Víctor Blanco-Gozalo

Cardiotrophin-1 therapy prevents gentamicin-induced nephrotoxicity in rats

Aminoglycosides are very effective antibiotics for the treatment of severe infections, but they rank among the most frequent causes of drug-induced nephrotoxicity. Thus, prevention of aminoglycoside nephrotoxicity is an unmet therapeutic objective. Cardiotrophin-1 (CT-1), a member of the IL-6 family of cytokines, has been reported to protect the kidney against toxic and ischemic acute kidney injury (AKI). We have assessed the effect of rat CT-1 in the severity of gentamicin (G)-induced AKI. Groups of male Wistar rats received the following for 6 consecutive days: i) isotonic saline solution (group CONT), ii) G, 150mg/kg/day, i.p. (group G), iii) CT-1, 100μg/kg/day i.v. (group CT-1), or iv) G and CT-1 at the doses described above. The G group showed a manifest AKI characterized by low creatinine clearance, high plasma creatinine and urea levels, increased urinary excretion of proteins, glucose and AKI markers such as N-acetyl-glucosaminidase, neutrophil gelatinase-associated lipocalin, kidney-injury molecule-1 and T-gelsolin, increased kidney levels of CD-68, iNOS, IL-1β and TNF-α, and markedly higher histological renal damage and leukocyte infiltration than the CONT and CT-1 groups. Administration of CT-1 together with G reduced almost all of the above-described manifestations of G-induced AKI. The results of this study have potential clinical application, as CT-1 is near to being used as a drug for organ protection.

Urinary proteomics in renal pathophysiology: Impact of proteinuria

Urinary differential proteomics is used to study renal pathophysiological mechanisms, find novel markers of biological processes and renal diseases, and stratify patients according to proteomic profiles. The proteomic procedure determines the pathophysiological meaning and clinical relevance of results. Urine samples for differential proteomic studies are usually normalized by protein content, regardless of its pathophysiological characteristics. In the field of nephrology, this approach translates into the comparison of a different fraction of the total daily urine output between proteinuric and nonproteinuric samples. Accordingly, alterations in the level of specific proteins found by this method reflect the relative presence of individual proteins in the urine; but they do not necessarily show alterations in their daily excretion, which is a key parameter for the understanding of the pathophysiological meaning of urinary components. For renal pathophysiology studies and clinical biomarker identification or determination, an alternative proteomic concept providing complementary information is based on sample normalization by daily urine output, which directly informs on changes in the daily excretion of individual proteins. This is clinically important because daily excretion (rather than absolute or relative concentration) is the only self‐normalized way to evaluate the real meaning of urinary parameters, which is also independent of urine concentration.

Increased Klk9 Urinary Excretion Is Associated to Hypertension-Induced Cardiovascular Damage and Renal Alterations.

AbstractEarly detection of hypertensive end-organ damage and secondary diseases are key determinants of cardiovascular prognosis in patients suffering from arterial hypertension. Presently, there are no biomarkers for the detection of hypertensive target organ damage, most outstandingly including blood vessels, the heart, and the kidneys.We aimed to validate the usefulness of the urinary excretion of the serine protease kallikrein-related peptidase 9 (KLK9) as a biomarker of hypertension-induced target organ damage.Urinary, plasma, and renal tissue levels of KLK9 were measured by the Western blot in different rat models of hypertension, including angiotensin-II infusion, DOCA-salt, L-NAME administration, and spontaneous hypertension. Urinary levels were associated to cardiovascular and renal injury, assessed by histopathology. The origin of urinary KLK9 was investigated through in situ renal perfusion experiments.The urinary excretion of KLK9 is increased in different experimental models of hypertension in rats. The ACE inhibitor trandolapril significantly reduced arterial pressure and the urinary level of KLK9. Hypertension did not increase kidney, heart, liver, lung, or plasma KLK9 levels. Hypertension-induced increased urinary excretion of KLK9 results from specific alterations in its tubular reabsorption, even in the absence of overt nephropathy. KLK9 urinary excretion strongly correlates with cardiac hypertrophy and aortic wall thickening.KLK9 appears in the urine in the presence of hypertension as a result of subtle renal handling alterations. Urinary KLK9 might be potentially used as an indicator of hypertensive cardiac and vascular damage.

Hypertension and Hyperglycemia Synergize to Cause Incipient Renal Tubular Alterations Resulting in Increased NGAL Urinary Excretion in Rats

Background Hypertension and diabetes are the two leading causes of chronic kidney disease (CKD) eventually leading to end stage renal disease (ESRD) and the need of renal replacement therapy. Mortality among CKD and ESRD patients is high, mostly due to cardiovascular events. New early markers of risk are necessary to better anticipate the course of the disease, to detect the renal affection of additive risk factors, and to appropriately handle patients in a pre-emptive and personalized manner. Methods Renal function and NGAL urinary excretion was monitored in rats with spontaneous (SHR) or L-NAME induced hypertension rendered hyperglycemic (or not as controls). Results Combination of hypertension and hyperglycemia (but not each of these factors independently) causes an increased urinary excretion of neutrophil gelatinase-associated lipocalin (NGAL) in the rat, in the absence of signs of renal damage. Increased NGAL excretion is observed in diabetic animals with two independent models of hypertension. Elevated urinary NGAL results from a specific alteration in its tubular handling, rather than from an increase in its renal expression. In fact, when kidneys of hyperglycaemic-hypertensive rats are perfused in situ with Krebs-dextran solution containing exogenous NGAL, they excrete more NGAL in the urine than hypertensive rats. We also show that albuminuria is not capable of detecting the additive effect posed by the coexistence of these two risk factors. Conclusions Our results suggest that accumulation of hypertension and hyperglycemia induces an incipient and quite specific alteration in the tubular handling of NGAL resulting in its increased urinary excretion.

Cardiotrophin-1 attenuates experimental colitis in mice

Cardiotrophin-1 (CT-1) holds potent anti-inflammatory, cytoprotective, and anti-apoptotic effects in the liver, kidneys, and heart. In the present study, the role of endogenous CT-1 and the effect of exogenous CT-1 were evaluated in experimental ulcerative colitis. Colitis was induced in CT-1 knockout and wild-type (WT) mice by administration of dextran sulphate sodium (DSS) in the drinking water during 7 days. CT-1 knockout mice showed higher colon damage and disease severity than WT mice. In addition, CT-1 (200 µg/kg/day, iv) or vehicle (as control) was administered during 3 days to WT, colitic mice, starting on day 4 after initiation of DSS. Disease activity index (DAI), inflammatory markers (tumor necrosis factor α (TNF-α), INFγ, IL-17, IL-10, inducible nitric oxide synthase (iNOS)), colon damage, apoptosis (cleaved caspase 3), nuclear factor κB (NFκB) and STAT-3 activation, and bacterial translocation were measured. Compared with mice treated with DSS, mice also treated with exogenous CT-1 showed lower colon damage, DAI, plasma levels of TNFα, colon expression of TNF-α, INFγ, IL-17, iNOS and cleaved caspase 3, higher NFκB and signal transducer and activator of transcription 3 (STAT3) pathways activation, and absence of bacterial translocation. We conclude that endogenous CT-1 plays a role in the defense and repair response of the colon against ulcerative lesions through an anti-inflammatory and anti-apoptotic effect. Supplementation with exogenous CT-1 ameliorates disease symptoms, which opens a potentially new therapeutic strategy for ulcerative colitis.

Sub-nephrotoxic cisplatin sensitizes rats to acute renal failure and increases urinary excretion of fumarylacetoacetase.

Nephrotoxicity limits the therapeutic efficacy of the antineoplastic drug cisplatin. Due to dosage adjustment and appropriate monitoring, most therapeutic courses with cisplatin produce no or minimal kidney damage. However, we studied whether even sub-nephrotoxic dosage of cisplatin poses a potential risk for the kidneys by predisposing to acute kidney injury (AKI), specifically by lowering the toxicity threshold for a second nephrotoxin. With this purpose rats were treated with a single sub-nephrotoxic dosage of cisplatin (3mg/kg, i.p.) and after two days, with a sub-nephrotoxic regime of gentamicin (50mg/kg/day, during 6 days, i.p.). Control groups received only one of the drugs or the vehicle. Renal function and renal histology were monitored throughout the experiment. Cisplatin treatment did not cause any relevant functional or histological alterations in the kidneys. Rats treated with cisplatin and gentamicin, but not those under single treatments, developed an overt renal failure characterized by both renal dysfunction and massive tubular necrosis. In addition, the urinary excretion of fumarylacetoacetase was increased in cisplatin-treated animals at subtoxic doses, which might be exploited as a cisplatin-induced predisposition marker. In fact, the urinary level of fumarylacetoacetase prior to the second nephrotoxin correlated with the level of AKI triggered by gentamicin in predisposed animals.