Splanchnic venous thrombosis in a nephrotic patient following COVID-19 infection: a case report

Background As the COVID-19 pandemic spread worldwide, case reports and small series identified its association with an increasing number of medical conditions including a propensity for thrombotic complications. And since the nephrotic syndrome is also a thrombophilic state, its co-occurrence with the SARS-CoV-2 infection is likely to be associated with an even higher risk of thrombosis, particularly in the presence of known or unknown additional risk factors. Lower extremity deep vein thrombosis (DVT) and pulmonary embolism (PE) are the most common manifestations of COVID-19-associated hypercoagulable state with other venous or arterial sites being much less frequently involved. Although splanchnic vein thrombosis (SVT) has been reported to be 25 times less common than usual site venous thromboembolism (VTE) and rarely occurs in nephrotic patients, it can have catastrophic consequences. A small number of SVT cases have been reported in COVID-19 infected patients in spite of their number exceeding 180 million worldwide. Case presentation An unvaccinated young adult male with steroid-dependent nephrotic syndrome (SDNS) who was in a complete nephrotic remission relapsed following contracting SARS-CoV-2 infection and developed abdominal pain and diarrhea. Abdominal US revealed portal vein thrombosis. The patient was anticoagulated, yet the SVT rapidly propagated to involve the spleno-mesenteric, intrahepatic and the right hepatic veins. In spite of mechanical thrombectomy, thrombolytics and anticoagulation, he developed mesenteric ischemia which progressed to gangrene leading to bowel resection and a complicated hospital course. Conclusion Our case highlights the potential for a catastrophic outcome when COVID-19 infection occurs in those with a concomitant hypercoagulable state and reminds us of the need for a careful assessment of abdominal symptoms in SARS-CoV-2 infected patients.

Impaired NEPHRIN localization in kidney organoids derived from nephrotic patient iPS cells

Mutations in the NPHS1 gene, which encodes NEPHRIN, cause congenital nephrotic syndrome, resulting from impaired slit diaphragm (SD) formation in glomerular podocytes. We previously reported NEPHRIN and SD abnormalities in the podocytes of kidney organoids generated from patient-derived induced pluripotent stem cells (iPSCs) with an NPHS1 missense mutation (E725D). However, the mechanisms underlying the disease may vary depending on the mutations involved, and thus generation of iPSCs from multiple patients is warranted. Here we established iPSCs from two additional patients with different NPHS1 mutations and examined the podocyte abnormalities in kidney organoids derived from these cells. One patient had truncating mutations, and NEPHRIN was undetectable in the resulting organoids. The other patient had a missense mutation (R460Q), and the mutant NEPHRIN in the organoids failed to accumulate on the podocyte surface to form SD precursors. However, the same mutant protein behaved normally when overexpressed in heterologous cells, suggesting that NEPHRIN localization is cell context-dependent. The localization of another SD-associated protein, PODOCIN, was impaired in both types of mutant organoids in a cell domain-specific manner. Thus, the new iPSC lines and resultant kidney organoids will be useful resources for dissecting the disease mechanisms, as well as for drug development for therapies.

P0666BRILLOUIN AND RAMAN SPECTROSCOPIES FOR NON-CONTACT ASSESSMENT OF MECHANO-CHEMICAL PROPORTIES OF URINARY PROTEINS: A PROOF OF CONCEPT STUDY

Background and Aims Proteinuria is a major marker of chronic kidney disease (CKD) severity, the predictor of renal function decline and cardiovascular mortality. The main pathway of CKD progressive is caused by tubular toxicity of filtering proteins, so more, the rapid development of renal failure is expected in those patients who have higher level of proteinuria. However, despite high level of proteinuria, paradoxically, some patients may have slow decline of renal function compared to those patients with lower level of urinary protein excretion. This may possibly due to their different mechanical (visco-elastic) and chemical properties, as well as the proteomics of excreting urinary proteins. Brillouin light scattering (BLS) and surface enhanced Raman scattering (SERS) spectroscopies are non-contact (laser optical-based) techniques providing visco-elastic and chemical property information of probed human biofluids. We aimed to study and compare the visco-elastic and chemical properties of urinary proteins using BLS and SERS spectroscopies in nephrotic patient with high protein excretion and healthy subject. Method Two urine samples from nephrotic patient (proteinuria>3.5 g/24h) and healthy subject (undetectable proteinuria) investigated using BLS and SERS spectroscopies. Brillouin spectroscopy performed using Torus single longitudinal mode laser in conjunction with high contrast JRS Instruments 6-pass tandem Fabry-Perot interferometer coupled with confocal microscope. Using Horiba LabRAM HR Raman microscope with 785 nm laser excitation andx100 microscope objective the SERS spectroscopy was performed on urine samples in contact 60 nm gold nanoparticles placed on gold film. Additionally, reversed-phase liquid chromatography-mass spectrometry (LC-MS) was conducted for profiling of urinary proteins LC-MS data was analysed by Mascot software using the SwissProt protein database. Results We found that elevated protein levels in urine alter the urine fluid elasticity sufficiently to be measurable by BLS spectroscopy, with urine from healthy and proteinuric subjects distinguishable to marked significance, which increases with sample concentration. BLS spectroscopy demonstrated that patients with High Protein Loss, characterized by stiffer urine (i.e. higher Brillouin shift and elastic modulus) and less viscous (i.e. less hypersound attenuation) compared to healthy subject. (Figure 1A). SERS measurements of two urine samples taken from patient with high protein loss in healthy subject (Figure 1B) showed the integrated Raman intensity ratio of 1338 cm-1 and 1002 cm-1 peaks is many times higher for the sample with high protein concentration vs sample with low protein concentration. Urinary protein sequencing and Mascot analysis (Table 1) demonstrated that proteinuric patient had different type of proteins with up to 187k Daltons of molecular weight. Conclusion In this proof of concept study, we demonstrated that laser-optical BLS and SERS techniques combined with LC-MS measurements revealed that human urine fluids of healthy and proteinuric subjects had strong variation in the visco-elastic and chemical properties coupled with various level of protein content.

Acute anterior myocardial infarction in a 22-year-old male nephrotic patient along with familial hyperlipidaemia

We report a case of acute myocardial infarction in a nephrotic male patient. A 22-year-old man with a 1-year history of nephrotic syndrome due to membranous nephropathy presented with acute chest pain and was admitted to our emergency room. An electrocardiogram showed ST elevation in leads consistent with anterior and inferior myocardial infarction. Subsequent cardiac catheterisation showed evidence of thrombotic occlusion of the anterior descending coronary artery. The patient had no long history of hypercholesterolaemia or hypertriglyceridaemia. The case suggests that young patients with a short-term nephrotic syndrome may be at an increased risk for acute coronary syndrome owing to hypercoagulability state.

Kinetics of Rituximab Excretion into Urine and Peritoneal Fluid in Two Patients with Nephrotic Syndrome

Clinical observations suggest that treatment of Rituximab might be less effective in patients with nephrotic range proteinuria when compared to nonnephrotic patients. It is conceivable that the reason for this is that significant amounts of Rituximab might be lost in the urine in a nephrotic patient and that these patients require a repeated or higher dosage. However, this has not been systematically studied. In this case report we describe two different patients with nephrotic range proteinuria receiving Rituximab. The first patient received Rituximab for therapy resistant cryoglobulinemic membranoproliferative glomerulonephritis and the other for second line treatment of Felty’s syndrome. We employed flow cytometry to determine the amount of Rituximab excretion in both urine and peritoneal fluid specimens in these patients following administration of Rituximab. We found that a significant amount of Rituximab is lost from the circulation by excretion into the urine. Furthermore we saw a close correlation of the excretion of Rituximab to the excretion of IgG molecules suggesting selectivity of proteinuria as the determining factor of Rituximab excretion. Further larger scale clinical studies could have the potential to evaluate an optimal cut-off value of IgG urinary loss before a possible administration of Rituximab therefore contributing to a more individualized treatment approach in patients with nonselective and nephrotic range proteinuria.