Human Neutrophil Elastase Proteolytic Activity in Ulcerative Colitis Favors the Loss of Function of Therapeutic Monoclonal Antibodies

Purpose: Proteases play an essential role in the pathophysiology of inflammatory bowel disease (IBD), contributing to the intestinal mucosal lesions through the degradation of the extracellular matrix and alteration of the barrier function. Ulcerative colitis (UC) is characterized by an extensive infiltrate of neutrophils into the mucosa and hence, increased proteolytic activity. Human neutrophil elastase (HNE) is a serine protease that has been reported to be increased in UC patients’ intestinal mucosa. Based on our previous studies, we hypothesized that HNE might induce proteolytic degradation and loss of function of therapeutic monoclonal antibodies in IBD patients. Patients and Methods: Elastase expression and elastinolytic activity were determined in mucosal explants from ulcerative colitis patients (n=6) and cultured ex vivo in the presence or absence of recombinant elafin. Enzymatic digestions of therapeutic monoclonal antibodies were performed using recombinant HNE and elafin. The integrity of the therapeutic antibodies was evaluated by immunoblotting and protein G binding assay, whereas their TNFneutralizing activity was assessed with a reporter cell line. Results: We found that HNE and its elastinolytic activity were increased in the gut mucosa of UC patients. We also demonstrated that HNE cleaved biological drugs, impairing the TNF-α neutralizing capacity of anti-TNF monoclonal antibodies. This proteolytic degradation was inhibited by the addition of the specific inhibitor, elafin. Conclusion: Our results suggest that the high level of proteolytic degradation by mucosal neutrophil elastase, along with a potential imbalance with elafin, contributes to the loss of function of biologic agents, which are currently used in patients with IBD. These findings might explain the non-responsiveness of UC patients to therapeutic monoclonal antibodies and suggest the potential beneficial concomitant use of elafin in this treatment.Facultad de Ciencias ExactasInstituto de Estudios Inmunológicos y Fisiopatológico

Apoptotic cell death induced by dendritic derivatives of aminolevulinic acid in endothelial and foam cells co-cultures

Photodynamic therapy (PDT) is an effective procedure for the treatment of lesions diseases based on the selectivity of a photosensitising compound with the ability to accumulate in the target cell. Atherosclerotic plaque is a suitable target for PDT because of the preferential accumulation of photosensitisers in atherosclerotic plaques. Dendrimers are hyperbranched polymers conjugated to drugs. The dendrimers of ALA hold ester bonds that inside the cells are cleaved and release ALA, yielding PpIX production. The dendrimer 6m-ALA was chosen to perform this study since in previous studies it induced the highest porphyrin macrophage: endothelial cell ratio (Rodriguez et al. in Photochem Photobiol Sci 14:1617–1627, 2015). We transformed Raw 264.7 macrophages to foam cells by exposure to oxidised LDLs, and we employed a co-culture model of HMEC-1 endothelial cells and foam cells to study the affinity of ALA dendrimers for the foam cells. In this work it was proposed an in vitro model of atheromatous plaque, the aim was to study the selectivity of an ALA dendrimer for the foam cells as compared to the endothelial cells in a co-culture system and the type of cell death triggered by the photodynamic treatment. The ALA dendrimer 6m-ALA showed selectivity PDT response for foam cells against endothelial cells. A light dose of 1 J/cm2 eliminate foam cells, whereas less than 50% of HMEC-1 is killed, and apoptosis cell death is involved in this process, and no necrosis is present. We propose the use of ALA dendrimers as pro-photosensitisers to be employed in photoangioplasty to aid in the treatment of obstructive cardiovascular diseases, and these molecules can also be employed as a theranostic agent

Medium/Long wavelength sensitive opsin diversity in Pitheciidae

New World primates feature a complex colour vision system. Most species have polymorphic colour vision where males have a dichromatic colour perception and females can be either ichromatic or trichromatic. The adaptive value of high allelic diversity of opsins, a light sensitive protein, found in primates’ eyes remains unknown. Studies revealing the allelic diversity are important as they shed light on our understanding of the adaptive value of differences in the colouration of species and their ecologies. Here we investigate the allelic types found in Pitheciidae, an understudied New World primate family, revealing the diversity of medium/long wavelength sensitive opsins both in cryptic and conspicuous species of this primate family. We found five alleles in Cacajao, six in Callicebinae (i.e. Plecturocebus, Cheracebus, and Callicebus), four in Chiropotes, and three in Pithecia, some of them reported for the first time. Both cryptic and conspicuous species in this group presented high allelic diversity

Perioperative fluid overload increases anastomosis thrombosis in the free TRAM flap used for breast reconstruction

To increase perfusion pressure with vasoactive drugs may be in conflict with the opinion of the reconstructive surgeon who maintains that the systemic administration of vasoactive agents causes vasoconstriction of the pedicle artery and the microvasculature. In free flap surgery, deliberate fluid therapy is used with a minimum of vasoactive drugs. This retrospective study was performed to analyse the perioperative fluid therapy, its effect on hemodynamic parameters and on the outcome of free flap surgery. One hundred and four patients were included in this retrospective study. The muscle sparing free transverse rectus abdominis myocutaneous flap was used for breast reconstruction. Perioperative hemodynamic data was used for this study. Twenty-seven patients had one or two complications requiring return to the operating room (OR). Two cases returned to the OR because of postoperative bleeding; in 11 patients, the anastomosis was revised. The reason for surgery in the latter group was venous stasis, due to thrombus formation at the venous anastomosis. The volume of fluid therapy was significantly higher in patients who returned to the OR due to thrombus formation at the anastomosis. Based on the results of this study, restricted intravenous fluid therapy or guided fluid therapy is recommended. Invasive monitoring such as central venous pressure and invasive arterial monitoring is recommended. Fluid loss should be replaced, and fluid overload should be avoided when the breast is reconstructed using free-tissue transfers

"Freshwater killer whales": beaching behavior of an alien fish to hunt land birds

The behavioral strategies developed by predators to capture and kill their prey are fascinating, notably for predators that forage for prey at, or beyond, the boundaries of their ecosystem. We report here the occurrence of a beaching behavior used by an alien and large-bodied freshwater predatory fish (Silurus glanis) to capture birds on land (i.e. pigeons, Columbia livia). Among a total of 45 beaching behaviors observed and filmed, 28% were successful in bird capture. Stable isotope analyses (δ¹³C and δ¹⁵N) of predators and their putative prey revealed a highly variable dietary contribution of land birds among individuals. Since this extreme behavior has not been reported in the native range of the species, our results suggest that some individuals in introduced predator populations may adapt their behavior to forage on novel prey in new environments, leading to behavioral and trophic specialization to actively cross the water-land interface

The Distances of the Magellanic Clouds

The present status of our knowledge of the distances to the Magellanic Clouds is evaluated from a post-Hipparcos perspective. After a brief summary of the effects of structure, reddening, age and metallicity, the primary distance indicators for the Large Magellanic Cloud are reviewed: The SN 1987A ring, Cepheids, RR Lyraes, Mira variables, and Eclipsing Binaries. Distances derived via these methods are weighted and combined to produce final "best" estimates for the Magellanic Clouds distance moduli.Comment: Invited review article to appear in ``Post Hipparcos Cosmic Candles'', F. Caputo & A. Heck (Eds.), Kluwer Academic Publ., Dordrecht, in pres

Negative Effect of Smoking on the Performance of the QuantiFERON TB Gold in Tube Test.

False negative and indeterminate Interferon Gamma Release Assay (IGRA) results are a well documented problem. Cigarette smoking is known to increase the risk of tuberculosis (TB) and to impair Interferon-gamma (IFN-γ) responses to antigenic challenge, but the impact of smoking on IGRA performance is not known. The aim of this study was to evaluate the effect of smoking on IGRA performance in TB patients in a low and high TB prevalence setting respectively. Patients with confirmed TB from Denmark (DK, n = 34; 20 smokers) and Tanzania (TZ, n = 172; 23 smokers) were tested with the QuantiFERON-TB Gold In tube (QFT). Median IFN-γ level in smokers and non smokers were compared and smoking was analysed as a risk factor for false negative and indeterminate QFT results. Smokers from both DK and TZ had lower IFN-γ antigen responses (median 0.9 vs. 4.2 IU/ml, p = 0.04 and 0.4 vs. 1.6, p < 0.01), less positive (50 vs. 86%, p = 0.03 and 48 vs. 75%, p < 0.01) and more false negative (45 vs. 0%, p < 0.01 and 26 vs. 11%, p = 0.04) QFT results. In Tanzanian patients, logistic regression analysis adjusted for sex, age, HIV and alcohol consumption showed an association of smoking with false negative (OR 17.1, CI: 3.0-99.1, p < 0.01) and indeterminate QFT results (OR 5.1, CI: 1.2-21.3, p = 0.02). Cigarette smoking was associated with false negative and indeterminate IGRA results in both a high and a low TB endemic setting independent of HIV status

Importance of Achromatic Contrast in Short-Range Fruit Foraging of Primates

Trichromatic primates have a ‘red-green’ chromatic channel in addition to luminance and ‘blue-yellow’ channels. It has been argued that the red-green channel evolved in primates as an adaptation for detecting reddish or yellowish objects, such as ripe fruits, against a background of foliage. However, foraging advantages to trichromatic primates remain unverified by behavioral observation of primates in their natural habitats. New World monkeys (platyrrhines) are an excellent model for this evaluation because of the highly polymorphic nature of their color vision due to allelic variation of the L-M opsin gene on the X chromosome. In this study we carried out field observations of a group of wild, frugivorous black-handed spider monkeys (Ateles geoffroyi frontatus, Gray 1842, Platyrrhini), consisting of both dichromats (n = 12) and trichromats (n = 9) in Santa Rosa National Park, Costa Rica. We determined the color vision types of individuals in this group by genotyping their L-M opsin and measured foraging efficiency of each individual for fruits located at a grasping distance. Contrary to the predicted advantage for trichromats, there was no significant difference between dichromats and trichromats in foraging efficiency and we found that the luminance contrast was the main determinant of the variation of foraging efficiency among red-green, blue-yellow and luminance contrasts. Our results suggest that luminance contrast can serve as an important cue in short-range foraging attempts despite other sensory cues that could be available. Additionally, the advantage of red-green color vision in primates may not be as salient as previously thought and needs to be evaluated in further field observations