Assessment of pre-operative maropitant citrate use in macaque (Macaca fasicularis & Macaca mulatta) neurosurgical procedures.

BACKGROUND: Retrospective analysis of post-operative vomiting (POV) in non-human primates at our institution was 11%. Based on this additional risk factor for post-operative complications, we aimed to eliminate or decrease POV by adding an antiemetic, maropitant citrate, to the pre-medication protocol. METHODS: Retrospective and prospective data were collected over a 5-year period from 46 macaques of two species during 155 procedures. Additionally, blood was collected from five Macaca mulatta to perform a pharmacokinetic analysis. RESULTS: A 1 mg/kg subcutaneous dose of maropitant given pre-operatively significantly decreased POV. Findings indicated post-neurosurgical emesis in Macaca fasicularis was significantly greater than in Macaca mulatta. Pharmacokinetic analysis of maropitant in Macaca mulatta determined the mean maximum plasma concentration to be 113 ng/mL. CONCLUSIONS: Maropitant administration prior to anesthesia for neurosurgeries decreased our incidence of POV to 1%. The plasma concentration reaches the proposed plasma level for clinical efficacy approximately 20 minutes after administration.

Endodontic treatment of canine teeth in a cynomolgus monkey ( Macaca fascicularis).

A case of bilateral superior canine tooth pulp necrosis in an 18-year-old male Macaca fascicularis is described . A skull computed tomography scan was performed to confirm the diagnostic suspicion. A successful bilateral endodontic treatment with coronotomy was performed using rotary nickel-titanium instruments. Post-operative dental radiographs confirmed the correct positioning of the sealant. A rapid and excellent clinical recovery was obtained after each surgery. This innovative approach may contribute to improving the quality of root canal treatments provided to non-human primates.

Novel H-shunt Venovenous Bypass for Liver Transplantation in Cynomolgus Macaques.

Cynomolgus monkeys are often used in preclinical transplantation research. Performing liver transplantation in cynomolgus monkeys is challenging because they poorly tolerate portal vein clamping during the anhepatic phase. Finding an alternative to portal vein clamping is necessary before preclinical liver transplant models can be performed with reliable outcomes. We used 3 different techniques to perform 5 liver transplants in male cynomolgus macaques (weight, 7.4-10.8 kg; mismatched for MHC I and II; matched for ABO). In procedure A, we clamped the portal vein briefly, as in human transplants, as well as the superior mesentery artery to minimize congestion at the expense of temporary ischemia (n = 2). In procedure B, we performed a temporary portocaval shunt with extracorporeal venovenous bypass (n = 1). For procedure C, we developed an H-shunt system (modified portocaval shunt) with extracorporeal bypass (n = 2). Postoperative immunosuppression comprised cyclosporine A, mycophenolate mofetil, and steroids. Recipients in procedure A developed hemodynamic instability and were euthanized within 2 d. The recipient that underwent procedure B was euthanized within 11 d due to inferior vena caval thrombosis. The H-shunt in procedure C led to minimal PV congestion during the anhepatic phase, and both recipients reached the 21-d survival endpoint with good graft function. Our novel H-shunt bypass system resulted in successful liver transplantation in cynomolgus macaques, with long-term posttransplant survival possible. This technical innovation makes possible the use of cynomolgus monkeys for preclinical liver transplant tolerance models.

Radiological and Microsurgical Anatomy for Variation of the Mandible: Comparative Study of Human and Macaca fascicularis.

Recent studies using cone-beam computer tomography (CBCT) have added to our understanding of anatomical variation in the mandible of humans. However, the distribution of nerves cannot be revealed by CBCT. There have been investigations of the distribution of nerves relating to the mandible, but some proposed causes of these variations remain controversial. In this study, we observed a total of 10 sides from five mandibles of Macaca fascicularis of unknown age and sex using CBCT and dissection under stereomicroscopy. Nine of the 10 sides had two mental foramina in each side. Innervation by the mental nerves depended on the locations of those foramina. The long branch to the mandibular angle ran with a branch of the facial artery, which joined the mental artery in all 10 sides. Five specimens had a median perforating canal in the mandibular bone. In addition, a branch of the sublingual artery, which joined with the small branches of the submental artery, entered the mandibular bone from the median lingual foramen. This foramen was located in the lower part of the mandibular symphysis and passed via the median perforating canal to exit from the median labial foramen, also located in the lower part of the mandibular symphysis. We speculate that the median perforating canal of the mandible, rarely found in humans, is the remnant of the feeding artery of the fetal mandible, and in M. fascicularis is seen in all specimens because they have no mental protuberance. Anat Rec, 300:1464-1471, 2017. © 2017 Wiley Periodicals, Inc.

Surgical technique for allogeneic uterus transplantation in macaques.

No study has reported an animal model of uterus transplantation (UTx) using cynomolgus macaques. We aimed to establish a surgical technique of allogeneic UTx assuming the recovery of a uterus from a deceased donor in cynomolgus macaques. Four allogeneic UTxs were performed in female cynomolgus macaques. Donor surgeries comprised en bloc recovery of organs with iliac vessels on both sides, and/or abdominal aorta/vena cava after sufficient perfusion from one femoral artery or external iliac artery. Before perfusion, 150 mL of whole blood was obtained from the donor for subsequent blood transfusion to the recipient. Four uterine grafts were orthotopically transplanted to recipients. End-to-side anastomosis was performed to the iliac vessels on one side in case 1 and iliac vessels on both sides in case 2; aorto-aorto/cavo-caval anastomosis was performed in cases 3 and 4. Arterial blood flow of the uterine grafts was determined by intraoperative indocyanine green (ICG) angiography. ICG angiography results showed sufficient blood flow to all uterine grafts, and anaemia did not progress. Under appropriate immune suppression, all recipients survived for more than 90 days post-transplantation, without any surgical complications. We describe a surgical technique for allogeneic UTx in cynomolgus macaques.

Establishment of a Novel Simplified Surgical Model of Acute Liver Failure in the Cynomolgus Monkey.

Models using large animals that are suitable for studying artificial liver support system (ALSS) are urgently needed. Presently available acute liver failure (ALF) models mainly involve pigs or dogs. Establishment of current surgical ALF models (hepatectomy/devascularization) requires either very good surgical skills or multistep processes-even multiple stages of surgery. Therefore, it is necessary to develop a simplified surgical method. Here we report a novel simplified surgical ALF model using cynomolgus monkeys. Six monkeys underwent portal-right renal venous shunt combined with common bile duct ligation and transection (PRRS + CBDLT). Postoperatively, the monkeys had progressively increased listlessness, loss of appetite, and obvious jaundice. Blood biochemistry levels (Amm, ALT, AST, TBiL, DBiL, ALP, LDH, CK, and Cr) and prothrombin time (PT) were significantly increased (all P < 0.01) and albumin (ALB) was markedly reduced (P < 0.01) compared with baseline values. Histological examination of liver specimens on postoperative day 10 revealed cholestasis and inflammation. PRRS + CBDLT produced ALF that closely correlated with clinical situations. Compared with other surgical or drug ALF models, ours was simplified and animals were hemodynamically stable. This model could provide a good platform for further research on ALSS, especially regarding their detoxification functions.

Beta-5 score to evaluate pig islet graft function in a primate pre-clinical model.

BACKGROUND: We developed a composite scoring system to accurately assess pig islet function in pre-clinical primate studies. METHODS: Two scoring methods that have been clinically validated in human islet allotransplantation were tested in six non-diabetic and nine streptozotocin (STZ)-induced diabetic primates: (i) SUITO index=[1500 × fasting C-peptide (ng/ml)]/[fasting blood glucose (FBG, mg/dl) - 63] and (ii) CP/G ratio =[fasting C-peptide (ng/ml) × 100]/FBG (mg/dl). Both scores were analysed as a function of the ß-cell mass of the native primate pancreas. Next, a proposed ß5 score based on FBG values, daily glycosuria, post-prandial glycosuria, polydipsia, and polyuria was validated on the same primates. Ranges of normal and pathologic values for each parameter were assessed during 5 months in non-diabetic and diabetic primates, respectively. Finally, scores were tested on the nine STZ-induced diabetic primates, four of which were transplanted with microencapsulated pig islets and five with macroencapsulated pig islets. All parameters required for each score were measured prior to transplantation and up to 12 weeks post-transplantation. For the CP/G ratio after transplantation, primate C-peptide was replaced by porcine C-peptide. RESULTS: The Suito index was not correlated with the pancreatic ß-cell mass in contrast to the CP/G ratio (R(2) = 0.17, P = 0.645 vs. R(2) = 0.76, P = 0.003; respectively). The internal consistency of the parameters implied by the ß5 score was confirmed by a Cronbach's alpha test of 0.97. Diabetes was confirmed by a significant decrease in the CP/G ratio and the ß5 score before and after diabetes induction, respectively. After transplantation, a significant correlation was found between the CP/G ratio and the ß5 score, which reflected the functionality of pig islet xenografts and diabetes control. In addition, the CP/G ratio and ß5 score were correlated with the glycosylated hemoglobin course after transplantation and diabetes correction with macroencapsulated pig islets. CONCLUSION: The proposed ß5 score provides a valid tool to accurately assess islet transplantation in a primate pre-clinical model.

Refinement of vascular access port placement in nonhuman primates: complication rates and outcomes.

Chronic vascular access is often needed in experimental animal studies, and vascular access ports (VAP) have been proposed as an alternative to conventional venipuncture. We previously reported on VAP implantation by using femoral venous cutdown (FVC) and tunneling. In an attempt to decrease the moderate complications associated with the FVC method, we developed the single-incision, peripheral-insertion (SIPI) method. In a retrospective evaluation, 92 FVC procedures were compared with 113 SIPI procedures in cynomolgus and rhesus macaques and baboons with as much as 2.5 y of follow-up. The rate of complications was significantly lower for the SIPI method than for the FVC method (19.4% versus 33.7%), particularly in regard to infectious complications (8.0% versus 27.3%, respectively). In addition, VAP patency for blood sampling and fluid infusion was significantly better for the SIPI method than for the FVC method, with 1-y patency rate of 83% and 46%, respectively, and 2-y patency rate of 74% and 36%, respectively. Additional advantages of the SIPI method include the simplified implantation of the VAP and access in the homecage without any sedation or restraint after appropriate training of animals to cooperate. We conclude that the SIPI method presents an opportunity for refinement and is superior to the FVC method for chronic vascular access.

First description of the surgical anatomy of the cynomolgus monkey liver.

No detailed description of nonhuman primate liver anatomy has been reported and little is known about the similarity between such livers and human liver. The cynomolgus monkey (Macaca fascicularis) was used to establish a preclinical model of genetically modified hepatocytes auto transplantation. Here, we report information gleaned from careful observation and notes obtained from 59 female cynomolgus monkeys undergoing 44 anatomical hepatic resections, 12 main portal vein division dissections and selective branch ligations, and 46 portographies. Additionally, three anatomical liver dissections after total resection at autopsy were performed and served to confirm peroperative observations and for photography to provide illustrations. Our results indicate that the cynomolgus monkey liver has four lobes: the median (the largest), the right and left lateral, and the caudate lobes. In 60% (N=20) of individuals the portal bifurcates into right and left portal veins, in the remaining 40% (N=14) the portal vein trifurcates into right anterior, right posterior, and left portal veins. The anatomy and branching pattern of the hepatic artery and bile ducts closely follow those of the portal branches. Functionally, the cynomolgus monkey liver can be divided into eight independent segments. Thus, we report the first detailed description of the hepatic and portal surgical anatomy of the cynomolgus monkey. The cynomolgus monkey liver is more similar to the human liver than are livers of any small or large nonprimate mammals that have been described.

Risk factors associated with surgical site infection and the development of short-term complications in macaques undergoing indwelling vascular access port placement.

BACKGROUND: Risk factors associated with surgical site infection (SSI) and the development of short-term complications in macaques undergoing vascular access port (VAP) placement are evaluated in this study. METHODS: Records from 80 macaques with VAPs were retrospectively reviewed. Logistic regression was used to identify factors associated with short-term post-operative complications. RESULTS: The primary outcome was SSI, which occurred in 21.6% (52.6% in the first 12 months vs. 13% thereafter) of procedures. SSI was associated with major secondary complications including VAP removal (11.4%), wound dehiscence (5.7%), and mechanical catheter occlusion (5.7%). In multivariate modeling, only surgical program progress was a statistically significant predictor of SSI, while animal compliance had a slightly protective effect. CONCLUSIONS: Vascular access ports have a moderate risk of complications, provided the surgical program optimizes best practices. Under complex experimental conditions, VAPs represent an important refinement, both improving animals' overall well-being and environment and reducing stress.

Refinement of a transplantation project in the non-human primate by the use of a humane endpoint.

An assessment scheme was developed to establish a humane endpoint in a pig-to-primate renal xenotransplantation project, with a view to minimizing and controlling any pain or suffering conditions in the animals involved while still achieving the scientific objective. In particular, the assessment criteria for identifying the earliest endpoint are described, bearing in mind both the researcher's need to obtain top-quality data and the ethical need to safeguard the animals. The scheme should also be applicable to other experiments involving non-human primates (e.g. allotransplantation, survival after major surgery, pharmacological safety tests) because it considers reproducible general parameters together with aspects specific to each experimental model.

Blockage of urine by intravesical ejaculate in cynomolgus monkeys.

BACKGROUND: The present communication reports intravesical semen coagulation and formation of a larger precipitate in two Cynomolgus monkeys. METHODS: Ultrasound of the urinary bladder and light microscopy of intravesical coagulates. RESULTS: These monkeys suffered from complete blockage of urine output and surgery was required to remove the sperm mass. Microscopic examination of the urine revealed millions of sperm as a cause of the mass and the blockage of urine output. CONCLUSIONS: Retrograde ejaculation of sperm may cause coagulation of ejaculates in the bladder of the cynomolgus monkey Macaca fascicularis. However, involvement of sperm mass in blockage of urine passage has not been described in this species.

Assessment of an intraprostatic injection technique through a perineal approach in macaques.

We developed a surgical procedure for accessing the prostate gland of the cynomolgus monkey (Macaca fascicularis) through the perineal cavity. The procedure can be used for direct injection of compounds into the prostate gland and (or) for the collection of biopsies. The rationale for developing this technique at our site was the need for precise injection into the gland with a low probability of error, as the compound tested in a subsequent study required prostate-specific antigen for activation. A perianal incision was made approximately 1 cm ventral to the anus, and the muscle and subcutaneous tissue were bluntly dissected between the urethra and the rectum. The prostate gland was easily visualized after dissection, and could be grasped gently by the capsule and exteriorized through the incision, thus allowing easy access to the prostate for study purposes. On the basis of mock injections with methylene blue dye and gross observation of prostate tissue at necropsies immediately after injection, we recommend that 2 injections be given per lobe of prostate, and injections should be to a depth of 2 to 3 mm to provide uniform distribution of injected compounds. To minimize back pressure and leakage from the injection site, a smallgauge needle (23-27 gauge) should be used and the needle held in place for approximately 30 s before withdrawal. Injection volumes 64 mul per g prostate or less did not cause the back flow of methylene blue dye into the seminal vesicles.

Cryopreservation and primary culture of cerebral neurons from cynomolgus monkeys (Macaca fascicularis).

We established the procedures for cryopreservation and primary culture of fetal cerebral neurons of cynomolgus monkeys (Macaca fascicularis). Three developmental stages of fetuses (80, 93, and 102 days of gestation) were compared to determine the optimal stage of cerebrum development for primary culture. Among the three fetuses, the 80-day-old fetus produced the most process-rich neurons with the highest survival. The number of total recovery cells from the cryopreserved 80-day-old fetus corresponded to 83.4% of that from fresh tissue. Besides, synchronous oscillations of intracellular calcium were first seen in primate cerebral neurons, which suggested the formation of synapse-networks. Cultured neurons expressed synaptophysin protein. Successful cryopreservation and subsequent cell culture of primate neurons would be useful tools for neuroscience research with species specificity.

Multi-tiered treatment of pressure sores in two cynomologous macaques (Macaca fascicularis).

Successful treatment of one Grade IlI and two Grade IV pressure sores on two female Macaca fascicularis, subsequent to a T11 hemilaminectomy and left spinal cord hemisection, was achieved through a combined strategy of wound care, diet, and husbandry. Wound care consisted of early and thorough debridement of all necrotic tissue, initial twice daily cleaning with an iodine scrub and application of a multi-ingredient ointment. Tissue hydrolyzer, a drying agent, vitamin E, ground selenium, and topical antibiotics were applied to the wound during the respective 45- and 46-day courses of treatment. Oral antibiotics were administered; vitamins C and E, and selenium were increased in the diet. No infection occurred and both animals recovered fully to complete the study. Importantly, pressure sores in subsequent study animals were prevented by post-operative padding of the perch with towel-covered foam and placement of a wheelchair cushion on the floor of the cage.

Peripheral nerve repair with collagen conduits.

This paper describes the repair of peripheral nerves with a tubular conduit fabricated from collagen. The tubular collagen matrix was made semipermeable to permit nutrient exchange and accessibility of neurotrophic factors to the axonal growth zone during regeneration. In-vitro studies showed that the semipermeable collagen conduit allowed rapid diffusion of molecules the size of bovine serum albumin and was adequately cross-linked for controlled resorption in vivo. Studies on primates suggest that collagen conduits worked as effectively as nerve autografts in terms of physiological recovery of motor and sensory responses. The results of in-vitro and in-vivo studies of the collagen conduit represent a significant step towards our specific aim of developing suitable off-the-shelf prostheses for clinical repair of damaged peripheral nerves.

Partial lobectomy via a ligature fracture technique: a method for multiple hepatic biopsies in nonhuman primates.

A ligature fracture technique was used to obtain multiple large (2 to 4 g) liver biopsy samples in both African green and cynomolgus monkeys. The technique was performed 195 times in 84 animals using three different surgical approaches, with no associated illness or mortality. In a subset of 18 animals, a slight decline in hematocrit percentage was noted during 14 days postsurgery (44.6 to 39.4%), but total plasma protein remained unchanged (5.98 to 5.95 g/dl). Serum alanine aminotransferase concentrations rose to 178.11 U/l at day 1 postoperatively, from a baseline value of 93.61 U/l. This elevation was transient, however, and declined to 49.65 U/l by day 14. Our experience has shown that the partial lobectomy via the ligature fracture technique is a safe and effective means to obtain multiple large samples of liver in nonhuman primates.

Respiration rate, heart rate, and body temperature values in cynomolgus monkeys (Macaca fascicularis) during barbiturate anesthesia.

Respiration rate, heart rate, and body temperature values were obtained from 14 cynomolgus monkeys (Macaca fascicularis) during neurosurgery under barbiturate anesthesia. Vital sign values markedly declined below baseline during the early stages of surgery, steadily increased as surgery progressed and neared completion, and finally returned to baseline by the end of the postsurgical recovery period. There was considerable variability among the 14 monkeys, but the ranking of each monkey relative to the others remained constant across the period of observation. The findings suggested that the cynomolgus monkey may be more sensitive to barbiturates than the rhesus monkey, and cynomolgus monkeys may exhibit considerable individual differences in their sensitivity to barbiturates.