Low body mass index is a risk factor for hyperkalaemia associated with angiotensin converting enzyme inhibitors and angiotensin II receptor blockers treatments.

WHAT IS KNOWN AND OBJECTIVE: Angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB) represent the cornerstones of hypertension and congestive heart failure treatment. Risk factors for hyperkalaemia associated with ACEI and ARB are chronic kidney disease and concomitant medications which increase serum potassium level. Body mass index (BMI) also affects pharmacokinetics of ACEI and ARB and potassium disposition. We evaluated the relationship between BMI and hyperkalaemia associated with ACEI and ARB treatments. METHODS: Study design is a retrospective case-control analysis. Patients who had been prescribed ACEI or ARB between June 2015 and June 2017 at Tokyo Women's Medical University, Medical Center East, were included. Patient clinical background was collected from medical records. Hyperkalaemia was defined as serum potassium above 5.5 meq/L. The concomitant use of ACEI and ARB, aldosterone antagonists, direct renin inhibitor, sulfamethoxazole-trimethoprim and non-steroidal anti-inflammatory drugs (NSAIDs) was regarded as hyperkalaemia-inducing medications. The relationship between BMI and hyperkalaemia associated with ACEI and ARB treatments was assessed using multivariable logistic regression analysis. RESULTS AND DISCUSSION: The study included 2987 patients aged 70.1 ± 12.9 years, 61.0% were men, and BMI was 23.8 ± 4.4 kg/m2 . The incidence of hyperkalaemia was 7.8%. Multivariable logistic regression analysis revealed that age >65 years, low BMI, diabetes, history of treatment for hyperkalaemia, serum sodium <135 meq/L, eGFR <30 mL/min/1.73m2 and the concomitant use of hyperkalaemia-inducing medications were independent risk factors for hyperkalaemia associated with ACEI and ARB. WHAT IS NEW AND CONCLUSION: This study demonstrated that BMI provides useful information for the identification of potential risk for hyperkalaemia associated with ACEI and ARB treatments.

MicroRNA-574-3p, identified by microRNA library-based functional screening, modulates tamoxifen response in breast cancer.

Most primary breast cancers express estrogen receptor α and can be treated via endocrine therapy using anti-estrogens such as tamoxifen; however, acquired endocrine resistance is a critical issue. To identify tamoxifen response-related microRNAs (miRNAs) in breast cancer, MCF-7 cells infected with a lentiviral miRNA library were treated with 4-hydroxytamoxifen (OHT) or vehicle for 4 weeks, and the amounts of individual miRNA precursors that had integrated into the genome were evaluated by microarray. Compared to the vehicle-treated cells, 5 'dropout' miRNAs, which were downregulated in OHT-treated cells, and 6 'retained' miRNAs, which were upregulated in OHT-treated cells, were identified. Of the dropout miRNAs, we found that miR-574-3p expression was downregulated in clinical breast cancer tissues as compared with their paired adjacent tissues. In addition, anti-miR-574-3p reversed tamoxifen-mediated suppression of MCF-7 cell growth. Clathrin heavy chain (CLTC) was identified as a miR-574-3p target gene by in silico algorithms and luciferase reporter assay using the 3' untranslated region of CLTC mRNA. Interestingly, loss and gain of miR-574-3p function in MCF-7 cells causes CLTC to be upregulated and downregulated, respectively. These results suggest that functional screening mediated by miRNA libraries can provide new insights into the genes essential for tamoxifen response in breast cancer.