Portal Vein Doppler Is a Sensitive Marker for Evaluating Venous Congestion in End-Stage Kidney Disease.

INTRODUCTION: Determining ultrafiltration volume in patients undergoing intermittent hemodialysis (IHD) is an essential component in the assessment and management of volume status. Venous excess ultrasound (VExUS) is a novel tool used to quantify the severity of venous congestion at the bedside. Given the high prevalence of pulmonary hypertension in patients with end-stage kidney disease (ESKD), venous Doppler could represent a useful tool to monitor decongestion in these patients. METHODS: This is a prospective observational study conducted in ESKD patients who were admitted to the hospital requiring IHD and ultrafiltration. Inferior vena cava maximum diameter (IVCd), portal vein Doppler (PVD), and hepatic vein Doppler (HVD) were performed in all patients before and after a single IHD session. RESULTS: Forty-one patients were included. The prevalence of venous congestion was 88% based on IVCd and 63% based on portal vein pulsatility fraction (PVPF). Both mean IVCd and PVPF displayed a significant improvement after ultrafiltration. The percent decrease in PVPF was significantly larger than the percent decrease in IVCd. HVD alterations did not significantly improve after ultrafiltration. CONCLUSIONS: Our study revealed a high prevalence of venous congestion in hospitalized ESKD patients undergoing hemodialysis. After a single IHD session, there was a significant improvement in both IVCd and PVPF. HVD showed no significant improvement with one IHD session. PVPF changes were more sensitive than IVCd changes during volume removal. This study suggests that, due to its rapid response to volume removal, PVD, among the various components of the VExUS grading system, could be more effective in monitoring real-time decongestion in patients undergoing IHD.

Eculizumab Use in Scleroderma Renal Crisis With Thrombotic Microangiopathy: A Case Report.

A Black woman in her 40s with past medical history significant for obesity treated with Roux-en-Y bypass surgery and a history of Raynaud's phenomenon, presented with acute pulmonary edema secondary to severe malignant hypertension and critically accelerated acute kidney injury, with evidence of systemic microangiopathic hemolytic anemia in the setting of clinical suspicion of systemic sclerosis sine scleroderma. Renin-angiotensin system blockade (angiotensin-converting enzyme inhibitor) was immediately started at the maximum possible dose in the setting of scleroderma renal crisis. Despite better control of blood pressure and volume status, kidney function continued to rapidly decline, thus a decision was made to go ahead with a kidney biopsy on day 3 of admission, which revealed severe features of scleroderma renal crisis with active thrombotic microangiopathy. The multidisciplinary team elected to treat the patient with terminal complement blockade using eculizumab in addition to high dose lisinopril and blood pressure control. Her serum creatinine peaked at 9.3 mg/dL shortly after eculizumab initiation, but improved soon after, dropping to 2.8 mg/dL after completion of the final eculizumab dose and 1.8 mg/dL 3 years later.

The Complement System in the Modern Era of Kidney Transplantation: Mechanisms of Injury and Targeted Therapies.

Kidney transplantation remains the treatment of choice for patients with end-stage kidney disease. Significant progress has been made over the course of many years to improve both patient and graft outcomes after transplant. Modern immunosuppressive therapy has reduced the rate of acute rejection and resulted in excellent short- and long-term graft survival. Over the past decade or so, we have become more cognizant of the role of the complement in many events related to the transplant process. A myriad of events that include the cause of death in deceased donors, organ procurement and preservation events, cold ischemia time, time to kidney anastomosis, ischemia-reperfusion injury, recipient immunologic response during and after transplantation, immunosuppressive drug toxicity, and recurrence of original disease all have been shown to affect graft survival. The involvement of the complement system and its activation around the time of kidney transplantation increasingly is recognized as a key player affecting long-term graft survival. In this review, we highlight the important role of the complement system at every stage of the kidney transplantation process. We review potential triggers of complement activation in kidney transplant patients and discuss novel therapeutic agents that can inhibit the complement system.

Acute Hemodialysis for Treatment of Severe Ethanol Intoxication.

A male college student presented to the emergency department with altered mental status and a serum ethanol level higher than the hospital laboratory assay. His course was complicated by mechanical ventilation, vasopressors, and cardiotoxicity. Thirteen hours into admission and despite aggressive supportive measures, the patient remained obtunded off sedation with serum ethanol level elevated at 428 mg/dL. A decision was made to initiate hemodialysis to expedite ethanol clearance and prevent further end-organ damage. Two hours into hemodialysis, mental status improved and serum ethanol level had decreased to 264 mg/dL. A total of 4 hours of hemodialysis were completed and serum ethanol level continued to downtrend. Dialysis increased the rate of ethanol elimination by a factor of 4 and prevented further cardiotoxicity or electrolyte level abnormalities. This case supports the use of hemodialysis for adult patients who meet the criteria of severe ethanol toxicity requiring critical care resources and having evidence of organ toxicity to 1 or more organ.

The utility of repeat kidney biopsy in systemic immunoglobulin light chain amyloidosis.

Background: The diagnostic utility of repeat kidney biopsy in AL amyloidosis patients in complete (CR) or very good partial hematologic response (VGPR) but with renal organ relapse is not clear.Methods: We present eight patients with AL amyloidosis who had a repeat kidney biopsy performed.Results: AL amyloidosis was initially diagnosed by a kidney biopsy. All patients had a favorable response to treatment (CR/VGPR) and five of them also had initially a renal organ response. A repeat kidney biopsy was done due to gradual deterioration of kidney function and/or proteinuria while maintaining a hematologic response. Repeat kidney biopsies showed findings consistent with amyloid deposits in all patients. Seven patients had renal progression with four of them requiring dialysis initiation. Only one patient had a favorable renal outcome. This patient had subacute kidney injury with decreasing proteinuria and was found to have granulomatous interstitial nephritis in addition to amyloid deposits and responded well to steroid treatment with rapid improvement in renal function.Conclusions: In AL amyloidosis patients who achieve a favorable hematologic response to treatment (CR/VGPR) but subsequently develop worsening renal insufficiency or proteinuria, a repeat kidney biopsy should generally not be performed. Amyloid deposits persist in the kidneys even after successful hematologic treatment and it is impossible to differentiate between new versus old amyloid deposits, which makes performing a repeat kidney biopsy unnecessary in most cases. Demonstration of amyloid deposits on repeat kidney biopsy would not aid in the decision making regarding re-initiation of hematologic treatment. A kidney biopsy should be considered only in cases when a specific alternative diagnosis is suspected.

Identification of Tpr and α-actinin-4 as two novel SLK-interacting proteins.

Expression and activity of the Ste20-like kinase, SLK, are increased during kidney development and recovery from ischemia-reperfusion injury. SLK mediates apoptosis in various cells, and can regulate cell cycle progression and cytoskeletal remodeling. In cells, SLK is detected in a high molecular mass complex, suggesting that SLK is a dimer/oligomer, or is in tight association with other proteins. To better understand the regulation, localization and function of SLK, we sought to identify proteins in this high molecular mass complex. Analysis by mass spectroscopy identified the nucleoporin, translocated promoter region (Tpr), and the cytoskeletal protein, α-actinin-4, as potential SLK-interacting proteins. Using a protein complementation assay, we showed that the 350 amino acid C-terminal, coiled-coil domain of SLK was responsible for homodimerization, as well as interaction with Tpr and α-actinin-4. The association of SLK with Tpr and α-actinin-4, respectively, was confirmed by co-immunoprecipitation. Subsets of total cellular SLK colocalized with Tpr at the nuclear envelope, and α-actinin-4 in the cytoplasm. Expression of Tpr attenuated activation-specific autophosphorylation of SLK, and blocked SLK-induced apoptosis and AP-1 activity. In contrast to the effect of Tpr, autophosphorylation of SLK was not affected by α-actinin-4. Thus, SLK interacts with Tpr and α-actinin-4 in cells, and these protein-protein interactions may control the subcellular localization and the biological activity of SLK.

Efficacy of vitamin E and N-acetylcysteine in the prevention of contrast induced kidney injury in patients with chronic kidney disease: a double blind, randomized controlled trial.

BACKGROUND: Contrast induced acute kidney injury is one of the most frequent causes of hospital acquired acute kidney injury. The present study aims to investigate the efficacy of vitamin E or N-acetylcysteine as an adjunct to current standard therapy in the prevention of this clinical predicament. We tested the hypothesis that vitamin E or N-acetylcysteine added to standard therapy with 0.45 % saline is superior in preserving renal function in patients with chronic kidney disease stage 1-4 undergoing elective computer-assisted tomography with nonionic radiocontrast agents when compared to 0.45 % saline alone. DESIGN: Prospective, randomized, single-center, double-masked, double dummy, placebo-controlled, parallel clinical trial. METHODS: The patients were randomized to either vitamin E (total dose 2160 mg i.v.) or N-acetylcysteine (total dose 4800 mg p.o.) in addition to 0.45 % saline (1 mL/kg/h over 24 h) or saline alone. Serum creatinine change between baseline and 24 h after radiocontrast was the primary outcome. Contrast induced acute kidney injury was defined as a rise in serum creatinine > 25 % over the baseline value within 48 h. RESULTS: Thirty patients (mean age 74.6 years; 17 females; 9 diabetics; all Caucasians; mean serum creatinine 1.35 mg/dL; mean creatinine clearance 56 mL/min) were enrolled. No patient developed contrast induced acute kidney injury. There was no significant difference in serum creatinine change between the three study arms. CONCLUSION: Following radiocontrast administration, neither vitamin E nor N-acetylcystein in addition to saline demonstrated an additional beneficial effect on kidney function when compared to saline alone.

Regulation of the Ste20-like kinase, SLK: involvement of activation segment phosphorylation.

Expression and activation of the Ste20-like kinase, SLK, is increased during kidney development and recovery from ischemic acute kidney injury. SLK promotes apoptosis, and it may regulate cell survival during injury or repair. This study addresses the role of phosphorylation in the regulation of kinase activity. We mutated serine and threonine residues in the putative activation segment of the SLK catalytic domain and expressed wild type (WT) and mutant proteins in COS-1 or glomerular epithelial cells. Compared with SLK WT, the T183A, S189A, and T183A/S189A mutants showed reduced in vitro kinase activity. SLK WT, but not mutants, increased activation-specific phosphorylation of c-Jun N-terminal kinase (JNK) and p38 kinase. Similarly, SLK WT stimulated activator protein-1 reporter activity, but activation of activator protein-1 by the three SLK mutants was ineffective. To test if homodimerization of SLK affects phosphorylation, the cDNA encoding SLK amino acids 1-373 (which include the catalytic domain) was fused with a cDNA for a modified FK506-binding protein, Fv (Fv-SLK 1-373). After transfection, the addition of AP20187 (an FK506 analog) induced regulated dimerization of Fv-SLK 1-373. AP20187-stimulated dimerization enhanced the kinase activity of Fv-SLK 1-373 WT. In contrast, kinase activity of Fv-SLK 1-373 T183A/S189A was weak and was not enhanced after dimerization. Finally, apoptosis was increased after expression of Fv-SLK 1-373 WT but not T183A/S189A. Thus, phosphorylation of Thr-183 and Ser-189 plays a key role in the activation and signaling of SLK and could represent a target for novel therapeutic approaches to renal injury.