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. 2018 May;6(10):e13707.
doi: 10.14814/phy2.13707.

Persistent expression of neutrophil gelatinase-associated lipocalin and M2 macrophage markers and chronic fibrosis after acute kidney injury

Hisako Saito  1 , Tetsuhiro Tanaka  1 , Shinji Tanaka  1 , Yoshiki Higashijima  1 , Junna Yamaguchi  1 , Mai Sugahara  1 , Marie Ito  1 , Lisa Uchida  1 , Sho Hasegawa  1 , Takeshi Wakashima  1 , Kenji Fukui  1 , Masaomi Nangaku  1
Affiliations

Persistent expression of neutrophil gelatinase-associated lipocalin and M2 macrophage markers and chronic fibrosis after acute kidney injury

Hisako Saito et al. Physiol Rep. 2018 May.

Abstract

Recent epidemiologic studies revealed a correlation between acute kidney injury (AKI) episodes and the progression to chronic kidney disease (CKD). Although the severity and duration of the initial insult likely predict the development of CKD, information regarding tissue markers predictive of early development of renal fibrosis is limited. We investigated key markers in fibrotic kidney in rats and mice. Seven- to eight-week-old male Sprague-Dawley rats underwent bilateral ischemia-reperfusion injury (IRI). Kidney tissues were collected to determine the markers correlated with the severity of kidney fibrosis. In a separate set, a specific chemokine (C-C motif) receptor 2 (CCR2) inhibitor, RS-102895, was administered to 9-week-old male C57BL/6J mice that underwent unilateral IRI (9.2 mg/kg/day in drinking water for 17 days) to investigate whether blockade of the monocyte chemotactic protein-1 (MCP-1) signaling was sufficient to prevent fibrosis. Among candidate tissue markers, neutrophil gelatinase-associated lipocalin (NGAL) and MCP-1 mRNA expressions were correlated with kidney fibrosis. Studies on macrophage polarity showed that mRNA expression of M2, but not M1 macrophage markers, were correlated with acute-phase serum creatinine and fibrosis. Pharmacological blockade of the MCP-1-CCR2 signaling downregulated CCR2, which was insufficient to improve fibrosis in mouse unilateral IRI model, suggesting that additional, redundant pathways contribute to fibrosis. These findings suggested that tissue NGAL expression and M2 macrophage markers are promising markers that show severity of kidney fibrosis. Mechanistic involvement of these markers in CKD pathogenesis warrant additional investigation.

Keywords: AKI biomarker; fibrosis; ischemia-reperfusion injury; macrophage polarity.

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Figures

Figure 1
Figure 1
Bilateral IRI (bIRI) was an appropriate model as AKI to CKD transition. (A) Level of serum creatinine (sCr) increased 1.55 ± 0.22 mg/dL 48 h after bilateral IRI (acute phase) compared with the sham group (*P < 0.05), then decreased 0.37 ± 0.07 mg/dL at day 28 (bIRI, n = 34; sham, n = 2; mean ± SD). (B) Masson trichrome staining of the kidney. bIRI‐induced tubulointerstitial fibrosis compared with the sham group both in the cortex and medulla (*P < 0.05). Tubulointerstitial fibrosis was severe in accordance with acute‐phase sCr (×40, scale bar = 500 μm) (bIRI, n = 34; sham, n = 2; mean ± SEM). (C) Relationship between acute‐phase sCr and tubulointerstitial fibrosis. A correlation was found between acute‐phase sCr level and the extent of tubulointerstitial fibrosis both in the cortex and medulla (bIRI, n = 34; sham, n = 2).
Figure 2
Figure 2
Relationship between mRNA expression of AKI biomarkers and renal fibrosis and acute‐phase serum creatinine (sCr). KIM‐1, L‐FABP, NGAL, MCP‐1, and its receptor CCR2 mRNA were measured. The relative expression levels of NGAL and MCP‐1 mRNA were higher than those of KIM‐1 and L‐FABP at 28 days. KIM‐1 (A) and L‐FABP (B) mRNA expressions were not consistently correlated with all these parameters, but NGAL (C), MCP‐1 (D), and its receptor CCR2 (E) were positively correlated with these parameters, except for the marginal trend between mRNA expression of CCR2 and kidney fibrosis in the cortex (n = 34).
Figure 3
Figure 3
Macrophage infiltration into kidney after IRI was correlated with renal fibrosis and acute‐phase serum creatinine. (A) Immunohistochemistry of macrophage (ED‐1). The number of macrophages increased in proportion to acute‐phase serum creatinine (sCr) level (×400, scale bar = 50 μm). (B) Correlation between the number of macrophages (ED‐1‐positive cells) and renal fibrosis. A positive correlation was found between the number of macrophages and renal fibrosis (bIRI; n = 34). (C) Correlation between the number of macrophages (ED‐1‐positive cells) and acute‐phase sCr. A correlation was found between the number of macrophages and acute‐phase sCr (bIRI; n = 34).
Figure 4
Figure 4
Relationship between M1 and M2 macrophage mRNA expressions and renal fibrosis and acute‐phase serum creatinine (sCr). M1 and M2 macrophage marker mRNA expressions were measured. M1 macrophage mRNA expressions were not correlated with these parameters (A), whereas M2 macrophage mRNA expressions were correlated with these parameters (B) (bIRI; n = 34).
Figure 5
Figure 5
Number of M2 macrophage marker, CD206, is correlated with renal fibrosis and acute‐phase serum creatinine. (A) Immunohistochemistry of M2 macrophage marker, CD206, shows that the macrophage infiltration into the kidney was severe in proportion to acute‐phase serum creatinine (sCr) level (×400, scale bar = 50 μm). (B) A correlation was found between the number of CD206 and renal fibrosis (bIRI; n = 34). (C) A correlation was found between the number of CD206 and acute‐phase sCr (bIRI; n = 34).
Figure 6
Figure 6
RS‐102895 reduced mRNA expression of CCR2 and M1 macrophage markers, but not M2 macrophage markers in ischemic left kidney. (A) mRNA expression of ischemic kidney. MCP‐1, CCR2, IL‐6, TNF‐α, iNOS, CD86, arginase 1, and CD206 mRNA expressions were measured. RS‐102895 reduced mRNA expression of CCR2, M1 macrophage markers, TNF‐α, iNOS, but not M2 macrophage markers, arginase 1, and CD206 (vehicle, RS‐102895; n = 6). (B) mRNA expression of the non‐ischemic right kidney. MCP‐1, CCR2, IL‐6, TNF‐α, iNOS, CD86, arginase 1, and CD206 mRNA expressions were measured in the contralateral non‐clamped right kidney. The expression of these markers was not different between the RS‐102895 and vehicle groups (vehicle, RS‐102895; n = 6).
Figure 7
Figure 7
RS‐102895 does not improve renal fibrosis and macrophage infiltration in the unilateral IRI mice model. (A) Immunohistochemistry of F4/80. Macrophage infiltration by immunohistochemistry of F4/80 (arrows) did not reduce by RS‐102895 compared with the vehicle group (×400, scale bar = 50 μm). (B) Immunohistochemistry of CD206. M2 macrophage infiltration did not reduce by RS‐102895 compared with the vehicle group (×400, scale bar = 50 μm). (C) Masson trichrome staining. RS‐102895 did not improve renal fibrosis (×200, scale bar = 100 μm, vehicle, RS‐102895; n = 6).
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References

    1. Alge, J. L. , and Arthur J. M.. 2015. Biomarkers of AKI: a review of mechanistic relevance and potential therapeutic implications. Clin. J. Am. Soc. Nephrol. 10:147–155. - PMC - PubMed
    1. Basile, D. P. , Bonventre J. V., Mehta R., Nangaku M., Unwin R., Rosner M. H., et al. 2016. Progression after AKI: understanding maladaptive repair processes to predict and identify therapeutic treatments. J. Am. Soc. Nephrol. 27:687–697. - PMC - PubMed
    1. Bonventre, J. V. , and Zuk A.. 2004. Ischemic acute renal failure: an inflammatory disease? Kidney Int. 66:480–485. - PubMed
    1. Chawla, L. S. , and Kimmel P. L.. 2012. Acute kidney injury and chronic kidney disease: an integrated clinical syndrome. Kidney Int. 82:516–524. - PubMed
    1. Chawla, L. S. , Amdur R. L., Amodeo S., Kimmel P. L., and Palant C. E.. 2011. The severity of acute kidney injury predicts progression to chronic kidney disease. Kidney Int. 79:1361–1369. - PMC - PubMed

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