Hematological and serum biochemical values in cynomolgus monkeys anesthetized with ketamine hydrochloride

Quality of hematology and clinical chemistry results in laboratory and zoo nonhuman primates: Effects of the preanalytical phase. A review

Most errors in clinical pathology originate in the preanalytical phase, which includes all steps from the preparation of animals and equipment to the collection of the specimen and its management until analyzed. Blood is the most common specimen collected in nonhuman primates. Other specimens collected include urine, saliva, feces, and hair. The primary concern is the variability of blood hematology and biochemistry results due to sampling conditions with the effects of capture, restraint, and/or anesthesia. Housing and diet have fewer effects, with the exception of food restriction to reduce obesity. There has been less investigation regarding the impact of sampling conditions of nonblood specimens.

Evaluating individual biomarkers for predicting health risks in zoo-housed chimpanzees (Pan troglodytes) and bonobos (Pan paniscus)

Although biomarkers are often used for predicting morbidity and mortality in humans, similar data are lacking in our closest relatives. This study analyzed 16 biomarkers in zoo-housed chimpanzees and bonobos from serum samples collected during both routine and nonroutine veterinary immobilizations. Generalized linear and generalized linear mixed models were used to determine the efficacy of each biomarker to predict all-cause morbidity, defined as the presence of at least one chronic condition, or cardiac disease as a subset of all-cause morbidity. Cox proportional hazards models were used to examine associations between biomarkers and mortality risk from any cause. Analyses were conducted using two data sets for each species, one with all values retained (chimpanzees: n = 148; bonobos: n = 33) and the other from samples collected during routine immobilizations only (chimpanzees: n = 95; bonobos: n = 23). Consistent results across both data sets in chimpanzees included associations of higher cortisol with all-cause morbidity risk, lower creatinine with cardiac disease risk, and higher creatinine with mortality risk, and in bonobos were increased cardiac disease risk with higher cortisol and lower dehydroepiandrosterone-sulfate, fructosamine, and triglycerides. However, there were some inconsistencies between data sets, such as tumor necrosis factor-α predicting mortality risk positively in chimpanzees when all values were retained, but negatively for routine values only. Despite the close evolutionary relationships between chimpanzees and bonobos, the only result observed in both species was a negative association between albumin and mortality risk in the all values retained data sets. Thus, data suggest some biomarkers may be useful predictors of future health outcomes, although a better understanding of both individual and species variation in biomarkers and their contribution to health risks is needed.

Reference Intervals and Percentiles for Hematologic and Serum Biochemical Values in Captive Bred Rhesus (Macaca mulatta) and Cynomolgus Macaques (Macaca fascicularis)

Several physiological characteristics and housing conditions are known to affect hematologic and serum biochemical values in macaques. However, the studies that have been conducted either report values calculated based on a small number of animals, were designed specifically to document the effect of a particular condition on the normal range of hematologic and serum biochemical values, or used parametric assumptions to calculate hematologic and serum biochemical reference intervals. We conducted a retrospective longitudinal cohort study to estimate reference intervals for hematologic and serum biochemical values in clinically healthy macaques based on observed percentiles without parametric assumptions. Data were obtained as part of the Biomedical Primate Research Centre (Rijswijk, The Netherlands) health monitoring program between 2018 and 2021. In total, 4009 blood samples from 1475 macaques were analyzed with a maximum of one repeat per year per animal. Data were established by species, gender, age, weight-for-height indices, pregnancy, sedation protocol, and housing conditions. Most of the parameters profoundly affected just some hematologic and serum biochemical values. A significant glucose difference was observed between the ketamine and ketamine-medetomidine sedation protocols. The results emphasize the importance of establishing uniform experimental groups with validated animal husbandry and housing conditions to improve the reproducibility of the experiments.

Naturally Occurring Endocrine Disorders in Non-Human Primates: A Comprehensive Review

Simple Summary

Nonhuman primates (NHP) can become ill due to a variety of diseases and disorders, yet endocrine disorders remain underreported. Therefore, an exhaustive literature search on this subject via widely used academic search systems, peer-reviewed publications, proceedings, and newsletters was performed. Selected major endocrine entities will be described emphasizing clinical signs, morphologic features, concomitant diseases, as well as available treatment options. In most cases, no clinical signs were noted and on gross pathology, the endocrine organs were unremarkable. The diagnosis was frequently made as incidental findings after standard histological examination. Although the findings were frequently incidental many have the potential to impact studies. This review explains that there is no standard procedure for diagnosing, monitoring, or treating endocrine disorders in NHP. More research is needed to evaluate these procedures and establish risk factors.

Abstract

Literature concerning veterinary medicine of non-human primates is continuously updated, yet endocrine disorders remain underreported. While case or survey reports of individual endocrinopathies are available, a comprehensive review is not. An exhaustive literature search on this subject via widely used academic search systems, (e.g., Google Scholar, PubMed, BioOne complete and Web of Science), and peer-reviewed publications, proceedings, and newsletters was performed. Selected major endocrine entities will be described with emphasis on clinical signs, morphologic appearances, concomitant diseases, as well as available treatment options. Mostly, no clinical signs were noted and on gross pathology, the endocrine organs were unremarkable. An endocrine-related diagnosis was frequently made as an incidental finding after standard histopathological examination. During the review, the pancreas represented the most affected endocrine organ and diabetes mellitus represented the most clinically significant disorder. Currently, no standard procedure for diagnosing, monitoring, or treating endocrine disorders in non-human primates exists.

COMPARISON OF THREE ANALYZERS FOR ASSESSING COMPLETE BLOOD COUNTS IN NONHUMAN PRIMATES

Diagnostic hematology can prove challenging to the exotic animal practitioner presented with a nonhuman primate patient. Few point-of-care automated cell counters are calibrated for primate samples. Twenty-one samples from 17 nonhuman primates presented to an exotic animal practice were analyzed. Samples were run on both canine and feline settings on each of two veterinary point-of-care analyzers: one that assays by impedance technology, and one that assays by laser flow cytometry. Samples were also sent to a reference laboratory to be assayed on an analyzer that performs simultaneous impedance and laser measurements of blood cells and has been calibrated for use in nonhuman primates. Fourteen analytes were assessed for each sample on each machine. Manual hematocrits and total white blood cell counts were also performed on 16 of the samples. Statistical analysis indicated some variance between individual parameters, but overall correlation was acceptable.

Research-Relevant Clinical Pathology Resources: Emphasis on Mice, Rats, Rabbits, Dogs, Minipigs, and Non-Human Primates

Clinical pathology testing for investigative or biomedical research and for preclinical toxicity and safety assessment in laboratory animals is a distinct specialty requiring an understanding of species specific and other influential variables on results and interpretation. This review of clinical pathology principles and testing recommendations in laboratory animal species aims to provide a useful resource for researchers, veterinary specialists, toxicologists, and clinical or anatomic pathologists.

(R)-Ketamine ameliorates lethal inflammatory responses and multi-organ injury in mice induced by cecum ligation and puncture

AIMS

Sepsis is a life-threatening organ dysfunction syndrome arising from infection-induced uncontrolled systemic inflammatory responses. Patients surviving severe sepsis also exhibit increased mortality due to enhanced vulnerability to infections. In this study, we examined whether (R)-ketamine could prevent against lethal sepsis-induced systemic inflammation and inflammatory organ injury.

MAIN METHODS

Septic model was induced by cecal ligation and puncture (CLP) surgery on adult mice. (R)-ketamine (10 or 15 mg/kg) was administrated intraperitoneally (i.p.) 24 h before and/or immediately after CLP.

KEY FINDINGS

Combined prophylactic and therapeutic use of (R)-ketamine (10 mg/kg), as well as either prophylactic or therapeutic use of (R)-ketamine at a single dose of 15 mg/kg did not reduce 14-day mortality after CLP. However, combined prophylactic and therapeutic use of (R)-ketamine (15 mg/kg) significantly increased 14-day survival rate, attenuated sepsis-induced marked drop in the rectal temperature and increase in the plasma levels of inflammatory cytokines [i.e., interleukin (IL)-6, IL-17A, tumor necrosis factor (TNF)-α, IL-1β, and IL-10] 12 h after CLP. Furthermore, (R)-ketamine alleviated sepsis-induced increase in the organ injury markers such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), myocardial kinase (CK-MB), and creatinine 24 h after CLP. Moreover, the increased lung wet/dry weight ratio, pulmonary morphological injury and the pulmonary levels of inflammatory cytokines were also attenuated by (R)-ketamine.

SIGNIFICANCE

Combined prophylactic and therapeutic use of (R)-ketamine could attenuate systemic inflammation and inflammatory multi-organ injury in mice after CLP-induced lethal sepsis. Therefore, (R)-ketamine would be a potential prophylactic and therapeutic drug for patients prone to sepsis.

Age, sex, and inflammatory markers predict chronic conditions, cardiac disease, and mortality among captive western lowland gorillas (Gorilla gorilla gorilla)

In humans, inflammatory markers predict health risks. As great apes experience many similar conditions, measuring inflammation may provide valuable health information. We examined four serum inflammatory markers in zoo-housed gorillas (n = 48): albumin, CRP, IL-6, and TNF-α. We first analyzed age- and sex-associated patterns, then used multimodel inference to evaluate models with age, sex, and inflammatory markers as predictors of all-cause morbidity, cardiac disease, and mortality. Older gorillas had lower albumin and higher IL-6, and males had higher albumin, lower CRP, and lower TNF-α. All-cause morbidity was best predicted by age, sex, and TNF-α, but the second model containing only age and sex was equivalent. Cardiac disease was best predicted by TNF-α alongside age and sex, with lower levels associated with increased risk. When outliers were removed, the model with TNF-α was second to the model containing only age and sex. Finally, mortality risk was best predicted by the model with only age and sex. Other models containing individual inflammatory markers were within top model sets for each health outcome. Our results indicate that age and sex are robust for predicting all-cause morbidity and mortality risk in gorillas; while models which include individual inflammatory markers also predict risk, they may not improve predictions over age and sex alone. However, given the prevalence of cardiac disease in great apes, these results suggest that TNF-α warrants further investigation. With their potential to provide valuable health information, data on inflammatory markers may contribute to the care and management of gorillas in human care.

Correlations of serum biochemistry profile with ultrasonic histogram of liver, gallbladder, and kidneys and morphometry of rescued long-tailed macaques (Macaca fascicularis)

BACKGROUND

Serum biochemistry and ultrasonography can be useful diagnostic tools in evaluating the general health condition of long-tailed macaques in rescue and rehabilitation centers.

METHODS

This study was conducted to determine and correlate the serum biochemistry profile of 24 apparently healthy male and female rescued long-tailed macaques (LTM) with the body weight, crown-rump length, and ultrasonic histogram of liver parenchyma, gallbladder lumen, and renal cortices.

RESULTS

There were no sex-related differences in serum biochemistry values of aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, blood urea nitrogen, total cholesterol, and total protein. Creatinine was positively correlated with body weights and crown-rump length. Multiple weak positive and negative correlations of organ-specific serum parameters and mean ultrasonic histogram of liver, gallbladder, and kidneys were observed.

CONCLUSION

This study established the correlations of serum biochemistry profile with ultrasonic histogram of liver, gallbladder, and kidneys and morphometry of rescued LTM.

Hematological and blood chemistry values in captive Japanese macaques (Macaca fuscata fuscata)

BACKGROUND

Biological information about captive Japanese macaques, including hematology and blood chemistry, is still lacking despite the fact that ethological and ecological data have accumulated during decades of field research.

METHODS

Hematological (511 examinations of 280 Japanese macaques) and blood chemistry data (between 33 and 284 examinations from between 29 and 257 individual macaques) in clinically healthy, simian retrovirus-free Japanese macaques tested between 2009 and 2013 were reviewed.

RESULTS AND CONCLUSIONS

Specific hematological and blood chemistry data for Japanese macaques without clinical signs of disease were provided in this study. Averages presented can be used as hematological parameters for Japanese macaques. Some differences between Japanese macaques and other closely related macaque species were found. Some parameters varied according to macaque age and sex, as well as regional origin. The data in this study will provide useful clinical indices for Japanese macaques in captive and similar conditions.

Reference values of hematological and biochemical parameters in young-adult cynomolgus monkey (Macaca fascicularis) and rhesus monkey (Macaca mulatta) anesthetized with ketamine hydrochloride

Nonhuman primate models are valuable in biomedical research. However, reference data for clinical pathology parameters in cynomolgus and rhesus monkeys are limited. In the present study, we established hematologic and biochemical reference intervals for healthy cynomolgus and rhesus monkeys anesthetized with ketamine hydrochloride. A total of 142 cynomolgus monkeys (28 males and 114 females) and 42 rhesus monkeys (22 males and 20 females) were selected and analyzed in order to examine reference intervals of 20 hematological and 16 biochemical parameters. The effects of sex were also investigated. Reference intervals for hematological and biochemical parameters were separately established by species (cynomolgus and rhesus) and sex (male and female). No sex-related differences were determined in erythrocyte-related parameters for cynomolgus and rhesus monkey housed in indoor laboratory conditions. Alkaline phosphatase and gamma glutamyltransferase were significantly lower in females than males in both cynomolgus and rhesus monkeys aged 48–96 months. The reference values for hematological and biochemical parameters established herein might provide valuable information for researchers using cynomolgus and rhesus monkeys in experimental conditions for biomedical studies.

Effect of different anesthetic mixtures-ketamine-xylazine, ketamine-acepromazine and tiletamine-zolazepam-on the physiological and blood biochemistry parameters of male rhesus monkeys (Macaca mulatta) at different ages

BACKGROUND

Anesthetic agents are commonly utilized in the handling of non-human primates for prevent the stress caused in physical exploration or physical restrain. For this reason, the objective of this work was to describe the effect of age and dissociative anesthetics (ketamine and tiletamine), and their combinations with acepromazine, xylazine and zolazepam, on the physiological and blood biochemical parameters in Macaca mulatta.

METHODS

Eighty male Macaca mulatta were divided into four experimental groups depending on the anesthetic mixture applied. Each group of 20 males was divided into five sub-groups according to age. Physiological parameters were recorded every 5 minutes during a 30-minute period. A blood sample was drawn to analyze blood biochemistry.

RESULTS

Statistical analyses revealed significant differences in the physiological parameters between the ketamine-acepromazine and ketamine-xylazine groups compared to the control group. The analysis of blood biochemistry found significant differences by age and by anesthetic mixture among all groups.

CONCLUSION

These findings contribute to standardizing this animal model in biological research.

Systemic messenger RNA as an etiological treatment for acute intermittent porphyria

Acute intermittent porphyria (AIP) results from haploinsufficiency of porphobilinogen deaminase (PBGD), the third enzyme in the heme biosynthesis pathway. Patients with AIP have neurovisceral attacks associated with increased hepatic heme demand. Phenobarbital-challenged mice with AIP recapitulate the biochemical and clinical characteristics of patients with AIP, including hepatic overproduction of the potentially neurotoxic porphyrin precursors. Here we show that intravenous administration of human PBGD (hPBGD) mRNA (encoded by the gene HMBS) encapsulated in lipid nanoparticles induces dose-dependent protein expression in mouse hepatocytes, rapidly normalizing urine porphyrin precursor excretion in ongoing attacks. Furthermore, hPBGD mRNA protected against mitochondrial dysfunction, hypertension, pain and motor impairment. Repeat dosing in AIP mice showed sustained efficacy and therapeutic improvement without evidence of hepatotoxicity. Finally, multiple administrations to nonhuman primates confirmed safety and translatability. These data provide proof-of-concept for systemic hPBGD mRNA as a potential therapy for AIP.

Successful Repeated Hepatic Gene Delivery in Mice and Non-human Primates Achieved by Sequential Administration of AAV5ch and AAV1

In the gene therapy field, re-administration of adeno-associated virus (AAV) is an important topic because a decrease in therapeutic protein expression might occur over time. However, an efficient re-administration with the same AAV serotype is impossible due to serotype-specific, anti-AAV neutralizing antibodies (NABs) that are produced after initial AAV treatment. To address this issue, we explored the feasibility of using chimeric AAV serotype 5 (AAV5^ch) and AAV1 for repeated liver-targeted gene delivery. To develop a relevant model, we immunized animals with a high dose of AAV5^ch-human secreted embryonic alkaline phosphatase (hSEAP) that generates high levels of anti-AAV5^ch NAB. Secondary liver transduction with the same dose of AAV1-human factor IX (hFIX) in the presence of high levels of anti-AAV5^ch NAB proved to be successful because expression/activity of both reporter transgenes was observed. This is the first time that two different transgenes are shown to be produced by non-human primate (NHP) liver after sequential administration of clinically relevant doses of both AAV5^ch and AAV1. The levels of transgene proteins achieved after delivery with AAV5^ch and AAV1 illustrate the possibility of both serotypes for liver targeting. Furthermore, transgene DNA and RNA biodistribution patterns provided insight into the potential cause of decrease or loss of transgene protein expression over time in NHPs.

Deciphering Sources of Variability in Clinical Pathology-It's Not Just about the Numbers

Preanalytical variables can have significant impacts on clinical pathology parameters evaluated during the conduct of a nonclinical safety or toxicity study. These preanalytical variables can be controlled by careful attention to factors such as animal dietary status (diet composition, fasted, and fed state), restraint and anesthesia, intercurrent procedures, timing of clinical pathology collections, and proficiency of animal technicians. The impact of preanalytical variables on test results can be significant enough to result in difficult interpretations and/or regulatory questions or can obfuscate the effects of a test article. Control of preanalytical variables starts with knowledge of what processes and procedures impact test results. Minimizing these effects improves the quality of results and maximizes the value of the study.

Interpreting and Integrating Clinical and Anatomic Pathology Results

The continuing education course on integrating clinical and anatomical pathology data was designed to communicate the importance of using a weight of evidence approach to interpret safety findings in toxicology studies. This approach is necessary, as neither clinical nor anatomic pathology data can be relied upon in isolation to fully understand the relationship between study findings and the test article. Basic principles for correlating anatomic pathology and clinical pathology findings and for integrating these with other study end points were reviewed. To highlight these relationships, a series of case examples, presented jointly by a clinical pathologist and an anatomic pathologist, were used to illustrate the collaborative effort required between clinical and anatomical pathologists. In addition, the diagnostic utility of traditional liver biomarkers was discussed using results from a meta-analysis of rat hepatobiliary marker and histopathology data. This discussion also included examples of traditional and novel liver and renal biomarker data implementation in nonclinical toxicology studies to illustrate the relationship between discrete changes in biochemistry and tissue morphology.

Efeitos de dois protocolos de sedação sobre as variáveis bioquímicas em gatos

RESUMO A utilização de protocolos de sedação como auxílio na contenção de felinos para realização de coletas de sangue é de grande importância, porém a utilização de alguns fármacos pode alterar resultados e a interpretação deles. Por outro lado, a contenção física pode gerar intenso estresse, especialmente em felinos, o que também pode interferir nos resultados. Este estudo teve como objetivo avaliar exames de bioquímica clínica sob o uso de contenção física e química em gatos submetidos a dois protocolos de sedação. Foram utilizados 50 gatos, 26 fêmeas e 24 machos, sem raça definida, submetidos a contenção física e, imediatamente após, a dois protocolos de sedação, DB (dexmedetomidina 5µg/kg e butorfanol 0,3mg/kg) e DBC (dexmedetomidina 5µg/kg, butorfanol 0,3mg/kg e cetamina 3mg/kg), aplicados por via intramuscular. Amostras de sangue foram coletadas após a contenção física e, em seguida, após o uso de um dos protocolos de sedação. Foram avaliados: ureia, creatinina, alaninoaminotransferase (ALT), fosfatase alcalina, proteína sérica total (PST), albumina, globulinas, colesterol, triglicérides, cálcio, magnésio e cloretos de amostras de soro, lactato e glicose de amostras de plasma fluoretado. Foi encontrada diferença estatística entre grupos para albumina, triglicérides, PST e colesterol, com maiores valores sendo encontrados no grupo DBC. Entre momentos, houve diferença para colesterol e fosfatase alcalina, com maiores valores no momento contenção física somente no grupo DBC. Já a glicose teve maiores valores após a sedação em ambos os grupos. O estudo revelou que o uso destes protocolos implica restrições para alguns parâmetros bioquímicos aqui estudados e que suas interpretações devem ser avaliadas cuidadosamente.

Reference intervals for biochemical and haematological analytes of juvenile captive-bred long-tailed macaques (Macaca fascicularis) from Mauritius with examination of the effects of individual characteristics using principal component analysis

BACKGROUND

The Mauritian cynomolgus macaque (Macaca fascicularis) is widely used in biomedical research. Determining reference intervals for biochemical and haematological analytes provides an important tool for clinical diagnosis and pre-clinical research.

METHODS

Blood samples from 736 Mauritian long-tailed macaques were analysed to determine reference intervals of 13 biochemical and 10 haematological analytes. The need for partitioning the reference interval between males and females was determined. To examine the variation associated with age, body weight and sex on the analytes, our correlating, multivariate data set was first reduced using principal component analysis, and then the effect of these characteristics on factor scores was examined using GLM analysis.

RESULTS

Partitioning of reference intervals, based on sex, was recommended for albumin, alkaline phosphatase and mean corpuscular haemoglobin. Sex significantly influenced the concentration of lymphocytes, granulocytes and white blood cells.

CONCLUSION

These findings provide useful reference data for research involving Mauritian long-tailed macaques.

Reference values of clinical pathology parameters in cynomolgus monkeys (Macaca fascicularis) used in preclinical studies

Nonhuman primates are increasingly used in biomedical research since they are highly homologous to humans compared to other rodent animals. However, there is limited reliable reference data of the clinical pathology parameters in cynomolgus monkeys, and in particular, only some coagulation and urinalysis parameters have been reported. Here, we reported the reference data of clinical chemical, hematological, blood coagulation, and urinalysis parameters in cynomolgus monkeys. The role of sex differences was analyzed and several parameters (including hematocrit, hemoglobin, red blood cell, blood urea nitrogen, total bilirubin, alkaline phosphatase, creatinine kinase, gamma-glutamyl tranferase, and lactate dehydrogenase) significantly differed between male and female subjects. In addition, compared to previous study results, lactate dehydrogenase, creatinine kinase, and aspartate aminotransferase showed significant variation. Interstudy differences could be affected by several factors, including age, sex, geographic origin, presence/absence of anesthetics, fasting state, and the analytical methods used. Therefore, it is important to deliberate with the overall reference indices. In conclusion, the current study provides a comprehensive and updated reference data of the clinical pathology parameters in cynomolgus monkeys and provides improved assessment criteria for evaluating preclinical studies or biomedical research.

Treg depletion in non-human primates using a novel diphtheria toxin-based anti-human CCR4 immunotoxin

Regulatory T cells (Treg) play an important role in modulating the immune response and has attracted increasing attention in diverse fields such as cancer treatment, transplantation and autoimmune diseases. CC chemokine receptor 4 (CCR4) is expressed on the majority of Tregs, especially on effector Tregs. Recently we have developed a diphtheria-toxin based anti-human CCR4 immunotoxin for depleting CCR4(+) cells in vivo. In this study, we demonstrated that the anti-human CCR4 immunotoxin bound and depleted monkey CCR4(+) cells in vitro. We also demonstrated that the immunotoxin bound to the CCR4(+)Foxp3(+) monkey Tregs in vitro. In vivo studies performed in two naive cynomolgus monkeys revealed 78-89% CCR4(+)Foxp3(+) Treg depletion in peripheral blood lasting approximately 10 days. In lymph nodes, 89-96% CCR4(+)Foxp3(+) Tregs were depleted. No effect was observed in other cell populations including CD8(+) T cells, other CD4(+) T cells, B cells and NK cells. To our knowledge, this is the first agent that effectively depleted non-human primate (NHP) Tregs. This immunotoxin has potential to deplete effector Tregs for combined cancer treatment.

Lineage-Specific Changes in Biomarkers in Great Apes and Humans

Although human biomedical and physiological information is readily available, such information for great apes is limited. We analyzed clinical chemical biomarkers in serum samples from 277 wild- and captive-born great apes and from 312 healthy human volunteers as well as from 20 rhesus macaques. For each individual, we determined a maximum of 33 markers of heart, liver, kidney, thyroid and pancreas function, hemoglobin and lipid metabolism and one marker of inflammation. We identified biomarkers that show differences between humans and the great apes in their average level or activity. Using the rhesus macaques as an outgroup, we identified human-specific differences in the levels of bilirubin, cholinesterase and lactate dehydrogenase, and bonobo-specific differences in the level of apolipoprotein A-I. For the remaining twenty-nine biomarkers there was no evidence for lineage-specific differences. In fact, we find that many biomarkers show differences between individuals of the same species in different environments. Of the four lineage-specific biomarkers, only bilirubin showed no differences between wild- and captive-born great apes. We show that the major factor explaining the human-specific difference in bilirubin levels may be genetic. There are human-specific changes in the sequence of the promoter and the protein-coding sequence of uridine diphosphoglucuronosyltransferase 1 (UGT1A1), the enzyme that transforms bilirubin and toxic plant compounds into water-soluble, excretable metabolites. Experimental evidence that UGT1A1 is down-regulated in the human liver suggests that changes in the promoter may be responsible for the human-specific increase in bilirubin. We speculate that since cooking reduces toxic plant compounds, consumption of cooked foods, which is specific to humans, may have resulted in relaxed constraint on UGT1A1 which has in turn led to higher serum levels of bilirubin in humans.

Sedative, hematologic and hemostatic effects of dexmedetomidine-butorphanol alone or in combination with ketamine in cats

Acute stress induced by physical restraint can interfere with the validity of laboratory findings. Sedation could minimize such stress. However, it is not known whether sedation can affect hematologic and hemostatic parameters in cats. The purpose of this study was to evaluate hematologic and hemostatic parameters in domestic cats subjected to physical restraint in addition to one of two sedation protocols. In total, 50 cats were subjected to physical restraint and were then randomly divided into two groups of 25 animals, receiving dexmedetomidine (5 µg/kg) and butorphanol (0.3 mg/kg; DB group) or dexmedetomidine (5 µg/kg), butorphanol (0.3 mg/kg) and ketamine (3 mg/kg; DBK group). The cats were assessed for acute stress, sedation level, onset of sedation and duration of sedation. Blood samples were collected after handling and after sedation. The complete blood count (CBC), platelet count, buccal mucosal bleeding time (BMBT), whole-blood clotting time, prothrombin time (PT), activated partial thromboplastin time (aPTT) and thrombin time (TT) were determined for each sample, before and after chemical restraint. No statistically significant differences were found in the hematologic parameters. Certain hemostatic parameters (PT, aPTT and TT) were higher in the DB group (P <0.05). The onset of sedation was similar in the two groups, and the duration of sedation was longer in the DBK group. Both sedation protocols were effective for short-duration chemical restraint for blood collection from the studied cats, and no clinically relevant effects on hematologic or hemostatic parameters were detected.

Hematologic reference intervals in Cynomolgus (Macaca fascicularis) monkeys

BACKGROUND

Reference intervals are important aids for interpreting clinical pathology laboratory data especially in Cynomolgus monkey (Macaca fascicularis), the non-human primate species most widely used in biomedical research. The purpose of this study was to establish hematologic reference intervals for Cynomolgus according to the International Federation of Clinical Chemistry and Clinical and Laboratory Standards Institute guidelines using the databank at a primatology center.

METHODS

Blood specimens from 272 healthy Cynomolgus imported from Mauritius, the Philippines and Vietnam, were analyzed. Reference intervals were established by nonparametric method. Effects of sex, age, body weight, and breeding origin were investigated.

RESULTS

Hemoglobin, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration decreased slightly and mean corpuscular volume increased slightly with age. Lower red blood cell concentration, hemoglobin, and hematocrit were observed in monkeys from the Philippines.

CONCLUSIONS

These hematology reference intervals, established according to international recommendations, can be used in settings using similar animals and analyzers.

Comparison of three different sedative-anaesthetic protocols (ketamine, ketamine-medetomidine and alphaxalone) in common marmosets (Callithrix jacchus)

BACKGROUND

Handling of common marmoset (Callithrix jacchus) usually requires chemical restraint. Ketamine has been associated with muscle damage in primates, while common marmosets, compared to other primates, additionally display an exceptional high sensitivity to ketamine-associated side-effects. Notably, muscle twitching movements of limbs and hands, and a marked increase in salivation are observed. We investigated two alternative intramuscular (i.m.) immobilisation protocols against ketamine (50 mg/kg; protocol 1) in a double-blind randomised crossover study in ten healthy adult common marmosets for use as a safe reliable, short-term immobilisation and sedation. These protocols comprised: alphaxalone (12 mg/kg; protocol 2) and 25 mg/kg ketamine combined with 0.50 mg/kg medetomidine (reversal with 2.5 mg/kg atipamezole; protocol 3A). Following completion and unblinding, the project was extended with an additional protocol (3B), comprising 25 mg/kg ketamine combined with 0.05 mg/kg medetomidine (reversal with 0.25 mg/kg atipamezole, twice with 35 min interval).

RESULTS

All protocols in this study provided rapid onset (induction times <5 min) of immobilisation and sedation. Duration of immobilisation was 31.23 ± 22.39 min, 53.72 ± 13.08 min, 19.73 ± 5.74 min, and 22.78 ± 22.37 min for protocol 1, 2, 3A, and 3B, respectively. Recovery times were 135.84 ± 39.19 min, 55.79 ± 11.02 min, 405.46 ± 29.81 min, and 291.91 ± 80.34 min, respectively. Regarding the quality, and reliability (judged by pedal withdrawal reflex, palpebral reflex and muscle tension) of all protocols, protocol 2 was the most optimal. Monitored vital parameters were within clinically acceptable limits during all protocols and there were no fatalities. Indication of muscle damage as assessed by AST, LDH and CK values was most prominent elevated in protocol 1, 3A, and 3B.

CONCLUSIONS

We conclude that intramuscular administration of 12 mg/kg alphaxalone to common marmosets is preferred over other protocols studied. Protocol 2 resulted in at least comparable immobilisation quality with acceptable and less frequent side effects and superior recovery quality. In all protocols, supportive therapy, such as external heat support, remains mandatory. Notably, an unacceptable long recovery period in both ketamine/medetomidine protocols (subsequently reversed with atipamezole) was observed, showing that α-2 adrenoreceptor agonists in the used dose and dosing regime is not the first choice for sedation in common marmosets in a standard research setting.

Age- and sex-based hematological and biochemical parameters for Macaca fascicularis

Background

The cynomolgus monkey (Macaca fascicularis) has been increasingly used in biomedical research, making knowledge of its blood-based parameters essential to support the selection of healthy subjects and its use in preclinical research. As age and sex affect these blood-based parameters, it is important to establish baseline indices for these parameters on an age and sex basis and determine the effects of age and sex on these indices.

Methods

A total of 917 cynomolgus monkeys (374 males and 543 females) were selected and segregated by age (five groups) and sex. A total of 30 hematological and 22 biochemical parameters were measured, and the effects of age and sex were analyzed.

Results

Baseline indices for hematological and biochemical parameters were separately established by age and sex. Significant effects by age, sex, and age-sex interaction were observed in a number of blood parameters. In the 49–60 months and 61–72 months age groups, red blood cell count, hemoglobulin, and hematocrit showed significantly lower values (P<0.01) in females than males. Serum alkaline phosphatase varied with age in both sexes (P<0.01) and was significantly higher in females than males (P<0.05) in the groups aged 13–24 months and 25–36 months; however, in the three groups aged over 25–36 months, serum alkaline phosphatase was significantly lower in females than males (P<0.01). Creatinine concentration increased with age (P<0.01) in all age groups; specifically in the groups aged 49–60 months and 61–72 months, creatinine was significantly higher (P<0.01) in males than females. Total protein and globulin both increased with age (P<0.01).

Conclusion

The baseline values of hematological and biochemical parameters reported herein establish reference indices of blood-based parameters in the cynomolgus monkey by age and sex, thereby aiding researchers in selecting healthy subjects and evaluating preclinical studies using this species.

Paracetamol prevents hyperglycinemia in vervet monkeys treated with valproate

Valproate administration increases the level of the inhibitory transmitter, glycine, in the urine and plasma of patients and experimental animals. Nonketotic hyperglycinemia (NKH), an autosomal recessive disorder of glycine metabolism, causes increased glycine concentrations in blood, urine, and cerebrospinal fluid (CSF), most likely due to a defect in the glycine cleavage enzyme or possibly deficits in glycine transport across cell membranes. We investigated the relationship between the hyperglycinemic effect of valproate and induced pyroglutamic aciduria via paracetamol in the vervet monkey. Firstly it was determined if valproate could induce hyperglycinemia in the monkey. The second aim was to increase glutamic acid (oxoproline) urine excretion using paracetamol as a pre-treatment and to assess whether valproate has an influence on the γ-glutamyl cycle. Hyperglycinemia was induced in healthy vervet monkeys when treated with a single oral dose of 50 mg/kg valproate. An acute dose of 50 mg/kg paracetamol increased oxoproline in the urine. Pre-treatment with paracetamol opposed the hyperglycinemic effect of valproate. However, the CSF:serum glycine ratio in a nonketotic monkey increased markedly after paracetamol treatment and remained high following valproate treatment. These results indicate that the γ-glutamyl cycle does indeed play a role in the hyperglycinemic effect of valproate treatment, and that paracetamol may have value in preventing and/or treating valproate-induced NKH.

Hematological and serum biochemical indices in healthy bonnet macaques (Macaca radiata)

BACKGROUND

Blood reference values for bonnet macaques (Macaca radiata) are limited. The goal of this study was to determine reference ranges for hematological and serum biochemical indices in healthy, socially housed bonnet macaques for males and females over a range of ages.

METHODS

Blood hematological and serum biochemical values were obtained from 50 healthy bonnet macaques of both sexes and aged 10-234 months.

RESULTS

Age and sex differences were present in a number of measures. Globulins, total protein, and creatinine (CREAT) values were highest among older subjects, while alkaline phophatase, albumin, and phosphorus values were higher in juveniles. Sex differences were present in concentrations of red blood cells and CREAT, with higher values in males.

CONCLUSION

The blood parameter data reported here as age-specific reference values for laboratory-housed, healthy bonnet macaques may be used to inform clinical care and laboratory primate research.

Lymphocyte infiltration of neocortex and hippocampus after a single brief seizure in mice

Various immune responses have been described in epileptic patients and animal models of epilepsy, but immune responses in brain after a single seizure are poorly understood. We studied immune responses in brain after a single brief generalized tonic-clonic seizure in mice. C57bl/6 mice, either unanesthetized or anesthetized (pentobarbital, ethyl chloride) received either electrical (15-30 mA, 100 Hz, 1s) or sham stimulation (subcutaneous electrodes over frontal lobe, no current). Electrical stimulation of unanesthetized mice resulted in tonic-clonic convulsions with hind-limb extension (maximal seizure), tonic-clonic convulsions without hind-limb extension (submaximal seizure), or no seizure. In contrast, such stimulation of anesthetized mice did not result in seizure. Mice were killed at 1h-7 days after seizure. Brains or regions dissected from brain (neocortex, hippocampus, midbrain, cerebellum) of each group were pooled, single cell suspensions prepared, and cells separated according to density. CD4(+) (CD3(+)CD45(Hi)) and CD8(+) (CD3(+)CD45(Hi)) T cell and CD45R(+) (CD45(Hi)) B cell numbers were determined by flow cytometry. At 24h after a maximal seizure, CD4(+) and CD8(+) T cells and CD45R(+) B cells appeared in brain, reaching peak numbers at 48 h, but were no longer detected at 7days. CD4(+) T cells and CD45R(+) B cells were preferentially found in neocortex compared with hippocampus, whereas CD8(+) T cells were preferentially found in hippocampus at 24h after a maximal seizure. In contrast, virtually no lymphocytes were detected in brains of unstimulated or sham stimulated mice, unanesthetized stimulated mice after submaximal or no seizure, and anesthetized stimulated mice at 1 h-7 day. Neither Ly6-G+ neutrophils nor erythrocytes were detected in brains of any animals, nor was there any detectable increase of blood-brain barrier permeability by uptake of Evans Blue dye. The results indicate that lymphocyte entry into brain after a single brief seizure is due to a selective process of recruitment into cortical regions.

Effects of serial anesthesia using ketamine or ketamine/medetomidine on hematology and serum biochemistry values in rhesus macaques (Macaca mulatta)

BACKGROUND

This study aimed at determining the cumulative effect of daily anesthesia, using two drug regimens, over hematological and biochemical parameters.

METHODS

Blood samples were obtained from rhesus monkeys 20 minutes after intramuscular administration of ketamine or ketamine/medetomidine combination for three consecutive days and results were evaluated to determine their effect on hematological and serum biochemistry values. Statistical significance of drug, day, and interaction of these two variables were evaluated.

RESULTS

Drug effect resulted in a dramatic increase of aspartate aminotransferase and creatine kinase values. Day effect resulted in decreases of RBC, HCT, Hgb, and alkaline phosphatase but an increase of other biochemical parameters evaluated. The drug/day interaction effect was found to be -significant for RBC, platelets, aspartate aminotransferase, alanine aminotransferase, and creatine kinase values.

CONCLUSION

The results of our study suggest a cumulative effect of serial anesthesia and should be an important consideration when interpreting hematology and serum biochemistry in rhesus macaques.

Evaluation of diabetes determinants in woolly monkeys (Lagothrix lagotricha)

Woolly monkeys (Lagothrix lagotricha) are a threatened specie in the wild with limited successful management in captivity due to diagnosed hypertension and suspected diabetic conditions. Six woolly monkeys with known hypertension problems were tested to determine if diabetes mellitus and current daily diet are underlying links to health problems for the captive population of this species. Blood and urine were collected and serum was analysed for fructosamine, glucose, glycated haemoglobin, insulin, triacylglycerides, total cholesterol, high-density lipoprotein cholesterol (HDL-Chol) and low-density lipoprotein cholesterol (LDL-Chol) while urine was tested for glucose concentrations. Diet disappearance was determined for 3 days prior to blood collection and nutrient content was calculated using Zoo Diet Analysis computer program. Serum analyses were within normal ranges (fructosamine (139-242 micromol/l), glucose (2.22-4.78 mmol/l), glycated haemoglobin (3.52-4.73%), insulin (6.2-13.0 microU/ml), triacylglycerides (0.38-3.4 mmol/l), total cholesterol (2.5-5.1 mmol/l), HDL-Chol (0.4-1.6 mmol/l) and LDL-Chol (1.8-3.4 mmol/l)). Urine glucose concentrations were below the detection limit. Diets were not limiting in starch and total sugars and were similar in non-starch polysaccharides. Potential dietary deficiencies were noted for vitamin A, vitamin D, calcium, phosphorus and selenium. When compared with the available primate reference ranges, the results do not indicate problems with diabetes mellitus or with glucose metabolism and therefore they are not causes of the diagnosed hypertension. Further research to ascertain the true cause of health related problems and the role of dietary factors is needed.

Effect of ketamine anesthesia on daily food intake in Macaca mulatta and Cercopithecus aethiops

Ketamine hydrochloride is frequently administered to non-human primates as a means of chemical restraint. This procedure can be a frequent source of stress to monkeys at research facilities, impacting animal health, well-being and research quality. This study was designed to measure ketamine's effect on daily food intake, a parameter that reflects and influences animal well-being and directly impacts research studies. On five occasions, baseline daily food intake was compared to daily food intake occurring 24, 48, 72, 96, and 120 h after an intramuscular injection of 10 mg/kg ketamine in male African green monkeys (AGMs) (Cercopithecus aethiops) and male and female rhesus macaques (Macaca mulatta). AGMs and female rhesus macaques had significantly reduced daily food intake during the first 4 days after receiving ketamine. The AGMs continued to display significantly reduced daily food intake on the fifth day after ketamine. The male rhesus macagues showed a trend toward reduced daily food intake, greatest during the first 2 days and remaining less than baseline intake through the fifth day following ketamine. The degree of observed food intake reduction was most severe at the 24 h (mean percent intake reduction: AGMs: 57%; rhesus males: 48%; rhesus females: 40%) and 48 h time points (AGMs: 24%; rhesus males: 14%; rhesus females: 13%). A subset of the AGMs that did not receive ketamine, but observed other animals in the room receive ketamine, showed reduced food intake at 24 and 48 h after ketamine, though not to the degree associated with ketamine administration. These results indicate that ketamine anesthesia is associated with a prolonged reduction in daily food intake in AGMs and rhesus macaques. Frequent use of ketamine in non-human primates may have a significant impact on animal health and well-being, and alternatives to its use warrant consideration.

Pharmacokinetics, toxicity, and functional studies of the selective Kv1.3 channel blocker 5-(4-phenoxybutoxy)psoralen in rhesus macaques

The small molecule 5-(4-phenoxybutoxy)psoralen (PAP-1) is a selective blocker of the voltage-gated potassium channel Kv1.3 that is highly expressed in cell membranes of activated effector memory T cells (TEMs). The blockade of Kv1.3 results in membrane depolarization and inhibition of TEM proliferation and function. In this study, the in vitro effects of PAP-1 on T cells and the in vivo toxicity and pharmacokinetics (PK) were examined in rhesus macaques (RM) with the ultimate aim of utilizing PAP-1 to define the role of TEMs in RM infected with simian immunodeficiency virus (SIV). Electrophysiologic studies on T cells in RM revealed a Kv1.3 expression pattern similar to that in human T cells. Thus, PAP-1 effectively suppressed TEM proliferation in RM. When administered intravenously, PAP-1 showed a half-life of 6.4 hrs; the volume of distribution suggested extensive distribution into extravascular compartments. When orally administered, PAP-1 was efficiently absorbed. Plasma concentrations in RM undergoing a 30-day, chronic dosing study indicated that PAP-1 levels suppressive to TEMs in vitro can be achieved and maintained in vivo at a non-toxic dose. PAP-1 selectively inhibited the TEM function in vivo, as indicated by a modest reactivation of cytomegalovirus (CMV) replication. Immunization of these chronically treated RM with the live influenza A/PR8 (flu) virus suggested that the development of an in vivo, flu-specific, central memory response was unaffected by PAP-1. These RM remained disease-free during the entire course of the PAP-1 study. Collectively, these data provide a rational basis for future studies with PAP-1 in SIV-infected RM.

Serum chemical biomarkers of cardiac injury for nonclinical safety testing

There has been a substantial increase in the number and efficacy of laboratory biomarkers for the evaluation of human cardiac injury over the last decade. The advantages of these over traditional laboratory tests have encouraged adoption of comparable markers in nonclinical studies for cardiac injury assessment. Of particular interest are markers that are not only more sensitive and/or specific than traditional parameters for cardiac injury, but also those that may directly bridge human and laboratory animal safety testing. However, a majority of recently developed markers are quantified through antibody-based assays, and cross-reactivity with the comparable analyte in nonhuman samples is difficult to predict and often species-variable. The utility of these novel biomarkers thus, depends upon adequate assay validation with each laboratory species of interest. In contrast, traditional laboratory parameters of cardiac injury lack the properties of an ideal biomarker, but are well established and have an extensive database in nonclinical safety assessment. The current status and utility of both recently developed and traditional biomarkers of cardiac injury in nonclinical testing, and considerations for validation of novel biomarkers of cardiac injury are reviewed.