Adult Baboons Research Articles

End-to-side nerve graft repair based on synergistic peripheral terminal motor branches: investigation in a nonhuman primate model

BACKGROUND: Spinal nerve avulsion frequently occurs in brachial plexus injury, becoming irreparable lesions. Nerve transfer at the very proximal site within a limited time interval after injury leads to satisfactory functional results. Oberlin reported a neurotization technique at a more peripheral location. Hypothetically, there might be useful functional results performing very peripheral end-to-side nerve graft repair using synergistic tiny terminal motor branches. We created one possible application of such a peripheral synergistic terminal end-to-side nerve transfer in a median nerve defect model in nonhuman primates. An end-to-side nerve graft repair bridging from the terminal motor branch of deep branch of the ulnar nerve to the thenar motor branch of median nerve was performed. The purpose of this study was to investigate the efficacy of this hypothesis. METHODS: Seven adult baboons were used in this study. At baseline, we electrophysiologically demonstrated no variation in innervation of median- and ulnar-nerve-innervated thenar muscles. Transection of the median nerve was performed. Subsequently, the abductor pollicis brevis muscle could neither be stimulated by the median nerve nor by the ulnar nerve. Baboons underwent end-to-side coaptation of a nerve graft to the deep branch of the ulnar nerve and end-to-end coaptation to the thenar motor branch of the median nerve. Assessment of functional recovery was performed by electrophysiological evaluation, thenar muscle weight, and video slow-motion analysis. RESULTS: All animals recovered opposition of the thumb 3 months after surgery. The abductor pollicis brevis muscle, preoperatively innervated by the median nerve, did not respond to electrophysiological stimulation of the transected median nerve but to stimulation of the ulnar nerve via the nerve graft. Length of nerve graft (in average 2.3 cm) showed no correlation to muscle weight or electrophysiological parameters. CONCLUSIONS: The results in this series demonstrate the efficacy of end-to-side nerve graft repair at the level of tiny very peripheral terminal motor branches in a nonhuman primate median nerve defect model. Applications of this technique may enhance functional results by avoidance of time-dependent end organ failure.

Histopathological effects of delayed reperfusion after middle cerebral artery occlusion in the anesthetized baboon

In patients with middle cerebral artery (MCA) territory stroke, attempts to recanalize the brain are currently being extended beyond the classic 3-h time window. Mechanical thrombectomy is particularly attractive as it may carry lesser risks of severe hemorrhagic transformation than thrombolysis. However, whether late reperfusion per se promotes hemorrhagic transformation and increases infarct volume as compared to permanent occlusion is unclear. There is no study of the histopathologic sequelae of late reperfusion following MCA occlusion (MCAo) in the non-human primate. Five young adult baboons completed a specially designed protocol of 20-h MCAo (under etomidate anaesthesia), followed by 4-week survival and finally perfusion-fixation. Infarct volume was measured histologically using validated stereological methods. The results were compared to our previously published series of 6 h and permanent MCAo performed with identical experimental and post mortem procedures. An infarct was present in each baboon, consistently involving the caudate head, internal capsule and putamen; the adjacent inferior frontal cortex was involved in one subject. Infarct volume was significantly larger than with 6 h MCAo, as expected, but did not differ from permanent MCAo. There was no evidence of hemorrhage around the infarcted area in any animal. We found that following a 20 h ischemic episode, the infarct volume was similar to that found with permanent occlusion, with no evidence of hemorrhagic transformation. Cautiously extrapolating to the human situation, our findings suggest that even late mechanical recanalization may not promote brain damage and could be considered in selected cases.

Blockade of tissue factor-factor X binding attenuates sepsis-induced respiratory and renal failure

Tissue factor expression in sepsis activates coagulation in the lung, which potentiates inflammation and leads to fibrin deposition. We hypothesized that blockade of factor X binding to the tissue factor-factor VIIa complex would prevent sepsis-induced damage to the lungs and other organs. Acute lung injury was produced in 15 adult baboons primed with killed Escherichia coli [1 x 10(9) colony-forming units (CFU)/kg], and then 12 h later, they were given 1 x 10(10) CFU/kg live E. coli by infusion. Two hours after live E. coli, animals received antibiotics with or without monoclonal antibody to tissue factor intravenously to block tissue factor-factor X binding. The animals were monitored physiologically for 34 h before being killed and their tissue harvested. The antibody treatment attenuated abnormalities in gas exchange and lung compliance, preserved renal function, and prevented tissue neutrophil influx and bowel edema relative to antibiotics alone (all P < 0.05). It also attenuated fibrinogen depletion (P < 0.01) and decreased proinflammatory cytokines, e.g., IL-6 and -8 (P < 0.01), in systemic and alveolar compartments. Similar protective effects of the antibody on IL-6 and -8 expression and permeability were found in lipopolysaccharide-stimulated endothelial cells. Blockade of factor X binding to the tissue factor-factor VIIa complex attenuates lung and organ injuries in established E. coli sepsis by attenuating the neutrophilic response and inflammatory pathways.

Morphology after synergistic terminal end-to-side nerve graft repair: Investigation in a nonhuman primate model

BACKGROUND: Functional efficacy of synergistic terminal end-to-side nerve graft repair in a median nerve defect model in nonhuman primates was recently published elsewhere. The purpose of this study was to investigate the morphology of the end-to-side repair site and the nerve graft used after synergistic terminal end-to-side nerve graft repair. METHODS: Experiments were carried out in seven adult baboons. Synergistic end-to-side nerve graft repair bridging from the terminal motor branch of deep branch of the ulnar nerve to the thenar motor branch of the median nerve was performed after transection of the median nerve at forearm level. Specimens were harvested three months after surgery. Chromotrope aniline blue was used for staining neural collagenic connective tissue. S100-antibody was used to quantify the number of Schwann cells. Axon counts were performed using NF (neurofilament) antibody staining. To enable profound morphological assessment, specimens were harvested 5 mm proximal to the end-to-side nerve graft repair site (deep branch of ulnar nerve), at the end-to-side nerve graft repair site (proximal graft), and at the distal end-to-end nerve graft suture site. The contralateral terminal deep branch of ulnar nerve served as a control. RESULTS: The area of collagenic connective tissue was 6% larger at the end-to-side repair site and 28% larger at the distal end of the nerve graft. Highest mean values were found at the distal site of the nerve graft. This was due to very strong collagenization of the nerve graft of animal number six. In other words, there was a moderate enhancement of collagenic connective tissue within the nerve graft in six animals. Schwann cell counts showed similar values within all nerve segments. There was no difference when compared to nonoperated control. The number of axons distal to the end-to-side repair site was smaller by 19% on average. Additionally, we found an average 23% decrease of axons at the end-to-end coaptation site compared to data of the deep branch of ulnar nerve. CONCLUSIONS: The results in this morphological study of synergistic end-to-side nerve graft repair at the level of very peripheral terminal motor branches in a nonhuman primate model demonstrate effective distal axonal sprouting and successful Schwann cell survival. As expected, we found a modest increase of neural collagenic connective tissue within the nerve graft in most animals (6 out of 7 animals).

Ontogeny of hematological cell and biochemical profiles in maternal and fetal baboons (Papio species)

The normal ranges of hematological cell profiles and biochemistry are documented in adult non-pregnant, pregnant, juvenile, and neonatal baboons. Despite the extensive use of the baboon as a model for the study of various aspects of pregnancy, there is no data from paired mothers and their fetuses at different stages of gestation. Hematologic and biochemical profile data were obtained from eight non-pregnant female baboons, 37 mothers and 38 fetal baboons at 30 +/- 2, 90 +/- 2, 125 +/- 2, and 175 +/- 2 days of gestation (mean +/- range; dGA; term, 180 dGA). Changes observed in fetal and maternal blood during normal baboon pregnancy were similar to those reported in human pregnancy. The level of alkaline phosphatase was two times higher in fetal blood circulation than that reported in human pregnancy.

Histologic and histomorphometric analysis of three types of dental implants following 18 months of occlusal loading: a preliminary study in baboons

The purpose of this study was to determine the percentage of 'bone area' (BA) and 'bone-to-implant contact' (BIC) of dental implants with different designs and surface modifications after functional loading. Three types of dental implants with fixed partial dentures were placed in the posterior jaws of adult baboons (commercially pure titanium (CpTi) screws, grit-blasted acid-etched (GBAE) screws, and titanium plasma-sprayed (TPS) cylinders), three of the same design per quadrant. After 18 months of functional loading, all implants investigated were successfully integrated in the jawbone and histologic and histomorphometric analyses were carried out. Statistical evaluation was performed with a mixed model with data given as least-square means and standard errors of the mean (SEM). Histologically, direct BIC without connective tissue interposed between implant surfaces and peri-implant bone was seen. Analysis of BA within 1 mm around implants showed significant differences between CpTi (50.5%) and TPS (39.7%) (+/-2.72 SEM; P<0.01) in the maxilla. To account for the different implant designs, absolute BIC was calculated. Significant differences were found between CpTi (23.9 mm) and TPS (15.1 mm) and between GBAE (27.2 mm) and TPS (15.1 mm) (+/-1.05 SEM; P<0.01) in the maxilla and between GBAE (26.5 mm) and TPS (19.6 mm) (+/-1.42 SEM; P<0.01) in the mandible. Overall, the data indicate that, in the maxilla, screw-shaped implants showed more absolute BIC than cylindrical implants, which had less maxillary than mandibular absolute BIC after 18 months of functional loading.

Evaluation of the aged female baboon as a model of pelvic organ prolapse and pelvic reconstructive surgery

This study examines the baboon as an animal model of pelvic organ prolapse (POP) by describing the pelvic floor anatomy and adapting human clinical assessment tools. The pelvic anatomy of an adult female baboon was observed at necropsy, and comparisons were made to the human and squirrel monkey. The pelvic organ prolapse quantification (POP-Q) system was used to assess vaginal support in 12 living adult baboons, including 6 young, reproductive-age, nulligravid females (4.8 +/- 0.5 years) and 6 older, multiparous females (23.0 +/- 0.5 years). The female baboon pelvic anatomy was found to have similar architecture to the human and squirrel monkey female. Six multiparous females with mean parity of 5 (range 2-8) showed no evidence of POP or differences in POP-Q measurements from 6 nulliparous females. The POP-Q system can be used to assess female baboon vaginal support. In a sample of baboons, pelvic support loss consistent with POP was not identified. As the pelvic anatomy is similar to the human female, the baboon may prove useful for evaluating surgical materials and for modeling pelvic floor reconstructive surgeries.

Mean xenograft survival of 14.6 days in a small group of hDAF-transgenic pig hearts transplanted orthotopically into baboons

Introduction In a discordant orthotopic xenotransplantation model (pig-to-baboon) donor pigs expressing human decay accelerating factor (hDAF) as a regulator of complement activity were used to prevent hyperacute xenograft rejection (HXR). We investigated a modified immunosuppressive therapy consisting of ERL080 (Novartis Pharma AG, Base, Switzerland), cyclosporin A (Neoral), steroids, and a cyclophosphamide (CyP) induction protocol with several reduced doses to prevent acute vascular rejection (AVR). Methods Donor hearts were harvested from hDAF-transgenic pigs (18.8 ± 2.6 kg, Imutran Ltd., a Novartis Pharma AG Company). Four adult baboons (25.6 ± 2.7 kg) with high titers of xenoreactive antibodies (XAb) served as recipients. Serological and hemodynamic parameters were measured. Finally, myocardial tissue was sampled for histological and immunohistochemical examinations. Results In the first baboon, an acute graft failure occurred after 1 hour due to preservation injury. The second succumbed after 11.1 day due to an acute renal failure. The third died after 13.1 days of an ileus. The fourth baboon had continuously excellent cardiac function (mean echocardiographic ejection fraction, 69.2%), but succumbed on day 20 due to anemia. Corrected mean xenograft survival (excluding the first baboon because of a technical failure) was 14.6 ± 2.6 days. XAb decreased after day 3 to constantly low levels (<1:64 titer) after CyP induction. White blood cell count decreased from 10.3 ± 0.8 to 0.9 ± 0.3 G/L after day 3. Macroscopically and histologically no typical signs of HXR or severe AVR could be detected. Conclusions These results confirm that hDAF transgen blocks HXR in this life-supporting model. AVR was prevented by using a modified quadruple immunosuppressive drug combination (Neoral, ERL080, steroids, and several small single doses of CyP). An optimum “fine-tuning” of immunosuppression is required to achieve the best risk-benefit ratio.

Sepsis-Induced Coagulation in the Baboon Lung Is Associated with Decreased Endothelial Tissue Factor Pathway Inhibitor.

Activation of tissue factor (TF)-dependent coagulation is an early event in the pathogenesis of sepsis, responsible for microvascular thrombosis and consequent organ injury. We hypothesized that sepsis-induced TF procoagulant activity may be paralleled by a decreased expression or function of its natural inhibitor, tissue factor pathway inhibitor (TFPI). To test this hypothesis we used a non-human primate sepsis model in which adult baboons were infused with live E. coli at 109 CFU/kg (sublethal dose), 1010 CFU/kg (lethal dose) or saline (control group) and the animals were sacrified after 2, 8, or 24 hours. Lung tissue was snap frozen for protein and mRNA extraction or fixed and processed for light and electron microscopy. Tissue cryosections were immunostained using double/multiple fluorescence labeling approaches for TF, TFPI, factor VII/FVIIa and fibrin, in conjunction with cell markers for endothelial cells (CD31 or von Willebrand factor), leukocytes (PSGL-1), macrophages (CD68), PMN (myeloperoxidase) and platelets (gpIIb/IIIa). Large amounts of TF were detected in leukocytes, endothelial cells and platelet-rich microthrombi, starting from 2 hours and throughout the examined period. Concomitantly, confocal and electron microscopy analysis revealed increased leukocyte infiltration, platelet aggregates and fibrin deposition in the intravascular and interstitial compartments. In addition, TF induction was documented by semiquantitative RT-PCR, ELISA, western blot and factor Xa activation assays. Whereas TFPI mRNA showed only a modest increase, tissue-associated TFPI protein was found considerably decreased, especially during the first eight hours post E. coli infusion. Moreover, TFPI inhibitory activity of lung extracts from septic animals was 6–8 fold lower comparing to controls. TF activity measurements in the presence of inhibitory anti TFPI antibodies showed that only a very small fraction of endogenous TF was inhibited by tissue-associated TFPI, suggesting that most of the active TFPI available in the vascular compartment was depleted. The decrease of TFPI inhibitory potency cannot be exclusively explained by its proteolytic degradation, as we did not find significant amounts of truncated TFPI on western blots. In conclusion, our studies demonstrate that the exposure to septic and inflammatory stimuli lead to a decrease of TFPI-dependent endothelial anticoagulant potential, simultaneous with a strong TF-dependent procoagulant response. Activation of TF-dependent coagulation pathway not adequately countered by TFPI may have important roles in the pathogenesis of sepsis-associated disseminated intravascular coagulation. Strategies aimed to restore the physiological anticoagulant function of TFPI may help preventing sepsis-induced multiple organ dysfunction syndrome and death.

Pleiotropic Effects of Genes for Insulin Resistance on Adiposity in Baboons

Previous research has suggested a genetic contribution to the development of insulin resistance and obesity. We hypothesized that the same genes influencing insulin resistance might also contribute to the variation in adiposity. A total of 601 (200 male, 401 female) adult baboons (Papio hamadryas) from nine families with pedigrees ranging in size from 43 to 121 were used in this study. Plasma insulin, glucose, C-peptide, and adiponectin were analyzed, and homeostasis model assessment of insulin resistance (HOMA IR) was calculated. Fat biopsies were collected from omental fat tissue, and triglyceride concentration per gram of fat tissue was determined. Body weight and length were measured, and BMI was derived. Univariate and bivariate quantitative genetic analyses were performed using SOLAR. Insulin, glucose, C-peptide, and adiponectin levels, HOMA IR, triglyceride concentration of fat tissue, body weight, and BMI were all found to be significantly heritable, with heritabilities ranging from 0.15 to 0.80. Positive genetic correlations (r(G)s) were observed for HOMA IR with C-peptide (r(G) = 0.88 +/- 0.10, p = 0.01), triglyceride concentration in fat tissue (r(G) = 0.86 +/- 0.33, p = 0.02), weight (r(G) = 0.50 +/- 0.20, p = 0.03), and BMI (r(G) = 0.64 +/- 0.22, p = 0.02). These results suggest that a set of genes contributing to insulin resistance also influence general and central adiposity phenotypes. Further genetic research in a larger sample size is needed to identify the common genes that constitute the genetic basis for the development of insulin resistance and obesity.

Cosupplementation with vitamin E and coenzyme Q10 reduces circulating markers of inflammation in baboons

Inflammation and oxidative stress are processes that mark early metabolic abnormalities in vascular diseases. We explored the effects of a high-fat, high-cholesterol (HFHC) diet on vascular responses in baboons and the potential response-attenuating effects of vitamin E and coenzyme Q(10) (CoQ(10)) supplementation. We used a longitudinal design by subjecting 21 baboons (Papio hamadryas) to sequential dietary challenges. After being maintained for 3 mo on a baseline diet (low in fat and cholesterol), 21 baboons were challenged with an HFHC diet for 7 wk. The serum C-reactive protein (CRP) concentrations did not change. Subsequent supplementation of the HFHC diet with the antioxidant vitamin E (250, 500, or 1000 IU/kg diet) for 2 wk reduced serum CRP concentrations from 0.91 +/- 0.02 to 0.43 +/- 0.06 mg/dL. Additional supplementation with CoQ(10) (2 g/kg diet) further reduced serum CRP to approximately 30% of baseline (0.28 +/- 0.03 mg/dL; P = 0.036 compared with the HFHC diet). Introduction of the HFHC diet itself significantly decreased serum P-selectin (from 48.8 +/- 7.2 to 32.9 +/- 3.7 ng/dL, P = 0.02) and von Willebrand factor (from 187.0 +/- 10.1 to 161.9 +/- 9.0%, P = 0.02) concentrations. However, neither vitamin E alone nor vitamin E plus CoQ(10) significantly altered the serum concentrations of P-selectin or von Willebrand factor. Dietary supplementation with vitamin E alone reduces the baseline inflammatory status that is indicated by the CRP concentration in healthy adult baboons. Cosupplementation with CoQ(10), however, significantly enhances this antiinflammatory effect of vitamin E.

Estrogen Receptor B mRNA is expressed in oocytes of the adult baboon ovary at all stages of follicle development

Although estrogen receptors are expressed in granulosa cells of antral (ERα; ERβ) and preantral (ERβ) follicles in the baboon adult ovary, in the present study we determined whether oocytes express ERα/ERβ mRNA and whether expression is dependent upon the stage of follicle development.

Genome-wide scan of resistin mRNA expression in omental adipose tissue of baboons.

The hormone resistin was recently discovered in adipose tissue of mice. Functional tests suggest a role for resistin in the regulation of insulin sensitivity. However, human studies have reported controversial results on the metabolic function of this hormone. A 1 g omental adipose tissue biopsy was obtained from 404 adult baboons. Resistin mRNA expression was assayed by real-time, quantitative RT-PCR, and univariate and bivariate quantitative genetic analyses were performed, via the variance decomposition approach. A genome scan analysis was conducted using resistin mRNA abundance in omental adipose tissue as a quantitative phenotype. A significant heritability of h2 = 0.23 (P = 0.003) was found for resistin mRNA abundance in omental adipose tissue. A genome scan detected a quantitative trait locus for resistin expression with an LOD score of 3.8, in the region between markers D19S431 and D19S714, corresponding to human chromosome 19 p13. This chromosomal region contains genes related to insulin resistance phenotypes, such as resistin, insulin receptor, angiopoietin-like 4 protein and LDL receptor. Individual variation in resistin mRNA expression has a significant genetic component, and a gene or genes on chromosome 19 p13 may regulate resistin mRNA levels in baboon omental adipose tissue.

Distraction osteogenesis of the nasal and antral osseous floor to enhance alveolar height

The purpose of the study was to obtain information on the possibility of using distraction osteogenesis (DO) to increase the height of posterior atrophic maxillary alveolar ridges by distracting very small alveolar crest bone segments and, secondly, to determine if it is possible to distract the bony antral floor itself, producing new bone between the sinus membrane and the alveolar crest. Three adult Papio anubis baboons were rendered edentulous in the posterior maxilla. Bilateral osteotomies were performed to produce a thin margin of crestal alveolar bone and in one area, a complete exposure of the antral floor. Distractors were placed against the antral and nasal floors and the thin 1- x 1.5-mm thick alveolar bone crest was distracted 10 mm over a period of 10 days. Animals were labeled with tetracycline at 3 and 4 months and were sacrificed at 5 months. A complete osseous regeneration of the nasal floor and alveolar ridge greater than 10 mm in height was produced in all cases. Histomorphometric analysis of the DO-induced osseous areas revealed cancellous bone with increasing thickness during the third and fourth month and formation of new bone cortices increasing in thickness during the same time. Significant new bone also formed in the antral floor areas that had been purposely interdicted by the osteotomies. The results of this study indicate that very small segments of bone of the posterior maxilla can be distracted to produce significant increases in the alveolar bone height and that a new osseous nasal-antral floor enhancement can be produced by this technique.

Hormonal correlates of changes in interest in unrelated infants across the peripartum period in female baboons ( Papio hamadryas anubis sp.)

In past research on human and nonhuman primates, maternal responsiveness and behavior has been thought of as an experiential, cognitive mechanism; however, recent findings have shown that maternal motivation and behavior may not be entirely divorced from the endocrine system. To investigate the relationship between interest in infants and the hormonal changes related to pregnancy, we examined the nature of social interactions across parturition between a large sample ( n = 133) of adult female baboons ( Papio hamadryas anubis sp.) and unrelated infants. Prepartum data were collected during ten 30-min focal observations for each subject. Each mother–infant pair was then observed through the infant's first 8 weeks of life. A total of 2325 h of observation was recorded. Urine was collected on 65 subjects, starting 5 weeks before the expected date of parturition and ending 4 weeks after parturition. Evidence for a connection between endocrine function and responsiveness toward infants was found. Affiliative behaviors during the prepartum period were positively correlated to the estrogen/cortisol ratio and high dominance rank. In the postpartum period, affiliative behaviors were positively correlated with prepartum progesterone and dominance rank, and negatively correlated with postpartum cortisol levels. Finally, a positive correlation was recorded during the postpartum period between prepartum progesterone and aggression, and a negative correlation between postpartum cortisol and aggression and submission. Our data suggest that the endocrine changes that may help regulate maternal care of offspring also influence the way in which pre- and postpartum female baboons interact with unrelated infants in their social group.

The effects of betamethasone (BM) on endothelial nitric oxide synthase (eNOS) expression in adult baboon femoral arterial endothelial cells

Glucocorticoids have significant effects on endothelium mediated vascular function throughout life. The baboon model has been used extensively to study cellular responses to glucocorticoids at several stages of the lifespan. Endothelial nitric oxide synthase (eNOS) is a major regulator of endothelium dependent arterial vasodilation. We have previously demonstrated that synthetic glucocorticoids down regulate eNOS in the baboon placenta. We have now conducted studies to determine whether glucocorticoids would alter eNOS expression in adult systemic vascular endothelial cells in this important animal model. We explored this potential mechanism in endothelial cells from femoral arteries of adult baboons at necropsy and cultured to the fourth passage. Endothelial cells were treated with 10–100 nM betamethasone for 24 h at 37 °C. Vascular endothelial growth factor (VEGF) was used as a positive control and medium as negative controls. The role of glucocorticoid receptor mediation in betamethasone-induced eNOS changes was investigated with the glucocorticoid receptor antagonist mifepristone. RNA (real-time quantitative RT-PCR) and protein (ELISA) were extracted and measured for eNOS. Expression and subcellular distribution of glucocorticoid receptor were detected with fluorescence labeled antibody microscopy. eNOS mRNA and protein in baboon endothelial cells were downregulated 25% by betamethasone treatment. This effect was attenuated by pre-incubation with mifepristone ( P < 0.01). VEGF upregulated eNOS transcription and translation ( P < 0.001), medium did not alter eNOS expression. We observed that mifepristone and VEGF increased glucocorticoid receptor cytoplasmic accumulation by fluorescence microscopy. We conclude that betamethasone can downregulate eNOS in cultured baboon endothelial cells via the glucocorticoid receptor pathway.

MEAN XENOGRAFT SURVIVAL OF 14,6 DAYS IN A SMALL GROUP OF HDAF-TRANSGENIC PIG HEARTS TRANSPLANTED ORTHOTOPICALLY INTO BABOONS

O55 Aims: In a discordant orthotopic xenotransplantation (oXHTx) model (pig-to-baboon) donor pigs expressing human decay accelerating factor (hDAF) as a regulator of complement activity were used to prevent hyperacute xenograft rejection (HXR). We investigated a modified immunosuppressive (IS) regimen consisting of ERL (Novartis Pharma AG, Basel), Neoral, steroids and a cyclophosphamide (CyP) induction protocol with several reduced doses to prevent acute vascular rejection (AVR). Methods: Donor hearts were harvested from hDAF-transgenic pigs (18.8+/−2.6 kg, Imutran Ltd., a Novartis Pharma AG Company). Four adult baboons (25.6+/−2.7 kg) with high titres of xenoreactive antibodies (XNAb) served as recipients. Serological and hemodynamic parameters were measured. Finally myocardial tissue was sampled for histological and immunohistochemical examinations. Results: First baboon had an acute graft failure after 1 h due to preservation injury. The second died after 11.1 d because of acute renal. The third died after 13.1 days from an ileus. The fourth baboon had continuously excellent cardiac function (mean echocardiographical ejection fraction: 69.2%), but died on day 20 due to anemia. Corrected mean xenograft survival (excluding first baboon because of technical failure) was 14.6+/−2.6 days. XNAb decreased on day 3 to constantly low levels (<1:64 titer) after CyP induction. White blood cell count decreased from 10.3+/−0.8 to 0.9+/−0.3 G/l after day 3. Macroscopically and histologically no typical signs of HXR or severe AVR could be detected. Conclusions: These results confirm that hDAF transgen blocks HXR in this life supporting model. AVR was prevented by using a modified quadruple IS drug combination (Neoral, ERL, steroids and several single small doses of CyP). An optimum “fine-tuning” of IS is required to achieve the best risk-benefit ratio.

Genotype-by-sex and environment-by-sex interactions influence variation in serum levels of bone-specific alkaline phosphatase in adult baboons ( Papio hamadryas)

While more than 77% of the people in the US with osteoporosis are women, the contributions of genotype-by-sex (G×S) and environment-by-sex interactions to sex differences in osteoporosis risk factors have not been studied. To address this issue, we conducted a statistical genetic analysis of serum concentrations of bone-specific alkaline phosphatase (Bone ALP), a highly specific marker of osteoblast function that is elevated in persons with conditions like osteoporosis characterized by excessive bone turnover or rapid bone loss. We assayed Bone ALP from 657 pedigreed baboons using a commercially available ELISA kit. Using a maximum likelihood variance decomposition approach, we treated sex as an environmental milieu in which genes influencing Bone ALP levels are expressed. We modeled the genetic covariance in Bone ALP between all relative pairs conditional on their sex so that the covariance is the product of the kinship, the genetic correlation between trait levels in the two sexes, and the genetic variances in the two sexes. Sex-specific maximum likelihood estimates (MLE) of residual heritability for Bone ALP were greater for females than for males ( h 2 = 0.44 vs. h 2 = 0.26, respectively), but likelihood ratio tests revealed only a marginally significant difference in sex-specific genetic variances ( P = 0.057). In contrast, the between-sex genetic correlation ( ρ G = 0.43) was significantly less than 1.0 ( P = 0.037), and the difference in sex-specific environmental variances was highly significant ( P = 0.00006). We report the first evidence for G×S interactions influencing variation in an osteoporosis risk factor. The diminished between-sex genetic correlation implies that different genes influence Bone ALP levels in the two sexes. The significant differences between environmental variances suggest that unmeasured factors, including those from the internal, biological environments of the two sexes, account for a greater proportion of the Bone ALP variation in males.

Increased lymphoid tissue apoptosis in baboons with bacteremic shock.

The molecular mechanisms of immune cell apoptosis during sepsis remain unclear. Two young adult baboons (Papio sp.) received a lethal dose of live Escherichia coli and were sacrificed at either 16 (for animal welfare concerns) or 24 h post-septic shock. An additional baboon, which received no bacteria, served as a control. Necropsy was performed immediately with subsequent immunohistochemical staining of lymphoid tissue. Immunohistologic analysis of tissues from the septic baboons revealed marked systemic lymphocyte apoptosis occurring in all lymphoid tissues examined. Focally, pyknotic and karyorrhectic lymphocytes demonstrated activation of a mitochondrial-dependent cell death pathway (active caspase 9 and apoptosis-inducing factor). Other regions demonstrated apoptotic lymphocytes with activation of a death receptor-dependent cell pathway (Fas ligand). Thus, we have demonstrated for the first time in primates that overwhelming gram-negative bacteremia produces an early and profound lymphocyte death that occurs through multiple cell death pathways. Bacteremic shock in the baboon may be an appropriate model for studying experimental therapies aimed at blocking lymphocyte apoptosis because their response appears comparable to humans dying from sepsis.

Adiponectin but not resistin is associated with insulin resistance-related phenotypes in baboons.

The hormones adiponectin and resistin have been associated with insulin resistance. This paper analyzed the potential relationship between adiponectin and resistin and insulin resistance-related phenotypes in baboons. One hundred eight adult baboons (84 female and 24 male) were studied. Weight was measured, and a blood sample was collected under fasting conditions for plasma and monocyte isolation. Fasting glucose, insulin, C-peptide, and adiponectin levels in plasma were measured by standard methods. Insulin resistance was calculated by the homeostasis model assessment index. Resistin mRNA abundance in monocytes was determined by real-time quantitative reverse transcription-polymerase chain reaction. Data were clustered by weight tertiles for statistical analysis. As observed in humans, the insulin resistance-related phenotypes were related to weight, plasma levels of adiponectin, and C-peptide. No significant relationship between resistin circulating levels or expression in monocytes and insulin resistance-related phenotypes was found in baboons. These findings suggest that resistin is not associated with insulin resistance. However, previous observations of relationships among weight, adiponectin, and insulin resistance are confirmed.