Videoendoscopic techniques for collection of multiple, serial intra-abdominal biopsy specimens in HIV-negative and HIV-positive pigtail macaques (Macaca nemestrina).

Tissue biopsy sampling by laparotomy is considered major surgery, which precludes serial sampling. This increases variability and requires a larger n value for pathogenesis studies. To address this problem, a study was conducted to develop and validate the feasibility of performing multiple, serial biopsy sampling by laparoscopy in pigtail macaques. Tissues were obtained laparoscopically from 2 HIV-negative and 2 HIV-positive (late postinoculation) macaques on days 0, 3, and 7, followed by necropsy on day 21. Anesthesia was induced with ketamine and atropine and maintained with isoflurane. Carbon dioxide pneumoperitoneum was maintained at 6 mm Hg. A triangulated threeport technique was used for insertion of pediatric (3.5-5.0 mm) laparoscopic instrumentation. Biopsies of kidney and spleen were obtained with a core-sampling biopsy needle, of small intestine and mesenteric lymph node with a pretied loop, and of liver with 3.5-5.0 mm biopsy forceps. Analgesics were administered for 24 h post operation, and animals were evaluated for postoperative complications. All monkeys maintained a good appetite. Mild postoperative pain was observed in one animal after the second surgery. There was no excessive bleeding or intestinal stenosis at biopsy sites. Skin infection, observed in 1/36 (2.8%) port sites, resolved with systemic antibiotics. Significant adhesions formed at 23/114 (20.2%) sites. Out of 34 samples evaluated for histopathology, 29 (85.3%) were satisfactory (minimal to mild tissue crushing). In situ hybridization results revealed few (4 of 29 samples tested) positive cells, which is consistent with the low level of HIV-2 virus found in cells late in the postinoculation period in pigtail macaques. The results of this study suggest that laparoscopic serial abdominal biopsy collection in healthy and immunocompromised pigtail macaques may be considered a minor procedure, and can be used to expedite serial tissue collection in survival studies.

Videoendoscopy: an effective and efficient way to perform multiple visceral biopsies in small animals.

Because major surgery is usually required to obtain biopsies of abdominal organs, regulations tend to limit the number of procedures on individual animals to one. This study was conducted to develop a more humane, minor, comparatively cost-effective, minimally invasive surgical procedure, which reduces surgical trauma and the number of animals used. Biopsy techniques were developed in two nonsurvival rabbit surgeries. Safety and efficacy of multiple procedures were assessed in survival studies on four rabbits. Anesthesia was induced with ketamine/xylazine and maintained with isoflurane. Initial carbon dioxide insufflation (6 mmHg) was achieved through a Veress needle. A triangulated 5-mm port technique allowed introduction of pediatric 3.5- to 5.0-mm laparoscopic instruments. Biopsies of liver, spleen, kidney, and full-thickness bowel were obtained and evaluated for suitability (size) for polymerase chain reaction, in-situ hybridization, and histopathology studies. Animals in survival studies were assessed for infection, pain, bleeding, adhesion development, bowel function, and intestinal stenosis. All had normal appetite and stools within 48 h postoperatively. Biopsies obtained from either a Tru-Cut Biopsy Needle, 3.5- to 5.0-mm biopsy cups, or with the aid ofa pre-tied loop were adequate for all studies. There was no postoperative bowel obstruction, wound infection, or bleeding. Mean hematocrit decrease at 24 h postoperative was 3.4% +/- 6.7%. Adhesions formed at 9/52 (17%) evaluable sites. Multiple visceral organ biopsy under videoendoscopic guidance constitutes a minor procedure and is a promising means for longitudinal studies in animals. Utility for ill animals remains to be determined.