Blood glucose fluctuation affects skin collagen metabolism in the diabetic mouse by inhibiting the mitogen-activated protein kinase and Smad pathways

BACKGROUND

We recently reported that in mice, blood glucose fluctuations (BGF) produced more detrimental effects on skin structure and function than did diabetes alone.

AIM

To determine whether treatment of BGF changes the collagen metabolism in the skin of diabetic mice, and to explore its possible molecular mechanism further.

METHODS

The study used diabetic and BGF animal models. Immunohistochemistry, western blotting and real-time PCR analysis were used to detect the expression of type I collagen, matrix metalloproteinase (MMP)-1, MMP-2 and MMP-13, tissue inhibitor of metalloproteinase (TIMP)-1, extracellular signal-regulated kinase, p38, and Smad2/3. The activities of mitogen-activated protein kinase (MAPK) and Smad signal molecules were also detected by western blotting, and the skin fibroblast ultrastructure was examined using an electron microscope.

RESULTS

BGF treatment produced a twofold reduction in type I collagen synthesis compared with diabetes-only mice. Expression of MMP-1, MMP-2 and MMP-13 increased markedly in the BGF-treated mice, but TIMP-1 expression was strongly downregulated by the BGF treatment. There was also evidence of higher levels of apoptosis of skin fibroblasts after BGF treatment.

CONCLUSIONS

BGF treatment can affect collagen production in the skin of diabetic BGF mice by inhibiting collagen synthesis and increasing collagen degradation. Furthermore, both MAPK and Smad signalling pathways seem to play a role in the inhibition of collagen production in diabetic mice treated with BGF.

Abstract P5-16-04: A phase I study of a DNA plasmid based vaccine encoding the HER-2/neu intracellular domain in subjects with HER2+ breast cancer

HER2+ breast cancer (BC) is associated with early disease relapse, usually to distant sites. This would suggest relapse is due to residual microscopic disease. Generation of vaccine-induced HER2-specific CD4+ T helper immunity (Th1) may result in immunologic eradication of residual HER2+ tumor cells and subsequent development of immunologic memory and epitope spreading (ES), which has been associated with a survival benefit in vaccinated BC patients. We have shown HER2 peptide-based vaccines can generate immunity in BC however, more recently we developed a plasmid DNA based vaccine (pNGVL3-hICD) which may have additional advantages over synthetic peptides. DNA vaccines offer a strategy to immunize against multiple tumor antigens and are able to elicit both CTL and Th1 immunity. Plasmid DNA can also remain at the vaccine site, providing a constant source of antigen. Intradermal (i.d.) delivery of DNA vaccines with GM-CSF as adjuvant may enhance immunogenicity due to local influx of dermal Langerhans cells. We have recently completed a phase I trial utilizing pNGVL3-hICD in optimally treated stage III and IV HER2+ BC patients and have defined vaccine safety profile, optimal dose and schedule; and demonstrated vaccine biologic activity.

Methods: A total of 66 subjects with stage III and IV HER2+ BC in complete remission were enrolled sequentially into 1 of 3 pNGVL3-hICD dose arms (22 subjects/arm): Arm 1=10µg, Arm 2=100 µg, and Arm 3 = 500µg. All vaccines were admixed with 100µg GM-CSF and given i.d. monthly for a total of 3 vaccines. Toxicity was assessed at baseline, during vaccination and at follow-up. Immune responses to HER ICD and ECD were assessed with IFN-γ ELISPOT at baseline and serially through week 60 post-vaccination. Linear regression analysis was used to compare differences in immune responses from baseline over the whole study period between dose arms. Vaccine site skin biopsies and peripheral lymphocytes were serially analyzed for plasmid persistence via RT-PCR.

Results: 64 subjects (20 in Arm 1; 22 in Arm 2; 22 in Arm 3) completed 3 vaccines. Age, stage/status, number of previous chemotherapy regimens, and use of bisphosphonate and trastuzumab therapies was similar across dose arms. Vaccine-related toxicity was primarily Grade 1/2 injection site reactions, myalgias, arthralgias and not significantly different between arms; no cardiac or grade IV toxicity was observed. Immune responses to HER2 ICD were significantly better in Arms 2 and 3 vs Arm 1 (p = 0.001 and 0.002, respectively) but not statistically different between Arms 2 and 3. 38 patients had DNA plasmid persistence at the vaccination site with no difference between arms. There has been no detection of DNA plasmid in lymphocytes from patients in all arms. Analyses of survival and ES (HER ECD immune responses) are on-going and will be presented.

Conclusions: pNGVL3-hICD was safe and effectively induced persistent HER2 ICD specific Th1 immunity without increased cardiac toxicity. Moreover, immunity was present more than 1 year after end of vaccination, indicative of vaccine-induced immunologic memory.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-16-04.

Quantitative assessment of external carotid artery territory supply with modified vessel-encoded arterial spin-labeling

BACKGROUND AND PURPOSE

In patients with carotid stenosis or occlusion, cerebral blood could be supplied through collateral pathways to improve regional blood flow and protect against ischemic events. The contribution of collaterals from the ICA can be assessed by depiction of vascular perfusion territories with ASL. However, so far there is no method available to evaluate the collateral perfusion territory from the ECA in MR imaging. In this study, we present a new labeling scheme based on VE-ASL to quantitatively assess the perfusion territory of the ECA.

MATERIALS AND METHODS

A new labeling approach with a Hadamard encoding scheme was developed to label major arteries, especially the ECA. Twelve healthy subjects with normal cerebrovascular anatomy were examined to demonstrate their perfusion territories. Eight patients with carotid artery stenosis or occlusion were assessed before and after surgery to show changes of their collateral blood supply.

RESULTS

The proposed method enables assessment of the perfusion territories of the ECA. Good agreement was found between the vascular territories and normal cerebrovascular anatomy in healthy subjects. For the patients with carotid stenosis or occlusion, our noninvasive results provided information on collateral flow comparable with that from DSA. Their collateral flows from the ECA, moreover, could be quantitatively estimated pre- and postoperatively.

CONCLUSIONS

The modified approach has been validated by the consistency of collateral perfusion territories with cerebrovascular anatomy, and quantitative assessment of collaterals proved useful for assisting in evaluating therapeutic interventions.

OT2-05-05: Phase I/II Study of Adoptive T Cell Therapy Following In Vivo Priming with a HER2 Peptide-Based Vaccine in Patients with Stage IV Breast Cancer

Background

Adoptive T cell therapy has evolved from preclinical setting to a potentially feasible treatment strategy for advanced breast cancer (BC). However, the ability to expand tumor antigen specific T cells ex vivo has been one of the major hurdles that has limited clinical translation of adoptive T cell therapy. Tumor specific T cells are rare in unprimed patients and generating large bulk cultures from rare precursor frequencies is difficult. We have found immunizing HER2+ patients to increase tumor specific T cell precursor frequencies to the levels of a vaccinated foreign antigen markedly improves the ability to generate large numbers of tumor specific T cells in vitro. We hypothesize that T cell expansion strategies that are facilitated by prior immunization will be clinically useful in the treatment of advanced BC.

Design: A Phase I/II non-randomized, single arm study. Priming with a HER2 ICD vaccine will be performed at 1 week intervals for a total of 3 vaccines. Patients will undergo leukapheresis 2 weeks after the 3rd vaccine to collect PBMC for T cell expansion. Patients will be pre-treated with cyclophosphamide 24 hours prior to 1st T cell infusion and then receive up to 3 dose-escalating infusions of T cells given 7–10 days apart. Three HER2 vaccine booster immunizations will then be administered at 1, 2, and 4 months after the final T cell infusion. Follow-up for persistent and continued immunity will then ensue.

Aims: To evaluate the safety of infusing escalating doses of HER2 specific T cells into patients with advanced HER2+ BC using ex vivo expanded autologous T cells, to investigate to what extent HER2 specific T cell immunity can be boosted or generated in individuals after infusion of HER2 specific T cells, to evaluate how long T cell immune augmentation persists in vivo after adoptive transfer of HER2 specific T cells and subsequent booster immunizations.

Criteria: Patients with HER2+ Stage IV BC who: have been maximally treated and not achieved a complete remission, have stable or slowly progressive disease, HER2+, and have adequate LVEF.

Statistical Methods: Toxicity will be determined by chemical and clinical parameters evaluated at various time points. If the true probability of a DLT is 0.11, then the probability of observing 0 DLT's in 20 patients is 0.097. If the true probability of a DLT is 0.18, then the probability of observing ≤1 DLT's in 20 patients is 0.102, and if the true probability of a DLT is 0.27, then the probability of observing ≤2 DLT's in 20 patients is 0.064. Therefore, with low observed rates of DLT (≤10%), we can be reasonably confident (∼90%) with 20 patients that the true DLT rate is < 0.27. Immunologic response, defined as the successful boosting of precursor frequency with infusion of HER2−specific T cells, will be evaluated by assessing the change in T cell level from baseline. To assess the durability of the T cell response, we are primarily interested in estimating the proportion of patients whose T cells persist at a level the same or greater as the level after the final T cell infusion as long as 6 months following the final booster vaccine.

Accrual: Target=20/Actual=14

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT2-05-05.

Investigation of irradiation by different nonablative lasers on primary cultured skin fibroblasts

BACKGROUND

A variety of lasers with different wavelengths and biological effects are widely used for nonablative skin rejuvenation, but the underlying mechanisms have not been fully investigated.

AIM

To investigate the effects of irradiation by different nonablative lasers on collagen synthesis and the antioxidant status of cultured fibroblasts to identify a possible mechanism for laser photorejuvenation.

METHODS

Cultured skin fibroblasts were irradiated with three different lasers: 532 nm potassium-titanyl phosphate (KTP), 1064 nm Q-switched neodymium:yttrium-aluminium-garnet (Nd:Yag) and 1064 nm long-pulse Nd:YAG, and production of collagen and changes in lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were assayed.

RESULTS

Irradiation by all three lasers led to a marked increase in collagen production. Two major antioxidant enzymes, SOD and GSH, were significantly increased, whereas MDA was markedly reduced after laser irradiation. No change in LDH activity was found between nonirradiated and irradiated fibroblasts.

CONCLUSION

This study indicates that the increased collagen synthesis by fibroblasts after laser treatment may be partly due to improved antioxidant capacity, which reduces oxidative stress and thus stimulates new collagen production.

Phase I-II Study of Denileukin Diftitox (ONTAK®) in Patients with Advanced Refractory Breast Cancer

Background: CD4+CD25+Foxp3+ regulatory T cells (Tregs) are potent suppressors of CD4+ and CD8+ T cells, produce the immunosuppressive cytokine TGF-β; and as such, may down-regulate immune responses to tumor antigens. Additionally, Tregs are increased in the peripheral blood (PB) and tumors of breast cancer patients; and are associated with poor prognosis. Depletion of PB and tumor-associated Tregs may induce anti-tumor immunity by augmenting anti-tumor effector T cells and enhancing endogenous tumor specific immunity. ONTAK®, a diphtheria/IL-2R fusion protein depletes PB Tregs when given intravenously (IV) and selectively targets tumor cells that overexpress IL-2R. Breast tumors have been shown to overexpress IL-2R which is associated with their malignant potential. We hypothesized that ONTAK® could (1) have direct anti-tumor activity in breast cancers that overexpress IL-2R, and (2) deplete Tregs resulting in generation of functional immune effector cells and enhanced anti-tumor immunity. A phase I-II study was conducted to evaluate the safety of IV ONTAK® and assess its effect on Tregs and endogenous immunity in patients with advanced refractory breast cancer.Materials and Methods: 15 patients with progressive stage IV breast cancer following standard therapy were sequentially enrolled and received IV ONTAK® 18 mcg/kg/day on Days1-5 every 21 days for a total of 6 cycles and/or maximal tumor response. Toxicity was evaluated on Days 1 8, and 14 of each cycle per CTEP CTCAE v3.0. Tumor response was evaluated per RECIST at baseline, and after cycles 3 and 6. PB was collected at baseline and after cycles 2, 4, and 6 for evaluation of Tregs, sIL-2R, and endogenous tumor-antigen specific T cell immunity to HER-2/neu (HER2), CEA, and MAGE-3 via RT-PCR, LUMINEX and IFN-γ ELISPOT assay, respectively. Expression of IL-2R in patient paraffin embedded tumor samples was analyzed by IHC analysis.Results: 15 subjects have been enrolled and 14/15 have completed treatment; median age is 58 years (range, 32-69) and median salvage regimens is 3 (range, 2-8). 7/14 subjects had triple negative tumors. 7 subjects completed 1-2 and 7 completed 3-6 ONTAK® cycles, respectively. 4 subjects who completed 6 cycles of ONTAK® had SD or PR per RECIST. ONTAK®-related toxicities have been primarily grade I and II fatigue, nausea, and headache; and transient grade 3 hypoalbuminemia and lymphopenia. Preliminary data in 2 subjects shows enhanced tumor-antigen specific T cell immunity defined as mean tumor antigen-specific T cell precursors:PBMC to CEA (pre- ONTAK® 1:250,000; post- ONTAK® 1:15,000) and HER2 (pre- ONTAK® 1:63,000; post- ONTAK® 1:6,312). Immunologic analyses are ongoing and will be presented along with clinical data on all patients.Conclusions: ONTAK® is well-tolerated when used as a salvage regimen in heavily pretreated breast cancer patients. Additionally, ONTAK® treatment can enhance endogenous immunity to known breast cancer antigens and potentially lead to more effective eradication of tumor.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4130.

Phase II Study of a HER-2/Neu (HER2) Intracellular Domain (ICD) Vaccine Given Concurrently with Trastuzumab in Patients with Newly Diagnosed Advanced Stage Breast Cancer

HER2 is a tumor antigen in breast cancer and several trials have demonstrated that breast cancer patients can be immunized against this protein. We have developed HER2 peptide based vaccines that are aimed at eliciting CD4+ Th1 tumor antigen specific T cell responses. Th1 effectors provide immunologic memory, enhance cross priming which will allow the elaboration of tumor specific CD8+ T cells, and stimulate epitope spreading which we have shown to be a potential biomarker of clinical response. 52 patients will be enrolled with the primary objective to determine relapse free survival after active immunization. Eligible patients are newly diagnosed with Stage III (B or C) or Stage IV breast cancer and begin vaccination within 6 months of starting maintenance trastuzumab. This interim report will present data on the first 25 patients enrolled; 21 stage IV and 4 locally advanced patients. The vaccine is well tolerated with all adverse events (AE) being Grade I or 2. The most common AE is injection site reaction. Moreover, the combination of HER2 vaccination with trastuzumab did not result in additive cardiac toxicity in these patients. Immune responses were evaluated by IFN-gamma ELISPOT. To date, 88% of patients immunized developed significant immunity to the components of the ICD vaccine. The majority, 75%, developed robust immunity to the HER2 protein. Our group has recently demonstrated that a broadening of immunity throughout the HER2 protein, to components of the protein that weren't in the vaccine, i.e. epitope spreading, may be associated with improved survival in vaccinated patients. 63% of immunized patients demonstrated evidence of intramolecular epitope spreading. We questioned whether such high frequencies of homing Type 1 T cells might modulate the immunosuppressive tumor microenvironment, so we evaluated whether circulating serum immunosuppressive cytokines were impacted by immunization. TGF-beta is an immunosuppressive cytokine secreted by tumor stroma and regulatory T cells. We found that the levels of serum TGF-beta decreased significantly in the majority of patients after vaccination. We further analyzed the correlation between the change of serum levels of TGF-beta post vaccination and HER2 ICD vaccine-induced T cell responses. We found that the greater the magnitude of the HER2 specific T cell response, as demonstrated by IFN-gamma secretion, the greater the decrease in serum TGF-beta (p=0.0045, r=0.742). The correlation between the increased epitope spreading T cell response and decreased levels of TGF-beta was even more significant (p=0.0003). The median overall survival has not been reached with 100% of patients alive at this time. Relapse free survival data will be presented.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5102.

A phase I study of a DNA plasmid based vaccine encoding the HER2/neu (HER2) intracellular domain (ICD) in subjects with HER2+ breast cancer

3054

Background: HER2 is overexpressed in 25% of breast cancers and plays a role in the malignant transformation of cells. Vaccine-induced immunity against the HER2 ICD correlates with antitumor responses in animal models. DNA-based vaccines offer a strategy to immunize against multiple tumor antigens and are able to elicit both CTL and T helper immune responses. Plasmid DNA can also remain at the vaccine site, providing a constant source of antigen. However, DNA vaccines have been poorly immunogenic due in part to inefficient APC transfection. Intradermal (i.d.) delivery of DNA vaccines with GM-CSF as adjuvant may enhance immunogenicity due to local influx of dermal Langerhans cells. A phase I study was conducted to evaluate the safety and immunogenicity of a DNA-based vaccine encoding the HER2 ICD. Methods: 44 subjects with stage III and IV HER2+ breast cancer in complete remission were enrolled sequentially into 2 vaccine arms (22 subjects/arm) and received 10μg pNGVL3-hICD (Arm 1) or 100μg pNGVL3-hICD (Arm 2). All vaccines were admixed with 100μg GM-CSF and given i.d. monthly for a total of 3 vaccines. Toxicity was assessed at baseline, during vaccination, and at follow-up. Immune responses were assessed with IFN-γ ELISPOT at baseline and post-vaccination. Vaccine site biopsies were analyzed for plasmid persistence via RT-PCR, 1 and 6 months after vaccination. Results: 43 subjects (21 in Arm 1; 22 in Arm 2) completed 3 vaccines. Vaccine-related toxicity in both arms was primarily grade I/II; no cardiac or grade IV toxicity was observed. 13/21 (62%) subjects in Arm 1 developed T-cell immunity, defined as HER2-specific T cell precursors:PBMC, to the HER2 protein (median 1:5,972, range 1:717–1:3,000,000) and to p776, a HER2 pan DR binding epitope (median 1:3,150, range 1:543–1:108,696). 13/19 (68%) subjects in Arm 1 had persistent plasmid DNA at the vaccine site. ELISPOT and RT-PCR analysis for Arm 2 are on-going. Conclusions: Immunization with a DNA plasmid-based HER2 vaccine is safe and immunogenic. Moreover, plasmid DNA persists at the vaccine site post-immunization and HER2+ cancer patients are able to develop immunity to the HER2 ICD.

No significant financial relationships to disclose.

Persistent immunity and survival after immunization with a HER2/neu (HER2) vaccine

3010

Background: Our initial vaccine studies showed that optimally treated breast cancer patients can be immunized against HER2 during active immunization. The majority of patients developed T-cell immunity to HER2 peptides and protein and also epitope spreading (ES). The goal of this study was to determine if patients previously immunized with a HER2 vaccine had persistent immunity years after active immunization and to assess their clinical outcome in terms of overall survival (OS). Methods: Subjects eligible for this IRB-approved long term follow-up (LTFU) study: (1) had HER2+ breast cancer and were immunized between 1996–1999 in a phase I HER2 peptide vaccine trial, (2) were at least 1 year out from their last vaccine, and (3) if donating blood samples could not be receiving chemotherapy. 52 patients (37 stage IV, 15 stage III) were identified and 21/52 patients (12 stage IV, 9 stage III) were determined to be living. All 21 subjects were contacted by letter and sent a LTFU Questionnaire. OS was defined as the time between date of vaccine study entry and death or last follow-up and was estimated using the Kaplan-Meier method. Cox proportional hazards were used to determine associations between OS and known clinical and vaccine-related immunologic factors; analyses included all 52 subjects. Long-term T-cell immunity was evaluated using IFN-γ ELISPOT assay. Results: Median follow-up time for the 21 patients still alive was 112 months (range, 104–126 months). Blood samples were collected in 10/21 subjects and 6/8 (75%) evaluble patients had persistent T-cell immunity to immunizing HER2 peptides; and 7/8 patients (88%) had T-cell immunity specific for HER2 protein and peptides not contained in their immunizing mix (defined as ES). In multivariate analysis, number of chemotherapy regimens prior to vaccination (HR=5.7 (CI 95%, 1.5–23; p=<0.001)), and development of ES after HER2 vaccination (HR=0.34 (CI 95%, 0.12–1.0; p=0.05)) were independent predictors of OS. Median OS for 33 subjects who developed ES was 84 months vs 25 months for 16 subjects who did not develop ES. Conclusions: HER2-specific T-cell immunity elicited with active immunization is durable years after vaccination has ended and the generation of ES is an independent predictor of OS.

No significant financial relationships to disclose.

Phase I study of infusion of HER2/neu (HER2) specific T cells in patients with advanced-stage HER2 overexpressing cancers who have received a HER2 vaccine

3000

Background: Adoptive T-cell therapy has shown promise in the treatment of advanced-stage melanoma. We have previously reported that expansion of HER2-specific T cells from peripheral blood mononuclear cells (PBMC) can be greatly facilitated by vaccine-priming. In this study, we evaluated the safety and clinical efficacy of infusion of HER2-specific T cells in patients with advanced HER2 overexpressing cancers. Methods: 10 patients with progressive HER2+ metastatic breast and ovarian cancer, not considered curable by conventional therapies, will be enrolled in this study. The patients must have been pre-immunized with a HER2-specific vaccine. Three escalating doses of T cells are given at 10-day intervals. Cyclophosphamide or denileukin diftitox is administrated before the first dose of T cells. Results: To date, 5 of 10 subjects have been enrolled. T cells were expanded with HER2-specific class II restricted peptides. After in vitro expansion cell products were >95% CD3+ with an average of 35% CD4+ and 60% CD8+ T cells. The maximal doses infused were 1x109-41x109 cells (median 10x109). Subjects tolerated the infusions well with the primary toxicity being related to the conditioning agent. Objective tumor regression has been observed in 2 of the 5 treated patients. One other patient has had stable disease after treatment. In patients with tumor regression, the magnitude of HER2-specific T cells in the infused product was 8-fold higher than that in patients without clinical responses. The total number of HER2-specific T cells infused was 43-fold higher in responding patients than in nonresponding patients. Moreover, HER2-specific CD4+ and CD8+ T cells persisted over a year and even augmented in magnitude post-infusion in responding patients. Conclusions: Adoptive transfer of autologous HER2 specific polyclonal T cells generated from PBMC after vaccine-priming is well tolerated and has shown evidence of some clinical efficacy in patients with advanced-stage HER2+ cancers.

No significant financial relationships to disclose.

Association of the level of HER2/neu (HER2) gene amplification in breast cancer and the magnitude of antigen specific T-cell immunity achieved after HER2 vaccination

3059

Background: Studies have demonstrated that the level of HER2 gene amplification in breast cancer, assessed by fluorescence in situ hybridization (FISH), correlates with favorable clinical response after treatment with trastuzumab. We questioned whether HER2 gene amplification impacted the development of HER2-specific T-cell immunity following immunization with a HER2 vaccine. Methods: Patients with HER2+ stage III or IV breast cancer, treated to complete remission or stable bone only disease, were enrolled in one of two concurrent clinical trials of HER2-specific vaccines. Eligibility criteria between the two studies were similar. Patients received either a plasmid DNA-based vaccine encoding the HER2 intracellular domain or a peptide-based vaccine composed of 3 HER2 class II epitopes. Peripheral blood was assessed for HER2-specific T-cell responses by interferon gamma (IFN-g) ELISPOT prior to, immediately after, and 6 months to 1 year after the end of vaccinations. Both immune response and FISH data were available on 31 patients. Results: Correlation of FISH levels to IFN-g spots/well in evaluable patients revealed the level of HER2 gene amplification was not related to the presence of pre-existent HER2-specific T-cell immunity prior to vaccination (p=0.43), the generation of a HER2-specific immune response after vaccination (p=0.35), or the persistence of the HER2-specific T-cell response (p=0.33). However, the magnitude of the T-cell response achieved was less as HER2 gene amplification increased (p=0.05). Conclusions: The level of HER2 gene amplification in the primary tumor can adversely impact the magnitude of HER2-specific T-cell immunity achieved after vaccination.

No significant financial relationships to disclose.

Combination of GM-CSF and cytosine in myelodysplasia results in improved neutrophil function

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was given concurrently with low-dose cytosine arabinoside for 3 weeks to patients with myelodysplasia. Neutrophil activation as evidenced by increased chemiluminescence and reduced surface expression of CD16 was consistently seen during therapy. An attendant fall in chemotaxis was also observed. These effects occurred even when neutrophil counts did not rise significantly at lower doses of GM-CSF. Although no improvement in anaemia or thrombocytopenia was observed, the neutrophil counts became normal during therapy without significant expansion of marrow cellularity or colony-forming ability. No major toxicities were observed, even at higher dosages of GM-CSF.

Comparison of the catabolic effects of fibronectin fragments in human knee and ankle cartilages

OBJECTIVE

To compare the response of knee and ankle cartilages to fibronectin fragments (Fn-f) in terms of kinetics of matrix proteoglycan (PG) degradation and synthesis, since previous data had shown that knee was more sensitive to Fn-f in terms of steady-state PG content.

DESIGN

Human knee and ankle cartilage explants were treated with the 29kDa Fn-f, and its effects on PG-degradation kinetics, on the half-lives of 35S-sulfate-labeled PG, on PG synthesis suppression and on matrix metalloproteinase -3 (MMP-3) were compared. Cultures were also treated with the interleukin (IL) receptor antagonist protein (IRAP) in order to determine whether IL-1 is involved in the Fn-f effect.

RESULTS

The Fn-f enhanced PG-degradation rates in both human knee and ankle cartilages. Knee cartilage showed a greater effect of Fn-f on half-lives of newly synthesized 35S-labeled PG than ankle. The extent of release of MMP-3 was similar for human ankle and knee cartilages. However, PG synthesis in knee cartilage was sensitive to 10- to 100-fold lower concentrations of Fn-f than was ankle cartilage. IRAP partially reversed Fn-f activity in ankle cartilages.

CONCLUSIONS

The role of Fn-f in proteolysis leading to cartilage damage appears to be minor in human cartilages than had previously been shown for bovine. This decreased proteolysis is true for both knee and ankle. The major difference between human ankle and knee cartilage appears to be greater sensitivity to PG synthesis suppression in knee cartilage. A further indication that IL-1 is involved in the pathway was provided by the partial reversal with IRAP.

Cutting edge: regulation of uterine NKT cells by a fetal class I molecule other than CD1

The peri-implantation uterus contains an expanded population of NK1.1(+) V alpha 14(+) TCR(int) (NKT) lymphocytes. Although these cells bear the above features in common with other NKT cells populations in thymus, bone marrow, liver, and spleen, they differ from these other populations in terms of an altered V beta repertoire and absence of a CD4(+) component. In this study, we demonstrate that the uterine population also differs from other NKT cell populations because they recognize a class I/class I-like molecule other than CD1, whereas most previously described V alpha 14(+) NKT cells are CD1-restricted. Moreover, the class I/class I-like molecule leading to the uterine NKT cell expansion may be supplied by the fetus. These data demonstrate a novel mechanism whereby the fetus is capable of modulating the maternal immune system.

Effects of oxygen on kynurenine-3-monooxygenase activity

Kynurenine-3-monooxygenase (KM), the third enzyme in the kynurenine (KYN) pathway from tryptophan to quinolinic acid (QA), is a monooxygenase requiring oxygen, NADPH and FAD for the catalytic oxidation of L-kynurenine to 3-hydroxykynurenine and water. KM is innately low in the brain and similar in activity to indoleamine oxidase, the rate-limiting pathway enzyme. Accumulation in the CNS of QA, a known excitotoxin, is proposed to cause convulsions in several pathologies. Thus, we theorized that hyperbaric oxygen (HBO) induced convulsions arise from increased QA via oxygen K, effects on this pathway [Brown OR, Draczynska-Lusiak. Oxygen activation and inactivation of quinolinate-producing and iron-requiring 3-hydroxyanthranilic acid oxidase: a role in hyperbaric oxygen-induced convulsions? Redox Report 1995; 1: 383-385]. To complement prior studies on the effects of oxygen on pathway enzymes, in this paper we report the effects of oxygen on KM. Brain and liver KM enzyme are not known to be identical, and some systemically-produced KYN pathway intermediates can permeate the brain and might stimulate the brain pathway. Thus, KM from both brain and liver was assayed at various oxygen substrate concentrations to evaluate, in vitro, the potential effects of increases in oxygen, as would occur in mammals breathing therapeutic and convulsive HBO. In crude tissue extracts, KM was not activated during incubation in HBO up to 6 atm. The effects of oxygen as substrate on brain and liver KM activity was nearly identical: activity was nil at zero oxygen with an apparent oxygen Km of 20-22 microM. Maximum KM activity occurred at about 1000 microM oxygen and decreased slightly to plateau from 2000 to 8000 microM oxygen. This compares to approximately 30-40 microM oxygen typically reported for brain tissue of humans or rats breathing air, and an unknown but surely much lower value (perhaps below 1 microM) intracellularly at the site of KM. Thus HBO, as used therapeutically and at convulsive pressures, likely stimulates flux through the KM-catalyzed step of the KYN pathway in liver and in brain and could increase brain QA, by Km effects on brain KM, or via increased KM pathway intermediates produced systemically (in liver) and transported into the brain.

Natural killer 1.1(+) alpha beta T cells in the periimplantation uterus

When the developing embryo implants into the uterine wall, resident maternal immune cells may encounter antigens present on the fetal tissues. The nature and constituents of the ensuing maternal immune response, and its regulation, are of considerable interest in understanding normal and abnormal pregnancy. Here, we report the presence of natural killer (NK)1.1(+) alpha beta T cells in the murine periimplantation uterus. These cells account for a large portion of both the T-cell and natural killer cell populations in early pregnancy, while their numbers in the non-pregnant uterus and later in pregnancy are greatly reduced. Phenotypically, these NK1.1+ alpha beta T cells belong to a previously described subset of cells that bear a V alpha 14-J alpha 281-encoded T-cell receptor. Unlike other organs, where both CD4(+) and CD4(-)/CD8(-) NK1.1(+) alpha beta T cells are found, the placental/decidual population appears to be entirely CD4(-)/CD8(-). The V beta repertoire of the placental/decidual population is also altered from that of other organs, with a majority of cells expressing V beta 3. Together, these features suggest the possibility of local development. NK1.1(+) alpha beta T cells are known to recognize the class I-like CD1 molecule. Consistent with this association, we demonstrate CD1 expression by tissues within the pregnant uterus. Our findings define an additional organ-specific immune environment where NK1.1(+) alpha beta T cells may play a role, and continue to demonstrate the specialized nature of the maternal intrauterine immune system during pregnancy.

Evidence that kynurenine pathway metabolites mediate hyperbaric oxygen-induced convulsions

Metabolism of tryptophan (TRP) through the kynurenine (KYN) pathway in brain, liver, and kidney produces intermediates including the neuroactive agonist quinolinic acid (QA) and the antagonists kynurenic acid (KA) and anthranilic acid (AA) for N-methyl D-aspartate (NMDA) receptors in the central nervous system. We hypothesized that elevated concentrations of QA, KA, or AA can moderate the convulsions that are observed during exposure of rats to hyperbaric oxygen (HBO). We found that i.p. administration of TRP or KYN (both of which cross the blood-brain barrier) had no effect on HBO-induced seizures. However, AA (administered i.p.) or gavage administration of the KYN pathway blocking drug Ro 61-8048, both of which enter the brain from the circulatory system, affect the time to first convulsion and/or coma during HBO in a manner consistent with a modulatory role for seizure activity.