Treatment of hyperlipidemia with proprotein convertase subtilisin/kexin type 9 inhibitor in a patient with nephrotic syndrome: a case report

Effect of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibition on Podocytes in Mouse Nephrotic Syndrome

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is known to play a crucial role in dyslipidemia, and an increase in serum PCSK9 levels has also been reported in patients with nephrotic syndrome (NS). However, the specific effects of PCSK9 in kidney disease and the therapeutic potential of targeting PCSK9 in NS remain elusive. We thus investigated the effects of evolocumab (EVO) in mice with adriamycin (ADR)-induced NS. Male BALB/c mice were divided into the following 4 groups: Control, N = 11; EVO (monoclonal antibody for PCSK9), N = 11; ADR, N = 11; and ADR+EVO, N = 11. We also performed in vitro experiments using immortalized murine podocyte cells to validate the direct effects of PCSK9 on podocytes. EVO decreased urinary albumin levels and ameliorated podocytopathy in mice with ADR nephropathy. Further, EVO suppressed the Nod-like receptor protein 3 (NLRP3) inflammasome pathway in podocytes. PCSK9 expression upregulated CD36, a scavenger receptor of oxidized low-density lipoprotein (Ox-LDL), which in turn stimulated the absorption of Ox-LDL in vitro. EVO downregulated CD36 expression in podocytes both in vitro and in vivo. Immunofluorescence staining analysis reveals that CD36 and PCSK9 colocalized in the glomerular tufts of mice with ADR nephropathy. In the patients with focal segmental glomerulosclerosis, the CD36+ area in glomerular tufts increased compared with those diagnosed with minor glomerular abnormalities. This study revealed that EVO ameliorated mouse ADR nephropathy through the regulation of CD36 and NLRP3 inflammasome signaling. EVO treatment represents a potential therapeutic strategy for human NS.

The risk factors for children with primary nephrotic syndrome: a systematic review and meta-analysis

BACKGROUND

To evaluate the risk factors of primary nephrotic syndrome (PNS) with urinary tract infection (UTI) in children.

METHODS

Multiple databases including PubMed, Excerpta Medica Database (EMBASE), Web of Science (WOS), the Cochrane Library, and China National Knowledge Infrastructure (CNKI) were used to search for relevant studies, which were full-text articles involved in the evaluation of differences between PNS with UTI and without UTI. All included articles were assessed for quality and the data analyses were conducted with Review Manager (5.4). Forest plots, sensitivity analysis, and bias analysis were also performed on the included articles.

RESULTS

Eight studies were included in this meta-analysis, with a total of 3,274 patients. Meta-analysis showed that a low level of serum albumin [mean difference (MD): -0.32 g/dL; 95% confidence interval (CI): (-0.55, -0.08); P=0.008], a low level of serum total protein [MD: -0.16 g/dL; 95% CI: (-0.20, -0.12); P<0.00001], a high level of urinary protein [MD: 5.09 mg/d; 95% CI: (3.13, 7.05); P<0.00001], a lower level of serum urea nitrogen [MD: -0.10 mg/dL; 95% CI: (-0.18, -0.02); P=0.01], and a higher level of serum cholesterol [MD: 2.26 mg/dL; 95% CI: (0.74, 3.78)] had a higher risk of PNS with UTI. There was no obvious publication bias among included studies.

DISCUSSION

Our research demonstrated that a low level of serum albumin, a low level of serum total protein, a high level of urinary protein, a low level of serum urea nitrogen, and a high level of serum cholesterol were the risk factors of PNS with UTI in children.

Effective cholesterol lowering after myocardial infarction in patients with nephrotic syndrome may require a multi-pharmacological approach: a case report

Background

Nephrotic syndrome causes severe hypercholesterolaemia due to increased production and altered clearance of lipoproteins from the liver. It is challenging for patients with nephrotic syndrome and coronary heart disease to meet LDL-cholesterol (LDL-C) goals for secondary prevention with conventional lipid-lowering therapy.

Case summary

We present a man with nephrotic syndrome caused by focal segmental glomerular sclerosis (FSGS) and hypercholesterolaemia. He presented at the emergency room (ER) with an ST-elevation myocardial infarction at the age of 26. On follow-up, the patient had persistent hypercholesterolaemia [LDL-C 3.9 mmol/L and lipoprotein(a) 308 nmol/L] despite a combination of lipid-lowering therapy with atorvastatin 80 mg/day and ezetimibe 10 mg/day. Addition of the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitory antibody evolocumab 140 mg bi-monthly did not improve cholesterol levels. However, after addition of the sodium-glucose cotransporter 2 (SGLT2) inhibitor empagliflozin 10 mg/day on top of other anti-proteinuric treatments, the patient’s proteinuria was reduced and a dramatic drop in LDL-C level by 3.2–0.6 mmol/L (−81%) was observed when evolocumab was re-introduced.

Discussion

We show that target LDL-C levels were obtained in this patient with therapy-resistant FSGS and hypercholesterolaemia following multi-pharmacological treatment with SGLT2 and PCSK9 inhibitors on top of conventional lipid-lowering therapy. The SGLT2-inhibitor reduced proteinuria and, speculatively, also reduced urinary loss of PCSK9-antibody. Therefore, in patients with nephrotic syndrome and cardiovascular disease novel therapeutic options to manage proteinuria could be considered to improve the efficacy of the lipid-lowering therapy, especially when the protein-based PCSK9 inhibitors are used.