IntroductionSevere hyperkalemia, with potassium (K+) levels ≥ 6.5 mEq/L, is a potentially life-threatening electrolyte imbalance. For prompt and effective treatment, it is important to know its risk factors, clinical manifestations, and predictors of mortality.MethodsAn observational cohort study was performed at 2 medical centers. A total of 923 consecutive Korean patients were analyzed. All were 19 years of age or older and were hospitalized with severe hyperkalemia between August 2007 and July 2010; the diagnosis of severe hyperkalemia was made either at the time of admission to the hospital or during the period of hospitalization. Demographic and baseline clinical characteristics at the time of hyperkalemia diagnosis were assessed, and clinical outcomes such as in-hospital mortality were reviewed, using the institutions' electronic medical record systems.ResultsChronic kidney disease (CKD) was the most common underlying medical condition, and the most common precipitating factor of hyperkalemia was metabolic acidosis. Emergent admission was indicated in 68.6% of patients, 36.7% had electrocardiogram findings typical of hyperkalemia, 24.5% had multi-organ failure (MOF) at the time of hyperkalemia diagnosis, and 20.3% were diagnosed with severe hyperkalemia at the time of cardiac arrest. The in-hospital mortality rate was 30.7%; the rate was strongly correlated with the difference between serum K+ levels at admission and at their highest point, and with severe medical conditions such as malignancy, infection, and bleeding. Furthermore, a higher in-hospital mortality rate was significantly associated with the presence of cardiac arrest and/or MOF at the time of diagnosis, emergent admission, and intensive care unit treatment during hospitalization. More importantly, acute kidney injury (AKI) in patients with normal baseline renal function was a strong predictor of mortality, compared with AKI superimposed on CKD.ConclusionsSevere hyperkalemia occurs in various medical conditions; the precipitating factors are similarly diverse. The mortality rate is especially high in patients with severe underlying disease, coexisting medical conditions, and those with normal baseline renal function.

Metformin is the first pharmacological option for treating type 2 diabetes. However, the use of this drug is not recommended in individuals with impaired kidney function because of the perceived risk of lactic acidosis. We aimed to assess the efficacy and safety of metformin in patients with type 2 diabetic kidney disease (DKD). RESEARCH DESIGN AND METHODSWe conducted a retrospective observational cohort study of 10,426 patients with type 2 DKD from two tertiary hospitals. The primary outcomes were all-cause mortality and end-stage renal disease (ESRD) progression. The secondary outcome was metformin-associated lactic acidosis. Taking into account the possibility that patients with less severe disease were prescribed metformin, propensity score matching (PSM) was conducted. RESULTSAll-cause mortality and incident ESRD were lower in the metformin group according to the multivariate Cox analysis. Because the two groups had significantly different baseline characteristics, PSM was performed. After matching, metformin usage was still associated with lower all-cause mortality (adjusted hazard ratio [aHR] 0.65; 95% CI 0.57-0.73; P < 0.001) and ESRD progression (aHR 0.67; 95% CI 0.58-0.77; P < 0.001). Only one event of metformin-associated lactic acidosis was recorded. In both the original and PSM groups, metformin usage did not increase the risk of lactic acidosis events from all causes (aHR 0.92; 95% CI 0.668-1.276; P 5 0.629). CONCLUSIONSIn the present retrospective study, metformin usage in advanced chronic kidney disease (CKD) patients, especially those with CKD 3B, decreased the risk of all-cause mortality and incident ESRD. Additionally, metformin did not increase the risk of lactic acidosis. However, considering the remaining biases even after PSM, further randomized controlled trials are needed to change real-world practice.Diabetes is the leading cause of chronic kidney disease (CKD) (1,2). According to the American Diabetes Association care guidelines, metformin is considered a first-line treatment for type 2 diabetes because of its efficacy, low cost, weight neutrality, and benefits regarding cardiovascular outcomes (3-5). In patients with CKD, however, the use of metformin is not recommended due to the risk of lactic acidosis (6,7).The risk of lactic acidosis and its fatal consequences have resulted in the withdrawal of biguanide, phenformin and buformin, from the market (8,9). However, decades of clinical experience have provided clinicians with insights into the low incidence of

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Reactive oxygen species contribute to the development of various human diseases. Ischemia is characterized by both significant oxidative stress and characteristic changes in the antioxidant defense mechanism. Heat shock protein 27 (HSP27) has a potent ability to increase cell survival in response to oxidative stress. In the present study, we have investigated the protective effects of PEP‐1–HSP27 against cell death and ischemic insults. When PEP‐1–HSP27 fusion protein was added to the culture medium of astrocyte and primary neuronal cells, it rapidly entered the cells and protected them against cell death induced by oxidative stress. Immunohistochemical analysis revealed that, when PEP‐1–HSP27 fusion protein was intraperitoneally injected into gerbils, it prevented neuronal cell death in the CA1 region of the hippocampus in response to transient forebrain ischemia. Our results demonstrate that transduced PEP‐1–HSP27 protects against cell death in vitro and in vivo, and suggest that transduction of PEP‐1–HSP27 fusion protein provides a potential strategy for therapeutic delivery in various human diseases in which reactive oxygen species are implicated, including stroke.

BackgroundWarfarin-related nephropathy (WRN) is a recently described disease entity, in which excessive warfarinization (international normalized ratio (INR) >3.0) causes acute kidney injury. Previous reports regarding WRN included few Asian patients who might have differed from the western WRN patients in terms of genetic and environmental factors.MethodsDuring the period of March 2003 to December 2011, the data about a total of 1297 patients who had serum creatinine (sCr) level measured within 1 week after INR >3.0 and within 6 months before INR >3.0 was analyzed through the retrospective review of electronic medical records of a single tertiary hospital in Korea.ResultWRN developed in 19.3% of patients having excessive warfarinization. The incidence was higher in the chronic kidney disease (CKD) group than the non-CKD group. The risk of WRN increased as the basal serum albumin level decreased and was strongly associated with highest quartile serum AST level at post INR elevation and the presence of congestive heart failure. But the presence of atrial fibrillation was protective against the development of WRN. Neither the presence of CKD nor basal estimated glomerular filtration rate (eGFR) was an independent risk factor for WRN. Despite no difference in the basal sCr level, the sCr level was higher in patients with WRN than those without WRN after follow-up. The mortality rates were also higher in patients with WRN.ConclusionsWRN developed in 19.3% of patients having excessive warfarinization. A lower basal serum albumin, highest quartile serum AST level at post INR elevation, and congestive heart failure were associated with the occurrence of WRN. The development of WRN adversely affected renal and patient outcomes.

BackgroundMany patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD) experience depression. Depression influences patient quality of life (QOL), dialysis compliance, and medical comorbidity. We developed and applied a group cognitive behavioral therapy (CBT) program including mindfulness meditation for ESRD patients undergoing HD, and measured changes in QOL, mood, anxiety, perceived stress, and biochemical markers.MethodsWe conducted group CBT over a 12-week period with seven ESRD patients undergoing HD and suffering from depression. QOL, mood, anxiety, and perceived stress were measured at baseline and at weeks 8 and 12 using the World Health Organization Quality of Life scale, abbreviated version (WHOQOL-BREF), the Beck Depression Inventory II (BDI-II), the Hamilton Rating Scale for Depression (HAM-D), the Beck Anxiety Inventory (BAI), and the Perceived Stress Scale (PSS). Biochemical markers were measured at baseline and after 12 weeks. The Temperament and Character Inventory was performed to assess patient characteristics before starting group CBT.ResultsThe seven patients showed significant improvement in QOL, mood, anxiety, and perceived stress after 12 weeks of group CBT. WHOQOL-BREF and the self-rating scales, BDI-II and BAI, showed continuous improvement across the 12-week period. HAM-D scores showed significant improvement by week 8; PSS showed significant improvement after week 8. Serum creatinine levels also improved significantly following the 12 week period.ConclusionIn this pilot study, a CBT program which included mindfulness meditation enhanced overall mental health and biochemical marker levels in ESRD patients undergoing HD.

Periostin plays a crucial role in fibrosis, and acute kidney injury results in a high risk of progression to chronic kidney disease. Therefore, we hypothesized that periostin was involved in the progression of acute kidney injury to kidney fibrosis. Unilateral ischemia-reperfusion injury (UIRI) was induced in 7- to 8-wk-old male wild-type and periostin-null mice, and the animals were observed for 6 wk. In vitro, human kidney-2 cells and primary-cultured human tubular epithelial cells were incubated under hypoxic conditions (5% O2, 5% CO2, and 90% N2) for 5 days. The cells were also cultured with recombinant periostin (rPeriostin) and a p38 mitogen-activated protein kinase (MAPK) inhibitor in a hypoxic incubator. At 6 wk after UIRI, interstitial fibrosis/tubular atrophy was significantly alleviated in periostin-null mice compared with wild-type controls. In addition, periostin-null mice had attenuated expression of fibrosis/apoptosis markers and phosphorylated-p38 MAPK compared with wild-type controls. In vitro, hypoxic injury increased the expression of fibrosis markers, periostin, and phosphorylated-p38 MAPK, which was comparable to or substantially greater than their expression levels following treatment with recombinant transforming growth factor-β1 under normoxic conditions. Furthermore, rPeriostin treatment under hypoxic conditions enhanced fibrosis/apoptosis markers and phosphorylated-p38 MAPK. In contrast, p38 MAPK inhibition ameliorated hypoxia-induced fibrosis, and the addition of the p38 MAPK inhibitor to rPeriostin significantly ameliorated the changes induced by rPeriostin. In conclusion, periostin promotes kidney fibrosis via the p38 MAPK pathway following acute kidney injury triggered by a hypoxic or ischemic insult. Periostin ablation may protect against chronic kidney disease progression.

BackgroundContinuous renal replacement therapy (CRRT) is an important treatment modality for severe acute kidney injury. As such, the epidemiology of CRRT in Korea needs further investigation.MethodsWe conducted a nationwide, population-based study analyzing the claims data from National Health Insurance Service of Korea. All index intensive care unit admission cases of CRRT in government-designated tertiary referral hospitals in Korea from 2005 to 2016 were included. Patients with a history of renal replacement therapy or who were under 20 years old were not considered. In addition to baseline and treatment characteristics, patient outcomes, including all-cause mortality and renal survival rates, were investigated. We stratified the study patients according to 3-year time periods and major regions of the nation.ResultsWe included 37,337 patients who received CRRT in Korea. The overall use of CRRT increased over time, and more than 80% of cases of acute renal replacement therapy were CRRT after 2014. Seoul was the region in which the majority of CRRT (45.0%) was performed. The clinical characteristics of CRRT patients were significantly different among time-intervals and regions. Both all-cause mortality and renal survival rates after CRRT were prominently improved in the recent time periods (P < 0.001).ConclusionCRRT is a widely used treatment strategy for severe acute kidney injury in Korea. The prognosis of CRRT patients has improved compared to the past. This epidemiological study of CRRT in Korea revealed notable trends with regard to time period and geographic region.