Adaptation of sea turtles to climate warming: Will phenological responses be sufficient to counteract changes in reproductive output?

Sea turtles are vulnerable to climate change since their reproductive output is influenced by incubating temperatures, with warmer temperatures causing lower hatching success and increased feminization of embryos. Their ability to cope with projected increases in ambient temperatures will depend on their capacity to adapt to shifts in climatic regimes. Here, we assessed the extent to which phenological shifts could mitigate impacts from increases in ambient temperatures (from 1.5 to 3°C in air temperatures and from 1.4 to 2.3°C in sea surface temperatures by 2100 at our sites) on four species of sea turtles, under a "middle of the road" scenario (SSP2-4.5). Sand temperatures at sea turtle nesting sites are projected to increase from 0.58 to 4.17°C by 2100 and expected shifts in nesting of 26-43 days earlier will not be sufficient to maintain current incubation temperatures at 7 (29%) of our sites, hatching success rates at 10 (42%) of our sites, with current trends in hatchling sex ratio being able to be maintained at half of the sites. We also calculated the phenological shifts that would be required (both backward for an earlier shift in nesting and forward for a later shift) to keep up with present-day incubation temperatures, hatching success rates, and sex ratios. The required shifts backward in nesting for incubation temperatures ranged from -20 to -191 days, whereas the required shifts forward ranged from +54 to +180 days. However, for half of the sites, no matter the shift the median incubation temperature will always be warmer than the 75th percentile of current ranges. Given that phenological shifts will not be able to ameliorate predicted changes in temperature, hatching success and sex ratio at most sites, turtles may need to use other adaptive responses and/or there is the need to enhance sea turtle resilience to climate warming.

Blood biochemistry of olive ridley (Lepidochelys olivacea) sea turtles foraging in northern Sinaloa, Mexico.

Blood parameters provide an excellent tool to evaluate the health status of wildlife. However, there are few studies about health parameters of sea turtles in Mexico. For olive ridley turtles (Lepidochelys olivacea), no information was available to establish the health baseline for the species. The objective of this study was to establish reference blood biochemistry values for olive ridley turtles in the northern Sinaloa foraging area. Between 2013 and 2015, 82 olive ridley turtles were captured. Body condition index (BCI) presented a mean of 1.46 ± 0.14 (1.17-2.02) that categorized the population with excellent body condition; in addition, 99% of the turtles captured had a good physical appearance. Blood was collected for biochemistry analysis from 60 turtles. Significantly higher values of total protein, albumin, A/G ratio (albumin/globulin) and PCV (packed cell volume or hematocrit) were observed in adult when compared to subadult turtles. On the other hand, no significant differences were found when females and males were compared. Based on the BCI, physical assessment, and blood parameters, and compared to other sea turtle species, olive ridley turtles in northern Sinaloa were considered in excellent health. To the best of our knowledge, this is the first study to establish normal blood biochemistry values of foraging olive ridley turtles in northern Sinaloa.

Two consecutive partial liver transplants in a patient with Classic Maple Syrup Urine Disease.

Maple syrup urine disease is caused by a deficiency in the branched chain ketoacid dehydrogenase (BCKAD) complex. This results in the accumulation of branched chain amino acids (BCAA) and branched chain ketoacids in the body. Even when aggressively treated with dietary restriction of BCAA, patients experience long term cognitive, neurological and psychosocial problems. Liver transplantation from deceased donors has been shown to be an effective modality in introducing adequate BCKAD activity, attaining a metabolic cure for patients. Here, we report the clinical course of the first known patient with classic MSUD who received two consecutive partial liver grafts from two different living non-carrier donors and his five year outcome posttransplant. We also show that despite the failure of the first liver graft, and initial acute cellular rejection of the second liver graft in our patient, his metabolic control remained good without metabolic decompensation.

Trace elements in blood of sea turtles Lepidochelys olivacea in the Gulf of California, Mexico.

This study determined the concentrations of heavy metals in blood collected from Pacific Ridley sea turtles (Lepidochelys olivacea) inhabiting the coast of Guasave, Mexico, in the Gulf of California. The highest reported metal concentration in blood was Zn, followed by Se. Of nonessential toxic metals, As was reported in higher percentage compared to Cd. The concentrations of metals detected were present as follows: Zn > Se > Mn > As > Ni > Cd > Cu. Cd concentration in blood is higher in our population in comparison with other populations of L. olivacea, and even higher in other species of sea turtles. Our study reinforces the usefulness of blood for the monitoring of the levels of contaminating elements, and is easily accessible and nonlethal for sea turtles.

Selected heavy metals and selenium in the blood of black sea turtle (Chelonia mydas agasiizzi) from Sonora, Mexico.

The concentration of heavy metals (Zn, Cd, Ni, Cu, Mn) and selenium (Se) was analyzed in blood collected from 12 black turtles (Chelonia mydas agasiizzi) captured in Canal del Infiernillo, Punta Chueca, Mexico. The most abundant metals were Zn (63.58 µg g(-1)) and Se (7.66 µg g(-1)), and Cd was the lower (0.99 µg g(-1)). The sequential concentrations of trace metals were Zn > Se > Cu > Mn > Ni > Cd. In conclusion, this information is important as a baseline when using blood as tissue analysis of heavy metals; however, these levels could represent recent exposure in foraging grounds of black turtles in the Sea of Cortez.

Release, biological potency, and biochemical integrity of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) combined with Augment(TM) Bone Graft or GEM 21S beta-tricalcium phosphate (beta-TCP).

Over 10 million surgical procedures are performed annually in the United States to treat musculoskeletal injuries, and a significant portion of these involve orthopedic bone grafting. The goals of the study were to evaluate the in vitro and in vivo release kinetics, biological potency and biochemical integrity of rhPDGF-BB combined with large (1000-2000 microm) and small (250-1000 microm) beta-TCP particles. Recombinant human platelet-derived growth factor B homodimer (rhPDGF-BB) is a protein growth factor under development as a therapeutic for accelerating bone healing. Release of the protein was monitored in vitro by ELISA, and in vivo by measurement of radioactive rhPDGF-BB implanted in rat calvarial defects. Biological activity was measured using a cell-based bioassay, and biochemical integrity was determined by SDS-PAGE and high pressure size exclusion chromatography (HPSEC). Release of rhPDGF-BB occurred rapidly from beta-TCP both in vitro and in vivo. Almost 100% of the rhPDGF-BB was recovered from large and small beta-TCP after 90 min in vitro. Approximately 90% of the rhPDGF-BB was depleted from calvarial defect sites within 72 h of implantation. RhPDGF-BB retained 100% of its biological potency compared to reference standard rhPDGF-BB, manifested as a single band at ~30 kDa by SDS-PAGE and a single peak eluted after 13 min by HPSEC following release from beta-TCP. RhPDGF-BB is rapidly released from large and small beta-TCP particles and is biochemically unaltered following release.

Cellular replication of human immunodeficiency virus type 1 occurs in vaginal secretions.

Most human immunodeficiency virus type 1 (HIV-1) transmission worldwide is the result of exposure to infectious virus in genital secretions. However, current vaccine candidates are based on virus isolates from blood. In this study, vaginal secretions from HIV-1-infected women were examined for evidence of cellular viral replication that produced virus with properties different from that in blood. Multiply spliced HIV-1 messenger RNA, which is found only in cells replicating virus, was detected in all vaginal lavage samples tested. There was a strong correlation between the amounts of multiply spliced HIV-1 messenger RNA and of cell-free HIV-1 RNA in the lavage samples. In addition, significant genotypic differences were found in cell-free virus from matched blood plasma and vaginal secretions. Moreover, drug resistance-associated mutations appeared in plasma virus several months before appearing in vaginal virus. These findings indicate that cellular replication of HIV-1 occurs in vaginal secretions and can result in a virus population with important differences from that in blood.

HIV in body fluids during primary HIV infection: implications for pathogenesis, treatment and public health.

OBJECTIVE: To describe initial viral dissemination to peripheral tissues and infectious body fluids during human primary HIV infection. DESIGN: Observational cohort study. METHODS: Blood plasma, cerebrospinal fluid (CSF), seminal plasma, cervicovaginal lavage fluid and/or saliva were sampled from 17 individuals with primary HIV infection (range of time from symptoms onset to sampling, 8--70 days) and one individual with early infection (168 days). Subjects' HIV-1 RNA levels in each fluid were compared with levels from antiretroviral-naive controls with established HIV infection. For study subjects, correlations were assessed between HIV-1 RNA levels and time from symptoms onset. Responses to antiretroviral therapy with didanosine + stavudine + nevirapine +/- hydroxyurea were assessed in each compartment. RESULTS: HIV-1 RNA levels were highest closest to symptoms onset in blood plasma (18 patients) and saliva (11 patients). CSF HIV-1 RNA levels (five patients) appeared lower closer to symptoms onset, although they were higher overall in primary versus established infection. Shedding into seminal plasma (eight patients) and cervicovaginal fluid (two patients) was established at levels observed in chronic infection within 3--5 weeks of symptoms onset. High-level seminal plasma shedding was associated with coinfection with other sexually transmitted pathogens. Virus replication was suppressed in all compartments by antiretroviral therapy. CONCLUSIONS: Peak level HIV replication is established in blood, oropharyngeal tissues and genital tract, but potentially not in CSF, by the time patients are commonly diagnosed with primary HIV infection. Antiretroviral therapy is unlikely to limit initial virus spread to most tissue compartments, but may control genital tract shedding and central nervous system expansion in primary infection.

Platelet-derived growth factor C (PDGF-C), a novel growth factor that binds to PDGF alpha and beta receptor.

We have characterized platelet-derived growth factor (PDGF) C, a novel growth factor belonging to the PDGF family. PDGF-C is a multidomain protein with the N-terminal region homologous to the extracellular CUB domain of neuropilin-1, and the C-terminal region consists of a growth factor domain (GFD) with homology to vascular endothelial growth factor (25%) and PDGF A-chain (23%). A serum-sensitive cleavage site between the two domains allows release of the GFD from the CUB domain. Competition binding and immunoprecipitation studies on cells bearing both PDGF alpha and beta receptors reveal a high affinity binding of recombinant GFD (PDGF-CC) to PDGF receptor-alpha homodimers and PDGF receptor-alpha/beta heterodimers. PDGF-CC exhibits greater mitogenic potency than PDGF-AA and comparable or greater mitogenic activity than PDGF-AB and PDGF-BB on several mesenchymal cell types. Analysis of PDGF-CC in vivo in a diabetic mouse model of delayed wound healing showed that PDGF-CC significantly enhanced repair of a full-thickness skin excision. Together, these studies describe a third member of the PDGF family (PDGF-C) as a potent mitogen for cells of mesenchymal origin in in vitro and in vivo systems with a binding pattern similar to PDGF-AB.

Human immunodeficiency virus 1 expression in the female genital tract in association with cervical inflammation and ulceration.

OBJECTIVES: Determining the source of human immunodeficiency virus 1 in the female genital tract and identifying factors that influence the amount of virus shed are important in the understanding of heterosexual human immunodeficiency virus 1 transmission. STUDY DESIGN: Cervicovaginal human immunodeficiency virus 1 ribonucleic acid shedding was quantified before and after treatment of cervical squamous intraepithelial lesions in 14 women. Genotypic analysis was performed on peptide HIV-1 env gp120 of the major human immunodeficiency virus 1 species in plasma and cervicovaginal lavage of selected samples. RESULTS: At 2 to 4 weeks after treatment, when cervices were inflamed and ulcerated, human immunodeficiency virus 1 ribonucleic acid in lavage samples increased 1.0 to 4.4 log 10. Genotypic analysis showed significant differences between the predominant human immunodeficiency virus 1 species in paired plasma and lavage samples from 2 of 4 women, suggesting that the increase in human immunodeficiency virus 1 was the result of local viral replication. CONCLUSIONS: Cervical inflammation and ulceration are associated with local human immunodeficiency virus 1 expression, which increases as much as 10,000-fold the amount of human immunodeficiency virus 1 shed into genital secretions. This may explain why sexually transmitted diseases are important risk factors for human immunodeficiency virus transmission.

Rapid CD4(+) T-cell loss induced by human immunodeficiency virus type 1(NC) in uninfected and previously infected chimpanzees.

To investigate the pathogenicity of a virus originating in a chimpanzee with AIDS (C499), two chimpanzees were inoculated with a plasma-derived isolate termed human immunodeficiency virus type 1(NC) (HIV-1(NC)). A previously uninfected chimpanzee, C534, experienced rapid peripheral CD4(+) T-cell loss to fewer than 26 cells/microl by 14 weeks after infection. CD4(+) T-cell depletion was associated with high plasma HIV-1 loads but a low virus burden in the peripheral lymph node. The second chimpanzee, C459, infected 13 years previously with HIV-1(LAV), experienced a more protracted course of peripheral CD4(+) T-cell loss after HIV-1(NC) inoculation, resulting in fewer than 200 cells/microl by 96 weeks postinoculation. The quantities of viral RNA in the plasma and peripheral lymph node from C459 were below the lower limits of detection prior to inoculation with HIV-1(NC) but were significantly and persistently increased after superinfection, with HIV-1(NC) representing the predominant viral genotype. These results show that viruses derived from C499 are more pathogenic for chimpanzees than any other HIV-1 isolates described to date.

Progressive infection in a subset of HIV-1-positive chimpanzees.

Chimpanzees are susceptible to infection with human immunodeficiency virus (HIV)-1; however, infected animals usually maintain normal numbers of CD4(+) T lymphocytes and do not develop immunodeficiency. We have examined 10 chronically infected HIV-1-positive chimpanzees for evidence of progressive infection. In addition to 1 animal that developed AIDS, 3 chimpanzees exhibit evidence of progressive HIV infection. All progressors have low CD4(+) T cell counts (<200 cells/microL), severe CD4:CD8 inversion, and marked reduction in interleukin-2 receptor expression by CD4(+) T cells. In comparison with HIV-positive nonprogressor chimpanzees, progressors have higher plasma and lymphoid virus loads, greater CD38 expression in CD8(+)/HLA-DR(+) T cells, and greater serum concentrations of soluble tumor necrosis factor type II receptors and beta2-microglobulin, all markers of HIV progression in humans. These observations show that progressive HIV-1 infection can occur in chimpanzees and suggest that the pathogenesis of progressive infection in this species resembles that in humans.

Correlation between human immunodeficiency virus type 1 RNA levels in the female genital tract and immune activation associated with ulceration of the cervix.

To address the hypothesis that local immune activation resulting from genital ulceration enhances human immunodeficiency virus type 1 (HIV-1) replication and shedding into the genital tract, paired plasma and cervicovaginal lavage (CVL) samples were obtained from 12 HIV-infected women before and after treatment of cervical intraepithelial lesions. Two weeks after treatment, inflammation and ulceration of the cervix were accompanied by major increases in mean concentrations of HIV-1 RNA (200-fold), tumor necrosis factor-alpha, interleukin 6, and soluble markers shed by activated lymphocytes and macrophages (sCD25 and sCD14, respectively) in CVL samples (P<.01 for each), but not plasma. Strong temporal and quantitative correlations were observed between concentrations of immunological markers and HIV-1 load in this compartment during a 10-week follow-up. Furthermore, in the presence of genital ulceration, HIV-1 in CVL samples was more readily captured by antibodies directed against virion-associated HLA-DR, a marker of host-cell activation, compared with virus in plasma. We suggest that local immune activation increases HIV-1 load in genital secretions, potentially increasing the risk of HIV-1 transmission.

Tissue factor overexpression in rat arterial neointima models thrombosis and progression of advanced atherosclerosis.

BACKGROUND: Tissue factor located in the atherosclerotic plaque might cause the clinically significant thrombotic events associated with end-stage disease. It might also affect intimal area by increasing matrix accumulation and stimulating smooth muscle cell (SMC) migration and proliferation. To test this hypothesis, we overexpressed tissue factor in a rat model of the human fibrous plaque. METHODS AND RESULTS: A neointima was generated by seeding tissue factor-overexpressing rat SMCs onto the luminal surface of a balloon-injured syngeneic rat carotid artery. The cells attached and expressed tissue factor over the long term. Mural thrombus accumulation was present at 4 and 7 days and increased neointimal SMC numbers and area by 2-fold at 2 and 4 weeks. Tissue factor overexpression accelerated reendothelialization compared with controls at 2 weeks and 1 month. Tissue factor-overexpressing SMCs exhibited increased migration both in vitro and in vivo. The increased migration by tissue factor-overexpressing SMCs in vitro was not dependent on activation of the coagulation cascade and could be blocked by an inhibitor of tissue factor. CONCLUSIONS: These results suggest that tissue factor plays a direct role in neointimal development by coagulation-dependent and -independent pathways.

Effect of platelet-derived growth factor receptor-alpha and -beta blockade on flow-induced neointimal formation in endothelialized baboon vascular grafts.

The growth of neointima and neointimal smooth muscle cells in baboon polytetrafluoroethylene grafts is regulated by blood flow. Because neointimal smooth muscle cells express both platelet-derived growth factor receptor-alpha and -beta (PDGFR-alpha and -beta), we designed this study to test the hypothesis that inhibiting either PDGFR-alpha or PDGFR-beta with a specific mouse/human chimeric antibody will modulate flow-induced neointimal formation. Bilateral aortoiliac grafts and distal femoral arteriovenous fistulae were placed in 17 baboons. After 8 weeks, 1 arteriovenous fistulae was ligated, normalizing flow through the ipsilateral graft while maintaining high flow in the contralateral graft. The experimental groups received a blocking antibody to PDGFR-alpha (Ab-PDGFR-alpha; 10 mg/kg; n=5) or PDGFR-beta (Ab-PDGFR-beta; 10 mg/kg; n=6) by pulsed intravenous administration 30 minutes before ligation and at 4, 8, 15, and 22 days after ligation. Controls received carrier medium alone (n=8). Serum antibody concentrations were followed. Grafts were harvested after 28 days and analyzed by videomorphometry. Serum Ab-PDGFR-alpha concentrations fell rapidly after day 7 to 0, whereas serum Ab-PDGFR-beta concentrations were maintained at the target levels (>50 microg/mL). Compared with controls (3.7+/-0.3), the ratio of the intimal areas (normalized flow/high flow) was significantly reduced in Ab-PDGFR-beta (1.2+/-0.2, P<0.01) but not in Ab-PDGFR-alpha (2.2+/-0.4). Ab-PDGFR-alpha decreased significantly the overall smooth muscle cell nuclear density of the neointima (P<0.01) compared with either the control or Ab-PDGFR-beta treated groups. PDGFR-beta is necessary for flow-induced neointimal formation in prosthetic grafts. Targeting PDGFR-beta may be an effective pharmacological strategy for suppressing graft neointimal development.

Correlation of human immunodeficiency virus type 1 RNA levels in blood and the female genital tract.

In this study, the correlations of human immunodeficiency virus type 1 (HIV-1) RNA levels in blood plasma, vaginal secretions, and cervical mucus of 52 HIV-1-infected women were determined. The amount of cell-free HIV-1 RNA in blood plasma was correlated with that in vaginal secretions (Spearman's rank correlation coefficient (r) = 0.64, P<.001). In both blood plasma and vaginal secretions, the amounts of cell-free and cell-associated HIV-1 RNA were highly correlated (r=0.76, P<.01 and r=0.85, P<.01, respectively). Cell-free HIV-1 RNA levels in blood plasma and vaginal secretions were negatively correlated with CD4+ T lymphocyte count (r=-0.44, P<.01 and r=-0.40, P<.01, respectively). Similar to the effect observed in blood plasma, initiation of antiretroviral therapy significantly reduced the amount of HIV-1 RNA in vaginal secretions. These findings suggest that factors that lower blood plasma virus load may also reduce the risk of perinatal and female-to-male heterosexual transmission by lowering vaginal virus load.

PDGFbeta receptor blockade inhibits intimal hyperplasia in the baboon.

BACKGROUND: We have evaluated the use of a mouse/human chimeric anti-platelet-derived growth factor-beta receptor antibody in combination with heparin to inhibit intimal hyperplasia in the saphenous artery of the baboon after balloon angioplasty. METHODS AND RESULTS: The study evaluated lesion development in sequential injuries made 28 days apart. Each animal received control treatment after the first injury and antibody/heparin therapy after the second injury to the contralateral artery. The antibody was administered by bolus intravenous injections (10 mg/kg) on study days 1, 4, 8, 15, and 22 and heparin coadministered by continuous intravenous infusion at a dose of 0.13 mg/kg per hour. Morphometric analysis of tissue sections showed a 53% decrease in intimal area after antibody/heparin treatment (P=0.005), corresponding to a 40% decrease in the intima-to-media ratio (P=0.005). Smooth muscle cell proliferation in the injured wall, measured at both 4 and 29 days after balloon injury, were similar in the control and antibody/heparin-treated animals. CONCLUSIONS: These data suggest that platelet-derived growth factor plays a key role in the development of intimal lesions at sites of acute vascular injury in the nonhuman primate.

Quantitative, competitive PCR assay for HIV-1 using a microplate-based detection system.

We have developed a quantitative competitive PCR (QC-PCR) assay in a microplate format for quantifying human immunodeficiency virus Type 1 (HIV-1) DNA or RNA in a broad range of source materials. Our QC-PCR assay is a modification of technique originally described by Piatak et al. (1993), which is based on the presence of a competitive internal standard containing an internal 80-bp deletion of HIV-1 gag target sequence. For improved detection and quantification of the wild-type and internal-standard PCR products in a microplate format, we introduced a non-HIV, 31-bp insert into the internal standard as a probe hybridization site that does not cross-hybridize with wild-type HIV-1 products. By using a primer pair in which one primer is biotinylated, QC-PCRs can be bound to a streptavidin-coated microplate, denatured and probed with a digoxigenin (Dig)-labeled, wild-type or internal-standard probe. The hybridized Dig-labeled probes are detected with an anti-Dig antibody conjugated to detector molecules for luminometry (aequorin) or optical densitometry (peroxidase), yielding results that are quantifiable over the range of 100-10,000 copies of HIV gag. Tested source materials for HIV-1 DNA or RNA quantification include plasma, vaginal lavage and cultured cells. The application of the QC-PCR assay using the microplate format affords a convenient and cost-effective method for quantifying HIV-1 proviral and viral loads from a variety of body fluids, cells and tissues.

Sequential injury of the rabbit abdominal aorta induces intramural coagulation and luminal narrowing independent of intimal mass: extrinsic pathway inhibition eliminates luminal narrowing.

We hypothesized that activation of the coagulation cascade is involved in arterial remodeling in response to sequential injury. An active site-inhibited recombinant human factor VIIa (FVIIai) was used to inhibit tissue factor, the primary cofactor in the extrinsic pathway of coagulation, in a sequential balloon injury model of the rabbit abdominal aorta. Single balloon injury produced limited intimal thickening at 3 weeks (intimal area, 0.40+/-0.05 mm2) and no loss in luminal area (12.2+/-0.9 mm2 before injury and 12.1+/-0.9 mm2 at 6 weeks after injury). Sequential balloon injury, 3 weeks after the first balloon denudation, produced a progressive loss of lumen, with 22% and 47% loss of luminal area, respectively, at 3 and 6 weeks. Luminal loss could not be accounted for by intimal growth (at 3 weeks after sequential injury, the intimal area was 0.47+/-0.08 mm2, <4% of the initial luminal area). Sequential injury acutely produced extensive mural and intramural fibrin deposition. Treatment with FVIIai inhibited both the fibrin deposition and the chronic loss of lumen. At 3 weeks after sequential injury, luminal cross-sectional areas were 9.8+/-0.6 mm2 for control rabbits and 14.3+/-1.4 mm2 for FVIIai-treated rabbits. Neither neointimal area nor cell proliferation was reduced by FVIIai treatment. The intimal cell proliferation index 3 days after injury was 7.6+/-1.1% in control rabbits versus 5.8+/-1.1% in treated rabbits (P>0.05). These results indicate that tissue factor is an important mediator of coagulation in repeat injury and implicate the extrinsic coagulation cascade in a blood vessel remodeling response that is independent of neointimal growth but leads to extensive loss of lumen.

Primate smooth muscle cell migration from aortic explants is mediated by endogenous platelet-derived growth factor and basic fibroblast growth factor acting through matrix metalloproteinases 2 and 9.

BACKGROUND: Migration of arterial smooth muscle cells (SMCs) is regulated by basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), and matrix metalloproteinases (MMPs) in the injured rat carotid artery. We have recently shown that migration of SMCs from baboon aortic explants depends on the activity of MMPs, but the identity of the stimulatory MMPs and the role of bFGF and PDGF in this primate system are not known. METHODS AND RESULTS: These experiments were designed to determine whether MMP2, MMP9, bFGF, or PDGF plays a role in SMC migration from medial explants of baboon aorta. Explants were cultured in serum-free medium with insulin, transferrin, and ovalbumin. Neutralizing antibodies to MMP2 and antibodies that inhibit activation of proMMP9 decreased SMC migration from the aortic explants. Antibodies to bFGF and to the alpha- and beta-subunits of the PDGF receptor also inhibited migration from the explants. Addition of bFGF and PDGF-BB but not PDGF-AA increased migration. The antibodies to bFGF but not the antibodies to the PDGF receptor subunits decreased the levels of MMP9, whereas all the antibodies decreased activated MMP2. CONCLUSIONS: These data demonstrate that SMC migration from primate aortic explants is dependent on endogenous MMP2, MMP9, PDGF, and bFGF. The data also suggest that PDGF-induced (PDGF-BB or possibly PDGF-AB) migration is dependent on MMP2, whereas bFGF-induced migration depends on both MMP2 and MMP9.