Ascites formation accompanied by portal vein thrombosis after porcine islet xenotransplantation via the portal vein in Rhesus macaque (Macaca mulatta).

Pig-to-nonhuman primate (NHP) islet transplantation has been widely conducted as a preclinical xenotransplantation model prior to human clinical trial. Portal vein thrombosis is one of the complications associated with islet infusion through the portal vein into the liver. Here, we briefly report severe case of ascites formation accompanied by portal vein thrombi after pig-to-NHP islet xenotransplantation in a rhesus monkey. Meticulous prophylactic treatment such as continuous heparin infusion should be implemented to prevent portal vein thrombi in pig-to-NHP islet transplantation models.

Tacrolimus-induced asymptomatic thrombotic microangiopathy diagnosed by laboratory tests in pig-to-rhesus corneal xenotransplantation: A case report.

Tacrolimus-associated thrombotic microangiopathy (TA-TMA) is a rare complication. TA-TMA is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and organ damage due to thrombus. We report asymptomatic TA-TMA diagnosed by laboratory tests in pig-to-rhesus corneal xenotransplantation. Corneal transplantation had been conducted from a wild-type SNU miniature pig to a rhesus macaque. The veterinary records were retrospectively reviewed in this case. The immunosuppressive regimen consisted of rituximab, basiliximab, and IVIg as inductive therapies, and steroids with tacrolimus (0.1 mg/kg/day) as maintenance therapies. Although there were no clinical symptoms, increased levels of lactate dehydrogenase, total bilirubin, blood urea nitrogen, and creatinine and decreased levels of hemoglobin and platelet were observed in laboratory tests on Day (D) 61. Systemic TA-TMA was tentatively diagnosed. Tacrolimus was discontinued starting on D71. Dalteparin, clopidogrel bisulfate (D77-D99), and IVIg (D72) were administered as a conservative treatment. Abnormal laboratory results were reversed on D99. When low-dose tacrolimus (0.07 mg/kg/day) was re-administered on D131 to prevent rejection of the graft, TMA was detected again by laboratory tests on D161, confirming the initial diagnosis. Discontinuation of tacrolimus on D162 and re-administration of Dalteparin (D161-D196) corrected the laboratory values on D161. This report shows that in pig-to-rhesus corneal xenotransplantation, clinically asymptomatic TMA can be induced by tacrolimus, and the discontinuation of tacrolimus and administration of anticoagulant seems sufficient to correct the laboratory TMA.

Gastrostomy tube placement for long-term oral drug administration in non-human primates.

BACKGROUND: Non-human primates (NHPs) are often used as recipients in preclinical transplantation research that in most cases involves administration of various drugs including immunosuppressants. Long-term oral drug administration, particularly tacrolimus, is challenging in the transplant recipient NHPs. Oral drug administration method using the mixture of drug and fruit juice has been used in NHPs, but this is not always effective in all monkeys. To those monkeys who are poorly compliant, oral drug administration in restraint or administration using gastrostomy tube should be necessary. The aim of this study was to compare the efficacy of between oral drug administration in restraint and administration using gastrostomy tube and to report complications and solutions to overcome the problems related to gastrostomy tube for long-term oral drug dosing in rhesus monkeys. METHODS: Fifteen of 4- to 5-year-old male and female healthy rhesus monkeys weighing 5.0-6.8 kg were used as recipients for porcine pancreatic islet transplantation. Oral drug administration in restraint was used for four monkeys, and gastrostomy tube was placed to other 11 monkeys (8-French Feeding tube, n=6; Tri-Funnel Replacement Gastrostomy tube, n=5). Oral immunosuppressive drugs such as sirolimus and tacrolimus were administered through the tube. The efficacy and the extent of ease for administration and related complications were compared between two groups. RESULTS AND CONCLUSIONS: The complication of gastrostomy included a transient inflammation in the skin and peritonitis caused by a leakage around implantation site (one case), which could be overcome by changing suture method and tube type to interlocking box suture and Tri-Funnel Replacement Gastrostomy tube, respectively. Despite these complications, oral drug administration using gastrostomy tube allowed us to perform accurate dosage of drug administration and to reduce the stress that both the monkey and the researcher may experience. Taken together, this study showed that gastrostomy tube placement is a better alternative to oral drug administration in restraint for long-term oral drug administration in rhesus monkeys who tend to refuse to eat the mixture of drug and fruit juice.

Computed tomography or necropsy diagnosis of multiple bullae and the treatment of pneumothorax in rhesus macaques (Macaca mulatta).

Pulmonary bullae and pneumothorax have various etiologies in veterinary medicine. We diagnosed multiple pulmonary bullae combined with or without pneumothorax by computed tomography (CT) or necropsy in seven rhesus macaques (Macaca mulatta) imported from China. Two of seven rhesus macaques accompanied by pneumothorax were cured by fixation of ruptured lung through left or right 3rd intercostal thoracotomy. Pneumonyssus simicola, one of the etiologies of pulmonary bullae, was not detected from tracheobronchiolar lavage. To the best of our knowledge, this is the first case report on the CT-aided diagnosis of pulmonary bullae and the successful treatment of combined pneumothorax by thoracotomy in non-human primates (NHPs).

Induction, management, and complications of streptozotocin-induced diabetes mellitus in rhesus monkeys.

BACKGROUND: Diabetes mellitus (DM) model using streptozotocin (STZ) which induces chemical ablation of ß cell in the pancreas has been widely used for various research purposes in non-human primates. However, STZ has been known to have a variety of adverse effects such as nephrotoxicity, hepatotoxicity, and even mortality. The purpose of this study is to report DM induction by STZ, toxicity associated with STZ and procedure and complication of exogenous insulin treatment for DM management in rhesus monkeys (Macaca mulatta) that are expected to be transplanted with porcine islets within 2 months. METHODS: Streptozotocin (immediately dissolved in normal saline, 110 mg/kg) was slowly infused via central catheter for 10 minutes in 22 rhesus monkeys. Clinical signs, complete blood count and blood chemistry were monitored to evaluate toxicity for 1 week after STZ injection. Monkey basal C-peptides were measured and intravenous glucose tolerance test was performed to confirm complete induction of DM. Exogenous insulin was subcutaneously injected to maintain blood glucose in diabetic rhesus monkeys and the complications were recorded while in insulin treatment. RESULTS: Severe salivation and vomiting were observed within 1 hour after STZ injection in 22 rhesus monkeys. One monkey died at 6 hours after STZ injection and the reason for the death was unknown. Pancreatitis was noticed in one monkey after STZ injection, but the monkey recovered after 5 days by medical treatment. Serum total protein and albumin decreased whereas the parameters for the liver function such as aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase significantly increased (P<.05) after STZ injection, but they were resolved within 1 week. Azotemia was not observed. Monkey fasting C-peptide levels after STZ injection were <0.1 ng/mL in 18 rhesus monkeys, but 0.34, 0.22, 0.16 ng/mL in three monkeys, respectively. The value of daily insulin requirement was 0.92±0.26IU/kg/d (range=0.45-1.29) in the monkeys. Diabetic ketoacidosis was observed in one rhesus monkeys, but the monkey recovered after 24 hours by fluid and insulin treatment. CONCLUSIONS: Streptozotocin was effective for inducing DM in rhesus monkeys, but various adverse effects such as pancreatitis, liver toxicity or death were observed. Therefore, careful and suitable medical managements should be implemented to eliminate the risks of mortality and severe adverse effects.

Bullous pemphigoid-like skin blistering disease in a rhesus macaque (Macaca mulatta).

Autoimmune bullous disease is very uncommon in non-human primates. We observed a bullous skin disease in a male rhesus monkey while conducting porcine islet xenotransplantation. Fifty days after the transplantation, multiple bullous skin lesions were observed. There was no mucosal involvement. Skin biopsy results demonstrated a subepidermal blister with no necrotic keratinocytes. Immunofluorescent staining showed linear IgG deposition at the roof of the blister. These skin lesions spontaneously disappeared. Considering these results, this monkey was diagnosed with bullous pemphigoid (BP). As far as we know, this is the first report of BP in non-human primates.

The effect of propofol on intravenous glucose tolerance test in rhesus monkey.

BACKGROUND: Many anesthetics have been shown to impair glucose metabolism and cause hyperglycemia. The aim of this study was to evaluate the effects of propofol on glucose metabolism and insulin secretion during intravenous glucose tolerance test (IVGTT) in rhesus monkey. METHODS: Serum cortisol, blood glucose, insulin, and C-peptide concentrations during IVGTT were measured in four rhesus monkeys under either conscious state or propofol anesthesia. RESULTS AND CONCLUSIONS: The levels of serum cortisol significantly increased under conscious condition, whereas these levels remained constant under propofol anesthesia. In propofol group, the levels of serum insulin and C-peptide significantly increased compared with those in conscious group. Accordingly, glucose disposal capacity was significantly improved, and the time to return to basal glucose levels was shortened in propofol group. This study showed that propofol significantly increased insulin and C-peptide, and the corresponding improvement in glucose disposal may be related to reduction of serum cortisol in monkey.

Genital tract cavernous hemangioma as a rare cause of postpartum hemorrhage.

Cavernous hemangiomas rarely involve the female genital tract. It is difficult to identify vascular malformations when these lesions are concealed in the vagina or deep vulva area. We present a rare case of vaginal cavernous hemangioma in a 30-year-old primiparous woman with an early severe postpartum hemorrhage (PPH) and delayed continuous bleeding from the episiotomy site. She was treated successfully with transarterial embolization of the left vaginal artery. To our knowledge, this is the first reported case of PPH caused by rupture of a vaginal hemangioma during vaginal delivery in English literature.