Candesartan Attenuates Diabetic Retinal Vascular Pathology by Restoring Glyoxalase-I Function

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Prophylactic ciprofloxacin treatment prevented high mortality, and modified systemic and intestinal immune function in tumour-bearing rats receiving dose-intensive CPT-11 chemotherapy

Infectious complications are a major cause of morbidity and mortality from dose-intensive cancer chemotherapy. In spite of the importance of intestinal bacteria translocation in these infections, information about the effect of high-dose chemotherapy on gut mucosal immunity is minimal. We studied prophylactic ciprofloxacin (Cipro) treatment on irinotecan (CPT-11) toxicity and host immunity in rats bearing Ward colon tumour. Cipro abolished chemotherapy-related mortality, which was 45% in animals that were not treated with Cipro. Although Cipro reduced body weight loss and muscle wasting, it was unable to prevent severe late-onset diarrhoea. Seven days after CPT-11, splenocytes were unable to proliferate (stimulation index=0.10±0.02) and produce proliferative and inflammatory cytokines (i.e., Interleukin (IL)-2, interferon-γ (IFN-γ), tumour necrosis factor-α (TNF-α) IL-1β, IL-6) on mitogen stimulation in vitro (P<0.05 vs controls), whereas mesenteric lymph node (MLN) cells showed a hyper-proliferative response and a hyper-production of pro-inflammatory cytokines on mitogen stimulation. This suggests compartmentalised effects by CPT-11 chemotherapy on systemic and intestinal immunity. Cipro normalised the hyper-responsiveness of MLN cells, and in the spleen, it partially restored the proliferative response and normalised depressed production of IL-1β and IL-6. Taken together, Cipro prevented infectious challenges associated with immune hypo-responsiveness in systemic immune compartments, and it may also alleviate excessive pro-inflammatory responses mediating local gut injury

Superior antitumoral activity of dimerized targeted single-chain TRAIL fusion proteins under retention of tumor selectivity

Although targeting of the death receptors (DRs) DR4 and DR5 still appears a suitable antitumoral strategy, the limited clinical responses to recombinant soluble TNF-related apoptosis inducing ligand (TRAIL) necessitate novel reagents with improved apoptotic activity/tumor selectivity. Apoptosis induction by a single-chain TRAIL (scTRAIL) molecule could be enhanced >10-fold by generation of epidermal growth factor receptor (EGFR)-specific scFv-scTRAIL fusion proteins. By forcing dimerization of scFv-scTRAIL based on scFv linker modification, we obtained a targeted scTRAIL composed predominantly of dimers (Db-scTRAIL), exceeding the activity of nontargeted scTRAIL ∼100-fold on Huh-7 hepatocellular and Colo205 colon carcinoma cells. Increased activity of Db-scTRAIL was also demonstrated on target-negative cells, suggesting that, in addition to targeting, oligomerization equivalent to an at least dimeric assembly of standard TRAIL per se enhances apoptosis signaling. In the presence of apoptosis sensitizers, such as the proteasomal inhibitor bortezomib, Db-scTRAIL was effective at picomolar concentrations in vitro (EC50 ∼2 × 10−12 M). Importantly, in vivo, Db-scTRAIL was well tolerated and displayed superior antitumoral activity in mouse xenograft (Colo205) tumor models. Our results show that both targeting and controlled dimerization of scTRAIL fusion proteins provides a strategy to enforce apoptosis induction, together with retained tumor selectivity and good in vivo tolerance

Bone marrow stromal cells attenuate sepsis via prostaglandin E2— dependent reprogramming of host macrophages to increase their interleukin-10 production

Sepsis causes over 200,000 deaths yearly in the US; better treatments are urgently needed. Administering bone marrow stromal cells (BMSCs—also known as mesenchymal stem cells) to mice before or shortly after inducing sepsis by cecal ligation and puncture reduced mortality and improved organ function. The beneficial effect of BMSCs was eliminated by macrophage depletion or pretreatment with antibodies specific for interleukin-10 (IL-10) or IL-10 receptor. Monocytes and/ or macrophages from septic lungs made more IL-10 when prepared from mice treated with BMSCs versus untreated mice. Lipopolysaccharide (LPS)-stimulated macrophages produced more IL-10 when cultured with BMSCs, but this effect was eliminated if the BMSCs lacked the genes encoding Toll-like receptor 4, myeloid differentiation primary response gene-88, tumor necrosis factor (TNF) receptor-1a or cyclooxygenase-2. Our results suggest that BMSCs (activated by LPS or TNF-α) reprogram macrophages by releasing prostaglandin E2 that acts on the macrophages through the prostaglandin EP2 and EP4 receptors. Because BMSCs have been successfully given to humans and can easily be cultured and might be used without human leukocyte antigen matching, we suggest that cultured, banked human BMSCs may be effective in treating sepsis in high-risk patient groups.Sepsis, a serious medical condition that affects 18 million people per year worldwide, is characterized by a generalized inflammatory state caused by infection. Widespread activation of inflammation and coagulation pathways progresses to multiple organ dysfunction, collapse of the circulatory system (septic shock) and death. Because as many people die of sepsis annually as from acute myocardial infarction1, a new treatment regimen is desperately needed. In the last few years, it has been discovered that BMSCs are potent modulators of immune responses2-5. We wondered whether such cells could bring the immune response back into balance, thus attenuating the underlying pathophysiology that eventually leads to severe sepsis, septic shock and death6,7. As a model of sepsis, we chose cecal ligation and puncture (CLP), a procedure that has been used for more than two decades8. This mouse model closely resembles the human disease: it has a focal origin (cecum), is caused by multiple intestinal organisms, and results in septicemia with release of bacterial toxins into the circulation. With no treatment, the majority of the mice die 24-48 h postoperatively. Originally published Nature Medicine, Vol. 15, No. 1, Jan 200

T Cell Responses to the RTS,S/AS01E and RTS,S/AS02D Malaria Candidate Vaccines Administered According to Different Schedules to Ghanaian Children

BACKGROUND: The Plasmodium falciparum pre-erythrocytic stage candidate vaccine RTS,S is being developed for protection of young children against malaria in sub-Saharan Africa. RTS,S formulated with the liposome based adjuvant AS01(E) or the oil-in-water based adjuvant AS02(D) induces P. falciparum circumsporozoite (CSP) antigen-specific antibody and T cell responses which have been associated with protection in the experimental malaria challenge model in adults. METHODS: This study was designed to evaluate the safety and immunogenicity induced over a 19 month period by three vaccination schedules (0,1-, 0,1,2- and 0,1,7-month) of RTS,S/AS01(E) and RTS,S/AS02(D) in children aged 5-17 months in two research centers in Ghana. Control Rabies vaccine using the 0,1,2-month schedule was used in one of two study sites. RESULTS: Whole blood antigen stimulation followed by intra-cellular cytokine staining showed RTS,S/AS01(E) induced CSP specific CD4 T cells producing IL-2, TNF-α, and IFN-γ. Higher T cell responses were induced by a 0,1,7-month immunization schedule as compared with a 0,1- or 0,1,2-month schedule. RTS,S/AS01(E) induced higher CD4 T cell responses as compared to RTS,S/AS02(D) when given on a 0,1,7-month schedule. CONCLUSIONS: These findings support further Phase III evaluation of RTS,S/AS01(E). The role of immune effectors and immunization schedules on vaccine protection are currently under evaluation. TRIAL REGISTRATION: ClinicalTrials.gov NCT00360230

Caveolin contributes to the modulation of basal and β-adrenoceptor stimulated function of the adult rat ventricular myocyte by simvastatin: A novel pleiotropic effect

The number of people taking statins is increasing across the globe, highlighting the Importance of fully understanding statins effects on the cardiovascular system. The beneficial impact of statins extends well beyond regression of atherosclerosis to include direct effects on tissues of the cardiovascular system (pleiotropic effects). Pleiotropic effects on the cardiac myocyte are often overlooked. Here we consider the contribution of the caveolin protein, whose expression and cellular distribution is dependent on cholesterol, to statin effects on the cardiac myocyte. Caveolin is a structural and regulatory component of caveolae, and is a key regulator of cardiac contractile function and adrenergic responsiveness. We employed an experimental model in which inhibition of myocyte HMG CoA reductase could be studied in the absence of paracrine influences from non-myocyte cells. Adult rat ventricular myocytes were treated with 10 μM simvastatin for 2 days. Simvastatin treatment reduced myocyte cholesterol, caveolin 3 and caveolar density. Negative inotropic and positive lusitropic effects (with corresponding changes in [Ca2]¡) were seen in statin-treated cells. Simvastatin significantly potentiated the inotropic response to β2-, but not β1-, adrenoceptor stimulation. Under conditions of β2-adrenoceptor stimulation, phosphorylation of phospholamban at Ser16and troponin I at Ser23/24was enhanced with statin treatment. Simvastatin increased NO production without significant effects on eNOS expression or phosphorylation (Ser1177), consistent with the reduced expression of caveolin 3, its constitutive Inhibitor. In conclusion, statin treatment can reduce caveolin 3 expression, with functional consequences consistent with the known role of caveolae in the cardiac cell. These data are likely to be of significance, particularly during the early phases of statin treatment, and in patients with heart failure who have altered ß-adrenoceptor signalling. In addition, as caveolin is ubiquitously expressed and has myriad tissue-specific functions, the impact of statin-dependent changes in caveolin is likely to have many other functional sequelae

Phosphodiesterase 4 Inhibition Reduces Innate Immunity and Improves Isoniazid Clearance of Mycobacterium tuberculosis in the Lungs of Infected Mice

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) is one of the leading infectious disease causes of morbidity and mortality worldwide. Though current antibiotic regimens can cure the disease, treatment requires at least six months of drug therapy. One reason for the long duration of therapy is that the currently available TB drugs were selected for their ability to kill replicating organisms and are less effective against subpopulations of non-replicating persistent bacilli. Evidence from in vitro models of Mtb growth and mouse infection studies suggests that host immunity may provide some of the environmental cues that drive Mtb towards non-replicating persistence. We hypothesized that selective modulation of the host immune response to modify the environmental pressure on the bacilli may result in better bacterial clearance during TB treatment. For this proof of principal study, we compared bacillary clearance from the lungs of Mtb-infected mice treated with the anti-TB drug isoniazid (INH) in the presence and absence of an immunomodulatory phosphodiesterase 4 inhibitor (PDE4i), CC-3052. The effects of CC-3052 on host global gene expression, induction of cytokines, and T cell activation in the lungs of infected mice were evaluated. We show that CC-3052 modulates the innate immune response without causing generalized immune suppression. Immune modulation combined with INH treatment improved bacillary clearance and resulted in smaller granulomas and less lung pathology, compared to treatment with INH alone. This novel strategy of combining anti-TB drugs with an immune modulating molecule, if applied appropriately to patients, may shorten the duration of TB treatment and improve clinical outcome

Prolonged Antigen Presentation Is Required for Optimal CD8+ T Cell Responses against Malaria Liver Stage Parasites

Immunization with irradiated sporozoites is currently the most effective vaccination strategy against liver stages of malaria parasites, yet the mechanisms underpinning the success of this approach are unknown. Here we show that the complete development of protective CD8+ T cell responses requires prolonged antigen presentation. Using TCR transgenic cells specific for the malaria circumsporozoite protein, a leading vaccine candidate, we found that sporozoite antigen persists for over 8 weeks after immunization—a remarkable finding since irradiated sporozoites are incapable of replication and do not differentiate beyond early liver stages. Persisting antigen was detected in lymphoid organs and depends on the presence of CD11c+ cells. Prolonged antigen presentation enhanced the magnitude of the CD8+ T cell response in a number of ways. Firstly, reducing the time primed CD8+ T cells were exposed to antigen in vivo severely reduced the final size of the developing memory population. Secondly, fully developed memory cells expanded in previously immunized mice but not when transferred to naïve animals. Finally, persisting antigen was able to prime naïve cells, including recent thymic emigrants, to become functional effector cells capable of eliminating parasites in the liver. Together these data show that the optimal development of protective CD8+ T cell immunity against malaria liver stages is dependent upon the prolonged presentation of sporozoite-derived antigen