduce metallic artefacts and improve the visualisation of anatomical structures around metal implants. An additional DSPRF technique can reduce the acquisition time of SEMAC images without the loss of SNR and image quality.

ADVANCES IN KNOWLEDGE

This study demonstrates that the use of the DSPRF transmission technique can reduce the acquisition time of SEMAC images without loss of image quality in patients with metal implants.

T2 mapping of the articular cartilage in the ankle: correlation to the status of anterior talofibular ligament

AIM

To evaluate differences in T2 relaxation time of ankle cartilage using magnetic resonance imaging (MRI) according to the status of the anterior talofibular ligament (ATFL).

MATERIALS AND METHODS

The talar trochlear cartilage (TTC) was evaluated in 52 patients with ankle pain that were categorized according to the status of ATFL; normal (NL; n = 23, mean age 40 years); partial tear (PT; n = 21, mean age 39 years); or complete tear (CT; n = 8, mean age 33 years). The TTC was divided into six compartments (medial anterior, medial centre, medial posterior, lateral anterior, lateral centre, and lateral posterior). The mean T2 value of each compartment was obtained using the multi-echo sequence. Data were analysed with parametric and non-parametric statistical tests.

RESULTS

The mean T2 values of the TTC showed significant differences between the three groups; NL, PT, and CT (p < 0.001). The T2 value between the three ligamentous groups were significantly different in the medial anterior, lateral anterior, and lateral centre compartments (p = 0.003, 0.002, 0.002, respectively). T2 values of the PT and CT groups were significantly higher than those of the NL group in the medial anterior compartment (p = 0.015, 0.002) and lateral anterior compartment (p = 0.026, <0.001). The T2 value of the CT group was significantly higher than that of NL and PT groups in the lateral centre compartment (p < 0.001, 0.031).

CONCLUSION

The T2 value of the TTC in patients with ATFL injury increased at the medial anterior, lateral anterior, and lateral centre compartments.

Blind oral endotracheal intubation of rats using a ventilator to verify correct placement

Endotracheal intubation in rats is challenging due to difficulties visualizing the epiglottis and vocal cords. No visualization of these structures results in repeated intubation attempts which can cause trauma to the oral cavity and/or oesophagus, and death of the animal due to respiratory failure. Here, we describe a simple blind oral tracheal intubation technique in the rat that decreases the frequency of repeated intubations using an intubation device that comprises a 16 G intravenous catheter and a modified 18 G epidural needle, and a rodent ventilator. The epidural needle is bent in such a way that it curves in conformity with the rat's oral airway in order to direct the catheter into the larynx, and the rodent ventilator is used to verify its correct placement. The first attempt success rate of endotracheal intubation using the blind oral tracheal intubation technique with a rodent ventilator was greater than the first attempt success rate using the blind oral tracheal intubation technique without using a rodent ventilator. Although this method is a simple modification of a previously described method of blind oral endotracheal intubation, our method is easy to learn, inexpensive and does not require specialized equipment.

Which oblique plane is more helpful in diagnosing an anterior cruciate ligament tear?

AIM

To evaluate the diagnostic role of additional oblique coronal and oblique sagittal magnetic resonance imaging (MRI) for an anterior cruciate ligament (ACL) tear.

MATERIALS AND METHODS

A total of 101 patients who had undergone preoperative knee MRI examinations with orthogonal and two sets of oblique images were enrolled in the study. Two radiologists evaluated the MRI images by the use of four methods: orthogonal images only (method A); orthogonal and additional oblique coronal images (method B); orthogonal and oblique sagittal images (method C); and orthogonal images with oblique coronal and sagittal images (method D). The status of the ACL (normal or tear) was determined by consensus. The sensitivity, specificity, and accuracy for an ACL tear with the use of each method were calculated in comparison with arthroscopy as the reference standard, and values were statistically analysed using the McNemar test. The diagnostic accuracies were compared using receiver operating characteristic (ROC) analysis.

RESULTS

Arthroscopy identified 10 partial ACL tears and 30 complete ACL tears. The specificities and accuracies for methods B, C, and D were significantly higher than the specificities and accuracies for method A (p<0.05). There was no significant difference in the sensitivity, specificity, and accuracy for methods B, C, and D. Diagnostic ability was not significantly different for each method, as determined by ROC analysis (p>0.05).

CONCLUSIONS

Additional oblique imaging for an ACL tear improved the specificity. Either of the oblique imaging methods is sufficient, and no further improvement in the diagnostic efficacy was achieved by simultaneous use.

A case of disseminated Nocardia farcinica diagnosed through DNA sequencing in a kidney transplantation patient

Nocardia is a rare gram-positive bacteria causing opportunistic infection, and belongs to the aerobic Actinomycetes group. As the mortality in the immunocompromised patients with nocardiosis is high, early diagnosis and treatment is very important. However, clinical manifestations of infection caused by Nocardia are very variable and early diagnosis is limited by the difficulty in obtaining specimens and its isolation. Rapid diagnosis of Nocardia infection may allow for earlier effective therapy, thus improving patient outcome. We report a case of Nocardia farcinica diagnosed by DNA sequencing through blood culture in a renal transplant recipient with severe pneumonia and multiple brain abscesses.

Association of MCP-1 and CCR2 polymorphisms with the risk of late acute rejection after renal transplantation in Korean patients

Among the factors modulating transplant rejection, chemokines and their respective receptors deserve special attention. Increased expression of monocyte chemoattractant protein-1 (MCP-1) and its corresponding receptor (chemokine receptor-2, CCR2) has been implicated in renal transplant rejection. To determine the impact of the MCP-1-2518G and CCR2-64I genotypes on renal allograft function, 167 Korean patients who underwent transplantation over a 25-year period were evaluated. Genomic DNA was genotyped using polymerase chain reaction followed by restriction fragment length polymorphism analysis. Fifty-five (32.9%) patients were homozygous for the MCP-1-2518G polymorphism. Nine (5.4%) patients were homozygous for the CCR2-64I polymorphism. None of the investigated polymorphism showed a significant shift in long-term allograft survival. However, a significant increase was noted for the risk of late acute rejection in recipients who were homozygous for the MCP-1-2518G polymorphism (OR, 2.600; 95% CI, 1.125–6.012; P = 0.022). There was also an association between the MCP-1-2518G/G genotype and the number of late acute rejection episodes (P = 0.024). Although there was no difference in the incidence of rejection among recipients stratified by the CCR2-V64I genotype, recipients with the CCR2-V64I GG genotype in combination with the MCP-1-2518G/G genotype had a significantly higher risk of acute or late acute rejection among the receptor-ligand combinations (P = 0.006, P = 0.008, respectively). The MCP-1 variant may be a marker for risk of late acute rejection in Korean patients.

Microscopic origin of surface-plasmon radiation in plasmonic band-gap nanostructures

We report spatial domain measurements of the damping of surface-plasmon excitations in metal films with periodic nanohole arrays. The measurements reveal a short coherent propagation length of a few microm inside nanohole arrays, consistent with delays of about 10 fs in ultrafast transmission experiments. This implies that the transmission spectra of the entire plasmonic band-gap structure are homogeneously broadened by radiative damping of surface-plasmon excitations. We show that a Rayleigh-like scattering of surface plasmons by the periodic hole array is the microscopic origin of this damping, allowing the reradiation rate to be controlled.

Effect of iron and ascorbate on cyclosporine-induced oxidative damage of kidney mitochondria and microsomes

The stimulatory effect of iron and ascorbate on the damaging action of cyclosporine in kidney mitochondria, microsomes and epithelial cells was examined. Cyclosporine induced malondialdehyde formation and hydrogen peroxide production in mitochondria and attenuated the activity of MnSOD and glutathione peroxidase. The damaging effect of cyclosporine (50 microM) plus Fe2+(20 microM) on mitochondrial and microsomal lipids and proteins as well as mitochondrial thiols was greater than the summation of the oxidizing action of cyclosporine alone and Fe2+ alone. As for tissue components, iron enhanced cyclosporine-induced viability loss in kidney epithelial cells. Fe2+, EDTA and H2O2- induced 2-alpha deoxyribose degradation was attenuated by 10 mM DMSO and 200 microM DTPA but not affected by 200 microM cyclosporine. The addition of Fe2+ caused a change in the absorbance spectrum of cyclosporine in the wavelength range 230-350 nm. The simultaneous addition of cyclosporine (50 microM) and ascorbate (100 microM) showed the enhanced peroxidative effect on mitochondrial and microsomal lipids, which was inhibited by DTPA and EDTA (1 mM). Similar to iron, ascorbate enhanced cyclosporine-induced cell viability loss. The results show that iron and ascorbate promote the damaging action of cyclosporine in kidney cortex mitochondria and microsomes and in kidney epithelial cells, which may contribute to the enhancement of cyclosporine-induced nephrotoxicity.