Etanercept blocks inflammatory responses orchestrated by TNF-α to promote transplanted cell engraftment and proliferation in rat liver.
Engraftment of transplanted cells is critical for liver-directed cell therapy, but most transplanted cells are rapidly cleared from liver sinusoids by proinflammatory cytokines/chemokines/receptors after activation of neutrophils or Kupffer cells (KCs). To define whether tumor necrosis factor alpha (TNF-α) served roles in cell-transplantation-induced hepatic inflammation, we used the TNF-α antagonist, etanercept (ETN), for studies in syngeneic rat hepatocyte transplantation systems. After cell transplantation, multiple cytokines/chemokines/receptors were overexpressed, whereas ETN before cell transplantation essentially normalized these responses. Moreover, ETN down-regulated cell-transplantation-induced intrahepatic release of secretory cytokines, such as high-mobility group box 1. These effects of ETN decreased cell-transplantation-induced activation of neutrophils, but not of KCs. Transplanted cell engraftment improved by several-fold in ETN-treated animals. These gains in cell engraftment were repeatedly realized after pretreatment of animals with ETN before multiple cell transplantation sessions. Transplanted cell numbers did not change over time, indicating absence of cell proliferation after ETN alone. By contrast, in animals preconditioned with retrorsine and partial hepatectomy, cell transplantation after ETN pretreatment significantly accelerated liver repopulation, compared to control rats.


CONCLUSIONS
TNF-α plays a major role in orchestrating cell-transplantation-induced inflammation through regulation of multiple cytokines/chemokines/receptor expression. Because TNF-α antagonism by ETN decreased transplanted cell clearance, improved cell engraftment, and accelerated liver repopulation, this pharmacological approach to control hepatic inflammation will help optimize clinical strategies for liver cell therapy.
Division of Pediatric Gastroenterology, Department of Pediatrics, Children's Hospital at Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY.
Preeti
P
Viswanathan
Sorabh
S
Kapoor
Vinay
V
Kumaran
Brigid
B
Joseph
Sanjeev
S
Gupta
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology / Q000627:therapeutic use; D049109:Cell Proliferation / Q000187:drug effects / Q000502:physiology*; D017690:Cell Transplantation; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D000068800:Etanercept; D022781:Hepatocytes / Q000637:transplantation*; D007074:Immunoglobulin G / Q000494:pharmacology / Q000627:therapeutic use*; D007249:Inflammation / Q000503:physiopathology / Q000517:prevention & control*; D007728:Kupffer Cells / Q000187:drug effects; D008099:Liver / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D023421:Models, Animal; D009504:Neutrophils / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000187:drug effects / Q000502:physiology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016207:Cytokines; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D000068800:Etanercept