Comparison of kidney weight and volume to selected anatomical parameters in the adult female rhesus monkey (Macaca mulatta)

Selected Resources for Pathology Evaluation of Nonhuman Primates in Nonclinical Safety Assessment

Humans and nonhuman primates (NHPs) share numerous anatomical and physiological characteristics, thereby explaining the importance of NHPs as essential animal models for translational medicine and nonclinical toxicity testing. Researchers, toxicologic pathologists, toxicologists, and regulatory reviewers must be familiar with normal and abnormal NHP biological traits when designing, performing, and interpreting data sets from NHP studies. The current compilation presents a list of essential books, journal articles, and websites that provide context to safety assessment and research scientists working with NHP models. The resources used most frequently by the authors have been briefly annotated to permit readers to rapidly ascertain their applicability to particular research endeavors. The references are aimed primarily for toxicologic pathologists working with cynomolgus and rhesus macaques and common marmosets in efficacy and safety assessment studies.

Ultrasonographic study of hemodynamics and CEUS in the rhesus monkey kidney

Nonhuman primates share many developmental similarities with humans. As the world has recognized the rhesus monkey as a standard experimental monkey, studies of rhesus monkey are very important and essential. The purpose of this study was to use gray-scale ultrasound, color Doppler flow imaging (CDFI), and contrast-enhanced ultrasound (CEUS) to study the ultrasound appearance of adult healthy rhesus monkey kidneys and to investigate the relationship between renal ultrasound manifestations and body weight, gender, and the left and right kidneys. Thirty adult healthy rhesus monkeys were studied in the experiments. The size of the kidney and the length and diameter of the renal artery were measured. The peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) of the renal artery and intrarenal arteries were measured by CDFI. In CEUS, the time-intensity curve (TIC) was used to obtain microvascular perfusion parameters. There were significant differences in renal size, diameter and length of the renal artery, and hemodynamics of the renal arteries between the different weight groups. In CEUS, there were significant differences in area under curve (AUC), time from peak to one half (THP), intensity peak (PI), time to peak (TTP), mean transit time (MTT), and wash-in-slope (WIS) between the different weight groups. There were no statistical differences between genders or the left and right kidneys. Our study provides valuable reference data for the studies of the kidney and indicates that CEUS can be used to evaluate renal perfusion in rhesus monkeys.

Estudo morfométrico de rins em felinos domésticos (Felis catus)

Resumo A saúde renal tem ao longo dos últimos anos chamado atenção dos médicos veterinários, pois o comprometimento deste órgão na insuficiência renal crônica se apresenta como a maior causa de morbidade e mortalidade em felinos. O presente estudo propõe a caracterização biométrica dos rins de gatos, Felis catus, sob os aspectos macroscópicos (comprimento, altura, largura, peso e volume), mesoscópico (altura do córtex e da medula, e a sua inter-relação) e microscópica (volume glomerular), a fim de se estabelecer possíveis diferenças decorrentes de idade, sexo e simetria bilateral. Foram utilizados, rins de 30 animais da espécie Felis catus (gato deméstico), sendo 15 machos e 15 fêmeas com idade variando entre 3 meses a 15 anos, divididos em três grupos: grupo 1 (3-9 meses), grupo 2 (3-5 anos) e grupo 3 (acima de 10 anos). Os rins foram fotografados, pesados, mensurados e processados para histologia. O volume glomerular foi obtido através de estereologia. Os dados macroscópicos permitiram observar uma imparcialidade morfométrica e morfológica quando comparados os lados, independente do grupo e do sexo, sobre o comprimento, altura, largura, peso e volume dos rins. Para o sexo foi detectado diferença significante entre machos e fêmeas independente da faixa etária para comprimento, altura, peso e volume, com exceção da largura. Considerando a idade houve diferença significativa para todos os parâmetros: comprimento, altura, largura, peso e volume. Nas mensurações de córtex, medula e sua inter-relação, quando considerada a simetria bilateral, não foi detectada diferença significante entre rim direito e esquerdo. Para o sexo, não foi detectada diferença entre machos e fêmeas na mesoscopia no córtex, na medula e na inter-relação córtex/medula. Quanto à idade, a mensuração da altura do córtex e a inter-relação córtex/medula apresentou diferença significante, porém essa diferença não foi estabelecida para a medula do rim. Foram encontradas diferenças significantes entre grupos e entre machos e fêmeas, em relação ao volume ocupado pelo glomérulo no parênquima renal. Em todas as técnicas biométricas utilizadas não foram detectadas diferenças entre os rins direito e esquerdo. As mensurações macroscópicas mostraram que machos apresentaram um rim maior em comprimento, altura, largura, peso e volume do que as fêmeas. A faixa etária está diretamente relacionada ao tamanho do rim, que cresce em todas as dimensões, fica mais pesado e com maior volume quando comparados jovens e adultos, e se mostra estável morfometricamente em relação aos adultos e senis. O parênquima renal não difere entre os sexos, mas a altura do córtex e a relação com a medula aumentam com a idade. O volume do glomérulo renal é maior em machos do que em fêmeas e também aumenta em relação à idade. Os rins mostraram um predomínio de colágeno tipo I nos animais do grupo 1 e 2, e colágeno tipo III nos animais do grupo 3.

Chronic administration of tenofovir to rhesus macaques from infancy through adulthood and pregnancy: summary of pharmacokinetics and biological and virological effects

The reverse transcriptase (RT) inhibitor tenofovir (TFV) is highly effective in the simian immunodeficiency virus (SIV) macaque model of human immunodeficiency virus infection. The current report describes extended safety and efficacy data on 32 animals that received prolonged (>or=1- to 13-year) daily subcutaneous TFV regimens. The likelihood of renal toxicity (proximal renal tubular dysfunction [PRTD]) correlated with plasma drug concentrations, which depended on the dosage regimen and age-related changes in drug clearance. Below a threshold area under the concentration-time curve for TFV in plasma of approximately 10 microg x h/ml, an exposure severalfold higher than that observed in humans treated orally with 300 mg TFV disoproxil fumarate (TDF), prolonged TFV administration was not associated with PRTD based on urinalysis, serum chemistry analyses, bone mineral density, and clinical observations. At low-dose maintenance regimens, plasma TFV concentrations and intracellular TFV diphosphate concentrations were similar to or slightly higher than those observed in TDF-treated humans. No new toxicities were identified. The available evidence does not suggest teratogenic effects of prolonged low-dose TFV treatment; by the age of 10 years, one macaque, on TFV treatment since birth, had produced three offspring that were healthy by all criteria up to the age of 5 years. Despite the presence of viral variants with a lysine-to-arginine substitution at codon 65 (K65R) of RT in all 28 SIV-infected animals, 6 animals suppressed viremia to undetectable levels for as long as 12 years of TFV monotherapy. In conclusion, these findings illustrate the safety and sustained benefits of prolonged TFV-containing regimens throughout development from infancy to adulthood, including pregnancy.