Dapagliflozin-induced drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) Followed By Acute Interstitial Nephritis (AIN): A Case Report.

A 78-year-old male was admitted to the hospital with acute renal failure and generalized erythema after starting dapagliflozin 10 mg/day for chronic kidney disease (CKD). A skin biopsy revealed superficial perivascular dermatitis with eosinophils. A renal biopsy revealed lymphocytic and eosinophilic infiltration of the interstitium, and focal tubulitis. The patient was diagnosed with a dapagliflozin-induced drug reaction with eosinophilia and systemic symptoms (DRESS), followed by acute interstitial nephritis (AIN), and prednisolone therapy was therefore initiated. The patient's renal function improved, and erythema disappeared. To our knowledge, this is the first report of DRESS caused by dapagliflozin, and the patient was successfully treated with prednisolone.

A Case of Combination of IgA Nephropathy and Interstitial Nephritis After COVID-19 Vaccination.

A 66-year-old male presented with renal dysfunction. At the time of presentation, his serum creatinine (sCr) was 2.55 mg/dL, estimated glomerular filtration rate (eGFR) was 20.93 ml/min/1.73 m2, urinary red blood cell (RBC) was 30-49/high power field, and urine protein-creatinine ratio was 0.43 g/gCr. The patient had no urinalysis abnormalities or renal dysfunction within the year prior to presentation but had gross hematuria after the third and fourth coronavirus disease 2019 (COVID-19) vaccinations. Therefore, immunoglobulin A nephropathy (IgAN) was suspected and a percutaneous renal biopsy was performed. Renal pathology confirmed IgAN and interstitial nephritis and glucocorticoid therapy was initiated. Glucocorticoids improved renal function, and microscopic hematuria resolved. Although previous reports have shown that the COVID-19 vaccine induces various renal diseases, complications associated with these two renal diseases are rare. In this case, while IgAN was suspected based on episodes of gross hematuria after vaccination, renal biopsy confirmed it and also revealed interstitial nephritis.

Improvement in Tubulointerstitial Nephritis With Glucocorticoid Therapy in an Anorexia Nervosa Patient.

Anorexia nervosa is a psychiatric disorder that is often diagnosed in adolescents and young adults. Renal-related complications of anorexia nervosa include abnormal water metabolism, electrolyte abnormalities, and nephrocalcinosis, which may lead to irreversible renal damage. Furthermore, tubulointerstitial nephritis has been reported as a renal pathological feature of anorexia nervosa. Immunosuppressive therapy, such as with glucocorticoids, has been recommended for idiopathic interstitial nephritis treatment; however, the effectiveness of immunosuppressive therapy for interstitial nephritis in patients with anorexia nervosa remains unestablished. Here, we report a case of interstitial nephritis in a patient with anorexia nervosa whose renal function was successfully improved with glucocorticoid therapy. The patient was a 38-year-old woman who was referred for renal dysfunction (estimated glomerular filtration rate: 7.6 mL/min/1.73 m2). She had anorexia nervosa and repeated episodes of vomiting. Hypokalemia (K: 2.1 mEq/L) and metabolic alkalosis (HCO3-: 54.2 mEq/L) were observed. Fluid therapy and potassium supplementation did not improve renal function; therefore, a percutaneous renal biopsy was performed. The renal pathology results revealed interstitial fibrosis, inflammatory cell infiltration in the interstitium, and tubulitis, suggesting a diagnosis of tubulointerstitial nephritis. Glucocorticoid therapy improved the patient's renal function to an estimated glomerular filtration rate of 19.91 mL/min/1.73 m2, and the renal function remained stable thereafter. This case suggests that glucocorticoid therapy may be considered for the treatment of interstitial nephritis in patients with anorexia.

Factors Associated with Glomerular Yield in Percutaneous Kidney Biopsy.

Percutaneous kidney biopsy is essential for diagnosing various kidney diseases. However, insufficient glomerular yield leads to misdiagnosis, a critical problem. We retrospectively investigated the risk of insufficient glomerular yield in percutaneous kidney biopsies. We included 236 patients who underwent percutaneous kidney biopsies between April 2017 and September 2020. We retrospectively analyzed the relationship between glomerular yield and patient characteristics. After the biopsy, 31 patients produced insufficient glomerular yields (cases with yielded glomeruli <10). Glomerular yield correlated negatively with hypertension (ß = -0.13, p = 0.04), and positively with glomerular density (ß = 0.59, p < 0.0001) and the volume of the biopsy core (number of punctures, number of biopsy cores, total length of biopsy core, length of core collected by one puncture, and cortical length). Patients yielding <10 glomeruli had lower glomerular densities (14.4 ± 1.6 vs. 22.9 ± 0.6/cm; p < 0.0001). These results suggest that glomerular density is crucial to glomerular yield. Furthermore, glomerular density was negatively correlated with hypertension, diabetes, and age. Hypertension was independently associated with low glomerular density (ß = -0.16, p = 0.02). Thus, the glomerular yield was associated with glomerular density and biopsy core length, and hypertension might be related to glomerular yield via low glomerular density.

Proteinuria and Renal Dysfunction Due to Extremely Low Birth Weight in a Patient with Silver-Russell Syndrome.

A 36-year-old woman diagnosed with Silver-Russell syndrome during childhood presented to our department after a primary care physician suspected renal dysfunction. At birth, she had an extremely low weight (1210 g), and in childhood, she was diagnosed with Silver-Russell syndrome. At the age of 14 she was found to have proteinuria; however, the condition was never further examined. One month prior to her presentation to our department, the following were noted: 3+ urinary protein, 3.9 urinary protein/creatinine ratio, and 48 mL/min/1.73 m2 estimated glomerular filtration rate. Abdominal computed tomography revealed small kidneys difficult to visualize using ultrasound. Therefore, an open renal biopsy was performed. The renal biopsy revealed no significant findings in the glomerulus except glomerular hypertrophy, and the glomerular density in the cortical area was low (0.6/mm2). The patient was diagnosed with oligomeganephronia. Proteinuria and renal dysfunction were likely due to glomerular hyperfiltration resulting from a low nephron count caused by low birth weight. Silver-Russell syndrome is characterized by intrauterine growth retardation and additional developmental disorders after birth. Here, we detected oligomeganephronia following kidney biopsy in a patient with Silver-Russell syndrome. We suspect that a reduced number of nephrons due to low birth weight caused proteinuria and renal dysfunction.

Hydroxychloroquine suppresses anti-GBM nephritis via inhibition of JNK/p38 MAPK signaling.

BACKGROUND: Anti-glomerular basement membrane (anti-GBM) nephritis, characterized by glomerular crescent formation, requires early treatment because of poor prognosis. Hydroxychloroquine (HCQ) is an antimalarial drug with known immunomodulatory, anti-inflammatory, and autophagy inhibitory effects; it is recognized in the treatment of autoimmune diseases such as systemic lupus erythematosus. However, its effect on anti-GBM nephritis remains unknown. In this study, we investigated the effect of HCQ on anti-GBM nephritis in rats. METHODS: Seven-weeks-old male WKY rats were administered anti-GBM serum to induce anti-GBM nephritis. Either HCQ or vehicle control was administered from day 0 to day 7 after the induction of nephritis. Renal function was assessed by measuring serum creatinine, proteinuria, and hematuria. Renal histological changes were assessed by PAS staining and Masson trichrome staining, and infiltration of macrophages was assessed by ED-1 staining. Mitogen-activated protein kinase (MAPK) was evaluated by western blotting, while chemokine and inflammatory cytokines were evaluated by enzyme-linked immunosorbent assay using urine sample. RESULTS: HCQ treatment suppressed the decline in renal function. Histologically, extracapillary and intracapillary proliferations were observed from day 1, while fibrinoid necrosis and ED-1 positive cells were observed from day 3. Rats with anti-GBM nephritis showed high levels of monocyte chemotactic protein-1 and tumor necrosis factor-α. These changes were significantly suppressed following HCQ treatment. In addition, HCQ suppressed JNK/p38 MAPK phosphorylation. CONCLUSION: HCQ attenuates anti-GBM nephritis by exerting its anti-inflammatory effects via the inhibition of JNK/p38 MAPK activation, indicating its therapeutic potential against anti-GBM nephritis.

Acute Kidney Injury Caused by Renin-Angiotensin System Inhibitors During Minimal Change Disease Treatment.

A 76-year-old Japanese man with nephrotic syndrome was admitted to our department for treatment. After his admission, he was administered prednisolone (PSL) at 40 mg/day, and a percutaneous renal biopsy was performed. However, on the first day of admission, his urinary protein decreased from 5.05 g/gCr to 1.85 g/gCr. On the fourth day of admission, his urinary protein further decreased to 0.38 g/gCr and the patient developed acute kidney injury (AKI). Renin-angiotensin system (RAS) inhibitors were suspected to be the cause of AKI; therefore, they were discontinued. After the renal function improved, the urinary protein worsened again to 5.49 g/gCr. Renal pathology suggested minimal change disease (MCD); therefore, PSL was continued. The patient's urinary protein subsequently improved and he had no renal function impairment. Minimal change disease can be complicated by AKI through intravascular volume depletion caused by high urinary protein and hypoalbuminemia. However, when MCD is complicated by RAS inhibitor-associated AKI, the urinary protein may notably decrease, and the patient may present with an atypical course of MCD-associated AKI.

Superiority of MRI for Evaluation of Sacral Insufficiency Fracture.

STUDY DESIGN: Retrospective observational study. BACKGROUND: Sacral insufficiency fractures (SIF) are relatively rare fractures and difficult to diagnose on plain radiographs. The primary objective of the present study was to evaluate the role of lumbar magnetic resonance imaging (MRI) for the diagnosis of SIF. The secondary objective was to identify the classification of SIF by computed tomography (CT). METHODS: A total of 77 (Male 11, female 66, mean 80.3 years) people were included in this study. Inclusion criteria for this study were: age ≥ 60 years and no history of high energy trauma. Exclusion criteria were high energy trauma and a current history of malignancy. Differences in the fracture detection and description in the various radiologic procedures were evaluated. Fracture patterns were evaluated with CT. The detection rates of additional pathologies in the MRI of the pelvis and lumbar spine were also recorded. RESULTS: The sensitivities for SIF were 28.5% in radiographs and 94.2% in CT, and all fractures were detected in MRI. MRI showed a more complex fracture pattern compared with CT in 65% of the cases. We observed 71.4% of single SIFs, 9.1% with other spinal fractures, 13.0% with other pelvic fractures, and 7.8% with other fractures. According to the SIF fracture pattern, the H/U type was 40.2%, transverse type was 33.7%, λ/T type was 24.7%, unilateral vertical type was 1.3%, and bilateral vertical type was 0%. CONCLUSIONS: an MRI of the lumbar spine including the sacrum with a coronal fat-suppressed T2-weighted image is useful for elderly patients with suddenly increasing low back pain at an early stage. This procedure improves an early SIF detection, recognition of concomitant pathologies, and adequate treatment for the patients.

Effect of Hemocoagulase on the Prevention of Bleeding after Percutaneous Renal Biopsy.

A percutaneous renal biopsy is an essential tool for the diagnosis of various renal diseases; however, post-biopsy bleeding is a major complication. Hemocoagulase is a detoxified and purified snake venom enzyme that is widely used to prevent post-procedural bleeding. In this study, we retrospectively analyzed the effect of hemocoagulase on post-renal biopsy bleeding. We included 221 patients who underwent percutaneous renal biopsy between April 2017 and December 2020 and analyzed post-renal biopsy hemoglobin (Hb) decline in patients who were administered a periprocedural hemocoagulase injection. After the renal biopsy, the mean Hb decrease in the entire patient cohort was 0.33 ± 0.84 g/dL. Periprocedural hemocoagulase injection lowered the Hb decline post-renal biopsy (0.50 ± 0.87 vs. 0.23 ± 0.80 g/dL, p = 0.0204). The propensity-matched cohort was also adjusted for factors influencing postprocedural bleeding; periprocedural hemocoagulase injection reduced the Hb decline post-renal biopsy (0.56 ± 0.89 vs. 0.17 ± 0.74 g/dL, p = 0.006). There were no adverse events (e.g., thrombosis and anaphylactic shock) due to hemocoagulase. Our study demonstrated the beneficial effect of hemocoagulase on post-renal biopsy Hb decline, suggesting its clinical value in preventing post-renal biopsy bleeding.

An Autopsy Case of Disseminated Varicella Zoster Virus Infection during the Treatment of Nephrotic Syndrome.

A 68-year-old woman developed systemic blisters while receiving treatment for nephrotic syndrome. As she also developed marked liver dysfunction and disseminated intravascular coagulation, she was admitted to our hospital. She was diagnosed with varicella zoster virus (VZV) infection. Treatment was administered in the intensive-care unit, but the patient died on day 24 post-admission after severe VZV infection. A post-mortem examination showed micro-abscesses and necrosis caused by varicella zoster infection in multiple organs, including the liver, kidneys, and gastrointestinal tract. Because VZV infection can become severe in immunocompromised patients, careful consideration is needed for the prevention and treatment of the viral infection.

Mitochonic acid-5 ameliorates chlorhexidine gluconate-induced peritoneal fibrosis in mice.

Peritoneal fibrosis is a serious complication of long-term peritoneal dialysis, attributable to inflammation and mitochondrial dysfunction. Mitochonic acid-5 (MA-5), an indole-3-acetic acid derivative, improves mitochondrial dysfunction and has therapeutic potential against various diseases including kidney diseases. However, whether MA-5 is effective against peritoneal fibrosis remains unclear. Therefore, we investigated the effect of MA-5 using a peritoneal fibrosis mouse model. Peritoneal fibrosis was induced in C57BL/6 mice via intraperitoneal injection of chlorhexidine gluconate (CG) every other day for 3 weeks. MA-5 was administered daily by oral gavage. The mice were divided into control, MA-5, CG, and CG + MA-5 groups. Following treatment, immunohistochemical analyses were performed. Fibrotic thickening of the parietal peritoneum induced by CG was substantially attenuated by MA-5. The number of α-smooth muscle actin-positive myofibroblasts, transforming growth factor ß-positive cells, F4/80-positive macrophages, monocyte chemotactic protein 1-positive cells, and 4-hydroxy-2-nonenal-positive cells was considerably decreased. In addition, reduced ATP5a1-positive and uncoupling protein 2-positive cells in the CG group were notably increased by MA-5. MA-5 may ameliorate peritoneal fibrosis by suppressing macrophage infiltration and oxidative stress, thus restoring mitochondrial function. Overall, MA-5 has therapeutic potential against peritoneal fibrosis.

Correlation between a Bedridden Status and the Long-term Outcome in Hemodialysis Patients after Intracerebral Hemorrhaging.

Objective The quality of life and activities of daily living (ADL) are generally poor among dialysis patients after intracerebral hemorrhaging, and their precise clinical course remains unclear. In addition, the association between the severity of cerebral hemorrhaging and the long-term prognosis in these patients has not been fully elucidated. This study aimed to evaluate the subsequent prognosis of hemodialysis patients who survived the acute phase of intracerebral hemorrhaging. Methods We included hemodialysis patients who were admitted to Nagasaki University Hospital between 2007 and 2015 for intracerebral hemorrhaging treatment. After excluding cases of in-hospital death, survivors were classified using the 5-point modified Rankin Scale (mRS), which specifically measures the ADL in patients with cerebrovascular diseases. The patients were followed up at the medical facilities to which they were transferred in the same medical zone until 2017. Results Out of 91 patients with cerebral hemorrhaging (65±11 years old, 66% men, hemodialysis duration 108±91 months), 62 survived until discharge. Twenty-one patients died during observation, largely due to infectious diseases, such as sepsis and pneumonia (n=16, 76%). Compared to patients with mRS 0-4 (n=31), those with mRS 5 (n=31) showed a significantly poorer prognosis. The hazard ratio adjusted for age and antiplatelets was 13.7 (95% confidence interval: 3.88-63.7, p<0.001). Conclusion Hemodialysis patients with intracerebral hemorrhaging who were bedridden showed poor outcomes. The major causes of death were infections. Therefore, these patients should be carefully monitored for infections in order to improve their prognosis.

Association between Serum Phosphate Levels and the Development of Aortic Stenosis in Patients Undergoing Hemodialysis.

We aimed to investigate the factors associated with the development of aortic stenosis (AS) in patients undergoing hemodialysis (HD), and to elucidate the prognosis of HD patients with AS. Patients on HD that had also undergone echocardiography at Nagasaki Renal Center between July 2011 and June 2012 were included. Patients with AS at the time of inclusion were excluded. The diagnosis of AS was based on an annual routine or additional echocardiography. The patients were followed up until June 2021. The association between patient background and AS was also evaluated. Of the 302 patients (mean age, 67.4 ± 13.3 years; male, 58%; median dialysis history, 4.7 years), 60 developed AS and 10 underwent aortic valve replacement. A Cox proportional hazards model revealed that age (hazard ratio (HR), 1.07; 95% confidential interval (CI), 1.04-1.10; p < 0.001) and serum phosphate levels (HR, 1.40; 95%CI, 1.16-1.67, p < 0.001) were independent risk factors for developing AS. Incidentally, there was no significant mortality difference between patients with AS and those without (p = 0.53). Serum phosphate levels are a risk factor for developing AS and should be controlled. Annual echocardiography may contribute to the early detection of AS and improves the prognosis of patients undergoing HD.

Association of Urinary Dickkopf-3 with Residual Renal Function Decline in Patients Undergoing Peritoneal Dialysis.

Background and Objectives: Urinary levels of dickkopf-3 (DKK-3) are associated with poor renal survival in patients with non-dialytic chronic kidney disease. However, it remains unknown whether urinary DKK-3 levels can predict residual renal function (RRF) decline in patients undergoing peritoneal dialysis (PD). Therefore, we investigated the correlation between urinary levels of DKK-3 and the subsequent rate of RRF decline in PD patients. Materials and Methods: This study included 36 PD patients who underwent multiple peritoneal equivalent tests during 2011-2021. The relationship between baseline clinical characteristics and the subsequent annual rate of Kt/V decline was investigated. Results: The annual rate of renal Kt/V decline was 0.29 (range: 0.05-0.48), which correlated with renal Kt/V (r = 0.55, p = 0.0005) and 24 h urinary DKK-3 excretion (r = 0.61, p < 0.0001). Similarly, 24 h urinary DKK-3 excretion (ß = 0.44, p = 0.0015) and renal Kt/V (ß = 0.38, p = 0.0059) were independently associated with the annual rate of renal Kt/V decline in multivariate analyses. Conclusions: Urinary DKK-3 assessment may help identify PD patients at a high risk of RRF decline.

Safety of Renal Biopsy by Physicians with Short Nephrology Experience.

Percutaneous renal biopsy is an essential tool for diagnosing various renal diseases; however, little is known about whether renal biopsy performed by physicians with short nephrology experience is safe in Japan. This study included 238 patients who underwent percutaneous renal biopsy between April 2017 and September 2020. We retrospectively analyzed the frequency of post-renal biopsy complications (hemoglobin decrease of ≥10%, hypotension, blood transfusion, renal artery embolization, nephrectomy and death) and compared their incidence among physicians with varied experience in nephrology. After renal biopsy, a hemoglobin decrease of ≥10%, hypotension and transfusion occurred in 13.1%, 3.8% and 0.8% of patients, respectively. There were no cases of post-biopsy renal artery embolism, nephrectomy, or death. The composite complication rate was 16.0%. The incidence of post-biopsy complications was similar between physicians with ≥3 years and <3 years of clinical nephrology experience (12.5% vs. 16.8%, p = 0.64). Furthermore, the post-biopsy composite complication rates were similar between physicians with ≥6 months and <6 months of clinical nephrology experience (16.3% vs. 15.6%, p > 0.99). Under attending nephrologist supervision, a physician with short clinical nephrology experience can safely perform renal biopsy.

An inhibitor of Krüppel-like factor 5 suppresses peritoneal fibrosis in mice.

BACK GROUND: Krüppel-like transcription factor 5 (KLF5) is a transcription factor regulating cell proliferation, angiogenesis and differentiation. It has been recently reported that Am80, a synthetic retinoic acid receptor α-specific agonist, inhibits the expression of KLF5. In the present study, we have examined the expression of KLF5 in fibrotic peritoneum induced by chlorhexidine gluconate (CG) in mouse and evaluated that Am80, as an inhibitor of KLF5, can reduce peritoneal fibrosis. METHODS: Peritoneal fibrosis was induced by intraperitoneal injection of CG into peritoneal cavity of ICR mice. Am80 was administered orally for every day from the start of CG injection. Control mice received only a vehicle (0.5% carboxymethylcellulose solution). After 3 weeks of treatment, peritoneal equilibration test (PET) was performed and peritoneal tissues were examined by immunohistochemistry. RESULTS: The expression of KLF5 was less found in the peritoneal tissue of control mice, while KLF5 was expressed in the thickened submesothelial area of CG-injected mice receiving the vehicle. Am80 treatment reduced KLF5 expression and remarkably attenuated peritoneal thickening, accompanied with the reduction of type III collagen expression. The numbers of transforming growth factor ß-positive cells, α-smooth muscle actin-positive cells and infiltrating macrophages were significantly decreased in Am80-treated group. PET revealed the increased peritoneal permeability in CG mice, whereas Am80 administration significantly improved the peritoneal high permeability state. CONCLUSIONS: These results indicate the involvement of KLF5 in the progression of experimental peritoneal fibrosis and suggest that Am80 may be potentially useful for the prevention of peritoneal fibrosis through inhibition of KLF5 expression.

Urinary Liver-Type Fatty Acid-Binding Protein Predicts Residual Renal Function Decline in Patients on Peritoneal Dialysis

BACKGROUND Liver-type fatty acid-binding protein (L-FABP) is a predictive marker for the early detection of acute kidney injury; however, less is known about how useful it is for predicting residual renal function (RRF) decline in patients on peritoneal dialysis (PD). MATERIAL AND METHODS The study subjects were 35 patients on PD who underwent multiple peritoneal equilibration tests (PETs) between October 2011 and October 2019. Urinary L-FABP levels were analyzed with enzyme-linked immunosorbent assay. The relationship between baseline clinical data, including urinary L-FABP levels and the subsequent annual rate of renal Kt/V decline, was investigated. RESULTS The median follow-up duration was 11 months and the rate of renal Kt/V decline was 0.29/y. Compared with outcomes in the group with renal Kt/V preservation, renal Kt/V decline was associated with both high daily levels of urinary protein excretion (0.60 g/d [range, 0.50-0.87] vs. 0.36 g/d [range, 0.19-0.48]; P=0.01) and high daily levels of urinary L-FABP excretion (111.2 mg/d [range, 76.1-188.6] vs. 61.5 mg/d [range, 35.7-96.0]; P=0.002). Multiple logistic regression analysis showed that only high daily levels of urinary L-FABP excretion were independently associated with renal Kt/V decline (odds ratio 1.03, 95% confidence interval 1.00-1.05; P=0.001). Furthermore, higher daily levels of urinary L-FABP excretion were significantly correlated with the higher annual rate of renal Kt/V decline (r=0.71, P<0.001). CONCLUSIONS We demonstrated that daily levels of urinary L-FABP are associated with RRF decline in patients on PD. The results of the present study indicate that assessment of urinary L-FABP levels may help predict RRF decline in patients on PD.

Risk Reduction for End-Stage Renal Disease by Dietary Guidance Using the Gustatory Threshold Test for Salty Taste.

Educational hospitalization of patients with chronic kidney disease (CKD) may slow the progression of renal dysfunction. However, the educational aspect that is more effective has not been identified to date. In this study, patients with CKD were evaluated for gustatory threshold for salty taste and received augmented salt reduction guidance under educational hospitalization at Nagasaki University Hospital from October 2016. In total, 277 eligible patients were enrolled and hospitalized from 2012 to 2019 (mean age of 69.2 years; men comprised 62.1%). We compared 141 patients (Group A) who were educated in the hospital after October 2016 and 136 patients (Group B) who received standard education in the hospital before October 2016. The changes in the estimated glomerular filtration rate (ΔeGFR) after hospitalization and dialysis induction rate within one year after hospitalization were evaluated. The ΔeGFR was significantly improved in Group A compared to Group B (A: 1.05 mL/min/1.73 m2/month, B: 0.55 mL/min/1.73 m2/month; p = 0.02). The dialysis induction rate was significantly lower in Group A than in Group B (A: 8.5%, B: 15.5%; p = 0.001). These trends were also observed by multivariate analyses. In conclusion, educational hospitalization with enhanced salt reduction guidance may reduce the risk of end-stage renal disease.

Hexapeptide derived from prothymosin alpha attenuates cisplatin-induced acute kidney injury.

BACKGROUND: Prothymosin alpha (ProTα) is a nuclear protein expressed in virtually all mammalian tissues. Previous studies have shown that ProTα exhibits protective effects against ischemia-induced cell death in various cell types. Recently, the 6-residue peptide P6Q (NEVDQE), the modified form of the active 6-residue core (51-56) in ProTα, has also been shown to have protective effects against retinal ischemia. However, it remains to be elucidated whether P6Q is effective against acute kidney injury (AKI). Therefore, we investigated the renoprotective effect of P6Q on cisplatin-induced AKI. METHODS: Cultured HK-2 cells were treated with cisplatin for 24 h and pretreatment with ProTα or P6Q was carried out 30 min before cisplatin treatment. Cell viability was evaluated using the MTT assay. In an in vivo study, 8-week-old male Wistar rats were divided into control, cisplatin treated, and cisplatin treated with P6Q injection groups. In the last of these, P6Q was injected intravenously before cisplatin treatment. Then, we evaluated the renoprotective effect of P6Q. RESULTS: In the study on cultured cells, pretreatment with ProTα or P6Q prevented cisplatin-induced cell death. In the in vivo study, pretreatment with P6Q significantly attenuated cisplatin-induced increase in serum creatinine and blood urea nitrogen levels, renal tubular cell injury, and apoptosis. Moreover, P6Q attenuated the mitochondrial apoptotic pathway and accelerated Akt phosphorylation after cisplatin-induced renal damage. CONCLUSION: Taken together, our findings indicate that P6Q can attenuate cisplatin-induced AKI and suppress the mitochondrial apoptotic pathway via Akt phosphorylation. These data suggest that P6Q has potential as a preventative drug for cisplatin-induced AKI.