The Development of a Canine Anorectal Autotransplantation Model Based on Blood Supply: A Preliminary Case Report

<div><p>Colostomy is conventionally the only treatment for anal dysfunction. Recently, a few trials of anorectal transplantation in animals have been published; however, further development of this technique is required. Moreover, it is crucial to perform this research in dogs, which resemble humans in anorectal anatomy and biology. We designed a canine anorectal transplantation model, wherein anorectal autotransplantation was performed by anastomoses of the rectum, inferior mesenteric artery (IMA) and vein, and pudendal nerves. Resting pressure in the anal canal and anal canal pressure fluctuation were measured before and after surgery. Graft pathology was examined three days after surgery. The anal blood supply was compared with that in three beagles using indocyanine green (ICG) fluorescence angiography. The anorectal graft had sufficient arterial blood supply from the IMA; however, the graft’s distal end was congested and necrotized. Functional examination demonstrated reduced resting pressure and the appearance of an irregular anal canal pressure wave after surgery. ICG angiography showed that the pudendal arteries provided more blood flow than the IMA to the anal segment. This is the first canine model of preliminary anorectal autotransplantation, and it demonstrates the possibility of establishing a transplantation model in dogs using appropriate vascular anastomoses, thus contributing to the progress of anorectal transplantation.</p></div

Case summary, purpose, surgical data, and used figures in all animals.

<p>Case summary, purpose, surgical data, and used figures in all animals.</p

Anorectal graft harvesting.

<p>A. Median laparotomy. B. Intraperitoneal view of the inferior mesenteric artery (red arrowhead) and inferior mesenteric vein (blue arrowhead). C. Circumanal incision. D. Perineal view of the left pudendal artery (red arrowhead), pudendal vein (blue arrowhead), and pudendal nerve (yellow arrowhead). E. The rectum is separated with a mesentery at the lower part (white dashed line). F. The harvested anorectal graft with preservation of the IMA, IMV, and PNs.</p

Fluctuations in anal canal continuous pressure in dog 2.

<p>A. Preoperative fluctuation in anal canal pressure. A regular rhythmic wave is observed. B. Intraoperative fluctuation in anal canal pressure. Before vascular anastomoses, the wave form is flat. C. Postoperative fluctuation in anal canal pressure. An irregular anal canal pressure wave appears after surgery.</p

Anorectal autotransplantation.

<p>A. Extraperitoneal view after venous anastomosis. B. Magnified view of the venous anastomosis (IMV: 3.5 mm in diameter). C. Magnified view of the arterial anastomosis (IMA: 3.0 mm in diameter). D. Perineal view of the nerve anastomosis (right PN: 2.0 mm in diameter, left PN: 1.5 mm in diameter). E. Abdominal closure. F. Perineal closure; the distal end of the graft is congested.</p

Donor anorectal graft harvesting.

<p>(A) Right pudendal nerves (PN) and pudendal artery (PA) and vein (PV) were separated by the blue (PN) and red (PA and PV) vessel loop. (B) Pelvic floor muscles were identified and cut. (C) The anorectal graft was harvested.</p

Indocyanine green fluorescence angiography of the anal blood supply A–D.

<p>Control study using dog 3. E–H. Evaluation of blood supply from the IMA in dog 4. I–L. Evaluation of blood supply from the PAs in dog 5. A, E, I. Perineal view of the anal segment immediately before angiography. B, F, J. Beginning of enhancement of the anal segment. C, G, K. Plateau of enhancement. D, H, L. Time course of brightness determined using region of interest software (red line: positive control, blue line: negative control, yellow line: anal canal, and green line: perianal skin).</p

The proportion of impacts on fish biodiversity from dam construction and global warming that is attributable to synergy alone (i.e. the difference, Δ, in projections between the additive and synergistic scenarios).

<p>(a) Δ species richness, (b) Δ habitable area, and (c) Δ % threatened species projected to arise from increases in total generating capacity (associated with hydropower dams), RCPs and year (associated with global warming). **<i>P</i> < 0.01, ***<i>P</i> < 0.001. Red and blue asterisks indicate positive and negative effects, respectively.</p

Sampling locations and environmental layers for MAXENT.

<p>(a) Sampling locations (solid circles) in the Indo-Burma region with the Chao Phraya (left) and Mekong (right). (b) Altitude layer obtained from USGS GTOP30 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref041" target="_blank">41</a>]. (c) Slope layer obtained from USGS HYDRO1K [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref042" target="_blank">42</a>]. (d) Topographic wetness index [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref044" target="_blank">44</a>] obtained from USGS HYDRO1K [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref042" target="_blank">42</a>]. (e) Distance from the river mouth (or sea) derived from the altitude layer using GIS software. (f) Human influence index (v2, 1995–2004) obtained from SEDAC EARTH DATA [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref046" target="_blank">46</a>]. (g) Ecoregions [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref047" target="_blank">47</a>] obtained from WWF Terrestrial Ecoregions of the World [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref048" target="_blank">48</a>]. (h) Fragment areas derived from the altitude layer and dam locations (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.g001" target="_blank">Fig 1A</a>) using GIS software. (i) Number of ecoregions within each fragment derived by intersecting the fragment layer and ecoregions using GIS software. (j) Mean temperature obtained from WorldClim global climat4 data (BIO1) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref049" target="_blank">49</a>]. (k) Maximum temperature obtained from the Bioclim data (BIO5) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref049" target="_blank">49</a>]. (l) Minimum temperature obtained from the Bioclim data (BIO6) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref049" target="_blank">49</a>]. (m) Precipitation obtained from the Bioclim data (BIO12) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref049" target="_blank">49</a>]. (n) Maximum precipitation obtained from the Bioclim data (BIO13) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref049" target="_blank">49</a>]. (o) Minimum precipitation obtained from the Bioclim data (BIO14) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160151#pone.0160151.ref049" target="_blank">49</a>]. Color gradations show relative values in each layer. Note that the graphical images are illustrative only; readers are referred to the original sources of the environmental layers.</p

Changes in fish biodiversity dues to dam construction at the intraregional scale within the Indo-Burma Region.

<p>Changes in fish biodiversity dues to dam construction at the intraregional scale within the Indo-Burma Region.</p