Searching for Keys : Unlocking Mesenchymal Stem Cells Homing Potentials After Acute Anal Sphincter Injury
Massarat Zutshi*1,2, Levilester Salcedo1, Margot S. Damaser2, Marc Penn3
1Colorectal Surgery, Cleveland Clinic Foundation, Cleveland, OH; 2Biomedical Engineering, Cleveland Clinic Foundation, Cleveland, OH; 3Cell biology and Regenerative Medicine, Cleveland Clinic Foundation, Cleveland, OH
Background :MCP-3 and SDF-1 upregulation after anal sphincterotomy has been demonstrated in our preliminary study. MCP-3 was upregulated more than SDF-1. In order to progress towards studies to re-establish homing in order to direct stem cells at a time remote from the injury, it is important to study if other cytokines are responsible for homing. We hypothesize that specific chemokines are expressed at the time of anal sphincter injury, which can be homing factors for mesenchymal stem cells (MSC). We aim to identify the cytokines that are upregulated that could be stem cell homing factors in the anal sphincter after acute injury.Method: Fifteen rats were grouped into: control (no injury; C=3), 24 hrs sham, (S-24 n=3), 10 days sham (S-10d n=3), 24 hrs partial sphincter excision group (PSE-24 n=3) and 10 days partial sphincter excision (PSE-10d) group. Sham injury was done by pressing a cue tip on the anal sphincter. Partial anal sphincter excision was done by excising 25% of the anal sphincter. The anal sphincter was isolated 24 hours, and 10 days after injury. Chemokine expression was assessed by gene array analysis. A list of chemokines that were upregulated after anal sphincter injury compared to the non injury and sham injury group. Statistical analysis was performed.Results: 84 chemokines were investigated. Comparing, C vs. PSE-24 44% (37 of 84) genes were significantly upregulated (P<0.05) while comparison of S-24 vs. PSE-24 showed 19% significant upregulation (P<0.05). Ten days after injury, comparison of C vs. PSE-10d showed 5 % significant upregulation (5 of 84) while S-10 vs. PSE-24 showed 4.7% significant upregulation ( 4 of 84). The chemokines which had the highest fold expression over control 24 hours after injury were CCl3, CxCl6, Trem1 CCl4 and CCr1 and CCr2. (Graph)Conclusion: Certain cytokines apart from MCP-3 and SDF-1 are upregulated and are downregulated on the 10th day. These can be further pursued to isolate key homing cytokines. These cytokines are being investigated by an in-vitro migration assay to establish if they can induce homing of mesenchymal stem cells. This will facilitate a better understanding to be able to target cellular therapy in the future.
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