Cytoplasmic PML promotes TGF-ß-associated epithelial-mesenchymal transition and invasion in prostate cancer.

Epithelial-mesenchymal transition (EMT) is a key event that is involved in the invasion and dissemination of cancer cells. Although typically considered as having tumour-suppressive properties, transforming growth factor (TGF)-ß signalling is altered during cancer and has been associated with the invasion of cancer cells and metastasis. In this study, we report a previously unknown role for the cytoplasmic promyelocytic leukaemia (cPML) tumour suppressor in TGF-ß signalling-induced regulation of prostate cancer-associated EMT and invasion. We demonstrate that cPML promotes a mesenchymal phenotype and increases the invasiveness of prostate cancer cells. This event is associated with activation of TGF-ß canonical signalling pathway through the induction of Sma and Mad related family 2 and 3 (SMAD2 and SMAD3) phosphorylation. Furthermore, the cytoplasmic localization of promyelocytic leukaemia (PML) is mediated by its nuclear export in a chromosomal maintenance 1 (CRM1)-dependent manner. This was clinically tested in prostate cancer tissue and shown that cytoplasmic PML and CRM1 co-expression correlates with reduced disease-specific survival. In summary, we provide evidence of dysfunctional TGF-ß signalling occurring at an early stage in prostate cancer. We show that this disease pathway is mediated by cPML and CRM1 and results in a more aggressive cancer cell phenotype. We propose that the targeting of this pathway could be therapeutically exploited for clinical benefit.

Anti-inflammatory effects of ischemic preconditioning on rat small bowel allografts.

INTRODUCTION: Minimizing the inflammatory events that follow intestinal transplantation may influence immediate graft function and improve outcome. Ischemic preconditioning (IPc) has been shown to ameliorate early inflammatory responses, and it may also attenuate the potentially damaging inflammation after intestinal transplantation. Herein, we examine the influence of intestinal IPc on inflammatory indices (tissue expression of ICAM-1, CD11a, and CD44 and serum levels of the soluble ICAM-1, sICAM-1) after heterotopic intestinal transplantation. METHODS: Lewis rats received full-length preconditioned or non-preconditioned Brown Norway intestinal allografts in the absence of immunosuppression. Preconditioned grafts were subjected to 1 cycle of 10 minutes of ischemia-reperfusion. Preconditioned and non-preconditioned isografts acted as controls. Blood was collected on alternate days post-transplant, and graft tissue harvested on sacrifice. ICAM-1, CD44, and CD11a expression was determined by immunohistochemistry, and the area of staining was quantified using image analysis. Serum soluble ICAM-1 levels were determined using an R&D Systems Quantikine enzyme immunoassay. RESULTS: (1) IPc ameliorated serum levels of sICAM-1 until severe rejection (day 7) overcame this down-regulation when compared to non-preconditioned allografts (day 3: 34,304 vs 40,479 pg/mL; day 5: 52,441 vs 61,593 pg/mL; day 7: 75,114 vs 73,309 pg/mL; day 9: 72,872 vs 76,314 pg/mL, respectively). (2) ICAM-1 expression was significantly lower in preconditioned allografts (1.02 vs 2.01 mm(2)). (3) CD44 tissue levels were also found to be lower in preconditioned allografts (0.86 vs 1.13 mm(2)). (4) There was a significant relationship between tissue ICAM-1 expression and serum levels of soluble ICAM-1 (P < .02). CONCLUSIONS: IPc improves inflammatory indices in the early stages following intestinal transplantation, and this might lead to a preserved cellular, architectural, and functional graft status. Furthermore, our results support the use of soluble ICAM-1 as a marker of endothelial activation, and thence of inflammation and developing rejection.

Effects of opioids on immunologic parameters that are relevant to anti-tumour immune potential in patients with cancer: a systematic literature review.

BACKGROUND: The immune system has a central role in controlling cancer, and factors that influence protective antitumour immunity could therefore have a significant impact on the course of malignant disease. Opioids are essential for the management of cancer pain, and preclinical studies indicate that opioids have the potential to influence these tumour immune surveillance mechanisms. The aim of this systematic literature review is to evaluate the clinical effects of opioids on the immune system of patients with cancer. METHODS: A systematic search of Ovid MEDLINE (PubMed) and Embase, Cochrane database and Web of Knowledge for clinical studies, which evaluated the effects of opioids on the immune system in patients with cancer, was performed. RESULTS: Five human studies, which have assessed the effects of opioids on the immune system in patients with cancer, were identified. Although all of these evaluated the effect of morphine on immunologic end points in patients with cancer, none measured the clinical effects. CONCLUSIONS: Evidence from preclinical, healthy volunteer and surgical models suggests that different opioids variably influence protective anti-tumour immunity; however, actual data derived from cancer populations are inconclusive and definitive recommendations cannot be made. Appropriately designed and powered studies assessing clinical outcomes of opioid use in people with cancer are therefore required to inform oncologists and others involved in cancer care about the rational use of opioids in this patient group.

HAGE (DDX43) is a biomarker for poor prognosis and a predictor of chemotherapy response in breast cancer.

BACKGROUND: HAGE protein is a known immunogenic cancer-specific antigen. METHODS: The biological, prognostic and predictive values of HAGE expression was studied using immunohistochemistry in three cohorts of patients with BC (n=2147): early primary (EP-BC; n=1676); primary oestrogen receptor-negative (PER-BC; n=275) treated with adjuvant anthracycline-combination therapies (Adjuvant-ACT); and primary locally advanced disease (PLA-BC) who received neo-adjuvant anthracycline-combination therapies (Neo-adjuvant-ACT; n=196). The relationship between HAGE expression and the tumour-infiltrating lymphocytes (TILs) in matched prechemotherapy and postchemotherapy samples were investigated. RESULTS: Eight percent of patients with EP-BC exhibited high HAGE expression (HAGE+) and was associated with aggressive clinico-pathological features (Ps<0.01). Furthermore, HAGE+expression was associated with poor prognosis in both univariate and multivariate analysis (Ps<0.001). Patients with HAGE+did not benefit from hormonal therapy in high-risk ER-positive disease. HAGE+and TILs were found to be independent predictors for pathological complete response to neoadjuvant-ACT; P<0.001. A statistically significant loss of HAGE expression following neoadjuvant-ACT was found (P=0.000001), and progression-free survival was worse in those patients who had HAGE+residual disease (P=0.0003). CONCLUSIONS: This is the first report to show HAGE to be a potential prognostic marker and a predictor of response to ACT in patients with BC.

The helicase HAGE prevents interferon-α-induced PML expression in ABCB5+ malignant melanoma-initiating cells by promoting the expression of SOCS1.

The tumour suppressor PML (promyelocytic leukaemia protein) regulates several cellular pathways involving cell growth, apoptosis, differentiation and senescence. PML also has an important role in the regulation of stem cell proliferation and differentiation. Here, we show the involvement of the helicase HAGE in the transcriptional repression of PML expression in ABCB5+ malignant melanoma-initiating cells (ABCB5+ MMICs), a population of cancer stem cells which are responsible for melanoma growth, progression and resistance to drug-based therapy. HAGE prevents PML gene expression by inhibiting the activation of the JAK-STAT (janus kinase-signal transducers and activators of transcription) pathway in a mechanism which implicates the suppressor of cytokine signalling 1 (SOCS1). Knockdown of HAGE led to a significant decrease in SOCS1 protein expression, activation of the JAK-STAT signalling cascade and a consequent increase of PML expression. To confirm that the reduction in SOCS1 expression was dependent on the HAGE helicase activity, we showed that SOCS1, effectively silenced by small interfering RNA, could be rescued by re-introduction of HAGE into cells lacking HAGE. Furthermore, we provide a mechanism by which HAGE promotes SOCS1 mRNA unwinding and protein expression in vitro. Finally, using a stem cell proliferation assay and tumour xenotransplantation assay in non-obese diabetic/severe combined immunodeficiency mice, we show that HAGE promotes MMICs-dependent tumour initiation and tumour growth by preventing the anti-proliferative effects of interferon-α (IFNα). Our results suggest that the helicase HAGE has a key role in the resistance of ABCB5+ MMICs to IFNα treatment and that cancer therapies targeting HAGE may have broad implications for the treatment of malignant melanoma.

Dual role of heat shock proteins (HSPs) in anti-tumor immunity.

Although surgery and radiotherapy are highly efficient in local tumor control, distal metastases and tumor recurrence often limit therapeutic outcome. It is becoming progressively more evident that curative tumor therapy depends on the presence and maintenance of an intact immune system which has the capacity to elicit cytotoxic effector functions against circulating tumor cells and distant metastases. Heat shock proteins (HSPs, also termed stress proteins) are involved in antigen processing and presentation and can act as "danger signals" for the adaptive and innate immune systems. This article reviews current knowledge relating to the induction and manifestation of stress protein-related immunological responses that are pertinent to the development and maintenance of protective anti-tumor immunity.

Induction of abscopal anti-tumor immunity and immunogenic tumor cell death by ionizing irradiation - implications for cancer therapies.

Although cancer progression is primarily driven by the expansion of tumor cells, the tumor microenvironment and anti-tumor immunity also play important roles. Herein, we consider how tumors can become established by escaping immune surveillance and also how cancer cells can be rendered visible to the immune system by standard therapies such as radiotherapy or chemotherapy, either alone or in combination with additional immune stimulators. Although local radiotherapy results in DNA damage (targeted effects), it is also capable of inducing immunogenic forms of tumor cell death which are associated with a release of immune activating danger signals (non-targeted effects), such as necrosis. Necrotic tumor cells may result from continued exposure to death stimuli and/or an impaired phosphatidylserine (PS) dependent clearance of the dying tumor cells. In such circumstances, mature dendritic cells take up tumor antigen and mediate the induction of adaptive and innate anti-tumor immunity. Locally-triggered, systemic immune activation can also lead to a spontaneous regression of tumors or metastases that are outside the radiation field - an effect which is termed abscopal. Preclinical studies have demonstrated that combining radiotherapy with immune stimulation can induce anti-tumor immunity. Given that it takes time for immunity to develop following exposure to immunogenic tumor cells, we propose practical combination therapies that should be considered as a basis for future research and clinical practice. It is essential that radiation oncologists become more aware of the importance of the immune system to the success of cancer therapy.

Effect of upper- and lower-limb exercise training on circulating soluble adhesion molecules, hs-CRP and stress proteins in patients with intermittent claudication.

OBJECTIVES: To investigate the effects of exercise training on levels of circulating biomarkers associated with the progression of atherosclerosis and risk of cardiovascular events in patients with intermittent claudication. METHODS: Circulating levels of soluble adhesion molecules (sVCAM-1, sICAM-1, sE-selectin), high sensitivity C-reactive protein (hs-CRP) and stress proteins (Hsp60 and Hsp70) in patients randomised to a 24-week programme of arm- or leg-cranking exercise were compared with those in usual care controls. RESULTS: Arm and leg exercise similarly improved lower-limb aerobic exercise capacity (20% vs 19%, respectively; P<0.001) and maximum walking distance (30% vs 35%, respectively; P<0.001). Improvements in training limb-specific peak oxygen consumption were attenuated for patients in the highest vs lowest quartile for circulating sVCAM-1 levels at baseline (3% vs 25% respectively, P<0.001). Although circulating hs-CRP levels tended to be lower in the arm-cranking group (-1.55 [95% CI: -1.06 to -2.26]mgl(-1)), exercise training had no effect on circulating levels of soluble adhesion molecules or stress proteins. CONCLUSIONS: These findings suggest that high levels of circulating sVCAM-1 are associated with an attenuated exercise training response and that arm-cranking exercise may provide an effective stimulus for evoking systemic anti-inflammatory adaptations in patients with intermittent claudication.

Analysis of purified gp96 preparations from rat and mouse livers using 2-D gel electrophoresis and tandem mass spectrometry.

The stress protein gp96 exhibits a number of immunological activities, the majority of studies into which have used gp96 purified from a variety of tissues. On the basis of 1-D gel electrophoresis, the purity of these preparations has been reported to range between 70% and 99%. This study analyzed gp96 preparations from rat and mouse livers using 2-D gel electrophoresis and liquid chromatography electrospray ionization tandem mass spectrometry (MS-MS). The procedure for purifying gp96 was reproducible, as similar protein profiles were observed in replicate gels of gp96 preparations. The purity of the preparations was typically around 70%, with minor co-purified proteins of varying molecular weights and mobilities being present. Dominant bands at 95-100 kDa in preparations from Wistar rats and C57BL/6 mice were identified as gp96 by ECL Western blotting. Multiple bands having similar, yet distinct molecular weights and differing pI mobility on ECL Western blots were confirmed as being gp96 in preparations from Wistar rats using MS-MS. The most striking feature of the 2-D gel analysis was the presence of additional dominant bands at 55 kDa in preparations from Wistar rats, and at 75-90 kDa in preparations from C57BL/6 mice. These were identified as gp96 by ECL Western blotting and, in the case of preparations from Wistar rats, by MS-MS. Although the lower molecular weight, gp96-related molecules might be partially degraded gp96, their reproducible presence, definition and characteristics suggest that they are alternative, species-specific isoforms of the molecule. A 55 kDa protein which exhibited a lower pI value than gp96 was present in all preparations and this was identified as calreticulin, another putative immunoregulatory molecule. This study confirms the reproducibility of the gp96 purification protocol and reveals the presence of multiple gp96 isoforms, some of which likely result from post-translational modifications such as differential glycosylation and phosphorylation.

Relative tolerance to upper- and lower-limb aerobic exercise in patients with peripheral arterial disease.

OBJECTIVES: To investigate the effects of peripheral arterial disease (PAD) on relative tolerance to upper- and lower-limb aerobic exercise. METHODS: Peak cardiorespiratory responses evoked by an incremental arm-cranking test (ACT) and an incremental leg-cranking test (LCT) were compared in patients with PAD (N=101; median age 69 year, range 50-85 years). Claudication distance (CD) and total distance before intolerable claudication pain (maximum walking distance: MWD) were also assessed during walking. RESULTS: Peak oxygen consumption (V O(2)) for the ACT was 94% of that measured for the LCT (1.01+/-0.03 versus 1.10+/-0.03lmin(-1), respectively; P<0.001), but in a significant proportion of patients (35%; P<0.001), exceeded that recorded for the LCT. The ratio of upper- to lower-limb peak V O(2) was higher (0.98+/-0.04 compared to 0.98+/-0.05lmin(-1) and 1.00+/-0.06 compared to 1.21+/-0.06lmin(-1); P<0.01), whereas walking performance (CD: 94+/-14 versus 187+/-25 m, P<0.01; MWD: 227+/-20 versus 394+/-33 m, P<0.01) was lower for patients in the lowest ankle to brachial pressure index quartile compared to patients in the highest quartile, respectively. CONCLUSION: Upper-limb aerobic conditioning could be a useful exercise stimulus for maintaining or improving cardiorespiratory function in patients with severe PAD as they have a greater relative upper-limb aerobic power.

Heat shock proteins in cardiovascular disease and the prognostic value of heat shock protein related measurements.

Are heat shock protein antibodies directly involved in the pathogenesis of cardiovascular disease?

VEGF and VEGF receptor expression in human chronic critical limb ischaemia.

OBJECTIVE: This study quantified endogenous VEGF and VEGF receptor expression in limbs of patients with chronic critical limb ischaemia (CLI). METHODS: Skin and muscle biopsies were obtained from the legs of 25 patients undergoing limb amputation for CLI. Samples were obtained at the amputation level (thigh or calf) and, distally, from the foot and in the vicinity of ischaemic ulcers and gangrene. Control biopsies were obtained from patients undergoing amputation for non-arterial reasons or knee arthroplasty (n=7). VEGF protein levels in tissue lysates were measured by ELISA, and VEGF and KDR mRNA levels were determined using quantitative PCR. RESULTS: At the amputation level, VEGF protein and VEGF and KDR mRNA levels in CLI limbs were similar to those in controls. In the foot VEGF mRNA in skin (P=0.005) and VEGF protein levels in muscle (P=0.02) were elevated compared to levels in a proximal biopsy from the same limb. VEGF and KDR mRNA levels in the vicinity of gangrene/ulcers (VEGF P=0.01, KDR P=0.03) also were elevated. CONCLUSIONS: VEGF expression is not deficient in CLI. Indeed, it is elevated at distal sites in the ischaemic limb. These findings question the rationale for VEGF supplementation in CLI.

Effects of intestinal ischemia-reperfusion injury on rat peripheral blood neutrophil activation.

Peripheral blood neutrophil activation status is indicative of remote organ damage after intestinal ischemia secondary to aortic aneurysm repair. However, the effects of direct intestinal ischemia-reperfusion (I/R) injury on neutrophil activation and its reflection of remote organ injury have not been evaluated. DA rats were subjected to 30 min of intestinal ischemia or sham surgery. Blood samples were taken before ischemia and 30, 60, and 120 min after reperfusion. Neutrophil counts were quantified and CD11b, CD62L, and NKR-P1 expression was assessed using flow cytometry. The sham procedure induced increases in neutrophil numbers (P < 0.001), which was transiently attenuated in animals subjected to intestinal I/R injury. CD11b expression increased in both groups, whereas CD62L and NKR-P1 (P < 0.01) expression decreased in both groups. These findings suggest that even mild surgical procedures induce demargination of neutrophils. Monitoring the peripheral blood for activated neutrophils is of no value in assessing the severity of direct intestinal I/R injury or predicting remote organ damage after intestinal ischemia.

Antimurine immunoglobulin antibody responses after the administration of murine monoclonal antibodies to rats are altered by small bowel allograft rejection.

BACKGROUND: This study monitored the induction of antimurine immunoglobulin antibody responses after the administration of anti-CD4 (OX38) and anti-LFA-1 (WT.1) monoclonal antibodies to DA rats. METHODS: Monoclonal antibody was administered i.v. on 3 consecutive days to untransplanted DA rats, and DA recipients of PVG small bowel allografts. Control animals received no monoclonal antibody. Antimurine immunoglobulin antibody levels in serum samples were determined by enzyme immunoassay. RESULTS: No antimurine immunoglobulin antibody was detected in untransplanted animals receiving OX38 alone. Reactivity was apparent in WT.1-treated animals, but this response was totally abrogated by the co-administration of OX38. A combination of OX38 and WT.1 had no effect on allograft recipient survival and antimurine immunoglobulin antibody responses were detected in all allograft recipients, irrespective of the treatment regimen. CONCLUSIONS: Although OX38 inhibited the antibody response both to itself and to WT.1 in untransplanted animals, the immune reaction induced by small bowel allograft rejection overcame this inhibitory capacity.

Heat shock proteins, anti-heat shock protein reactivity and allograft rejection.

Heat shock proteins are families of highly conserved immunodominant molecules, reactivity to which has been implicated in the pathogenesis of a number of autoimmune and vascular disease states. However, heat shock proteins are cytoprotective, and in clinical and experimental arthritis, anti-heat shock protein reactivity can down modulate immune responses via a self-Hsp reactive, Th2-type mechanism. Despite a number of studies associating heat shock protein expression and anti-heat shock protein reactivity with allograft rejection, the balance between protective and damaging effects and the precise influence of these responses on graft outcome is unclear. This article reviews current knowledge surrounding heat shock proteins, autoimmunity, and allograft rejection and presents a perspective on the potential influence of these proteins and the stress response on allograft outcome.

The inflammatory response to upper and lower limb exercise and the effects of exercise training in patients with claudication.

PURPOSE: We have previously shown that a program of upper limb exercise training can induce significant improvements in walking distance in patients with claudication. This study assessed whether upper limb exercise avoids the systemic inflammatory responses associated with lower limb exercise and also whether the inflammatory response to acute lower limb exertion is modified by a program of supervised exercise training. METHODS: Fifty-two patients with stable intermittent claudication were randomized into two groups who underwent 6 weeks of supervised upper (n = 26) or lower (n = 26) limb cardiorespiratory exercise training. A parallel control group (n = 15) was provided with lifestyle advice only. Neutrophil activation markers (CD11b and CD66b) and plasma levels of von Willebrand factor (marker of endothelial damage) in response to an acute bout of sustained upper and lower limb exercise were assessed before and after the period of training. Plasma levels of soluble E-selectin (marker of endothelial activation) were also determined before and after the training period. RESULTS: An acute bout of sustained lower limb exercise significantly increased the intensity of CD11b and CD66b expression by peripheral blood neutrophils in all groups, whereas upper limb exercise had no effect. Resting neutrophil expression of CD11b and CD66b and circulating von Willebrand factor levels were unaffected by the training program, as were the inflammatory responses to an acute bout of sustained upper and lower limb muscular work, despite the fact that both training programs significantly increased walking distances. CONCLUSIONS: These findings indicate that upper limb exercise training programs may offer certain advantages over currently prescribed lower limb programs. Our results show that exercising nonischemic muscles in a way that promotes improved cardiorespiratory function and walking capacity can avoid the potentially deleterious systemic inflammatory responses associated with lower limb exertion in patients with stable intermittent claudication.

Induction of antigraft and antirecipient antibody responses after fully allogeneic and semiallogeneic rat small bowel transplantation.

BACKGROUND: Given the potential influence of alloantibodies on organ graft outcome, this study investigated the induction of antigraft and antirecipient antibodies after allogeneic and semiallogeneic rat small bowel transplantation. METHODS: Fully allogeneic, unidirectional rejection and unidirectional graft-versus-host disease (GvHD) heterotopic small bowel transplantation was performed using DA, PVG, and (PVGxDA)F1 donor-recipient combinations. Serum was obtained before and at time points after transplantation and incubated with blood from untransplanted DA and PVG rats. Antibody binding to T cells was detected by whole blood flow cytometry using FITC-conjugated anti-rat IgM murine monoclonal antibody. Antibody levels were determined by reference to a standard curve of fluorescent intensity generated using a serum sample with known anti-target cell IgM activity. Data are presented as arbitrary units/ml (AU/ml). RESULTS: In the PVG-->DA combination, five of six DA recipients had detectable anti-graft (PVG) antibodies by day 4 after transplantation (mean 72 AU/ml) and all animals were positive by day 6 (976 AU/ml). Antirecipient (DA) antibodies were also induced, however, they were only apparent after 6 days in five of eight animals (90 AU/ml). Antigraft (DA) antibody responses were also induced in the DA-->PVG combination (day 6-218 AU/ml), however no antirecipient (PVG) response was apparent. Transplantation induced antirecipient (DA) antibodies in the unidirectional GvHD model (day 6-90 AU/ml) and an anti-graft (PVG) response in the unidirectional rejection model (day 6-60 AU/ml). However, the latter was quantitatively lower than that generated in the PVG-->DA combination (day 6-976 AU/ml). CONCLUSIONS: Antigraft and antirecipient antibody responses are simultaneously induced after fully allogeneic small bowel transplantation, despite rejection being the predominant clinical feature. Further studies are required to elucidate their influence on graft outcome.

Serum heat shock protein and anti-heat shock protein antibody levels in aging.

We have previously reported the presence of Hsp60 and Hsp70 in the peripheral circulation of normal individuals. Given that the capacity to generate stress proteins declines with age, this study measured Hsp60 and Hsp70 levels in the sera of 60 individuals aged between 20 and 96 years. Levels of anti-human Hsp60, anti-human Hsp70 and anti-mycobacterial Hsp65 antibody were also measured. Senieur-approximated elderly subjects were well and randomly selected from the Belfast Elderly Longitudinal Free-living Aging STudy (BELFAST). Samples from younger individuals were obtained from the Northern Ireland Blood Transfusion Service. Hsp60, anti-Hsp60, anti-Hsp70 and anti-mycobacterial Hsp65 antibodies were detected in all samples, whereas Hsp70 was detectable in only 46 of the samples analysed (77%). Regression analysis revealed a progressive decline in Hsp60 (759ng/ml < 40 years; 294ng/ml > or = 90 years) and Hsp70 (400ng/ml < 40 years; 20ng/ml > or = 90 years) levels with age whereas no relationship was apparent for anti-Hsp60 and Hsp65 antibody levels. Hsp70 antibody levels tended to increase with age (115U/ml < 40 years; 191U/ml > or = 90 years). This study in Senieur-approximated subjects demonstrates an apparent decrease in Hsp60 and Hsp70 with increasing age that does not appear to be related to anti-heat shock protein antibody status. These findings support in vitro work that demonstrates an age-related reduced ability to respond to stress. Further studies are required to understand the basis for declining serum Hsp60 and Hsp70 levels in aging and to elucidate their origin and role in the maintenance of homeostasis and resistance to environmental challenges.

Heat shock proteins in health and disease: therapeutic targets or therapeutic agents?

For many years, heat shock or stress proteins have been regarded as intracellular molecules that have a range of housekeeping and cytoprotective functions, only being released into the extracellular environment in pathological situations such as necrotic cell death. However, evidence is now accumulating to indicate that, under certain circumstances, these proteins can be released from cells in the absence of cellular necrosis, and that extracellular heat shock proteins have a range of immunoregulatory activities. The capacity of heat shock proteins to induce pro-inflammatory responses, together with the phylogenetic similarity between prokaryotic and eukaryotic heat shock proteins, has led to the proposition that these proteins provide a link between infection and autoimmune disease. Indeed, both elevated levels of antibodies to heat shock proteins and an enhanced immune reactivity to heat shock proteins have been noted in a variety of pathogenic disease states. However, further evaluation of heat shock protein reactivity in autoimmune disease and after transplantation has shown that, rather than promoting disease, reactivity to self-heat shock proteins can downregulate the disease process. It might be that self-reactivity to heat shock proteins is a physiological response that regulates the development and progression of pro-inflammatory immunity to these ubiquitously expressed molecules. The evolving evidence that heat shock proteins are present in the extracellular environment, that reactivity to heat shock proteins does not necessarily reflect adverse, pro-inflammatory responses and that the promotion of reactivity to self-heat shock proteins can downregulate pathogenic processes all suggest a potential role for heat shock proteins as therapeutic agents, rather than as therapeutic targets.

Effects of FK409 on intestinal ischemia-reperfusion injury and ischemia-induced changes in the rat mucosal villus microcirculation.

BACKGROUND: The small intestine is extremely sensitive to ischemia-reperfusion (I/R) injury and a range of microcirculatory disturbances contribute to tissue damage. Nitric oxide (NO) seems to be involved in tissue protection after I/R injury. This study therefore assessed the effects of the NO donor, FK409, on intestinal I/R injury and changes induced in intestinal microcirculation. METHODS: PVG rats were subjected to 30-min intestinal ischemia with a subgroup of animals receiving FK409 (10 mg/kg i.v.) 30 min before ischemia and 30 min postreperfusion. Controls underwent sham surgery. The mucosal surface was visualized via an incision made in an exteriorized ileal segment and FITC-BSA or acridine orange was used to quantitate macromolecular leak (MML) and leukocyte adhesion, respectively. MML from, and numbers of adherent leukocytes within, individual villi were determined every 15 min for 2 hr after removal of the vessel clamp. Heart rate and mean blood pressure (mBP) were monitored throughout the experiment. RESULTS: Eleven of 12 untreated animals subjected to intestinal I/R injury failed to survive the 2 hr reperfusion period, whereas all 12 FK409-treated animals survived. MML and leukocyte adhesion were increased in untreated animals (P<0.001), and blood flow stasis eventually ensued. Although FK409 decreased mBP (P<0.001), MML and leukocyte adhesion were significantly (P<0.001) reduced, and villus blood flow was maintained throughout the observation period. CONCLUSIONS: FK409 prevented mortality after intestinal I/R, significantly reduced leukocyte adhesion, and maintained blood flow after intestinal ischemia and may therefore be of value in reducing tissue damage and improving outcome after small bowel transplantation.