AUTHOR=Bennington Julie , Lankford Shannon , Magalhaes Renata S. , Shankle Douglas , Fanning Jason , Kartini Cucu , Suparto Irma , Kusumawardhani Winda , Putra M. ArRaniri , Mariya Silmi , Badlani Gopal , Williams J. Koudy 

TITLE=Chemokine Therapy in Cats With Experimental Renal Fibrosis and in a Kidney Disease Pilot Study

JOURNAL=Frontiers in Veterinary Science

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2021.646087

DOI=10.3389/fvets.2021.646087

ISSN=2297-1769

ABSTRACT=<p><bold>Background:</bold> Chronic tubulointerstitial fibrosis is a common final pathway leading to end stage kidney disease in cats and has no effective treatment. The use of cell-based molecules to treat kidney fibrosis may be a promising approach. The objectives were to test the effects of intra-renal chemokine CXCL12 injection in a pre-clinical cat model of unilateral ischemia/reperfusion (I/R)-induced kidney fibrosis and then, within a clinical pilot study, test the safety/feasibility of CXCL12 injection in cats that might have early chronic kidney disease (CKD).</p><p><bold>Methods:</bold><italic>Pre-clinical</italic>: Thirty cats received intra-renal injection of 100, 200, or 400 ng of recombinant human CXCL12, or sterile saline, into the I/R kidney 70 days post-injury, or were non-injured, non-injected controls (<italic>n</italic> = 6/group). Kidney collagen content was quantified 4 months post-treatment using Masson's Trichrome and Picrosirius Red (PSR) stained tissues. In a separate study (<italic>n</italic> = 2) exploring short-term effects of CXCL12, 200 ng CXCL12 was injected into I/R kidneys and then harvested either 30 min (<italic>n</italic> = 1) or 1 month (<italic>n</italic> = 1) post-injection. Kidney concentrations of CXCL12, matrix metalloproteinase 1 (MMP-1), and lysyl oxidase-like enzyme 2 (LOXL-2) were quantified <italic>via</italic> ELISA. <italic>Clinical Pilot</italic>: 14 client-owned cats with potential early kidney disease received a single-treatment, bilateral intra-renal injection of 200 ng CXCL12 (<italic>n</italic> = 7), or received no injection (<italic>n</italic> = 7). Blood/urine samples were collected monthly for 9 months to assess renal function and CKD staging.</p><p><bold>Results:</bold><italic>Pre-clinical</italic>: I/R increased the affected kidney collagen content, which both mid and high doses of CXCL12 restored to normal (<italic>ps</italic> &lt; 0.05 vs. untreated). I/R increased collagen fiber width, which both mid and high doses of CXCL12 restored to normal (<italic>p</italic> &lt; 0.001 vs. untreated). Early changes in kidney MMP-1, associated with collagen breakdown, and subsequent decreases in LOXL-2, associated with collagen cross-linking, in response to CXCL12 treatment may contribute to these findings. <italic>Clinical Pilot</italic>: Bilateral intra-renal injection of CXCL12 using ultrasound guidance in cats with CKD was feasible and safe in a general practice clinical setting with no obvious side effects noted during the 9-month follow-up period.</p><p><bold>Conclusions:</bold> Intra-renal injection of CXCL12 may prove to be an effective treatment for kidney fibrosis in cats with CKD. Additional mechanistic and clinical evaluations are needed.</p>