Expression of the anti-inflammatory suppressor of cytokine signaling 3 (SOCS3) in human clear cell renal cell carcinoma.

The oncogenic transcription factor signal transducer and activator of transcription 3 (STAT3) is a cytokine-activated transcription factor controlling inflammation, cell proliferation, survival, and differentiation in normal tissue as well as in tumor growth. One of its most important negative regulators is the suppressor of cytokine signaling 3 (SOCS3). Here, we analyzed SOCS3 and other tumor-associated local immune regulators in human clear cell renal cell carcinoma (ccRCC). Analyses were performed in tumor and adjacent tumor-free healthy renal tissue from 35 patients with ccRCC. For functional analysis, ccRCC Caki-1 cell lines were stimulated with IL-6 and IFNγ in cell culture assays. We observed significantly lower SOCS3 messenger RNA (mRNA) levels in tumor tissue compared to healthy tissue. SOCS3 mRNA strongly correlated within tumor and healthy tissue. Interestingly vice versa, SOCS3 protein levels were significantly higher in tumor tissue than in healthy tissue. IL-22 and IL-22R1 mRNA displayed no differences in tumor and healthy tissue. Stimulation of Caki-1 cells with IFNγ resulted in markedly increased SOCS3 mRNA levels. We conclude that SOCS3 along with STAT3 participates in regulatory mechanisms in ccRCC, which certainly features only one of multiple factors involved but nevertheless merits further attention.

Serum and urinary NGAL but not KIM-1 raises in human postrenal AKI.

BACKGROUND: We examined the value of the novel acute kidney injury (AKI) markers neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in acute postrenal impairment. These biomarkers have been evaluated in prerenal and intrarenal AKI so far, but not in human acute postrenal kidney injury. With regard to multimorbid and critically ill patients the discrimination of different AKI origins often remains a challenge. As the trend goes towards a diagnostic panel of AKI markers, we hereby aim to contribute to evaluate further options of discrimination in an observational case-control study. MATERIALS AND METHODS: Blood and urine samples were obtained from 53 patients with acute obstructive nephropathy secondary to ureteral calculi and 52 age-matched healthy controls. Serum NGAL (sNGAL), urinary NGAL (uNGAL) and urinary KIM-1 (uKIM-1) levels were determined using a commercially available ELISA kit, creatinine applying the Jaffé's method. RESULTS: While urinary levels of KIM-1 were not significantly different between patients with obstructive nephropathy and controls, a striking increase in sNGAL (P < 0·001) and uNGAL (P < 0·01) levels was detected in the obstructive nephropathy group. Within the obstructive nephropathy group, sNGAL (P = 0·01) and uNGAL (P = 0·049) but not uKIM-1 correlated positively with the white blood cell count and uNGAL correlated positively (P = 0·002) with the extent of leucocyturia. CONCLUSIONS: High levels of sNGAL and uNGAL observed in stone-induced acute obstructive nephropathy may represent a valuable marker of postrenal AKI. Low uKIM-1 levels may help to discriminate postrenal AKI events using a panel of markers in this setting.

Current developments in early diagnosis of acute kidney injury.

Acute kidney injury (AKI) is a very frequent and serious clinical problem, accounting for overall high morbidity and mortality. Up to date, mortality due to AKI is virtually unchanged over the past 50 years. This may partly be explained due to a delay in initiating renal protective and appropriate therapeutic measures since until now there are no reliable early-detecting biomarkers. The gold standard, serum creatinine, displays poor specificity and sensitivity with regard to identification of the incipient phase of AKI, and this is also true for cystatin C. We aimed to review novel biomarkers of AKI in urine and serum which have now progressed to the clinical phase. The main focus refers to their diagnostic and prognostic value. For this purpose, a web-based literature search using PubMed was performed comprising the following terms: renal failure, acute kidney injury and biomarkers. New molecules such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), N-acetyl-ß-D-glucosaminidase (NAG), monocyte chemotactic peptide (MCP-1), Il-18, liver-type fatty acid-binding protein (L-FABP) and Netrin-1 are available and represent promising new markers that, however, need to be further evaluated in the clinical setting for suitability. In clinical settings with incipient AKI, not only the development and the implementation of more sensitive, practicable and accurate biomarkers are required for well-timed treatment initiation. Just as important is a substantial improvement of refined and applicable prophylactic therapeutic options in these situations. Before full adoption in clinical practice can be accomplished, adequately powered clinical trials testing a row of biomarkers are strongly warranted.