Association between potassium supplementation and the occurrence of acute kidney injury in patients with hypokalemia administered liposomal amphotericin B: a nationwide observational study

Background: Hypokalemia and acute kidney injury (AKI) occur in patients administered liposomal amphotericin B (L-AMB), a wide-spectrum anti-fungicidal drug. However, the association between potassium supplementation and the occurrence of AKI in patients with hypokalemia who were administered L-AMB is not well understood.Methods: Using nationwide claims data and laboratory data, the occurrence of AKI during L-AMB treatment was retrospectively compared between patients with hypokalemia who were or were not supplemented with potassium and between those adequately or inadequately supplemented with potassium (serum potassium levels corrected to ≥3.5 mEq/L or remained < 3.5 mEq/L, respectively) before or after L-AMB treatment initiation.Results: We identified 118 patients who developed hypokalemia before L-AMB treatment initiation (43 received potassium supplementation [25 adequate and 18 inadequate supplementation] and 75 did not receive potassium supplementation), and 117 patients who developed hypokalemia after L-AMB initiation (79 received potassium supplementation [including 23 adequate and 15 inadequate supplementation] and 38 did not receive potassium supplementation). The occurrence of any stage of AKI was similar between patients with hypokalemia, regardless of potassium supplementation (i.e., before L-AMB treatment initiation [supplementation, 51%; non-supplementation, 45%; P = 0.570] or after L-AMB initiation [supplementation, 28%; non-supplementation, 32%; P = 0.671]). After adjusting for confounding factors, we found that the occurrence of any stage of AKI was not associated with potassium supplementation before L-AMB initiation (odds ratio [OR]: 1.291, 95% confidence interval [CI]: 0.584–2.852, P = 0.528) or after L-AMB initiation (OR: 0.954, 95% CI: 0.400–2.275, P = 0.915). The occurrence of any stage of AKI tended to decline in patients with hypokalemia who were adequately supplemented with potassium (44%) before, but not after, L-AMB initiation relative to that in patients inadequately supplemented with potassium (61%), however this result was not significant (P = 0.358).Conclusion: Potassium supplementation was not associated with any stage of AKI in patients with hypokalemia who were administered L-AMB

The DsbA-L gene is associated with respiratory function of the elderly via its adiponectin multimeric or antioxidant properties

Oxidative stress and inflammation play a key role in the age-related decline in the respiratory function. Adipokine in relation to the metabolic and inflammatory systems is attracting growing interest in the field of respiratory dysfunction. The present clinical and experimental studies investigated the role of the disulfide bond-forming oxidoreductase A-like protein (DsbA-L) gene, which has antioxidant and adiponectin multimeric (i.e. activation) properties, on the respiratory function of the elderly. We performed a retrospective longitudinal genotype-phenotype relationship analysis of 318 Japanese relatively elderly participants (mean age ± standard deviation: 67.0 ± 5.8 years) during a health screening program and an in vitro DsbA-L knock-down evaluation using 16HBE14o-cells, a commonly evaluated human airway epithelial cell line. The DsbA-L rs1917760 polymorphism was associated with a reduction in the ratio of forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) and %FEV1 and with the elevation of the prevalence of FEV1/FVC < 70%. We also confirmed that the polymorphism was associated with a decreased respiratory function in relation to a decrease in the ratio of high-molecular-weight adiponectin/total adiponectin (as a marker of adiponectin multimerization) and an increase in the oxidized human serum albumin (as an oxidative stress marker). Furthermore, we clarified that DsbA-L knock-down induced oxidative stress and up-regulated the mucus production in human airway epithelial cells. These findings suggest that the DsbA-L gene may play a role in protecting the respiratory function of the elderly, possibly via increased systemic adiponectin functions secreted from adipocytes or through systemic and/or local pulmonary antioxidant properties

Expression of an X-Ray Irradiated EGFP-Expressing Plasmid Transfected into Nonirradiated Human Cells

To investigate the repairability of X-ray-induced DNA damage, particularly non-double-strand breaks in living cells, enhanced green fluorescent protein (EGFP)-expressing plasmids were exposed to X-rays and then transfected into non-irradiated human cells, MCF7 and MCF10A. Live-cell imaging of EGFP fluorescence was performed to measure the efficiency of plasmid repair in cells. The number of EGFP-expressing cells significantly decreased with increasing X-ray dose for both cell lines. The obtained kinetic curves of EGFP expression indicating plasmid repair were quantitatively compared with algebraically calculated ones based on the values of the transfected plasmids that had been treated with nicking or restriction enzymes. Then, assuming a Poisson distribution of SSBs, the number of cells carrying these nicked plasmids that could express EGFP were estimated. Our experimental results revealed considerably fewer cells expressing EGFP compared with the expected values we had calculated. These results suggest that the lower proportion of cells expressing EGFP as a measure of plasmid repair was due not only to the complex chemical structures of termini created by single-strand breaks compared with those created by enzyme treatments, but also that base lesions or AP sites proximately arising at the strand break termini might compromise EGFP expression. These results emphasize that radiation-induced DNA breaks are less repairable than enzymatically induced ones, which is not apparent when using conventional gel electrophoresis assays of plasmid DNA

Repair susceptibility of X-irradiated EGFP plasmid DNA transfected into non-irradiated cells

Ionizing radiation is known to cause various chemical damage to cells. Whole-cell irradiation inevitably causes damage not only in genomic DNA but also intracellular organelles. To investigate the repairability of DNA damage separately from the effects on organelles, EGFP-expressing plasmids were exposed to X-rays in solution and then transfected into non-irradiated human MCF-7 breast cancer cells, which induce a low expression of DNA damage response protein BRCA1. Live-cell imaging of EGFP fluorescence of the cells was performed to measure repair efficiency of the plasmids in the cells. The kinetics of the fluorescent expression after irradiation of several doses were compared with those treated with a nicking or restriction enzyme used as positive controls to induce single- (SSB) or double-strand breaks (DSB), respectively. Assuming a Poisson distribution of the strand breaks in the plasmid, expected kinetic curves were also calculated. The numbers of EGFP-expressing cells observed were considerably fewer than the calculated values. That is, the difficulty of DNA repair is peculiar to irradiation. These results suggest that the lower EGFP expression efficiencies were not only due to complex chemical structures of DNA-strand-break termini compared with those created by enzyme treatments, but also that localization of non-DSB type lesions might be facilitated by irradiation and thus compromise DNA repair efficiency. In the future, we test MCF-10A (BRCA1 positive) to reveal the role of DNA damage responses in the repair dynamics. We also conduct high-LET irradiation to cells to produce more dense ionizations in the plasmid.第3回QST国際シンポジウム「Quantum Life Science

ヒト細胞中に移入されたX 線照射水和EGFP 発現プラスミド DNA の修復感受性

Clustered DNA damage is defined as two or morelesions (base lesions, single strand breaks or abasic(AP) sites ) localized within one or two helical turn(s).Although repair susceptibility of a synthesized baselesion (or AP) cluster in oligonucleotides have beeninvestigated, those induced actually by irradiation is notclarified yet. To elucidate the repair susceptibility of radiation-induced clustered damage, in the present study,fully hydrated DNA films containing 35 water moleculesper nucleotide, as well as DNA solutions (1×TE, 1μg/μl) were used as samples. In the hydrated DNA films,diffusible water radicals are hardly generated by ionizingradiation. Thus, the major process of radiation actionis direct ionization or impact of secondary electrons toDNA. The EGFP-expressing plasmids were exposedto X-rays with a 1/e dose for each sample, and thentransfected into non-irradiated human cells (MCF-7).Those cells were observed for 48h with fluorescence microscope.DNA repair efficiencies were obtained as thenumber of fluorescence expression cells. The efficiencyfor the hydrated DNA film was significantly lower thanthat for the solution sample. These results indicate thatDNA damage induced in the hydrated DNA would beclustered lesions and difficult to be repaired.日本放射線影響学会第62回大