Amanda Lima Deluque, Lucas Ferreira de Almeida, Beatriz Magalhães Oliveira, Cláudia Silva Souza, Ana Lívia Dias Maciel, Heloísa Della Coletta Francescato, Cleonice Giovanini, Roberto Silva Costa, Terezila Machado Coimbra
J Pathol Transl Med. 2024;58(5):219-228. Published online August 27, 2024
Background Activation of the mitogen-activated protein kinase (MAPK) pathway induces uncontrolled cell proliferation in response to inflammatory stimuli. Adriamycin (ADR)-induced nephropathy (ADRN) in rats triggers MAPK activation and pro-inflammatory mechanisms by increasing cytokine secretion, similar to chronic kidney disease (CKD). Activation of the vitamin D receptor (VDR) plays a crucial role in suppressing the expression of inflammatory markers in the kidney and may contribute to reducing cellular proliferation. This study evaluated the effect of pre-treatment with paricalcitol on ADRN in renal inflammation mechanisms.
Methods Male Sprague-Dawley rats were implanted with an osmotic minipump containing activated vitamin D (paricalcitol, Zemplar, 6 ng/day) or vehicle (NaCl 0.9%). Two days after implantation, ADR (Fauldoxo, 3.5 mg/kg) or vehicle (NaCl 0.9%) was injected. The rats were divided into four experimental groups: control, n = 6; paricalcitol, n = 6; ADR, n = 7 and, ADR + paricalcitol, n = 7.
Results VDR activation was demonstrated by increased CYP24A1 in renal tissue. Paricalcitol prevented macrophage infiltration in the glomeruli, cortex, and outer medulla, prevented secretion of tumor necrosis factor-α, and interleukin-1β, increased arginase I and decreased arginase II tissue expressions, effects associated with attenuation of MAPK pathways, increased zonula occludens-1, and reduced cell proliferation associated with proliferating cell nuclear antigen expression. Paricalcitol treatment decreased the stromal cell-derived factor 1α/chemokine C-X-C receptor type 4/β-catenin pathway.
Conclusions Paricalcitol plays a renoprotective role by modulating renal inflammation and cell proliferation. These results highlight potential targets for treating CKD.
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Perirenal fat differs in patients with chronic kidney disease receiving different vitamin D-based treatments: a preliminary study Ana Checa-Ros, Antonella Locascio, Owahabanun-Joshua Okojie, Pablo Abellán-Galiana, Luis D’Marco BMC Nephrology.2025;[Epub] CrossRef
Alveolar macrophages participate in the host defense against P. carinii, but the mechanisms in degradation and clearance of the organism from lung has not been well established. We observed the transmission and scanning electron microscopic features and evaluated the expression of TNF-alpha and Surfactant-D in the interaction of P.
carinii with alveolar macrophages. Expression of TNF-alpha and Surfactant-D in the experimentally induced P. carinii pneumonia in rat was examined by immunohistochemistry and immunoelectron microscopy. Electron microscopically, the alveolar macrophages phagocytized trophozoites and cysts of P. carinii micro-organisms.
Immunohistochemically TNF-alpha was strongly expressed in the cytoplasms of alveolar macrophages. Postembedding immunogold labeling for Surfactant-D protein was expressed on the pellicles of trophozoites and cysts, P.
carinii micro-organisms in the cytoplasms of macrophages, free floating surfactant materials and multilamellar bodies of type II epithelial cells. We conclude that alveolar macrophages interacted with P. carinii micro-organisms respond with increased expression of TNF-alpha. TNF-alpha may bind to P.
carinii and exert a direct toxic effect upon the micro-organisms. Surfactant-D protein may augment binding of P. carinii to the alveolar macrophages and enhance the clearance of the micro-organisms.