Our findings suggest that the combined use of apoptosis and necroptosis inhibitors can provide additional cytoprotection in AKI. Furthermore, this is the first study to demonstrate that Nec-1 inhibits tubular kidney cell death and restores cell viability via a nonapoptotic mechanism.

Necroptosis is a nonapoptotic cell death pathway. We aim to study the effect of necrostatin-1 (a specific necroptosis inhibitor) in cisplatin-induced injury. We analyzed the effect of the combined use of inhibitors of apoptosis (z-vad) and necroptosis (necrostatin-1) in acute kidney injury by cisplatin in human proximal tubule cells. Our results showed moderate effectiveness in cytoprotection after treatment with z-vad. But the concomitant use of inhibitors (z-vad and necrostatin-1) presented synergistic and additive protection. The present study analyzed the caspase-3 activity and we observed a significant decrease in the group treated with z-vad and cisplatin. However we did not observe changes in the group treated with both inhibitors (z-vad and necrostatin-1) and cisplatin. Thus, demonstrating that necroptosis is a caspase-independent mechanism. We also analyzed the effect of necrostatin-1 in vivo model. C57BL/6 mice were treated with cisplatin and/or inhibitors. The concomitant use of inhibitors (z-vad and necrostatin-1) recovered renal function and decreased levels of urinary Ngal. Additionally, we analyzed the expression of RIP-1, a specific marker for necroptosis. In animals treated with cisplatin and z-VAD levels of RIP-1 were higher. This result reinforces that necroptosis occurs only in conditions where apoptosis was blocked. However, the use of both inhibitors (z-vad and necrostatin-1) provided additional protection. In conclusion, our study has a significant potential to show in vitro and in vivo protection obtained by necrostatin-1. Therefore, our results suggest that necroptosis may be an important mechanism of cell death after kidney injury.

Prostate cancer is one of the most common types of cancer in men, and unfortunately many prostate tumours remain asymptomatic until they reach advanced stages. Diagnosis is typically performed through Prostate-Specific Antigen (PSA) quantification, Digital Rectal Examination (DRE) and Transrectal Ultrasonography (TU). The antigen (PSA) is secreted by all prostatic epithelial cells and not exclusively by cancerous ones, so its concentration also increases in the presence of other prostatic diseases. DRE and TU are not reliable for early detection, when histological analysis of prostate tissue obtained from a biopsy is necessary. In this context, fluorescence techniques are very important for the diagnosis of cancer. In this paper we explore the potential of using endogenous phorphyrin blood fluorescence as tumour marker for prostate cancer. Substances such as porphyrin derivatives accumulate substantially more in tumours than in normal tissues; thus, measuring blood porphyrin concentration by autofluorescence intensity may provide a good parameter for determining tumour stage. In this study, the autofluorescence of blood porphyrin was analyzed using fluorescence and excitation spectroscopy on healthy male NUDE mice and in those with prostate cancer induced by inoculation of DU145 cells. A significant contrast between the blood of normal and cancer subjects could be established. Blood porphyrin fluorophore showed an enhancement on the fluorescence band around 632 nm following tumour growth. Fluorescence detection has advantages over other light-based investigation methods: high sensitivity, high speed and safety. However it does carry the drawback of low specificity of detection. The extraction of blood porphyrin using acetone can solve this problem, since optical excitation of further molecular species can be excluded, and light scattering from blood samples is negligible.

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Acute renal failure (ARF) is a frequent complication of Gram-negative sepsis, with a high risk of mortality. Lipopolysaccharide (LPS)-induced ARF is associated with hemodynamic changes that are strongly influenced by the overproduction of nitric oxide (NO) through the cytokine-mediated up-regulation of inducible NO synthase. LPS-induced reductions in systemic vascular resistance paradoxically culminate in renal vasoconstriction. Collagen XVIII is an important component of the extracellular matrix expressed in basement membranes. Its degradation by matrix metalloproteases, cathepsins and elastases results in the formation of endostatin, claimed to have antiangiogenic activity and to be a prominent vasorelaxing agent. We evaluated the expression of endostatin/collagen XVIII in an endotoxemic ARF model. ARF was induced in C57BL/6 mice by intraperitoneal injection of LPS (10 mg/kg) followed by sacrifice 4 and 12 h later. Kidney tissue was the source of RNA and protein and the subject of histological analysis. As early as 4 h after LPS administration, blood urea, creatinine and NO levels were significantly increased compared to control. Endostatin/collagen XVIII mRNA levels were 0.71 times lower than sham-inoculated mice 4 h after LPS inoculation, returning to normal levels 12 h after LPS inoculation. Immunohistological examination revealed that acute injury caused by LPS leads to an increase of endostatin basement membrane staining in association with the decrease of CD31 endothelial basement membrane staining. These results indicate that in the early phase of endotoxemic ARF the endostatin levels were not regulated by gene expression, but by the metabolism of collagen XVIII