Performance of urinary neutrophil gelatinase-associated lipocalin, clusterin, and cystatin C in predicting diabetic kidney disease and diabetic microalbuminuria: a consecutive cohort study.

BACKGROUND: Tubular biomarkers have been regarded as emerging and promising markers for early diagnosis of diabetic kidney disease (DKD). The study was to determine the diagnostic capabilities of tubular biomarkers (urinary neutrophil gelatinase-associated lipocalin [NGAL], clusterin, and cystatin C) for DKD and diabetic microalbuminuria, and whether or not the tubular biomarkers appear earlier than microalbuminuria. METHODS: In this consecutive cohort study, 146 type 2 diabetes mellitus (T2DM) patients with a disease duration of ≥6 years were enrolled. Thirty age- and gender-matched subjects without any systemic diseases were recruited as the control group. Urinary samples collected before treatment were tested for NGAL, clusterin, and cystatin C. RESULTS: The levels of biomarkers were higher in patients with DKD (p < 0.001); and positively correlated with the urinary albumin creatinine ratio (UACR; p < 0.001). With respect to the diagnosis of DKD, the areas under the receiver operating characteristic curve (AUCs) for urinary NGAL, clusterin, and cystatin C were 0.816 (95% confidence interval [CI], 0.741-0.891), 0.775 (95% CI: 0.694-0.857), and 0.803 (95% CI: 0.722-0.884), respectively. The levels of urinary NGAL and cystatin C in the normoalbuminuria group (UACR <30 mg /g•Cr) were elevated compared with the control group, unlike urinary clusterin. There was no statistical difference in the levels of the three biomarkers between groups with different levels of haemoglobin A1C (HbA1c). The diagnostic AUCs for urinary NGAL, clusterin, and cystatin C in patients with diabetic microalbuminuria were 0.841 (95% CI: 0.775-0.907), 0.783(95% CI: 0.710-0.856), and 0.805 (95% CI: 0.733-0.877), respectively. CONCLUSIONS: Urinary NGAL, clusterin, and cystatin C may be promising biomarkers for diagnosing DKD and diabetic microalbuminuria. It is possible that urinary NGAL and cystatin C increase before the onset of microalbuminuria in T2DM patients.

Exosomal microRNA-141 is upregulated in the serum of prostate cancer patients.

PURPOSE: Novel biomarkers for the diagnosis of prostate cancer (PCa) are urgently required. Increasing evidence suggests that exosomal microRNAs (miRNAs or miRs) in serum may be potential noninvasive biomarkers for certain diseases. The objective of the present study was to investigate and assess whether exosomal miR-141 is an effective biomarker for human PCa. METHODS: In the present study, exosomes were isolated from the serum of patients with PCa, patients with benign prostate hyperplasia (BPH), and healthy volunteers. The total RNA was extracted from the exosomes and the level of miR-141 was analyzed by quantitative reverse transcription-polymerase chain reaction. The expression levels of miR-141 were compared between the whole serum and the serum exosomes of the three groups. Subsequently, the relevance of the exosomal expression of miR-141 to the clinicopathological factors in PCa was investigated. RESULTS: The expression of miR-141 was higher in exosomes compared with whole serum (control group, P=0.0003; BPH group, P=0.0016; PCa group, P<0.0001). The level of serum exosomal miR-141 was significantly higher in the patients with PCa compared with the patients with BPH and the healthy controls (3.85-fold, P=0.0007 and 4.06-fold, P=0.0005, respectively). In addition, the expression levels were significantly higher in metastatic PCa compared with localized PCa (P<0.0001). Receiver-operating characteristic curve revealed that the serum exosomal miR-141 yielded an area under the curve of 0.8694, with 80% sensitivity and 87.1% specificity in discriminating patients with metastatic PCa from the patients with localized PCa. CONCLUSION: Serum exosomes may serve as a more suitable material compared with the whole serum for measuring circulating miR-141 levels in patients with PCa. Exosomal miR-141 is upregulated in the serum from patients with PCa compared with patients with BPH or the healthy volunteers, and it may be a useful potential biomarker for the diagnosis of metastatic PCa.

A C-terminal truncated mutation of licC attenuates the virulence of Streptococcus pneumoniae.

LicC has been identified as a virulence factor of Streptococcus pneumoniae. However, its role in virulence is still not fully understood because deletion of licC is lethal for the bacterium. In this study, a mutant with 78-bp truncation at the C-terminus of licC was obtained from a signature-tagged mutagenesis (STM) library. The mutant was viable with a large reduction in enzymatic activity as CTP:phosphocholine cytidylyltransferase detected in vitro using a firefly luciferase assay. The mutation attenuated the adhesion and invasion of S. pneumoniae ST556 (serotype 19F) to epithelial cells by 72% and 80%, respectively, and increased the phagocytosis by macrophages for 16.5%, compared to the parental strain. When the mutation was introduced into the encapsulated D39 strain (serotype 2), it led to attenuated virulence in mouse models either by intranasal colonization or by intraperitoneal infection. In addition, the phosphocholine (PCho) on cell surface was decreased, and the choline binding proteins (CBPs) were impaired, which may explain the attenuated virulence of the mutant. These observations indicate that C-terminus of licC is accounted for the main activity of LicC in PCho metabolism and is essential for the virulence of S. pneumoniae, which provides a novel target for drug design against pneumococcal infection.

Performance of urinary NGAL and L-FABP in predicting acute kidney injury and subsequent renal recovery: a cohort study based on major surgeries.

BACKGROUND: Acute kidney injury (AKI) is a frequent complication of major surgery. The current study evaluated the power of two biomarkers [urinary neutrophil gelatinase-associated lipocalin (NGAL) and liver-type fatty acid binding protein (L-FABP)] to detect the occurrence of AKI and to predict the recovery from renal dysfunction in a major surgery cohort. METHODS: In this prospective study, 199 patients undergoing major surgery were enrolled. Urinary samples collected from participants before surgery, and 0, 4, and 12 h and 1, 2, 7, and 14 days after surgery were tested for NGAL and L-FABP. RESULTS: Thirty-seven (18.6%) subjects developed AKI. Urinary NGAL and L-FABP were significantly increased from the time surgery was completed (p<0.05). The peak levels of NGAL and L-FABP occurred 12 and 4 h postoperatively (16.4- and 172.0-fold compared to baseline) in AKI group, respectively. The area under the receiver operating characteristic (ROC) curve (AUC) in NGAL (at 12 h), L-FABP (at 4 h), the most predictive model (NGAL at 12 h+L-FABP at 4 h), and the best combination at the same time point (12 h) was 0.83 [95% confidence interval (CI), 0.74-0.91], 0.85 (95% CI 0.77-0.93), 0.94 (95% CI 0.89-0.98), and 0.91 (95% CI 0.85-0.97), respectively. However, the largest AUC of single and combined biomarkers for predicting non-recovery after AKI only reached 0.70. CONCLUSIONS: Urinary NGAL and L-FABP can be used to detect AKI and combining NGAL and L-FABP may improve the diagnostic performance; however, NGAL and L-FABP may be poor predictors for renal recovery after AKI.

[Identification of LicC activity in pneumococcal infection].

AIM: To clone and express licC and its truncated form genes (25 amino acids from 3'-terminus were deleted and named deltaLicC) of Streptococcus pneumoniae, analyze the enzymatic activities of the proteins. METHODS: The recombinant plasmid pQE80-licC, pQE80-deltalicC were constructed, and the target proteins were expressed in E. coli BL21 under isopropy-beta-D-thiogalactoside (IPTG) induction. The proteins' activities were determined using bioluminescence test based on firefly luciferase assay system. RESULTS: The prokaryotic expression vector pQE80-licC, pQE80-deltalicC were successfully constructed and identified.The soluble proteins were obtained through inducing expression in E. coli BL21. It was showed that the activity of deltaLicC was markedly lower than that of LicC (P<0.05). CONCLUSION: The homemade bioluminescence assay method can miner the activity of LicC reliably and accurately. The important role of 25 amino acids from 3'-terminus for the activity of LicC was confirmed, and it was suggested that suppressing of LicC maybe was a useful method for treatment S.pneumococcal infection, especially drug resistant strain.