Liver Regeneration and Intracellular Stress After Open and Laparoscopic Left Partial Hepatectomy in a Porcine Model

C.S. Mammas, MD PhD, G. Mammas, Associate Professor, Nikolaos Arkadopoulos, Assistant Professor, A. Pafiti, Associate Professor, N. Kavantzas, Assistant Professor, Chr. Nikolaou, Associate Professor, I. Dontas, Associate Professor, C. Tiniakou, Ass. Aretaieion University Hospital of Athens, Surgical Experimental Unit ‘K.TOYNTAS’, ‘University Department of Paediatrics of Saint Sofia’s Hospital’, National and Kapodistrian University of Athens

Objectives: The project compares the intracellular stress and the liver regeneration response after Open Left Partial Hepatectomy (OLPH) and Laparoscopic Left Partial Hepatectomy (LLPH), in a porcine model.
Materials and Methods: Two pairs of double-series of twenty-nine liver tissues taken from twenty nine porcine livers, after OLPH and LLPH and on the 7th postoperative day(PD7), were randomly allocated into two groups: the OLPH group (n1=19×2) and the LLPH group(n2=10×2).The liver tissue sections in each group, had been prepared and stained with PCNA and Ubiquitin. Both a PCNA based proliferative index(LCPI) and an Ubiquitin based cellular stress index(LCCSI), were estimated by microscopical visualization. LCCSI’s and LCPI’s were compared at a time: a) between, after operation(PD0) and on PD7 in each group and b) between the groups on the time after operation and on PD7.
Results: By using rank-order statistical methods for small samples, statistical comparisons of the LCCSIs between PD0 and PD7, in each group, showed no statistically significant difference in the LLPH group(α=.05), while in the OLPH group there was a statistically significant difference favouring the time after operation(p=.019). Statistical comparisons of the LCCSIs between the two groups after operation and on the PD7 respectively, resulted in a statistically significant difference, favoring the OLPH group after operation(p<.1), while there was no statistically significant difference between the two groups, on the PD7(α=.05). Statistical comparisons of the LCPIs, between PD0 and PD7 in each group, showed no statistically significant difference in the OLPH group(α=5%), while in the LLPHgroup there was a statistically significant difference favouring the time after operation(p=.011). Regarding statistical comparisons between the two groups after operation, there was no statistically significant difference(α=5%), while on the PD7, there was a statistically significant difference, favouring the OLPH group(p=.002).
Conclusions: In a porcine model, a more increased intracellular stress such as that after OLPH, in comparison with that of LLPH,  may result in a more increased liver regeneration response