Presepsin production in monocyte/macrophage-mediated phagocytosis of neutrophil extracellular traps.

Presepsin, a biomarker discovered in Japan, has been clinically applied as a diagnostic aid for sepsis. Recently, however, it has been reported that presepsin levels are elevated in patients with severe systemic lupus erythematosus without infection, suggesting the existence of a production mechanism that does not involve bacterial phagocytosis. In this study, we aimed to elucidate the mechanism of presepsin production without bacterial phagocytosis and explore the clinical significance of presepsin. Neutrophil extracellular traps (NETs) were induced by Escherichia coli and phorbol myristate acetate (PMA) in neutrophils isolated from the peripheral blood of healthy subjects. NET induction alone did not increase presepsin levels, but co-culturing with monocytes significantly increased them. The addition of a NET formation inhibitor also suppressed presepsin levels, suggesting that presepsin production is greatly influenced by monocyte phagocytosis of NETs. Phagocytosis of NETs by THP-1 and U937 cells, which was induced by CD14 expression, also increased presepsin levels. This study suggests that presepsin can be used to assess the severity of inflammatory diseases, such as autoimmune diseases, and monitor treatment effects.

Usefulness of presepsin / creatinine ratio as a new index that corrects for renal function.

Background : Presepsin (P-SEP) is a highly specific sepsis marker, and its fluctuation with respect to advanced renal impairment or sample agitation has not been fully investigated. We evaluated several renal function-corrected P-SEP indices to establish a simple index and its reference range. Methods : Blood samples for P-SEP measurement were collected with minimal agitation. P-SEP levels were measured using the rapid automated immunoanalyzer "PATHFAST." This study included 85 chronic kidney disease (CKD) patients, 65 healthy volunteers, and 4 sepsis patients. Results : Patients stratified by estimated glomerular filtration rate (GFR) had significantly higher P-SEP levels for CKD stage G3, especially the advanced GFR stage. We evaluated presepsin / creatinine (P-SEP / CRE) and P-SEP / eGFR ratios as possible indices for renal function. The P-SEP / CRE ratio exhibited no increase correlating with the GFR stage and was identical in the normal and CKD groups ;  P-SEP / eGFR decreased if GFR stage worsened. The P-SEP / CRE ratio became significantly higher in sepsis patients and was a more useful index with a reference range of 67-263. Conclusions : P-SEP levels were inversely correlated with renal function, indicating the necessity to consider the influence of renal impairment in CKD patients. The P-SEP / CRE ratio is helpful for sepsis diagnosis, even in patients with renal impairment. J. Med. Invest. 68 : 105-111, February, 2021.

Dual disruption of eNOS and ApoE gene accelerates kidney fibrosis and senescence after injury.

The relationship between cellular senescence and fibrosis in the kidney is being elucidated and we have identified it as therapeutic target in recent studies. Chronic kidney disease has also become a lifestyle disease, often developing on the background of hypertension and dyslipidemia. In this study, we clarify the effect of interaction between these two conditions on kidney fibrosis and senescence. Wild type mice (WT), apolipoprotein E-/- mice (ApoEKO), and endothelial nitric oxide synthase (eNOS)-/- ApoE-/- mice (DKO) were obtained by breeding. Unilateral ureteral obstruction (UUO) was performed on 8-10 week old male mice and the degree of renal tubular injury, fibrosis and kidney senescence were evaluated. DKO manifested elevated blood pressure, higher total cholesterol and lower HDL than WT. DKO showed sustained kidney injury molecule-1 protein expression. Kidney fibrosis was significantly higher in ApoEKO and DKO. mRNA expression of genes related to kidney fibrosis was the highest in DKO. The mRNA expression of Zinc-α2-Glycoprotein and heme oxygenase-1 were significantly decreased in DKO. Furthermore, mRNA expression of p53, p21 and p16 were increased both in ApoEKO and DKO, with DKO being the highest. Senescence associated ß-gal positive tubule area was significantly increased in DKO. Increased DNA damage and target of rapamycin-autophagy spatial coupling compartments (TASCCs) formation was found in DKO. Mice with endothelial dysfunction and dyslipidemia developed kidney fibrosis and accelerated senescence even in young mice after injury. These data highlight the fact managing lifestyle-related diseases from a young age is important for CKD prevention.

Author Correction: Circulating Apolipoprotein L1 is associated with insulin resistance-induced abnormal lipid metabolism.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Circulating Apolipoprotein L1 is associated with insulin resistance-induced abnormal lipid metabolism.

Circulating ApolipoproteinL1 (ApoL1) is a component of pre-ß-high-density lipoprotein (HDL), however little is known about the relationship of ApoL1 with cardiometabolic factors. Considering previous studies reporting the correlation of ApoL1 to triglyceride, we have hypothesized that ApoL1 associates with insulin-related metabolism. The current study examined their associations in 126 non-diabetic subjects and 36 patients with type 2 diabetes (T2DM). Non-diabetic subjects demonstrated triglyceride (standardized coefficients [s.c.] = 0.204, p < 0.05), body mass index (s.c. =0.232, p < 0.05) and HDL cholesterol (s.c. = -0.203, p < 0.05) as independent determinant of ApoL1 levels, and the significant elevation of ApoL1 in metabolic syndrome. Lipoprotein fractionation analysis revealed the predominant distribution of ApoL1 in large HDL fraction, and the significant increase of ApoL1 in large LDL fraction in high ApoL1 samples with insulin resistance. In T2DM, ApoL1 was higher in T2DM with metabolic syndrome, however ApoL1 was lower with ß cell dysfunction. Insulin significantly promotes ApoL1 synthesis and secretion in HepG2 cells. In conclusion, circulating ApoL1 may be associated with abnormal HDL metabolism in insulin resistant status. This may suggest a regulation of insulin signal on the ApoL1 level, leading to offer a novel insight to the ApoL1 biology.

Clinical evaluation of presepsin considering renal function.

Presepsin, a glycoprotein produced during bacterial phagocytosis, is used as a sepsis marker for bacterial infections. However, presepsin levels are affected by renal function, and the evaluation criteria according to kidney function or in chronic kidney diseases remain controversial. Furthermore, presepsin may be increased by sample stirring, but no studies have evaluated this effect.In this study, we excluded the effect of stirring by standardizing the blood collection conditions, analyzed the influence of kidney function on presepsin concentrations, and recalculated the reference range based on the findings. EDTA-whole blood from 47 healthy subjects and 85 patients with chronic kidney disease was collected to measure presepsin by PATHFAST. Presepsin was found to be significantly correlated with the levels of creatinine (r = 0.834), eGFRcreat (r = 0.837), cystatin-C (r = 0.845), and eGFRcys (r = 0.879). Furthermore, in patients with CKD, presepsin levels stratified by eGFRcys showed a significant increase in the CKD G2 patient group and with advancing glomerular filtration rate stage. The following values were obtained: Normal: 97.6 ± 27.4 pg/mL, CKD G1: 100.2 ± 27.6 pg/mL, CKD G2: 129.7 ± 40.7 pg/mL, CKD G3: 208.1 ± 70.2 pg/mL, CKD G4: 320.2 ± 170.1 pg/mL, CKD G5: 712.8 ± 336.3 pg/mL. The reference range, calculated by a nonparametric method using 67 cases of healthy volunteers and patients with chronic kidney disease G1, was found to be 59-153 pg/mL, which was notably lower than the standard reference range currently used. Presepsin concentrations were positively correlated with a few biomarkers of renal function, indicating the necessity to consider the effect of renal function in patients with renal impairment. Using the recalculated reference range considering kidney function may improve the accuracy of evaluating presepsin for diagnosis of sepsis compared to the standard reference currently in use.

Cut-off value of total adiponectin for managing risk of developing metabolic syndrome in male Japanese workers.

AIM: To determine the optimal cut-off value of serum total adiponectin for managing the risk of developing metabolic syndrome (MetS) in male Japanese workers. METHODS: A total of 365 subjects without MetS aged 20-60 years were followed up prospectively for a mean of 3.1 years. The accelerated failure-time model was used to estimate time ratio (TR) and cut-off value for developing MetS. RESULTS: During follow-up, 45 subjects developed MetS. Age-adjusted TR significantly declined with decreasing total adiponectin level (≤ 4.9, 5.0-6.6, 6.7-8.8 and ≥ 8.9 µg/ml, P for trend = 0.003). In multivariate analyses, TR of MetS was 0.12 (95% CI 0.02-0.78; P = 0.03) in subjects with total adiponectin level of 5.0-6.6 µg/ml, and 0.15 (95% CI 0.02-0.97; P = 0.047) in subjects with total adiponectin level ≤ 4.9 µg/ml compared with those with total adiponectin level ≥ 8.9 µg/ml. The accelerated failure-time model showed that the optimal cut-off value of total adiponectin for managing the risk of developing MetS was 6.2 µg/ml. In the multivariate-adjusted model, the mean time to the development of MetS was 78% shorter for total adiponectin level ≤ 6.2 µg/ml compared with > 6.2 µg/ml (TR 0.22, 95% CI: 0.08-0.64, P = 0.005). CONCLUSION: Our findings suggest that the cut-off value for managing the risk of developing MetS is 6.2 µg/ml in male Japanese workers. Subjects with total adiponectin level ≤ 6.2 µg/ml developed MetS more rapidly than did those with total adiponectin level > 6.2 µg/ml.

Dual involvement of growth arrest-specific gene 6 in the early phase of human IgA nephropathy.

BACKGROUND: Gas6 is a growth factor that causes proliferation of mesangial cells in the development of glomerulonephritis. Gas6 can bind to three kinds of receptors; Axl, Dtk, and Mer. However, their expression and functions are not entirely clear in the different glomerular cell types. Meanwhile, representative cell cycle regulatory protein p27 has been reported to be expressed in podocytes in normal glomeruli with decreased expression in proliferating glomeruli, which inversely correlated with mesangial proliferation in human IgA nephropathy (IgAN). METHODS: The aim of this study is to clarify Gas6 involvement in the progression of IgAN. Expression of Gas6/Axl/Dtk was examined in 31 biopsy proven IgAN cases. We compared the expression levels with histological severity or clinical data. Moreover, we investigated the expression of Gas6 and its receptors in cultured podocytes. RESULTS: In 28 of 31 cases, Gas6 was upregulated mainly in podocytes. In the other 3 cases, Gas6 expression was induced in endothelial and mesangial cells, which was similar to animal nephritis models. Among 28 podocyte type cases, the expression level of Gas6 correlated with the mesangial hypercellularity score of IgAN Oxford classification and urine protein excretion. It also inversely correlated with p27 expression in glomeruli. As for the receptors, Axl was mainly expressed in endothelial and mesangial cells, while Dtk was expressed in podocytes. In vitro, Dtk was expressed in cultured murine podocytes, and the expression of p27 was decreased by Gas6 stimulation. CONCLUSIONS: Gas6 was uniquely upregulated in either endothelial/mesangial cells or podocytes in IgAN. The expression pattern can be used as a marker to classify IgAN. Gas6 has a possibility to be involved in not only mesangial proliferation via Axl, but also podocyte injury via Dtk in IgAN.