Higher sclerostin is associated with pulmonary hypertension in pre-dialysis end-stage kidney disease patients: a cross-sectional prospective observational cohort study

BACKGROUND

Pulmonary hypertension (PH) is a complication of chronic kidney disease (CKD) that contributes to mortality. Sclerostin, a SOST gene product that reduces osteoblastic bone formation by inhibiting Wnt/β-catenin signaling, is involved in arterial stiffness and CKD-bone mineral disease, but scanty evidence to PH. This study explored the relationship between sclerostin and PH in CKD 5, pre-dialysis end-stage kidney disease (ESKD) patients.

METHODS

This cross-sectional prospective observational cohort study included 44 pre-dialysis ESKD patients between May 2011 and May 2015. Circulating sclerostin levels were measured using an enzyme-linked immunosorbent assay. PH was defined as an estimated pulmonary artery systolic pressure > 35 mmHg on echocardiography.

RESULTS

Patients with higher sclerostin levels ≥ 218.18pmol/L had echocardiographic structural cardiac abnormalities, especially PH (P < 0.01). On multivariate logistic analysis, sclerostin over 218.19pmol/L was significantly associated with PH (odds ratio [OR], 41.14; 95% confidence interval [CI], 4.53-373.89, P < 0.01), but multivariate Cox regression analysis showed the systemic vascular calcification score over 1 point (Hazard ratio [HR] 11.49 95% CI 2.48-53.14, P = 0.002) and PH ([HR] 5.47, 95% CI 1.30-23.06, P = 0.02) were risk factors for all-cause mortality in pre-dialysis ESKD patients.

CONCLUSIONS

Serum sclerostin and PH have a positive correlation in predialysis ESKD patients. The higher systemic vascular calcification score and PH have an association to increase all-cause mortality in pre-dialysis ESKD patients.

Smoking amplifies the risk of albuminuria in individuals with high sodium intake: the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2011 and 2014-2018

Background

Smoking and sodium intake (SI) have been evaluated as risk factors for kidney disease; however, the data are inconsistent. We assessed the association between SI and cotinine-verified smoking status and the risk of albuminuria.

Methods

An observational study using the Korea National Health and Nutrition Examination Survey (2008-2011 and 2014-2018) was performed. We included 37,410 adults with an estimated glomerular filtration rate of ≥60 mL/min/1.73 m2 . The smoking status was assumed based on the urine cotinine/creatinine ratio (Ucot/Ucrea). SI was estimated from spot urine sodium using the Kawasaki formula.

Results

Ucot/Ucrea levels were significantly higher in current smokers (920.22 ± 9.00 ng/mg) than in ex-smokers and nonsmokers (48.31 ± 2.47 and 23.84 ± 1.30 ng/mg) (p < 0.001). Ucot/Ucrea levels were significantly higher in second-hand smokers than in participants without a history of smoking (p < 0.001). Ucot/ Ucrea levels were positively associated with SI (p for trend < 0.001). Smoking status was not associated with albuminuria. SI had a linear relationship with albuminuria (p < 0.001). In groups with the highest Ucot/Ucrea levels, the highest SI quartile indicated a significantly higher risk of albuminuria than that in the lowest quartile (risk ratio, 2.22; 95% confidence interval, 1.26-3.92; p = 0.006). The risk of albuminuria was not significant in groups with the lowest and middle tertile adjusted for multiple risk factors.

Conclusion

Smokers consume higher dietary sodium and dietary SI was positively related to the risk of albuminuria. Smoking is not associated with albuminuria as a single factor. The risk of albuminuria is the higher in participants with smoking and high SI.

A Case Report of Thrombotic Thrombocytopenia After ChAdOx1 nCov-19 Vaccination and Heparin Use During Hemodialysis

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare but life-threatening complication. VITT strongly mimics heparin-induced thrombocytopenia (HIT) and shares clinical features. Heparin is commonly used to prevent coagulation during hemodialysis. Therefore, nephrologists might encounter patients needing dialysis with a history of heparin exposure who developed thrombotic thrombocytopenia after vaccination. A 70-year-old male presented with acute kidney injury and altered mental status due to lithium intoxication. He needed consecutive hemodialysis using heparin. Deep vein thrombosis of left lower extremity and accompanying severe thrombocytopenia of 15,000/µL on 24 days after vaccination and at the same time, nine days after heparin use. Anti-platelet factor 4 antibody test was positive. Anticoagulation with apixaban and intravenous immunoglobulin (IVIG) infusion resolved swelling of his left calf and thrombocytopenia. There were no definitive diagnostic tools capable of differentiating between VITT and HIT in this patient. Although VITT and HIT share treatment with IVIG and non-heparin anticoagulation, distinguishing between VITT and HIT will make it possible to establish a follow-up vaccination plan in a person who has had a thrombocytopenic thrombotic event. Further research is needed to develop the tools to make a clear distinction between the clinical syndromes.

Impact of acute kidney injury on long-term adverse outcomes in obstructive uropathy

Obstructive uropathy is known to be associated with acute kidney injury (AKI). This study aimed to investigate the etiologies, clinical characteristics, consequences and also assess the impact of AKI on long-term outcomes. This multicenter, retrospective study of 1683 patients with obstructive uropathy who underwent percutaneous nephrostomy (PCN) analyzed clinical characteristics, outcomes including progression to end-stage kidney disease (ESKD), overall mortality, and the impact of AKI on long-term outcomes. Obstructive uropathy in adults was most commonly caused by malignancy, urolithiasis, and other causes. AKI was present in 78% of the patients and was independently associated with preexisting chronic kidney disease (CKD). Short-term recovery was achieved in 56.78% after the relief of obstruction. ESKD progression rate was 4.4% in urolithiasis and 6.8% in other causes and older age, preexisting CKD, and stage 3 AKI were independent factors of progression. The mortality rate (34%) was highly attributed to malignant obstruction (52%) stage 3 AKI was also an independent predictor of mortality in non-malignant obstruction. AKI is a frequent complication of adult obstructive uropathy. AKI negatively affects long-term kidney outcomes and survival in non-malignant obstructions. A better understanding of the epidemiology and prognostic factors is needed for adult obstructive uropathy.

P0567ACUTE KIDNEY INJURY IN OBSTRUCTIVE UROPATHY; EPIDEMIOLOGY, RENAL OUTCOME AND MORTALITY

Background and Aims

Urinary tract obstruction (UTO) is a common clinical problem leading to acute or chronic renal impairment. Unlike pediatric population in which congenital anomalies of urinary tract account for a majority of UTO and contribute to end stage renal disease (ESRD), etiologies, clinical manifestation and outcome in adult UTO remain uncertain due to lack of large epidemiological data.

Method

We performed a multi-center, retrospective study analyzing 1,711 patients who underwent percutaneous nephrostomy (PCN) from 2001 to 2015.

Results

The most common cause of UTO was malignancies (55.6%) followed by urolithiasis (28.5%) and others. Metastatic colorectal cancer were the most common type of malignancies. Patients with UTO caused by malignancies were significantly older, had more advanced stage acute kidney injury (AKI) and higher mortality rate, while those with urolithiasis had higher prevalence of hypertension, diabetes, cardio-cerebro-vascular diseases. Eighty two percentage of patients developed AKI and 15.2% of patients needed a temporary dialysis. Older age, malignancy associated UTO and high uric acid level were independently associated with AKI. Among patients with AKI, 38.2% patients showed a renal functional recovery defined as eGFR ≥60ml/min/1.73m2 on day 7 after PCN. Multivariate analysis showed that older age and lower hemoglobin level were independent factors predicting a nonrecovery of renal function. During the median follow up period of ∼∼months, overall mortality rate was 33.9% with the highest rate was found in malignancy associated UTO (51.9%), followed by other causes (15.9%) and urolithiasis (8.8%). Malignancy associated UTO (OR 4.754, 95% CI 3.151-7.174, p&lt;0.001), lower albumin level (OR 0.731, 95% CI 0.568-0.942, p&lt;0.001) and stage 3 AKI (OR 2.529, 95% CI 1.332-4.803, p=0.005) were found to be independently associated with mortality. However, the impact of AKI on overall mortality was more prominent in non-malignancy associated UTO with stepwise increase of mortality as KDIGO stage increased.

Conclusion

In conclusion, malignancy is the most common cause of upper UTO in adults and AKI is frequently associated. Short term renal recovery after PCN was observed only in 38.2% patients and older age, lower hemoglobin level were associated with nonrecovery of renal function. Malignancy associated UTO showed the highest mortality rate compared to urolithiasis or other causes and stage 3 AKI as well as lower hemoglobin and lower albumin level were found to be independent predictors of mortality in UTO.

P0920THE METHIONINE RESTRICTION DIET ATTENUATES CHRONIC KIDNEY PROGRESSION IN MICE

Background and Aims

The clinical usefulness of protein-restricted diets is known to slow the progression of obesity, fatty liver, aging and cancer. Protein-restricted diet in chronic kidney disease is known to alleviate the deterioration of the renal function. The purpose of this study is to confirm whether the reduction in new function can be improved when methionine restricted (MR) diet is supplied in the chronic kidney disease (CKD) animal model and to study the its renoprotection mechanism.

Method

We used four-week-old C57L/B6 to make a CKD model by administration 0.025% adenine chow mixed with R3 diet for four weeks for the control group. For the MR diet group, we supplied the mixture of 0.025% adenine with methionine/Choline Deficient Diet. We measured serum blood urea nitrogen (BUN), serum creatinine, gut permeability, stool short chain fatty acid (SCFA), kidney α-SMA and renal pathology. This study was approved by Korea University Institutional Animal Care and Use Committee (KOREA-2019-0047).

Results

The principal coordinates analysis of the microbiome showed the two groups have distinctive component features. The stool SCFA, especially butyrate was increased in the MR diet group. However, gut permeability using FITC-dextran showed no significant change. The kidney α-SMA and MT stain area showed that the MR diet could improve renal fibrosis. The kidney inflammation including neutrophil and macrophage infiltration was also improved in histology analysis. The macrophage phenotype was more favorable to M2 type. Serum BUN and creatinine were significantly attenuated in the MR diet group.

Conclusion

In conclusion, the MR diet has a reno-protective effect in adenine induced CKD. The MR diet increased butyrate production and decreased renal inflammation and fibrosis. These results shed light on the role of protein restriction diet for CKD management in the real world.