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.