Fluctuating risk of acute kidney injury-related mortality for four weeks after exposure to air pollution: A multi-country time-series study in 6 countries.

BACKGROUND: Recent studies have reported that air pollution is related to kidney diseases. However, the global evidence on the risk of death from acute kidney injury (AKI) owing to air pollution is limited. Therefore, we investigated the association between short-term exposure to air pollution-particulate matter ≤ 2.5 µm (PM2.5), ozone (O3), and nitrogen dioxide (NO2)-and AKI-related mortality using a multi-country dataset. METHODS: This study included 41,379 AKI-related deaths in 136 locations in six countries during 1987-2018. A novel case time-series design was applied to each air pollutant during 0-28 lag days to estimate the association between air pollution and AKI-related deaths. Moreover, we calculated AKI deaths attributable to non-compliance with the World Health Organization (WHO) air quality guidelines. RESULTS: The relative risks (95% confidence interval) of AKI-related deaths are 1.052 (1.003, 1.103), 1.022 (0.994, 1.050), and 1.022 (0.982, 1.063) for 5, 10, and 10 µg/m3 increase in lag 0-28 days of PM2.5, warm-season O3, and NO2, respectively. The lag-distributed association showed that the risk appeared immediately on the day of exposure to air pollution, gradually decreased, and then increased again reaching the peak approximately 20 days after exposure to PM2.5 and O3. We also found that 1.9%, 6.3%, and 5.2% of AKI deaths were attributed to PM2.5, warm-season O3, and NO2 concentrations above the WHO guidelines. CONCLUSIONS: This study provides evidence that public health policies to reduce air pollution may alleviate the burden of death from AKI and suggests the need to investigate the several pathways between air pollution and AKI death.

Exogenous pancreatic kininogenase protects against tacrolimus-induced renal injury by inhibiting PI3K/AKT signaling: The role of bradykinin receptors.

BACKGROUND: Tissue kallikrein offers a wide spectrum of biological activity in the protection against various types of injury. However, information on its role in tacrolimus (TAC)-induced renal injury is limited. OBJECTIVES: This study aimed to assess the beneficial effects of pancreatic kininogenase (PK) in a rat model of chronic TAC nephrotoxicity and in vitro. METHODS: Sprague Dawley rats were treated daily with either TAC or PK or a combination of the two for four weeks. The influence of PK on renal injury was examined in terms of renal function, histopathology, cytokine expression, oxidative stress, intracellular organelles, programmed cell death, and PI3K/AKT signaling. Human kidney proximal tubular (HK-2) cells and mouse mesangial (SV40 MES13) cells treated with TAC and PK were also studied. RESULTS: PK treatment improved renal function and histopathology. This effect was paralleled by downregulation of proinflammatory and profibrotic cytokine expression. TAC-induced oxidative stress was closely associated with endoplasmic reticulum stress and mitochondrial dysfunction, resulting in excessive programmed cell death (apoptosis and autophagy) that was significantly abrogated by concurrent PK interference with PI3K/AKT signaling. PK also stimulated bradykinin receptor 1 (B1R) and B2R mRNA synthesis and increased bioactive nitric oxide (NO) and cAMP concentrations in TAC-treated kidneys. Blockade of either B1R or B2R eliminated the renoprotective effects of PK. In HK-2 and SV40 MES13 cells, PK decreased TAC-induced overproduction of intracellular reactive oxygen species and inhibited apoptotic cells, whereas cell viability was improved. Moreover, activated PI3K/AKT signaling in HK-2 cells was inhibited by PK and the PI3K inhibitor, LY294002. CONCLUSIONS: These findings indicate that PK treatment protects against chronic TAC nephrotoxicity via inhibition of PI3K/AKT signaling.

Excess mortality among patients on dialysis: Comparison with the general population in Korea.

BACKGROUND: Although patients with end-stage renal disease (ESRD) experience excess mortality compared with the general population, the standardized mortality ratio (SMR) for Korean patients on dialysis has not yet been investigated. In this study, we evaluated the SMR among all Korean ESRD patients on maintenance dialysis in 2009 and 2010, and compared it according to age categories, sex, and dialysis modality. METHODS: We used data from all patients on maintenance dialysis between January 1, 2009 and December 31, 2010 in Korea using the database of the Korean Health Insurance Review and Assessment Service, and the SMR was determined by calculating of the ratio between the number of actual deaths and expected deaths. RESULTS: A total of 45,568 patients in 2009 and 48,170 patients in 2010 were included in the analysis. The overall age- and sex-adjusted SMR was 10.3 [95% confidence interval (CI), 10.0-10.6] in 2009 and 10.9 (95% CI, 10.7-11.2) in 2010. The SMR for females was much higher than for males. The SMR gradually decreased with increasing age groups. The overall SMR for maintenance hemodialysis patients was lower than that of peritoneal dialysis patients. CONCLUSION: The SMR among Korean ESRD patients is likely to be higher than in other countries. Further evaluation is needed to attempt to improve the outcomes.