Nucleolar organizer region proteins enhancement in nucleoplasm's of renal tubular cells is an indication of kidney impairment in Leishmania-infected dogs.

Hyperactivation of tubular cells contributes for the progression of kidney lesions. The exacerbated expression of immunological proteins and ribosomal DNA (rDNA) transcriptional activity are observed in tubular cells. This intensified expression results in more prominent hypertrophic changes and is often accompanied by increased expression of factors involved in different phases of ribosomal biosynthesis, such as the nucleolar organizer regions (NOR). The aim of this study was to evaluate whether there is an association between NOR proteins, renal impairment, and clinical status in Leishmania-infected dogs (CanL). Forty-five dogs with CanL and six uninfected controls were assessed in this study. PCR was performed to detect parasites' nucleic acids in kidney. Histopathological analyses were performed in kidney fragments, and NOR was detected by Ag stain (AgNOR). Leishmania-infected dogs showed more intense inflammation and collagen deposition compared with uninfected controls. Biochemical alterations were observed only in Leishmania-infected dogs. AgNORs per cell were significantly higher in clinically affected dogs and higher histopathological lesion score was observed in Leishmania-infected dogs. Positive correlations between number of NORs per cell in medullary region and histopathological lesion score were observed. Furthermore, AgNOR expression, intensity of renal lesions, and clinical sigs was associated in Leishmania-infected dogs. We propose that the detection of AgNOR proteins could be used to better estimate the kidney tubular damage at the time of examination in Leishmania-infected dogs as a marker to estimate renal impairment in dogs with CanL.

The balance between IL-12/IL4 in renal tissue switches the inflammatory response arm and shows relationship with the clinical signs in Leishmania-infected dogs.

The pathogenesis of Canine leishmaniosis (CanL) is associated with altered cytokine expression and parasitic tissue shows a lot of inflammation. The aim of this study was to assess the renal inflammation and cytokine expression in eight symptomatic and eight asymptomatic Leishmania- infected dogs, and seven uninfected control dogs. Kidney fragments were stained with hematoxylin and eosin for morphometric evaluation. mRNA expression levels of interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-2, IL-4, IL-10, and IL-12 were assessed in the kidney fragments using quantitative real time-polymerase chain reaction. Inflammation, quantified by the average area of the infiltrated immune cells, was greater in symptomatic dogs than in those asymptomatic, whereas asymptomatic dogs exhibited higher inflammation than the control dogs (p > 0.05, Tukey's test). Expression levels of IFN-γ, TNF-α, IL-4, IL-10, and IL-12 were upregulated in symptomatic dogs and downregulated in asymptomatic dogs compared with those of the uninfected group. Furthermore, IL-4 showed higher expression in symptomatic dogs than in asymptomatic ones (p < 0.05, Mann-Whitney test), which was directly associated with clinical manifestations (p < 0.05, Chi-square test). However, IL-12 was predominantly expressed in symptomatic dogs, shifting the balance from IL-12/IL-4 to IL-12, which elicits a change in the inflammatory response. Leishmania was not found in the renal tissues in any one of the studied groups. Our data suggests that the balance between IL-12 and IL-4 plays an important role in the regulation of inflammation in renal tissue and clinical presentations in CanL.