Jeffrey D Fortman

The Laboratory Nonhuman Primate

Important Biologic Features Husbandry Management Veterinary Care Experimental Methodology Resources References

Pleiotropic effects of interleukin-6 in a “two-hit” murine model of acute respiratory distress syndrome

Patients with acute respiratory distress syndrome (ARDS) exhibit elevated levels of interleukin-6 (IL-6), which correlate with increased morbidity and mortality. The exact role of IL-6 in ARDS has proven difficult to study because it exhibits either pro- or anti-inflammatory actions in mouse models of lung injury, depending on the model utilized. In order to improve understanding of the role of this complex cytokine in ARDS, we evaluated IL-6 using the clinically relevant combination of lipopolysaccharide (LPS) and ventilator-induced lung injury (VILI) in IL-6−/– mice. Bronchoalveolar lavage fluid (BAL), whole-lung tissue, and histology were evaluated for inflammatory markers of injury. Transendothelial electrical resistance was used to evaluate the action of IL-6 on endothelial cells in vitro. In wild-type mice, the combination model showed a significant increase in lung injury compared to either LPS or VILI alone. IL-6−/– mice exhibited a statistically significant decrease in BAL cellular inflammation as well as lower histologic scores for lung injury, changes observed only in the combination model. A paradoxical increase in BAL total protein was observed in IL-6−/– mice exposed to LPS, suggesting that IL-6 provides protection from vascular leakage. However, in vitro data showed that IL-6, when combined with its soluble receptor, actually caused a significant increase in endothelial cell permeability, suggesting that the protection seen in vivo was likely due to complex interactions of IL-6 and other inflammatory mediators rather than to direct effects of IL-6. These studies suggest that a dual-injury model exhibits utility in evaluating the pleiotropic effects of IL-6 in ARDS on inflammatory cells and lung endothelium.

Clinical and histopathological evaluation of 13 cases of adenocarcinoma in aged rhesus macaques (Macaca mulatta)

In recent years, the emphasis on aging research, has led to an increase in the number of aged macaques being maintained in some research facilities with a subsequent increase in the occurrence of age‐related diseases. One of the most commonly reported age related diseases is intestinal adenocarcinoma. At the University of Illinois at Chicago (UIC), which maintains a colony of approximately 55 aged rhesus macaques 13 cases of intestinal adenocarcinoma were diagnosed within a 25‐month period. This report provides a comprehensive description of the clinical findings for intestinal adenocarcinoma in aged rhesus macaques, including results from physical examinations, laboratory tests, radiographic evaluations, gross and histopathologic findings as well as a comparison with the disease condition in humans. The use of carcinoembryonic antigen as a potential tumor marker was evaluated by immunohistochemical analysis of tissue specimens in 10 cases. Intestinal adenocarcinoma is a disease condition that should be of concern to individuals responsible for the care of aged rhesus macaques.

Transvaginal Ultrasonographic (TVS) Evaluation of Baboon Gestation From 37-62 Days Postconception

Our objective was to determine the growth of the embryo and surrounding structures during baboon (Papio anubis) gestation using transvaginal sonography (TVS). To this end, we evaluated 19 timed‐mated baboons using TVS between 37 and 62 days of gestation. After visualization of the gestational sac, amniotic sac, and yolk sac, the three largest diameters of each of these extra embryonic structures were measured using longitudinal and transverse views. Embryonic crown–rump length (CRL) was also recorded. Embryonic heart rates were determined using the M‐mode function of the ultrasound equipment. All 19 gestations developed without complications. No significant trend could be demonstrated for heart rate or yolk sac diameters over the 37–62 day gestational age period. Mean (SD) gestational age in days, heart rate, and yolk sac diameter, respectively, for the group were 48 (7.8) days (range: 37–61), 180 (15) beats per minute (range: 156–221) and 5 (0.1) mm (range: 3–8). Significant correlations (P < 0.0001) were determined between gestational age and CRL and gestational and amniotic sacs. We conclude that TVS allows a clear visualization of the embryo proper and all the cavities within the gestational sac of the baboon gestation. This study has determined the normal pattern of changes of these cavities from 37–62 days of gestation. Future applications of these findings may include sampling fluid from these cavities for biochemical, cytological, and metabolic studies. Am. J. Primatol. 43:323–328, 1997.

Assessment of the risk of fetal loss after the coelocentesis procedure using a baboon model

Objectives: The aims of this study were to gain some insight with regard to the safety of the coelocentesis procedure and, to determine pH, pCO2, and base excess status of the extracoelomic fluid 40 days after fertilization. Methods: Twenty-eight timed-mated baboons from the breeding colony of the Biological Resource Laboratory at the University of Illinois at Chicago were studied. The initial 19 animals were used to determine the ultrasonographic relations between the different compartments of the gestational sac from 38 to 62 days of pregnancy. Under aseptic conditions, in 9 animals coelocenteses were then performed, under continuous transvaginal ultrasound guidance to avoid the amniotic or yolk sacs. Extracoelomic fluid (1–5 ml) was aspirated using 10-ml syringes. Only one attempt of sampling was performed in each of the 9 animals. Extracoelomic fluid pH, pCO2, and base excess were compared with maternal femoral venous blood. Pregnancies were followed by transabdominal ultrasound evaluations on day 3 after the procedure and weekly until day 140 after fertilization. Results: Extracoelomic fluid could be aspirated easily using a 20-gauge needle. Only one pregnancy loss was detected within 3 days after the procedure. No complications occurred in the remaining 8 pregnancies. Extracoelomic fluid pH (7.45 ± 0.01) and pCO2 (39.9 ± 2.4 mm Hg) were significantly different from maternal femoral venous blood pH (7.41 ± 0.01) and pCO2 (47.1 ± 1.4 mm Hg; p < 0.02), while base excess values were similar. Conclusions: This preliminary study performed at 40 days after fertilization in the baboon model suggests that the coelocentesis procedure is technically simple and presents a relatively low risk to mother and fetus if a 20-gauge needle is used and the amount of aspirated extracoelomic fluid is <3 cm3. At this gestational age, the extracoelomic fluid is more alkalotic than maternal femoral venous blood.

Bleeding the laboratory mouse: Not all methods are equal.

The laboratory mouse is the model most frequently used in hematologic studies and assessment of blood parameters across a broad range of disciplines. Often, analysis of blood occurs in a nonterminal manner. However, the small body size of the mouse limits collection based on volume, frequency, and accessible sites. Commonly used sites in the mouse include the retro-orbital sinus, facial vein, tail vein, saphenous vein, and heart. The method of blood acquisition varies considerably across laboratories and is often not reported in detail. In this study, we report significant alterations in blood parameters, particularly of total white blood cells, specific populations of dendritic cells and myeloid-derived suppressor cells, and hematopoietic progenitor cells, as a result of site and manner of sampling. Intriguingly, warming of mice prior to tail bleeding was found to significantly alter blood values. Our findings suggest that the same method should be used across an entire study, that mice should be warmed prior to tail bleeds to make levels uniform, and that accurate description of bleeding methods in publications should be provided to allow for interpretation of comparative reports and inter- and intralaboratory experimental variability.

Epigenetic contribution of the myosin light chain kinase gene to the risk for acute respiratory distress syndrome.

&NA; Acute respiratory distress syndrome (ARDS) is a devastating clinical syndrome with a considerable case fatality rate (˜30%–40%). Health disparities exist with African descent (AD) subjects exhibiting greater mortality than European descent (ED) individuals. Myosin light chain kinase is encoded by MYLK, whose genetic variants are implicated in ARDS pathogenesis and may influence ARDS mortality. As baseline population‐specific epigenetic changes, that is, cytosine modifications, have been observed between AD and ED individuals, epigenetic variations in MYLK may provide insights into ARDS disparities. We compared methylation levels of MYLK cytosine‐guanine dinucleotides (CpGs) between ARDS patients and intensive care unit (ICU) controls overall and by ethnicity in a nested case–control study of 39 ARDS cases and 75 non‐ARDS ICU controls. Two MYLK CpG sites (cg03892735 and cg23344121) were differentially modified between ARDS subjects and controls (P < 0.05; q < 0.25) in a logistic regression model, where no effect modification by ethnicity or age was found. One CpG site was associated with ARDS in patients aged <58 years, cg19611163 (intron 19, 20). Two CpG sites were associated with ARDS in EDs only, gene body CpG (cg01894985, intron 2, 3) and CpG (cg16212219, intron 31, 32), with higher modification levels exhibited in ARDS subjects than controls. Cis‐acting modified cytosine quantitative trait loci (mQTL) were identified using linear regression between local genetic variants and modification levels for 2 ARDS‐associated CpGs (cg23344121 and cg16212219). In summary, these ARDS‐associated MYLK CpGs with effect modification by ethnicity and local mQTL suggest that MYLK epigenetic variation and local genetic background may contribute to health disparities observed in ARDS.