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 pre cludes serial sampling. This increases variability and requires a larger n value for pathogenesis studies. To address this problem, a study was conduc ted to develop and validate the feasibility of performing multiple, serial biopsy sampling by laparoscopy in pigtail macaques. Tissues were obtained l aparoscopically from 2 HIV-negative and 2 HIV-positive (late postinoculatio n) macaques on days 0, 3, and 7, followed by necropsy on day 21. Anesthesia was induced with ketamine and atropine and maintained with isoflurane. Car bon dioxide pneumoperitoneum was maintained at 6 mm Hg. A triangulated thre e-port technique was used for insertion of pediatric (3.5-5.0 mm) laparosco pic instrumentation. Biopsies of kidney and spleen were obtained with a cor e-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 we re administered for 24 h post operation, and animals were evaluated for pos toperative complications. All monkeys maintained a good appetite. Mild post operative pain was observed in one animal after the second surgery. There w as no excessive bleeding or intestinal stenosis at biopsy sites. Skin infec tion, observed in 1/36 (2.8%) port sites, resolved with systemic antibiotic s. 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 samp les tested) positive cells, which is consistent with the low level of HIV-2 virus found in cells late in the postinoculation period in pigtail macaque s. The results of this study suggest that laparoscopic serial abdominal bio psy collection in healthy and immunocompromised pigtail macaques may be con sidered a minor procedure, and can be used to expedite serial tissue collec tion in survival studies.