Michele Mongillo

Kidney injury molecule-1 expression in rat proximal tubule after treatment with segment-specific nephrotoxicants: a tool for early screening of potential kidney toxicity.

Dose-response expression of kidney injury molecule-1 (KIM-1) gene in kidney cortex and its correlation with morphology and traditional biomarkers of nephrotoxicity (plasma creatinine and blood urea nitrogen, BUN) or segment-specific marker of proximal tubule injury (kidney glutamine synthetase, GSK) were studied in male rats treated with proximal tubule segment-specific nephrotoxicants. These included hexachloro-1:3-butadiene (HCBD, S3 segment-specific), potassium dichromate (chromate, S1-S2 segment-specific), and cephaloridine (Cph, S2 segment-specific). Rats were treated with a single intraperitoneal (ip) injection of HCBD 25, 50, and 100 mg/kg, subcutaneous (sc) injection of chromate 8, 12.5, and 25 mg/kg; or ip injection of Cph 250, 500, and 1,000 mg/kg. KIM-1 gene showed a dose-dependent up-regulation induced by all segment-specific nephrotoxicants. Interestingly, magnitude of the up-regulation reflected the severity of microscopic tubular changes (degeneration, necrosis, and regeneration). Even low-severity microscopic observations were evidenced by significant gene expression changes. Furthermore, KIM-1 showed significant up-regulation even in the absence of morphological changes. In contrast, traditional and specific markers demonstrated low sensitivity or specificity. In conclusion, this study suggested KIM-1 as a sensitive molecular marker of different levels of tubular injury, and it is likely to represent a potential tool for early screening of nephrotoxicants.

Regucalcin down-regulation in rat kidney tissue after treatment with nephrotoxicants☆

Gene expression of regucalcin (Rgn), a calcium-binding protein, was investigated in kidney of male Wistar rats treated with proximal tubule segment-specific nephrotoxicants, namely hexachloro-1:3-butadiene (HCBD), specific for S(3) segment (pars recta) and potassium dichromate (chromate) specific for S(1)-S(2) segments (pars convoluta), according to age of animals and dose of chemicals. In the age-dependent study, male Wistar rats were treated with a single injection of HCBD (100mg/kg b.w. i.p.) or chromate (25 mg/kg b.w. s.c.) at 5 weeks or 12 weeks of age; in dose-response study, rats were treated with a single injection of three doses of HCBD (25, 50, and 100 mg/kg b.w. i.p.) or chromate (8, 12.5, and 25mg/kg b.w. s.c.) at 8 weeks of age. Forty-eight hours after treatment, Rgn and glutamine synthetase (GS) activity in kidney cortex, blood urea nitrogen (BUN) and plasma creatinine were measured; light microscopy was performed also. The results show that young rats are less susceptible to chromate (severe necrosis is evident only in adult rats), whereas age does not influence HCBD nephrotoxicity. Rgn is down regulated by HCBD at both age points, but not by chromate at 5 weeks of age. In addition, HCBD causes down-regulation of Rgn from the low dose in 8-week-old rats, whereas chromate causes the same effect at the high dose only. GS activity in kidney cortex shows a similar behavior, even if sensitive to low doses of chromate also, whereas BUN and creatinine increase after the high dose of both chemicals only. Accordingly, light microscopy shows a segment-specific, dose-dependent increase of severity of damage caused by the chemicals. Rgn gene expression appears a sensitive genomic marker to evaluate the renal impairment caused by chemicals and its down-regulation seems to be related to damage, early or already established, to S(3) segment of the proximal tubule.

Hepatitis B vaccination at three months of age: A successful strategy?

Vaccination of infants, children and adolescents against the hepatitis B virus (HBV) is mandatory in Italy. It is crucial to assess whether vaccinated subjects have protective antibody level during adulthood when the risk of HBV infection increases due to lifestyle or occupational exposure. Two groups of students attending to University of Padova Medical School were enrolled between 2004 and 2011 and HBV antibodies and antigens were measured. The first group (Group A) comprised students vaccinated at three months of age and the second group (Group B) comprised students vaccinated after the first year of life. The follow-up was 18.0 (Group A) and 17.9 (Group B) years. The students vaccinated at three months of age had a higher rate of non-protective antibodies (47.2%) comparing to those vaccinated after the first year of life (17.0%, P<0.0001) with a significantly lower antibody level (P<0.001). The rate of non-protective antibodies was inversely related to vaccination age. The results clearly show that children vaccinated after the first year of life are better protected against HBV. On the other hand, both groups show a good immunological memory as evidenced by the achievement of protective antibody level after the booster dose in 97.8% of subjects.

Prevalence of Markers for Hepatitis B Virus and Vaccination Compliance Among Medical School Students in Italy

The prevalence of markers for hepatitis B virus (HBV) and the rate of compliance with HBV vaccination laws were investigated in a study at Padua University Medical School (Italy). Of 2,361 students, 385 (16.3%) tested negative for antibody to hepatitis B surface antigen. When vaccination was actively offered to these students, there was a low rate of compliance (47.0% [181 students]) but a good rate of seroconversion (93.1% [95 of 102 students]). Screening for HBV markers appears to be crucial to efforts to increase rates of vaccination coverage.

Hyaline droplet accumulation in kidney of rats treated with hexachloro-1:3-butadiene: influence of age, dose and time-course †

The present research investigates the occurrence of hyaline droplet (HD) accumulation related to age, dose and time after treatment in male Wistar rats given a single i.p. injection of hexachloro‐1:3‐butadiene (HCBD). In the study on age, rats from 1 to 12 months of age were treated with 100 mg kg−1 body weight (b.w.) HCBD dose. Rats treated at 2 months of age showed a greater accumulation of HD than the other age groups; HD accumulation was not observed in 1‐month‐old rats. In the dose–response study, the treatment with 25, 50 and 100 mg kg−1 b.w. at 2 months of age caused HD accumulation in the proximal convoluted tubule at all doses, with the 100 mg kg−1 b.w. group slightly more affected. Finally, in the time‐course study, rats treated with a 100 mg kg−1 b.w. dose at 2 months of age and sacrificed at 6, 12, 24, 48, 72 and 96 h post‐dosing showed a time‐related HD accumulation in terms of incidence and severity, after 6 h, with a peak at 24 and 48 h and decreasing at 72 and 96 h. The present results show that HD accumulation is an early finding, and is unrelated to dose level and particularly evident in rats of 2 month of age. These findings in male rats treated with HCBD emphasize the importance of considering the age of rats at the start of a study. The more sensitive model was used in the detection of nephrotoxic effects of chemicals. Copyright

Testosterone and Estradiol Affect Renal Oxidative Metabolism and Glutathione Pathway of Wistar Rats

The impact of sexual hormones on kidney metabolism may be relevant to modulate the effect of nephrotoxic substances. In the present research the effects of castration, testosterone, and estradiol on renal oxidative metabolism [cytochrome P-450 (CYP)], glutathione pathway [glutathione content (GSH), glutathione S-transferases (GST) activities, and cysteine-conjugate s-lyase [as glutamine transaminase K (GTK) activity] have been studied. Naive male rats have a significantly lower GSH content but show a significantly higher GST activities and CYP content than females, whereas no sex difference was for GTK activity. Castration significantly reduces GSH content and GTK activity in females and CYP content in males, partially but significantly restored by testosterone. Testosterone significantly increases GSH content and GTK activity in males and GTK activity and CYP content in females. Estradiol increases GSH content in males, whereas decreases GST activities in females and CYP content in both sexes. Castration followed by testosterone treatment increases GTK activity in both sexes whereas increases CYP content and reduces GSH content in females. Castration followed by estradiol treatment increases GSH content and reduces GST activities in males and CYP content in both sexes. In conclusion, the results suggest that sex hormones influence metabolic pathways of the kidney and that they are probably responsible of the sex- related differences of chemical-induced nephrotoxicity. An univocal model to define sex-related toxicity of xenobiotic substances is far to be identified.

Strategy for hepatitis A seroprevalence survey in a population of young people.

In the present research a novel operative strategy of health surveillance with a reduced number of serologic tests is proposed. The approach consists to identify sub-populations with high predictable serological profile that makes the serological tests unnecessary. The study is focused on assays done to detect the response against hepatitis A, which in Italy displays low/intermediate endemicity. Receiver operating characteristics analysis performed on data from documented and self-reported vaccination information of a cohort of students from Padua University Medical School confirmed that anti-hepatitis A antibodies measurement might be avoided in subjects younger than 30 years with negative documented or self-reported history of vaccination or subjected to current vaccination schedule.