Adult Male Cynomolgus Monkeys Research Articles

Sleep dysfunction and gut dysbiosis related amino acids metabolism disorders in cynomolgus monkeys after middle cerebral artery occlusion

IntroductionThis study aimed to explore the characteristics of post-stroke sleep dysfunction and verify their association with gut dysbiosis and the related amino acid metabolism disorders. This was achieved by using fecal microbiota transplantation (FMT) in a non-human primate stroke model. MethodsTwenty adult male cynomolgus monkeys were divided into the sham (n = 4), middle cerebral artery occlusion (MCAO, n = 5), MCAO + FMT (n = 3), and donor (n = 8) groups. The MCAO+FMT group received FMT at post-MCAO week 4. Sleep parameters, gut microbiota, gamma-aminobutyric acid (GABA), and glutamine (Gln) in the cerebrospinal fluid (CSF) were measured at baseline and postoperative weeks 4, 8, and 12. ResultsAt postoperative weeks 4, 8, and 12, the MCAO group showed decreased sleep efficiency, measured as the percentage of sleep during the whole night (82.3 ± 3.2 % vs 91.3 ± 2.5 %, 79.0 ± 3.75 % vs 90.8 ± 3.2 %, and 69.5 ± 4.8 % vs 90.5 ± 2.7 %; all P < 0.05), lower relative abundance of Lactobacillus (all P < 0.05), and reduced GABA concentrations in the CSF (317.3 ± 30.6 nmol/L vs 437.7 ± 25.6 nmol/L, 303.1 ± 48.9 nmol/L vs 4 40.9 ± 37.8 nmol/L, and 337.9 ± 49.4 nmol/L vs 457.4 ± 39.2 nmol/L; all P < 0.05) compared with the sham group. Sleep efficiency at post-FMT weeks 4 and 8 (84.7 ± 1.1 % vs 79.0 ± 3.75 %, and 84.1 ± 2.0 % vs 69.5 ± 4.8 %; both P < 0.05) and GABA concentration in the CSF at post-FMT week 4 (403.1 ± 25.4 nmol/L vs 303.1 ± 48.9 nmol/L, P < 0.05) was higher in the MCAO+FMT group than in the MCAO group. ConclusionsPost-stroke sleep dysfunction in monkeys is characterized by impaired sleep coherence, associated with decreased levels of probiotics such as Lactobacillus, GABA, and Gln in the CSF and can be ameliorated using FMT.

Metformin decelerates aging clock in male monkeys

In a rigorous 40-month study, we evaluated the geroprotective effects of metformin on adult male cynomolgus monkeys, addressing a gap in primate aging research. The study encompassed a comprehensive suite of physiological, imaging, histological, and molecular evaluations, substantiating metformin's influence on delaying age-related phenotypes at the organismal level. Specifically, we leveraged pan-tissue transcriptomics, DNA methylomics, plasma proteomics, and metabolomics to develop innovative monkey aging clocks and applied these to gauge metformin's effects on aging. The results highlighted a significant slowing of aging indicators, notably a roughly 6-year regression in brain aging. Metformin exerts a substantial neuroprotective effect, preserving brain structure and enhancing cognitive ability. The geroprotective effects on primate neurons were partially mediated by the activation of Nrf2, a transcription factor with anti-oxidative capabilities. Our research pioneers the systemic reduction of multi-dimensional biological age in primates through metformin, paving the way for advancing pharmaceutical strategies against human aging.

Dl-3-n-Butylphthalide Alleviates Secondary Brain Damage and Improves Working Memory After Stroke in Cynomolgus Monkeys.

Remote secondary neurodegeneration is associated with poststroke cognitive impairment (PSCI). Dl-3-n-butylphthalide (NBP) improves PSCI clinically. However, whether it ameliorates PSCI by alleviating secondary neurodegeneration remains uncertain. Nonhuman primates provide more relevant models than rodents for human stroke and PSCI. This study investigated the effects of NBP on PSCI and secondary neurodegeneration in cynomolgus monkeys after permanent left middle cerebral artery occlusion (MCAO). Thirteen adult male cynomolgus monkeys were randomly assigned to sham (n=4), MCAO+placebo (n=5), and MCAO+NBP groups (n=4). The MCAO+placebo and MCAO+NBP groups received saline and NBP injections intravenously, respectively, starting at 6-hour postsurgery for 2 weeks, followed by soybean oil and NBP orally, respectively, for 10 weeks after MCAO. Infarct size was assessed at week 4 by magnetic resonance imaging. Working memory and executive function were evaluated dynamically using the delayed response task and object retrieval detour task, respectively. Neuron loss, glia proliferation, and neuroinflammation in the ipsilateral dorsal lateral prefrontal cortex, thalamus, and hippocampus were analyzed by immunostaining 12 weeks after MCAO. Infarcts were located in the left middle cerebral artery region, apart from the ipsilateral dorsal lateral prefrontal cortex, thalamus, or hippocampus, with no significant difference between the MCAO+placebo and MCAO+NBP group. Higher success in delayed response task was achieved at weeks 4, 8, and 12 after NBP compared with placebo treatments (P<0.05), but not in the object retrieval detour task (all P>0.05). More neurons and less microglia, astrocytes, CD68-positive microglia, tumor necrosis factor-α, and inducible NO synthase were observed in the ipsilateral dorsal lateral prefrontal cortex and thalamus after 12 weeks of NBP treatment (P<0.05), but not in the hippocampus (P>0.05). Our findings indicate that NBP improves working memory by alleviating remote secondary neurodegeneration and neuroinflammation in the ipsilateral dorsal lateral prefrontal cortex and thalamus after MCAO in cynomolgus monkeys.

Establishment of anterior cruciate ligament reconstruction model in cynomolgus monkey with autogenous hamstring tendon transplantation

To investigate the feasibility of establishing an anterior cruciate ligament (ACL) reconstruction model using hamstring tendon autograft in cynomolgus monkeys. Twelve healthy adult male cynomolgus monkeys, weighing 8-13 kg, were randomly divided into two groups ( n=6). In the experimental group, the ACL reconstruction model of the right lower limb was prepared by using a single bundle of hamstring tendon, and the ACL of the right lower limb was only cut off in the control group. The survival of animals in the two groups was observed after operation. Before operation and at 3, 6, and 12 months after operation, the knee range of motion, thigh circumference, and calf circumference of the two groups were measured; the anterior tibial translation D-value (ATTD) was measured by Ligs joint ligament digital body examination instrument under the loads of 13-20 N, respectively. At the same time, the experimental group underwent MRI examination to observe the graft morphology and the signal/ noise quotient (SNQ) was caculated. All animals survived to the end of the experiment. In the experimental group, the knee range of motion, thigh circumference, and calf circumference decreased first and then gradually increased after operation; the above indexes were significantly lower at 3 and 6 months after operation than before operation ( P<0.05), and no significant difference was found between pre-operation and 12 months after operation ( P>0.05). In the control group, there was no significant change in knee range of motion after operation, showing no significant difference between pre- and post-operation ( P>0.05), but the thigh circumference and calf circumference gradually significantly decreased with time ( P<0.05), and the difference was significant when compared with those before operation ( P<0.05). At 6 and 12 months after operation, the thigh circumference and calf circumference were significantly larger in the experimental group than in the control group ( P<0.05). At 3 and 6 months after operation, the knee range of motion was significantly smaller in the experimental group than in the control group ( P<0.05). Under the loading condition of 13-20 N, the ATTD in the experimental group increased first and then decreased after operation; and the ATTD significantly increased at 3, 6 months after operation when compared with the value before operation ( P<0.05). But there was no significant difference between the pre-operation and 12 months after operation ( P>0.05). There was no significant change in ATTD in the control group at 3, 6, and 12 months after operation ( P>0.05), and which were significantly higher than those before operation ( P<0.05). At each time point after operation, the ATTD was significantly smaller in the experimental group than in the control group under the same load ( P<0.05). The MRI examination of the experimental group showed that the ACL boundary gradually became clear after reconstruction and was covered by the synovial membrane. The SNQ at each time point after operation was significantly higher than that before operation, but gradually decreased with time, and the differences between time points were significant ( P<0.05). The ACL reconstruction model in cynomolgus monkey with autogenous hamstring tendon transplantation was successfully established.

A pharmacokinetic study of extended-release buprenorphine in cynomolgus monkeys (Macaca fasicularis).

A novel buprenorphine (BUP) extended-release formulation (BUP-XR) produced as a lipid-encapsulated, low viscosity BUP suspension for subcutaneous (SC) injection to control pain was evaluated for pharmacokinetics and safety in four adult male cynomolgus monkeys. Each animal was given 0.2 mg/kg reformulated BUP-XR SC. Clinical observations were made during the course of the study. Blood samples were obtained from each animal before BUP-XR administration, 6, 24, 48, 72, and 96 h post-BUP-XR injection. Plasma levels of buprenorphine were analyzed using HPLC-MS/MS. The PK values calculated included peak plasma concentration of the BUP analyte, time to peak plasma concentration, plasma half-life, area under the plasma concentration-time curve, clearance, apparent volume of distribution, and elimination rate constant (Cmax , Tmax , T½ , AUC0-t , CL, Vd, and Ke, respectively). Observable adverse clinical signs were not detected. BUP concentration peaked from 6 to 48 h, then declined in a linear fashion. Quantifiable plasma BUP was measured in all monkeys at all time points. Results indicate that a single BUP-XR dose at 0.2 mg/kg can reliably provide plasma levels of BUP reported in the literature to be therapeutically relevant for up to 96 h. Because of the lack of any clinical observations or adverse effects at the injection site or absence of observable abnormal behaviors, it may be concluded that the use of BUP-XR is safe and efficacious in this species of non-human primate at the dose regimen described in this study for up to 96 h post-administration.

Effects of selective dopamine D3 receptor partial agonist/antagonists on oxycodone self-administration and antinociception in monkeys.

Recent studies suggest that dopamine D3 receptors (D3R) may be a therapeutic target for opioid use disorders (OUD). This study examined the effects of the D3Rpartial agonist (±)VK4-40 and the D3R-selective antagonist (±)VK4-116, compared to the mu-opioid receptor antagonist naltrexone (NTX), in nonhuman primate models of OUD and antinociception. Adult male and female (N = 4/sex) cynomolgus monkeys were trained to self-administer oxycodone (0.003-0.1 mg/kg/injection) first under a fixed-ratio (FR) and then a progressive-ratio (PR) schedule of reinforcement during daily 1- and 4-hr sessions, respectively. Under the FR schedule, intravenous NTX (0.01-0.1 mg/kg), (±)VK4-116 (1.0-10 mg/kg), and (±)VK4-40 (1.0-10 mg/kg) were studied in combination with the peak oxycodone dose and a dose on the descending limb of the dose-effect curve; NTX and (±)VK4-40 were also studied at the peak of the PR dose-response curve (N = 4). Following saline extinction, each compound was examined on oxycodone-induced reinstatement. Finally, these compounds were assessed in adult male rhesus monkeys (N = 3) in a warm-water (38 °C, 50 °C, 54 °C) tail withdrawal assay. NTX decreased responding on the peak of the FR oxycodone dose-response curve, but increased responding on the descending limb. (±)VK4-40, but not (±)VK4-116, significantly decreased peak oxycodone self-administration; (±)VK4-40 did not increase responding on the descending limb. NTX and (±)VK4-40, but not (±)VK4-116, attenuated oxycodone-induced reinstatement. Under PR responding, NTX and (±)VK4-40 decreased breakpoints. Oxycodone-induced antinociception was attenuated by NTX, but not by (±)VK4-40 or (±)VK4-116. Together, these results suggest that further research evaluating the effects of (±)VK4-40 as a novel pharmacotherapy for OUD is warranted.

OCE-205 in rats and non-human primates: Pharmacokinetic and pharmacodynamic analysis

Treatment for complications associated with the hemodynamic consequences of decompensated cirrhosis remains suboptimal. Terlipressin, the latest pharmacological management of hepatorenal syndrome–acute kidney injury (HRS-AKI), targets the vasopressin system but has serious side effects. OCE-205 is a novel peptide designed to target the vasopressin receptor system as a mixed V1a agonist/antagonist, resulting in effective partial agonism without V2 agonism. We examined the in vivo pharmacokinetic/pharmacodynamic properties of OCE-205 in healthy rats and cynomolgus monkeys. OCE-205 was administered by IV or SC bolus injection; arginine vasopressin (AVP) or terlipressin were comparators. After IV OCE-205 administration in rats, mean plasma concentration decreased in a mostly linear manner to 2 mg/mL after 120 min, and for SC administration, slowly decreased to ∼50 ng/mL after 300 min. Compared with pre-test values, arterial blood pressure values significantly increased after all OCE-205 doses tested. For monkeys, the concentration after IV OCE-205 administration was mostly linear to 5 ng/mL after 180 min, and for SC administration, ∼3 ng/mL after 480 min. Subcutaneous OCE-205 administration increased mean arterial pressure (MAP) versus baseline, with ΔMAP in OCE-205–treated animals marked and long-lasting while terlipressin induced an increase from baseline in MAP, with negligible ΔMAP, on average, by 150 min after administration in all groups. AVP, but not OCE-205, significantly increased blood lactate concentrations. OCE-205 was well tolerated in adult male rats and cynomolgus monkeys following single-dose bolus administration. The preclinical results of OCE-205, with its demonstrated V1a selective partial agonist activity and potentially tolerable safety profile, suggest its potential utility for treatment of the cardiovascular complications of cirrhosis. Institutional protocol numberProcedures were approved by the Ferring Research Institute (FRI) Institutional Animal Care and Use Committee (IACUC) on November 27, 2006 under protocol FRI 06-011, and by the Sinclair Research Center IACUC under protocol S11177.

Effects of long‐term ethanol consumption on cognitive function in group‐housed monkeys

In the United States there are approximately 14.4 million adults diagnosed with alcohol use disorder (AUD). Despite this, there is an incomplete understanding of how chronic stress influences the development of AUD. Previous studies have shown that long‐term alcohol drinking negatively impacts cognitive flexibility (the ability to alter behavior in response to changing contingencies) and impulsive choice (the tendency to overvalue smaller, immediate rewards compared to larger, delayed rewards). However, the timing and extent of deficits that result from specific drinking patterns have not been well‐characterized. A better understanding of the progression of cognitive dysfunction is critical because deficits in these processes can perpetuate problematic alcohol use. In the present study, group‐housed adult male cynomolgus monkeys formed social hierarchies, which represent a continuum from environmental enrichment in high‐ranking (dominant; DOM; n=6) monkeys to chronic social stress in low‐ranking (subordinate; SUB; n=6) monkeys. Monkeys were trained to drink an unflavored 4% ethanol (EtOH) solution via schedule induction, then had access to self‐administer EtOH 22 hours/day, 4 days/week in the home cage (“free access”) while concurrently pressing a lever to deliver food pellets. To assess the effects of EtOH consumption on cognitive flexibility, monkeys performed a stimulus discrimination and reversal task (SD/SDR) on non‐drinking days using home cage touchscreen technology. Three stimuli appeared on the screen and the task ended when the monkey chose the correct stimulus on 18 of 20 consecutive trials. The task was administered just after induction and again after 6 months of free access. At this point, two modifications were made to increase task difficulty. First, two stimuli were added as additional distractors. In addition, the session was extended to 90 minutes and the total number of reversals was measured. We also characterized impulsive choice using a mean adjusted delay discounting task just after induction and after 4 months of free access. We hypothesized that subordinate monkeys would have greater EtOH intakes versus dominant monkeys and, as a result, would show greater cognitive dysfunction. As hypothesized, subordinate monkeys maintained greater (1.77 ± 0.95 g/kg) mean daily EtOH intakes compared to dominant monkeys (0.85 ± 0.91 g/kg) during 6 months of free access. However, there were no significant differences between dominant and subordinate monkeys in discrimination or reversal trials to criterion, or number of errors at baseline or after 6 months of free access using the 3‐stimuli SD/SDR task. There were also no rank‐related differences in these dependent variables (or number of reversals completed) when the task was modified to include 5 stimuli. Regarding the delay discounting task, both groups showed decreased impulsive choice from baseline to 4 months of free access, however the effect was lesser in subordinates. Although there are rank‐related differences in mean EtOH intake, monkeys do not appear to have significant EtOH‐induced deficits in these two domains of cognitive function in the present study. This study is ongoing and results following one year of access to EtOH will be assessed.

An Optimal Animal Model of Ischemic Stroke Established by Digital Subtraction Angiography-Guided Autologous Thrombi in Cynomolgus Monkeys.

ObjectiveIschemic stroke seriously threatens human health, characterized by the high rates of incidence, disability, and death. Developing a reliable animal model that mimics most of the features of stroke is critical for pathological studies and clinical research. In this study, we aimed to establish and examine a model of middle cerebral artery occlusion (MCAO) guided by digital subtraction angiography (DSA) in cynomolgus monkeys.Materials and MethodsIn this study, 15 adult male cynomolgus monkeys were enrolled. Under the guidance of DSA, a MCAO model was established by injecting an autologous venous clot into the middle cerebral artery (MCA) via femoral artery catheter. Thrombolytic therapy with alteplase (rt-PA) was given to eight of these monkeys at 3 h after the occlusion. Blood test and imaging examination, such as computed tomography angiography (CTA), CT perfusion (CTP), brain magnetic resonance imaging (MRI), and brain magnetic resonance angiography (MRA), were performed after the operation to identify the post-infarction changes. The behavioral performance of cynomolgus monkeys was continuously observed for 7 days after operation. The animals were eunthanized on the 8th day after operation, and then the brain tissues of monkeys were taken for triphenyltetrazolium chloride (TTC) staining.ResultsAmong the 15 cynomolgus monkeys, 12 of them were successfully modeled, as confirmed by the imaging findings and staining assessment. One monkey died of brain hernia resulted from intracranial hemorrhage confirmed by necropsy. DSA, CTA, and MRA indicated the presence of an arterial occlusion. CTP and MRI showed acute focal cerebral ischemia. TTC staining revealed infarct lesions formed in the brain tissues.ConclusionOur study may provide an optimal non-human primate model for an in-depth study of the pathogenesis and treatment of focal cerebral ischemia.

Atherosclerotic Lesion of the Carotid Artery in Indonesian Cynomolgus Monkeys Receiving a Locally Sourced Atherogenic Diet.

The atherosclerotic lesion is a principal hallmark of atherosclerotic animal models. This study aimed to assess lesions of the carotid artery in Indonesian cynomolgus monkeys exposed to an IPB-1 atherogenic diet. A total of 20 adult male cynomolgus monkeys received the local IPB-1 diet for two years. Blood lipid profiles, morphology, and carotid ultrasound of monkeys were measured. Nine of them were euthanized to confirm atherosclerotic lesions. Common carotid arteries (CCA) and carotid bifurcation (BIF) samples were collected and stained using Verhoef-van Giessen and CD68 immunohistochemistry. The results reveal the presence of severe atherosclerosis plaques in six out of nine animals (66.7%) corresponding to intermediately and hyper-responsive groups. The hyper-responsive group displayed the highest response in the developing intimal area (IA) at the CCA (0.821 mm2), whereas the hyporesponsive group had the smallest IA (0.045 mm2) (p = 0.0001). At the BIF, the hyporesponsive group showed the smallest IA (p = 0.001), but there was no difference between the intermediately and hyper-responsive groups (p = 0.312). The macrophage marker CD68 was also expressed on the cartotid of the intermediately and hyper-responsive groups. These results indicate that severe atherosclerotic lesions with high infiltration of macrophages were formed in the carotid arteries of intermediately and hyper-responsive Indonesian cynomolgus monkeys fed with the local atherogenic diet IPB-1 over two years, thus confirming atherosclerosis in a nonhuman primate model.

Pegbelfermin, a PEGylated FGF21 analogue, has pharmacology without bone toxicity after 1-year dosing in skeletally-mature monkeys

Pegbelfermin (PGBF) is a PEGylated fibroblast growth factor 21 (FGF21) analogue in development for treatment of nonalcoholic steatohepatitis (NASH). Mouse models highlight potential utility of FGF21 in NASH, but also suggest negative effects on bone, though these findings are confounded by profound FGF21-related decreases in body mass/growth. This study aimed to profile PGBF-related bone effects in adult nonhuman primates after long-term, clinically-relevant exposures. Adult male cynomolgus monkeys received weekly subcutaneous PGBF (0.3, 0.75 mg/kg) or control injections for 1 year (n = 5/group). Assessments included body weight, clinical chemistry, adiponectin levels, bone turnover biomarkers, skeletal radiography, pharmacokinetics, immunogenicity, and histopathology. Bone densitometry and body composition were evaluated in vivo and/or ex vivo with dual-energy x-ray absorptiometry, peripheral quantitative computed tomography, and biomechanical strength testing. After 1 year of PGBF administration, there was clear evidence of sustained PGBF pharmacology in monkeys (peak increase in serum adiponectin of 1.7× and 2.35× pretest at 0.3 and 0.75 mg/kg PGBF, respectively) and decreased body weight compared with control at exposures comparable to those tested in humans. At 0.75 mg/kg PGBF, pharmacologically-mediated reductions in lean mass, lean area, and fat area were observed relative to controls. There were no PGBF-related effects on bone biomarkers, radiography, densitometry, or strength. Together, these data demonstrate that PGBF did not adversely alter bone metabolism, density, or strength following 1 year of dosing at clinically relevant (0.7–2.2× human AUC[0-168 h] at 20 mg once weekly), pharmacologically-active exposures in adult monkeys, suggesting a low potential for negative effects on bone quality in adult humans.

White matter demyelination predates axonal injury after ischemic stroke in cynomolgus monkeys

Unraveling the pathology of stroke is a prerequisite for designing therapeutic strategies. It was reported that myelin injury exceeded axonal loss in the peri-infarct region of rodent white matter stroke. An in-depth investigation of the post-stroke white matter damage in higher-order species might innovate stroke intervention. In this study, adult male cynomolgus monkeys received surgical middle cerebral artery occlusion (MCAO), and serial magnetic resonance scans to non-invasively assess brain damage. Spontaneous movements were recorded to evaluate post-stroke behavior. The axon and myelin loss, as well as immune cell infiltration were examined using immunohistochemistry. Magnetic resonance imaging revealed cerebral infarcts and white matter injury after MCAO in monkeys, which were confirmed by neurological deficits. Immunostaining of white matter fibers showed substantial demyelination whilst retention of axons in the infarcts 8 days post MCAO, while a progressive loss of myelin and axons was observed after one month. Gliosis, microglia activation, and leukocyte infiltration were identified in the lesions. These results demonstrate that demyelination predates axonal injury in non-human primate ischemic stroke, which provides a time window for stroke intervention focusing on prevention of progressive axonal loss through myelin regeneration.

Development of a novel gripping test for the evaluation of the finger fine motor ability in MPTP-treated monkeys

Assessing the finger fine motor ability is extremely important. However, conventional behavioral tests in monkeys are complicated and costly. We attempted to develop a new task to assess the precise finger grip in Parkinson's disease monkeys based on the principles of objectification, multipurpose, and simplification. This study involved seven adult male cynomolgus monkeys. A gripping test based on the previous food reaching test was developed. Parallel experiments of food reaching test and gripping test affected by the treatments of levodopa and deep brain stimulation of the subthalamic nucleus were performed to verify the utility of the gripping test. We found that gross motor ability (measured by food reaching test) could be significantly improved by both the subthalamic nucleus and levodopa administration, which reproduced the results of our previous study. The finger fine motor ability (measured by the gripping test) could be significantly improved by levodopa administration, but not by the subthalamic nucleus. Our results verified the utility and reliability of the gripping test, which is a simple, convenient, and objective task for evaluating the finger fine motor skill in Parkinson's disease monkeys. Mechanisms of the efficacy of deep brain stimulation on fine motor ability require further investigation.

Metabolic and morphometric changes in Indonesian cynomolgus monkeys (Macaca fascicularis) fed an atherogenic diet composed of locally sourced ingredients.

Background and Aim:This study was designed to determine the effects of a new atherogenic diet formulated at Institut Pertanian Bogor (IPB) (Bogor, Indonesia) on metabolic, morphometric, and carotid artery imaging of cynomolgus monkeys.Materials and Methods:A total of 20 adult male cynomolgus monkeys fed IPB-1 atherogenic diet for 1 year. Total plasma cholesterol (TPC), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, and morphometric measurements were evaluated at baseline and monthly during the study. Carotid plaques and intima-media thickness (IMT) were measured using ultrasonography at baseline and after 8 months of treatment.Results:This diet increased TPC, LDL, and TPC/HDL ratio and induced carotid atherosclerosis in this model. The TPC, LDL, and TPC/HDL ratio were positively associated; however, HDL was negatively associated with carotid plaques and IMT.Conclusion:The IPB-1 atherogenic diet formulated with locally and readily available ingredients provides an economically and scientifically feasible monkey model to study atherosclerosis in Indonesia and Southeast Asia.

Nonhuman primate model of persistent erectile and urinary dysfunction following radical prostatectomy: Feasibility of minimally invasive therapy.

Persistent urinary incontinence (UI) and/or erectile dysfunction (ED) occur in 30-50% of post-radical prostatectomy patients regardless of nerve sparing approaches. Identification of potential treatment options for these patients will require testing in an animal model that develops these chronic conditions. The objective was to characterize a nonhuman primate (NHP) model of persistent post-prostatectomy ED and UI and then test the feasibility of periurethral injection of the chemokine CXCL-12. Ten adult male cynomolgus monkeys were used. Two were used for study of normal male nonhuman primate genitourinary anatomy. Five were used for measures of sexual behavior, peak intra-corporal pressure (ICP), abdominal leak point pressures (ALPP) 3 and 6-months post open radical prostatectomy (ORP). Three additional ORP animals received ultrasound-guided peri-urethral injection of chemokine CXCL12 6 weeks after ORP, and UI/ED evaluated for up to 3 months. The anatomy, innervation, and vascular supply to the prostate and surrounding tissues of these male NHPs are substantially similar to those of human beings. ORP resulted in complete removal of the prostate gland along with both neurovascular bundles and seminal vesicles while permitting stable restoration of vesico-urethral patency. ORP produced sustained (6 months) decreases in ALPP, ICP's, and sexual function. Transurethral injection of chemokine CXCL12 was feasible and had beneficial effects on erectile and urinary function. ORP in NHPs produced persistent erectile and urinary tract dysfunction. Periurethral injection of CXCL-12 was feasible and improved both urinary incontinence and erectile dysfunction and suggests that this model can be used to test new approaches for both conditions.

Effects of ethanol on cocaine self-administration in monkeys responding under a second-order schedule of reinforcement

BackgroundConcurrent alcohol use among cocaine abusers is common but the behavioral variables that promote co-abuse are not well understood. The present study examined the effects of intragastric (i.g.) ethanol (EtOH) administration in monkeys responding under a schedule of cocaine reinforcement in which extensive drug seeking was maintained by conditioned stimuli. MethodsFour adult male cynomolgus monkeys (Macaca fascicularis) were trained to respond under a second-order fixed-interval (FI) 600s (fixed-ratio (FR) 30:S) schedule of cocaine (0.003–0.56mg/kg/injection) presentation. Sessions ended after 5 injections or 90min had elapsed. Different EtOH doses (0.5–2.0g/kg, i.g.) were administered 30min before the session, typically on Tuesdays and Fridays. Blood ethanol concentrations (BECs) were also assessed. Pattern of FI responding was assessed by determining quarter-life (QL) values. ResultsCocaine self-administration was characterized as an inverted U-shaped function of dose; QL values increased monotonically with dose. EtOH pretreatments dose-dependently decreased self-administration at several cocaine doses in 3 of 4 monkeys. In one animal, EtOH increased low-dose cocaine-maintained responding. For all monkeys, QL values were increased by EtOH when low- and high-cocaine doses were self-administered, suggesting additive effects of EtOH and cocaine. Furthermore, BECs were not altered following cocaine self-administration. ConclusionsThe reductions in cocaine self-administration and the increases in QL values following EtOH, suggest that EtOH was enhancing cocaine-related conditioned reinforcement. A better understanding of the behavioral mechanisms that mediate the co-abuse of alcohol and cocaine will lead to improved treatments for both drugs.

Attenuation of Responses to Endotoxin by the Triggering Receptor Expressed on Myeloid Cells-1 Inhibitor LR12 in Nonhuman Primate

The triggering receptor expressed on myeloid cells-1 is an immunoreceptor that amplifies the inflammatory response mediated by toll-like receptors engagement. Triggering receptor expressed on myeloid cells-1 inhibitory peptides such LR12 have been shown to prevent hyperresponsiveness and death in several experimental models of septic shock. Twelve adult male Cynomolgus (Macaca fascicularis) monkeys exposed to an intravenous bolus of endotoxin (10 μg/kg) were randomized to receive LR12 or placebo (n = 6 per group) as an initial intravenous bolus followed by an 8-h continuous intravenous infusion. An additional group of four only received vehicle infusion. Vital signs were monitored for 8 h. Blood was sampled at H0, 1, 2, 4, and 8 for analysis of clinical chemistries, leukocyte count, coagulation parameters, and cytokine plasma concentration. LR12 showed no effect on heart rate and body temperature. By contrast to the placebo group, which experienced a 25 to 40% blood pressure decrease after endotoxin administration, LR12-treated monkeys remained normotensive. Endotoxin induced leukopenia at 2 h (mean leukocyte count, 7.62 g/l vs. 21.1 at H0), which was attenuated by LR12. LR12 also attenuated cytokine production. The triggering receptor expressed on myeloid cells-1 inhibitor LR12 is able to mitigate endotoxin-associated clinical and biological alterations, with no obvious side effects. This study paves the way for future phases Ia and Ib trials in humans.

Increased Epidermal Growth Factor–Like Ligands Are Associated With Elevated Vascular Nicotinamide Adenine Dinucleotide Phosphate Oxidase in a Primate Model of Atherosclerosis

To characterize the relationship between the expression of epidermal growth factor (EGF)-like ligands and vascular nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression and activity in a primate model of atherosclerosis. Adult male Cynomolgus monkeys were fed a normal or atherogenic (AS) diet for 45 months, after which animals from the AS group were placed on a normal diet for 8 months (regression). The expression of membrane-associated EGF-like ligands was increased in arteries from animals on the AS diet and normalized in the regression group. EGF-like ligands were distributed throughout atherosclerotic vessels but predominantly colocalized with macrophages. Consistent with ligand shedding, circulating heparin-bound EGF was elevated in the plasma of AS monkeys but not in those on regression diet. Atherosclerosis was associated with the activation of EGF receptor signaling. Expression of NADPH oxidase subunits Nox1 and Nox2 but not Nox4 or Nox5 was increased in arteries from monkeys on the AS diet and returned to normal with regression. Levels of Nox1 and Nox2 positively correlated with EGF-like ligands. In cultured monkey smooth muscle cells, treatment with EGF-like ligands increased Nox1 expression and activity. These data identify EGF-like ligands as potential modulators of atherogenesis, resulting in part from increased vascular NADPH oxidase activity.

A Longitudinal Analysis of Circulating Stress‐Related Proteins and Chronic Ethanol Self‐Administration in Cynomolgus Macaques

Alcoholics have alterations in endocrine and immune functions and increased susceptibility to stress-related disorders. A longitudinal analysis of chronic ethanol intake on homeostatic mechanisms is, however, incompletely characterized in primates. Plasma proteins (n = 60; Luminex) and hormones (adrenocorticotropic hormone [ACTH]; cortisol) were repeatedly measured in adult male cynomolgus monkeys (Macaca fascicularis, n = 10) during a 32-month experimental protocol at baseline, during induction of water and ethanol (4% w/v in water) self-administration, after 4 months, and after 12 months of 22-hour daily concurrent access to ethanol and water. Significant changes were observed in ACTH, cortisol, and 45/60 plasma proteins: a majority (28/45) were suppressed as a function of ethanol self-administration, 8 proteins were elevated, and 9 showed biphasic changes. Cortisol and ACTH were greatest during induction, and correlations between these hormones and plasma proteins varied across the experiment. Pathway analyses implicated nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) as possible mediators of ethanol-induced effects on immune-related proteins in primates. Chronic ethanol consumption in primates leads to an allostatic state of physiological compromise with respect to circulating immune- and stress-related proteins in NF-κB- and STAT/JAK-related pathways in correlation with altered endocrine activity.

RhBMP-2 Induces Transient Bone Resorption Followed by Bone Formation in a Nonhuman Primate Core-Defect Model

Bone resorption preceding bone formation has been reported following the administration of recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered in an absorbable collagen sponge (ACS) in metaphyseal bone. This study characterizes treatment with rhBMP-2/ACS in metaphyseal bone with use of a nonhuman primate core-defect model. Unilateral proximal femoral core defects were treated with 360 microg of rhBMP-2/ACS or ACS alone or were left untreated in seven, five, and five adult male cynomolgus monkeys, respectively. Distal femoral core defects in seven of the above animals were treated with 360 microg of rhBMP-2/ACS in one limb and ACS alone in the contralateral limb. Retention of rhBMP-2 in the proximal part of the femora was determined with use of tracer amounts of (125)I-rhBMP-2 imaged with a gamma camera. The distal part of the femora was evaluated with in vivo computed tomography. Computed tomography and histological evaluation were performed on harvested segments in all animals at twenty-four weeks. The histological response in the proximal and distal parts of the femora containing core defects treated with 360 microg of rhBMP-2/ACS in one limb and ACS alone in the contralateral limb was evaluated at one, two, and four weeks in three animals per time point. Approximately 39.9%, 24.2%, 3.4%, and 0.5% of the rhBMP-2 was retained in the proximal part of the femora at one, seven, fourteen, and twenty-one days, respectively. The mineral density and trabecular volume fraction of the core defects treated with rhBMP-2/ACS, those treated with ACS alone, and untreated core defects in the proximal part of the femora were 81%, 54%, and 20%, respectively, and 94%, 36%, and 31%, respectively, of the corresponding region in the contralateral limbs at twenty-four weeks. The mineral density and trabecular volume fraction of the region surrounding the core defects treated with rhBMP-2/ACS, those treated with ACS alone, and untreated core defects were 112%, 105%, and 104%, respectively, and 117%, 108%, and 107%, respectively, of the corresponding region in the contralateral limbs. Treatment with rhBMP-2/ACS increased the size of the proximal and distal core defects compared with treatment with ACS alone. Histological evaluation of the rhBMP-2/ACS-treated limbs demonstrated that bone resorption was initiated at one week in association with osteoclasts and receptor activator of nuclear factor-kappaB ligand-positive stained spindle-shaped cells and peaked at two weeks. Bone formation was observed at two weeks and was ongoing at twenty-four weeks. Treatment of metaphyseal core defects with rhBMP-2/ACS resulted in bone resorption followed by bone formation in nonhuman primates.