Clinical Courses of Graft Failure Caused by Chronic Allograft Dysfunction in Kidney Transplantation

BACKGROUND

Chronic allograft dysfunction (CAD) is a main cause of graft failure in kidney transplantation.

METHODS

We retrospectively analyzed 279 kidney transplant recipients who survived with a functioning graft for at least 2 years. CAD was defined as chronic graft deterioration, excluding other specific causes. We defined the pattern of decline in estimated glomerular filtration rate (eGFR), as follows: (1) "plateau" was defined as decline in eGFR ≤2 mL/min/1.73 m²/year; "long plateaus" were those lasting more than 5 years; (2) "rapid decline" was a decrease in eGFR ≥20 mL/min/1.73 m²/year. Patients diagnosed with CAD were categorized according to the occurrence of rapid decline and/or long plateau as follows: group 1, neither rapid decline nor long plateau; group 2, rapid decline only; group 3, long plateau only; and group 4, both rapid decline and long plateau.

RESULTS

From a total of 81 graft losses, 51 (63%) failed because of CAD, with a median of 9.4 years. Sixteen patients belonged to group 1, 14 to group 2, 12 to group 3, and nine to group 4. Mean graft survival times in the four groups were 7.7 ± 1.1, 6.1 ± 3.1, 16.2 ± 2.5, and 10.8 ± 3.6 years, respectively (P < .001). There were significant differences among groups in donor age, year of transplantation, mean eGFR at baseline, and acute rejection rate after transplantation.

CONCLUSIONS

The results indicate that this cohort of kidney transplant recipients who had CAD comprised subgroups with different clinical courses.

Role of mitogen-activated protein kinase pathways in migration of gingival epithelial cells in response to stimulation by cigarette smoke condensate and infection by Porphyromonas gingivalis

BACKGROUND AND OBJECTIVE

Previous studies have shown that cigarette smoke (CS) and periodontal pathogens could alter wound healing responses of gingival epithelial cells. To elucidate molecular mechanisms leading to these epithelial changes, we studied the signaling pathway involved in the modulation of cell migration by CS condensate (CSC) and the infection by a prominent periodontal pathogen, Porphyromonas gingivalis.

MATERIAL AND METHODS

Human gingival epithelial cells (Ca9-22) were treated with CSC or vehicle control for 24 h. Activation of mitogen-activated protein kinases (MAPK) in cells with or without infection by P. gingivalis was assessed by polymerase chain reaction array and immunoblotting using phospho-specific antibodies. Cell migration was assessed using in vitro wound closure model, and specific pharmacologic inhibitors of MAPK pathways were used to characterize further the extent of involvement of the MAPK pathways.

RESULTS

Polymerase chain reaction array showed that gene expression of several members of the MAPK, particularly p38 and JNK, was upregulated more than twofold in Ca9-22 cells stimulated with 10 μg/mL CSC. Coincubation with P. gingivalis induced a different pattern of gene expression for MAPK pathways, but it did not suppress the MAPK-related genes upregulated by CSC. A significant phosphorylation of ERK1/2 and p38 was observed in cells stimulated with 10 μg/mL CSC (p < 0.05), whereas coincubation with a higher concentration of CSC (250 μg/mL) evoked no such activation. P. gingivalis infection resulted in a tendency to reduce the phosphorylation of ERK1/2 and p38, which had been enhanced by stimulation with 10 μg/mL CSC. Incubation with ERK1/2 and p38 inhibitors significantly reduced the wound closure of CSC-stimulated cells, by approximately 43% and 46%, respectively (p < 0.05).

CONCLUSION

CSC exerts effects on the migration of human gingival epithelial cells through the activation of the MAPK ERK1/2 and p38 signaling pathways. P. gingivalis infection attenuates the CSC-induced migration at least partly by suppressing the phosphorylation of ERK1/2 and p38, but other pathways are likely to be involved in this modulatory process.

Body size evolution of a shell-brooding cichlid fish from Lake Tanganyika

The substrate-brooding cichlid fish Telmatochromis temporalis in Lake Tanganyika demonstrates a simple example of ecological speciation between normal and dwarf morphs through divergent natural selection on body size. The dwarf morph most likely evolved from the ancestral normal morph; therefore, elucidating the evolution of its small body size is a key to understanding this ecological speciation event. Previous studies suggest that the small body size of the dwarf morph is an adaptation to the use of empty snail shells as shelters (males) and spawning sites (females), but this idea has not been fully evaluated. Combining original and previously published information, this study compared likelihood values to determine the primary factor that would be responsible for regulating the body size of the dwarf morph. Male body size is most likely regulated by the ability to turn within shells, which may influence the predation avoidance of adult fish. Females are smaller than males, and their body size is most likely regulated by the ability to lay eggs in the small spaces within shells close to the shell apices where predation risk on eggs is lower. This study provides new evidence supporting the hypothesis that different natural selection factors affected body size of the different sexes of the dwarf morph, which has not been reported in other animal species.

Cigarette smoke condensate modulates migration of human gingival epithelial cells and their interactions with Porphyromonas gingivalis

BACKGROUND AND OBJECTIVE

Epithelial cells are recognized as the first line of defense against bacterial infection and environmental harmful stimuli such as cigarette smoke (CS). Although previous studies explored the effects of nicotine on host cells, mechanisms by which CS affects cellular functions remain uncertain. The present study investigated the effects of CS condensate (CSC) on in vitro wound closure of gingival epithelial cells and their potential interactions with a major periodontal pathogen, Porphyromonas gingivalis.

MATERIAL AND METHODS

Human gingival epithelial cells (Ca9-22) were treated with CSC for 24 h. Cell proliferation was determined using a WST-1 assay. Cell migration was assessed using a wound closure model. The expression of integrins was analyzed by confocal scanning laser microscopy and real-time PCR. Intracellular invasion of P. gingivalis was evaluated by confocal scanning laser microscopy and an antibiotic protection assay.

RESULTS

Low concentrations (1-10 μg/mL) of CSC showed no significant effect on cell proliferation. CSC demonstrated dual effects on epithelial wound closure of Ca9-22 cells: high concentrations (i.e. 250 μg/mL) significantly inhibited the wound closure whereas low concentrations (i.e. 10 μg/mL) promoted it (p < 0.01). CSC induced distinct changes in cytoskeleton. When CSC-exposed cells were infected with P. gingivalis for 2 h, a significant inhibition of wound closure was observed concurrent with a decrease in integrin α3 expression near the wound area. A significantly increased P. gingivalis invasion into Ca9-22 was observed when exposed to low concentrations of CSC.

CONCLUSION

Low concentrations of CSC increased invasion of human gingival epithelial cells by P. gingivalis and induced changes in cytoskeleton and integrin expression, thereby modulating the cell migration.

Control of parathyroid hormone hydrolysis by the kidney

In order to assess the role of the kidney in controlling the degradation, fate, half-life, and consequently the functional level of the parathyroid hormone in vivo, highly purified bovine parathyroid hormone (bPTH 1-84) and synthetic N-terminal peptide of the bovine parathyroid hormone (bPTH 1-34) were iodinated and their hydrolysis by the kidney and liver tissue of rats were measured under various levels of parathyroid function and calcium metabolism. While the hydrolysis of bPTH 1-84 did not change significantly in response to acute change of serum parathyroid hormone in response to injections of EDTA, phosphate, and calcium or after parathyroidectomy, less bPTH 1-34 was hydrolyzed 60 min after injection of EDTA or phosphate along with the rise of serum PTH than in the controls. No significant change was found in the hydrolysis of bPTH 1-34 after calcium infusion or parathyroidectomy with a consequent fall of serum parathyroid hormone. Increase of calcium ions in the incubation medium in vitro resulted in a more pronounced increase of bPTH 1-34 hydrolysis than that of bPTH 1-84. Hydrolysis of the N-terminal portion of parathyroid hormone probably plays a more important role in the acute control of the functional level of the parathyroid hormone than the hydrolysis of the whole molecule.

Vitamin D and parathyroid hormone degradation by the kidney

Parathyroid function is controlled by the regulation of hormone secretion as well as degradation, through the action of calcium and vitamin D derivatives. In order to clarify the relationship between vitamin D metabolism and parathyroid degradation system, parathyroid hormone (PTH)-degrading activities of the kidney were measured in vitamin D repleted and depleted rats given various derivatives of vitamin D. Kidney calcium content rose markedly in animals given 10 microgram/kg 1 alpha(OH) vitamin D3 and 1,000 microgram/kg dihydrotachysterol and PTH-degrading activity rose only in these animals, indicating a parallelism between kidney calcium content and PTH-degrading activity of the kidney tissue. These vitamin D derivatives also increased the PTH-degrading activity of kidney tissue when they were added in vitro.

Synthesis of nano-TaOx oxygen reduction reaction catalysts on multi-walled carbon nanotubes connected via a decomposition of oxy-tantalum phthalocyanine

Nano-TaO_x particles were supported on MWCNTs via a thermal decomposition of oxy-tantalum phthalocyanine. The ORR activity solely-originated from nano-TaO_x was above 0.9 V versus RHE with larger currents than conventional micro-TaO_x in acidic media.

Bower-building behaviour is associated with increased sperm longevity in Tanganyikan cichlids

We investigated the evolutionary relationship between spawning behaviour and sperm motility traits among Tanganyikan mouth-brooding cichlid species that have developed diverse mating behaviours and male sexual traits. Mouth-brooding behaviour is common among these fish, but different species demonstrate a range of spawning behaviours, bower construction, male sexual traits and timing of gamete release. We observed spawning behaviours and compared sperm motility traits of 28 Tanganyikan mouth-brooding cichlids to elucidate the evolutionary correlations between these traits. Sperm longevity was considerably longer in bower-building species that construct crater-shaped spawning sites compared with species that do not build bowers. Male bower builders released sperm in the pit of the bower prior to spawning, and the time from ejaculation to fertilization was longer. Conversely, most mouth-brooding cichlids deposited semen directly into the female buccal cavity, and spawned eggs were immediately picked up to be placed inside the cavity; thus, the time from ejaculation to fertilization was short. These observations suggest that increased sperm longevity is favoured in bower builders. Comparative phylogenetic analyses suggested that bower-building behaviour and greater time from ejaculation to fertilization are associated with the extension of sperm longevity, whereas sperm competition rank does not play a major role. In addition, bower-building behaviour preceded the emergence of increased sperm longevity. These results indicate that the extension of sperm longevity as a result of the emergence of bower builders may have acted as an evolutionary attractor for sperm longevity.

Association of PD-L1 overexpression with activating EGFR mutations in surgically resected nonsmall-cell lung cancer

BACKGROUND

Recent clinical trials have shown that immune-checkpoint blockade yields a clinical response in a subset of individuals with advanced nonsmall-cell lung cancer (NSCLC). We examined whether the expression of programmed death-ligand 1 (PD-L1) is related to clinicopathologic or prognostic factors in patients with surgically resected NSCLC.

PATIENTS AND METHODS

The expression of PD-L1 was evaluated by immunohistochemical analysis in 164 specimens of surgically resected NSCLC. Cell surface expression of PD-L1 in NSCLC cell lines was quantified by flow cytometry.

RESULTS

Expression of PD-L1 in tumor specimens was significantly higher for women than for men, for never smokers than for smokers, and for patients with adenocarcinoma than for those with squamous cell carcinoma. Multivariate analysis revealed that the presence of epidermal growth factor receptor gene (EGFR) mutations and adenocarcinoma histology were significantly associated with increased PD-L1 expression in a manner independent of other factors. Cell surface expression of PD-L1 was also significantly higher in NSCLC cell lines positive for activating EGFR mutations than in those with wild-type EGFR. The EGFR inhibitor erlotinib downregulated PD-L1 expression in the former cell lines but not in the latter, suggesting that PD-L1 expression is increased by EGFR signaling conferred by activating EGFR mutations. A high level of PD-L1 expression in resected tumor tissue was associated with a significantly shorter overall survival for NSCLC patients.

CONCLUSIONS

High expression of PD-L1 was associated with the presence of EGFR mutations in surgically resected NSCLC and was an independent negative prognostic factor for this disease.

Interleukin-33 induces interleukin-17F in bronchial epithelial cells

BACKGROUND

IL-33 is clearly expressed in the airway of patients with asthma, but its role in asthma has not yet been fully understood. IL-17F is also involved in the pathogenesis of asthma. However, the regulatory mechanisms of IL-17F expression remain to be defined. To further indentify the role of IL-33 in asthma, we investigated the expression of IL-17F by IL-33 in bronchial epithelial cells and its signaling mechanisms.

METHODS

Bronchial epithelial cells were stimulated with IL-33. The levels of IL-17F expression were analyzed using real-time PCR and ELISA. Next, the involvement of ST2, MAP kinases, and mitogen- and stress-activated protein kinase1 (MSK1) was determined by Western blot analyses. Various kinase inhibitors and anti-ST2 neutralizing Abs were added to the culture to identify the key signaling events leading to the expression of IL-17F, in conjunction with the use of short interfering RNAs (siRNAs) targeting MSK1.

RESULTS

IL-33 significantly induced IL-17F gene and protein expression. The receptor for IL-33, ST2, was expressed in bronchial epithelial cells. Among MAP kinases, IL-33 phosphorylated ERK1/2, but not p38MAPK and JNK. It was inhibited by the pretreatment of anti-ST2 neutralizing (blocking) Abs. MEK inhibitor significantly blocked IL-17F production. Moreover, IL-33 phosphorylated MSK1, and MEK inhibitor diminished its phosphorylation. Finally, MSK1 inhibitors and transfection of the siRNAs targeting MSK1 significantly blocked the IL-17F expression.

CONCLUSIONS

IL-33 induces IL-17F via ST2-ERK1/2-MSK1 signaling pathway in bronchial epithelial cells. These data suggest that the IL-33/IL-17F axis is involved in allergic airway inflammation and may be a novel therapeutic target.