Articles

Re: Hervé Baumert, Mehrak Hekmati, Irene Dunia, et al. Laparoscopy in Ureteral Engineering: a Feasibility Study. Eur Urol 2008;54:1154–63

By: Tomasz Drewaa lowast and Piotr Chlostab

Published online: 01 March 2009

Abstract Full Text Full Text PDF (69 KB)

Refers to article:

Laparoscopy in Ureteral Engineering: A Feasibility Study

Hervé Baumert, Mehrak Hekmati, Irene Dunia, Dhouha Mansouri, Walid Massoud, Vincent Molinié, E. Lucio Benedetti and Bernard Malavaud

Accepted 4 January 2008

November 2008 (Vol. 54, Issue 5, pages 1154 - 1163)

We have read, with great interest, two previous works of Baumert and colleagues on tissue-engineering methods used for regeneration of the urinary tract, but the last one was a little confusing [1].

The title is misleading. It gives the impression that laparoscopy technique can influence or support tissue regeneration. Organ regeneration is related to cells, matrix, and host tissue. We believe, like Yannas [2] and Feil et al [3], that the presence of proper progenitor cells and matrix are crucial for inductive regeneration in vivo and in vitro.

We think that data analysis in this paper is too weak to support the thesis. The authors used three pigs to prove that laparoscopic technique is superior to, or at least the same as, an open technique for implantation of tissue-engineered grafts, but we did not find any group operated using an open technique.

We agree that electron microscopy is an adequate tool and probably the best morphological study for observing the ultrastructure and possible toxic and harmful effects related to laparoscopy. Even though the authors referred to the histology analysis in their previous works, we could not find the comparable electron microscopy analysis related to open procedure in the cited paper [4]. It should be mentioned that immunohistochemistry data lack any scale. Expression of cytokeratines, α-actin and von Willebrand factor must be presented using gradation related to all slides, not only to those shown on figures. Finally, it has to be emphasized that nothing can be observed, even under electron microscopy. The influence of laparoscopic technique on cells, tissues, and particularly on rapidly dividing cells is usually related to oxidative stress [5]. The induction of oxidative stress is connected with pressures and gases used for creation of working space as well as for anaesthesia. The prooxidant–antioxidant balance in the blood of the host organism is also a crucial factor.

Answers to questions about laparoscopy’s harmful effects should be supported with analysis of lipid peroxidation expressed, for example, as malondialdehyde (MDA) concentration. Thiobarbituric acid-reactive substances (TBARS) or diphenyl-2-picrylhydrazyl (DPPH) reactive substances can be measured. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the erythrocytes and transplanted cells would elucidate the antioxidant status of organism and graft. Probably most important for graft (neoureter) functioning is the DNA-oxidative possible damage caused by laparoscopy. This can be simply measured as products of oxidative DNA damage repair (8-oxo-2′-deoxyguanosine and 8-oxoguanine) excreted, for example, into urine.

The last question is related to statistics. Why did the authors construct only three grafts? Tissue-engineering methods provide the opportunity to create a huge amount of cells, which can be used for 10, 15, or even 20 such neoureters. Were three neoureters sufficient for any analysis?

Reading this paper, we had an impression that implantation and excision of neoureters were possible using a laparoscopy technique.Conflicts of interest: The authors have nothing to disclose.

References

  • [1] H. Baumert, M. Hekmati, I. Dunia, et al. Laparoscopy in ureteral engineering: a feasibility study. Eur Urol. 2008;54:1154-1163 Abstract, Full-text, PDF, Crossref.
  • [2] I.V. Yannas. Facts and theories of induced organ regeneration. Adv Biochem Eng Biotechnol. 2005;93:1-38 Crossref.
  • [3] G. Feil, S. Maurer, U. Nagele, et al. Immunoreactivity of p63 in monolayered and in vitro stratified human urothelial cell cultures compared with native urothelial tissue. Eur Urol. 2008;53:1066-1073 Abstract, Full-text, PDF, Crossref.
  • [4] H. Baumert, D. Mansouri, G. Fromont, et al. Terminal urothelium differentiation of engineered neoureter after in vivo maturation in the “omental bioreactor”. Eur Urol. 2007;52:1492-1498 Abstract, Full-text, PDF, Crossref.
  • [5] M. Demirbas, M. Samli, Y. Aksoy, C. Guler, A. Kilinc, C. Dincel. Comparison of changes in tissue oxidative-stress markers in experimental model of open, laparoscopic, and retroperitoneoscopic donor nephrectomy. J Endourol. 2004;18:105-108 Crossref.

Footnotes

a Departments of Urology and Tissue Engineering, Collegium Medicum, Nicolaus Copernicus University, Bydgoszcz, Poland

b Department of Urology, Institute of Oncology, Kielce, Poland

lowast Corresponding author. Department of Urology, Department of Tissue Engineering, Nicolaus Copernicus University, Karlowicza 24, 85-090 Bydgoszcz, Poland. Tel. +48525854500; Fax: +48525854540.