Tri-mannose grafting of chitosan nanocarriers remodels the macrophage response to bacterial infection.

BACKGROUND: Infectious diseases are still a leading cause of death and, with the emergence of drug resistance, pose a great threat to human health. New drugs and strategies are thus urgently needed to improve treatment efficacy and limit drug-associated side effects. Nanotechnology-based drug delivery systems are promising approaches, offering hope in the fight against drug resistant bacteria. However, how nanocarriers influence the response of innate immune cells to bacterial infection is mostly unknown. RESULTS: Here, we used Mycobacterium tuberculosis as a model of bacterial infection to examine the impact of mannose functionalization of chitosan nanocarriers (CS-NCs) on the human macrophage response. Both ungrafted and grafted CS-NCs were similarly internalized by macrophages, via an actin cytoskeleton-dependent process. Although tri-mannose ligands did not modify the capacity of CS-NCs to escape lysosomal degradation, they profoundly remodeled the response of M. tuberculosis-infected macrophages. mRNA sequencing showed nearly 900 genes to be differentially expressed due to tri-mannose grafting. Unexpectedly, the set of modulated genes was enriched for pathways involved in cell metabolism, particularly oxidative phosphorylation and sugar metabolism. CONCLUSIONS: The ability to modulate cell metabolism by grafting ligands at the surface of nanoparticles may thus be a promising strategy to reprogram immune cells and improve the efficacy of encapsulated drugs.

The impact of intrauterine and extrauterine weight gain in premature infants on later body composition.

BackgroundThe impact of intrauterine and extrauterine growth on later insulin resistance and fat mass (FM) in very low birth weight (VLBW) infants is not well established. The aim of our study was to evaluate the effects of intrauterine and early/late extrauterine growth on later insulin resistance and body composition in VLBW infants from 6 months' corrected age (CA) to 36 months.MethodsProspective measurements of body composition by dual-energy X-ray absorptiometry and insulin resistance by homeostasis model assessment insulin resistance (HOMA-IR) along with other fasting plasma biochemistries were made in 95 VLBW infants at 6, 12, 18, and 24 months' CA and 36 months' postnatal age. Mixed-effect models were used to evaluate the effects of age, sex, maturation status, and Δweight SD score on percentage FM (PFM), FM index (FMI), fat-free mass index (FFMI), and HOMA-IR.ResultsPFM and FMI were negatively associated with a decrease in weight-SD scores from birth to 36 weeks' postmenstrual age (PMA; P=0.001) and from 36 weeks' PMA to 6 months' CA (P=0.003). PFM and FMI were higher in AGA than in small for gestational age (SGA) infants. HOMA-IR was not associated with the Δweight-SD scores in either period.ConclusionsCatch-down growth in terms of weight is associated with persistently lower adiposity but not insulin resistance up to 36 months of age.

Natural Anti-Infective Pulmonary Proteins: In Vivo Cooperative Action of Surfactant Protein SP-A and the Lung Antimicrobial Peptide SP-BN.

The anionic antimicrobial peptide SP-B(N), derived from the N-terminal saposin-like domain of the surfactant protein (SP)-B proprotein, and SP-A are lung anti-infective proteins. SP-A-deficient mice are more susceptible than wild-type mice to lung infections, and bacterial killing is enhanced in transgenic mice overexpressing SP-B(N). Despite their potential anti-infective action, in vitro studies indicate that several microorganisms are resistant to SP-A and SP-B(N). In this study, we test the hypothesis that these proteins act synergistically or cooperatively to strengthen each other's microbicidal activity. The results indicate that the proteins acted synergistically in vitro against SP-A- and SP-B(N)-resistant capsulated Klebsiella pneumoniae (serotype K2) at neutral pH. SP-A and SP-B(N) were able to interact in solution (Kd = 0.4 µM), which enabled their binding to bacteria with which SP-A or SP-B(N) alone could not interact. In vivo, we found that treatment of K. pneumoniae-infected mice with SP-A and SP-B(N) conferred more protection against K. pneumoniae infection than each protein individually. SP-A/SP-B(N)-treated infected mice showed significant reduction of bacterial burden, enhanced neutrophil recruitment, and ameliorated lung histopathology with respect to untreated infected mice. In addition, the concentrations of inflammatory mediators in lung homogenates increased early in infection in contrast with the weak inflammatory response of untreated K. pneumoniae-infected mice. Finally, we found that therapeutic treatment with SP-A and SP-B(N) 6 or 24 h after bacterial challenge conferred significant protection against K. pneumoniae infection. These studies show novel anti-infective pathways that could drive development of new strategies against pulmonary infections.

Genetic analysis of specific and redundant roles for p38alpha and p38beta MAPKs during mouse development.

p38α MAPK is an important regulator of cellular responses induced by external cues, but the elucidation of physiological functions for p38α has been complicated by the possible functional redundancy in vivo with the related family member p38ß. We found that mice with combined deletion of p38α and p38ß display diverse developmental defects at midgestation, including major cardiovascular abnormalities, which are observed neither in single knockout nor in double heterozygous embryos. Expression analysis indicates specific functions of p38α and p38ß in the regulation of cardiac gene expression during development. By using knock-in animals that express p38ß under control of the endogenous p38α promoter, we also found that p38ß cannot perform all of the functions of p38α during embryogenesis. Our results identify essential roles for p38α and p38ß during development and suggest that some specific functions may be explained by differences in expression patterns.

Cooperative action of SP-A and its trimeric recombinant fragment with polymyxins against Gram-negative respiratory bacteria.

The exploration of therapies combining antimicrobial lung proteins and conventional antibiotics is important due to the growing problem of multidrug-resistant bacteria. The aim of this study was to investigate whether human SP-A and a recombinant trimeric fragment (rfhSP-A) have cooperative antimicrobial activity with antibiotics against pathogenic Gram-negative bacteria. We found that SP-A bound the cationic peptide polymyxin B (PMB) with an apparent dissociation constant (K D) of 0.32 ± 0.04 µM. SP-A showed synergistic microbicidal activity with polymyxin B and E, but not with other antibiotics, against three SP-A-resistant pathogenic bacteria: Klebsiella pneumoniae, non-typable Haemophilus influenzae (NTHi), and Pseudomonas aeruginosa. SP-A was not able to bind to K. pneumoniae, NTHi, or to mutant strains thereof expressing long-chain lipopolysaccharides (or lipooligosaccharides) and/or polysaccharide capsules. In the presence of PMB, SP-A induced the formation of SP-A/PMB aggregates that enhance PMB-induced bacterial membrane permeabilization. Furthermore, SP-A bound to a molecular derivative of PMB lacking the acyl chain (PMBN) with a K D of 0.26 ± 0.02 µM, forming SP-A/PMBN aggregates. PMBN has no bactericidal activity but can bind to the outer membrane of Gram-negative bacteria. Surprisingly, SP-A and PMBN showed synergistic bactericidal activity against Gram-negative bacteria. Unlike native supratrimeric SP-A, the trimeric rfhSP-A fragment had small but significant direct bactericidal activity against K. pneumoniae, NTHi, and P. aeruginosa. rfhSP-A did not bind to PMB under physiological conditions but acted additively with PMB and other antibiotics against these pathogenic bacteria. In summary, our results significantly improve our understanding of the antimicrobial actions of SP-A and its synergistic action with PMB. A peptide based on SP-A may aid the therapeutic use of PMB, a relatively cytotoxic antibiotic that is currently being reintroduced into clinics due to the global problem of antibiotic resistance.

Pascual-Castroviejo type II syndrome (P-CIIS). Importance of the presence of persistent embryonic arteries.

INTRODUCTION: Cutaneous hemangioma and vascular malformation are two vascular abnormalities frequently associated with absence or hypoplasia of one or both carotid and/or vertebral arteries, presence of persistent embryonic arteries, especially the trigeminal, cerebellar malformations, and coarctation of the aortic arch and/or congenital cardiopathy. This disease is known as Pascual-Castroviejo type II syndrome (P-CIIS) and by the acronym PHACE. MATERIAL AND METHODS: Three patients (two females and one male) with facial hemangioma are studied during the first years of age by magnetic resonance angiography (MRA) and their vascular evolution to adult age followed through several MRA controls. RESULTS: All the three patients showed persistence of the trigeminal artery associated to other intra- and extracranial vascular abnormalities of type hemangioma or hemangiomatous arteries that presented progressive involution with decreased arterial caliber without appearing cerebrovascular stroke or hypoxic zones because, at the same time, collateral vascularization appeared through connections between the embryonic arteries and the peripheral branches of the internal carotids or connections between branches of the external and internal carotids. Only one patient had obstruction of a branch of the left middle cerebral artery after 3 days, with gastroenteritis with elevated fever at 17 months of life that caused parenchymal infarct in the left cerebral region supplied by the obstructed artery. CONCLUSIONS: The presence of embryonic arteries, especially the trigeminal, and connections between branches of the internal and external carotids, mainly through the internal maxillary and ophthalmic arteries, ensure the cerebral supply in the P-CIIS despite the progressive involvement of the cerebral arteries.

The antibiotic bedaquiline activates host macrophage innate immune resistance to bacterial infection.

Antibiotics are widely used in the treatment of bacterial infections. Although known for their microbicidal activity, antibiotics may also interfere with the host's immune system. Here, we analyzed the effects of bedaquiline (BDQ), an inhibitor of the mycobacterial ATP synthase, on human macrophages. Genome-wide gene expression analysis revealed that BDQ reprogramed cells into potent bactericidal phagocytes. We found that 579 and 1,495 genes were respectively differentially expressed in naive- and M. tuberculosis-infected macrophages incubated with the drug, with an over-representation of lysosome-associated genes. BDQ treatment triggered a variety of antimicrobial defense mechanisms, including phagosome-lysosome fusion, and autophagy. These effects were associated with activation of transcription factor EB, involved in the transcription of lysosomal genes, resulting in enhanced intracellular killing of different bacterial species that were naturally insensitive to BDQ. Thus, BDQ could be used as a host-directed therapy against a wide range of bacterial infections.

The discovery of antibiotic drugs, which treat diseases caused by bacteria, has been a hugely valuable advance in modern medicine. They work by targeting specific cellular processes in bacteria, ultimately stopping them from multiplying or killing them outright. Antibiotics sometimes also affect their human hosts and can cause side-effects, such as gut problems or skin reactions. Recent evidence suggests that antibiotics also have an impact on the human immune system. This may happen either indirectly, by affecting 'friendly' bacteria normally present in the body, or through direct effects on immune cells. In turn, this could change the effectiveness of drug treatments. For example, if an antibiotic weakens immune cells, the body could have difficulty fighting off the existing infection ­ or become more vulnerable to new ones. However, even though new drugs are being introduced to combat the worldwide rise of antibiotic-resistant bacteria, their effects on immunity are still not well understood. For example, bedaquiline is an antibiotic recently developed to treat tuberculosis infections that are resistant to several drugs. Giraud-Gatineau et al. wanted to determine if bedaquiline altered the human immune response to bacterial infection independently from its direct anti-microbial effects. Macrophages engulf foreign particles like bacteria and break them down using enzymes stored within small internal compartments, or 'lysosomes'. Initial experiments using human macrophages, grown both with and without bedaquiline, showed that the drug did not harm the cells and that they grew normally. A combination of microscope imaging and genetic analysis revealed that exposure to bedaquiline not only increased the number of lysosomes within macrophage cells, but also the activity of genes and proteins that increase lysosomes' ability to break down foreign particles. These results suggested that bedaquiline treatment might make macrophages better at fighting infection, even if the drug itself had no direct effect on bacterial cells. Further studies, where macrophages were first treated with bedaquiline and then exposed to different types of bacteria known to be resistant to the drug, confirmed this hypothesis: in every case, the treated macrophages became efficient bacterial killers. In contrast, older anti-tuberculosis drugs did not have any such potentiating effect on the macrophages. This work sheds new light on our how antibiotic drugs can interact with the cells of the human immune system, and can sometimes even boost our innate defences. Such immune-boosting effects could one day be exploited to make more effective treatments against bacterial infections.

PET/CT in lymphoma: prospective study of enhanced full-dose PET/CT versus unenhanced low-dose PET/CT.

UNLABELLED: PET/CT combines functional and morphologic data and increases diagnostic accuracy in a variety of malignancies. This study prospectively compares the agreement between contrast-enhanced full-dose PET/CT and unenhanced low-dose PET/CT in lesion detection and initial staging of Hodgkin's disease and non-Hodgkin's lymphoma. METHODS: Forty-seven biopsy-proven lymphoma patients underwent a 18F-FDG PET/CT study that included unenhanced low-dose CT and enhanced full-dose CT for initial staging. Patients who had undergone previous diagnostic CT for initial staging were excluded. For every patient, each modality of PET/CT images was evaluated by either of 2 pairs of readers, with each pair comprising 1 experienced radiologist and 1 experienced nuclear physician. While evaluating one of the 2 types of PET/CT, the readers were unaware of the results of the other type. Lesion detection, number of sites affected in each anatomic region, and disease stage were assessed. Agreement between techniques was determined by the kappa-statistic, and discordances were studied by the McNemar test. Clinical, analytic, histopathologic, diagnostic CT, and PET data; data from other imaging techniques; and follow-up data constituted the reference standard. RESULTS: For region-based analysis, no significant differences were found between unenhanced low-dose PET/CT and contrast-enhanced full-dose PET/CT, although full-dose PET/CT showed fewer indeterminate findings and a higher number of extranodal sites affected than did low-dose PET/CT. Agreement between the 2 types of PET/CT was almost perfect for disease stage (kappa = 0.92; P < 0.001). CONCLUSION: Our study showed a good correlation between unenhanced low-dose PET/CT and contrast-enhanced full-dose PET/CT for lymph node and extranodal disease in lymphomas, suggesting that unenhanced low-dose PET/CT might suffice in most patients as the only imaging technique for the initial staging of lymphomas, reserving diagnostic CT for selected cases.

Clinical role of Sm-153 EDTMP in the treatment of painful bone metastatic disease.

PURPOSE: Sm-153 EDTMP is an effective treatment of painful bone metastases from different neoplasms. However, there are few studies describing clinical experience with this therapeutic modality. The aim of this clinical study was to evaluate the efficacy of Sm-153 EDTMP in a group of patients with skeletal metastases and poor pain control with conventional therapies. MATERIALS AND METHODS: Sixty-four patients with painful bone metastases treated with Sm-153 EDTMP were retrospectively evaluated. Nine patients were treated twice. The most common primaries were breast in 28 cases (44%) and prostate in 27 (41%). Treatment efficacy was assessed by a visual analog scale, analgesic consumption, and performance status before and after treatment. Response was graded as complete, moderate, or minor. Toxicity evaluation included analytic parameters (blood counts, renal function) and clinical follow up. RESULTS: Efficacy and toxicity were evaluated separately for each dose (total doses: 73), and complete follow up was only possible in 62 of 73 administrations. The response rate was 85% (21% complete, 40% moderate, and 24% minor). Onset of improvement took place a median of 7 days after Sm-153 EDTMP administration, and pain relief persisted for a mean of 3 months. No relevant toxicity was found in the early phase. Myelotoxicity appeared in 29% of the administrations and was mild in most cases (there was one case of grade 4 leukopenia). CONCLUSIONS: Sm-153 EDTMP is a good therapeutic option for patients with painful bone metastases. It is an effective treatment of pain relief without major secondary effects.

Positron emission tomography/computed tomography in the management of Hodgkin's disease and non-Hodgkin's lymphoma.

The incidence of Hodgkin's disease (HD) and Non-Hodgkin's lymphoma (NHL) is around 8% of all malignancies. Fortunately, HD and NHL are among the few malignancies that are potentially curable with current existing treatment modalities, even in advanced or recurrent disease. Accurate staging, early therapy monitoring, and posttreatment evaluation of lymphomas are important for optimum management of these patients. We reviewed the imaging findings of patients with histologically proved lymphoma who underwent staging positron emission tomography/computed tomography (PET/CT), early monitoring therapy PET/CT (after 3 cycles of chemotherapy), and posttreatment PET/CT. PET/CT imaging findings are shown. Utility of PET/CT in recognizing false-positive and false-negative cases of CT and PET alone is addressed. Pitfalls and diagnostic difficulties are analyzed. PET/CT is a new imaging technology that improves the evaluation of lymphoma. This review will help the reader to better understand the imaging findings and applications of PET/CT in the management of lymphoma.

[Non-Hodgkin's lymphoma staging: a prospective study of the value of positron emission tomography/computed tomography (PET/CT) versus PET and CT]. / Estadificación de los linfomas no hodgkinianos: estudio prospectivo de la tomografía por emisión de positrones/tomografía computarizada (PET/TC) frente a la PET y a la TC.

BACKGROUND AND OBJECTIVE: To prospectively analyze the diagnostic accuracy of PET/CT in non-Hodgkin's lymphoma (NHL) and to evaluate the most appropriate study protocol of this technique. PATIENTS AND METHOD: Seventy-six biopsy proven NHL patients were enrolled in this prospective study for 3 years. Patients initially underwent a low-dose CT without intravenous contrast, then a PET emission scan and finally a full-dose CT with intravenous contrast. For every patient, two modalities of PET/CT images were reconstructed: a low-dose unenhanced PET/CT and a full-dose enhanced PET/CT. Each modality was evaluated by either of two pairs of readers, different for each modality. Enhanced CT and PET images were evaluated by an independent radiologist and nuclear medicine physician respectively. RESULTS: Agreement between reference standard and techniques was as follows: 52.2% of patients with enhanced CT (κ=0.458), 46% with PET (κ=0.335), 75% with low-dose unenhanced PET/CT (κ=0.664) and 76.8% with full-dose enhanced PET/CT (κ=0.679), with p<0.001. Although all techniques underestimated the stage in comparison to gold standard, the lowest percentage was for full-dose enhanced PET/CT (20.3%). CONCLUSIONS: PET/CT improved staging accuracy of NHL, being full-dose enhanced PET/CT the most accurate technique in our study.

Positron emission tomography/computed tomography: diagnostic accuracy in lymphoma.

An accurate initial staging of patients with non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) is critical for the selection of an appropriate treatment. Computed tomography (CT) remains the standard imaging technique, although it is based on anatomic criteria. Positron emission tomography (PET) with 2-deoxy-2-[fluorine-18]fluoro-d-glucose (FDG) provides useful functional information but requires anatomical correlation to localise lesions accurately. We have prospectively compared the accuracy of combined PET/CT with that of CT and PET alone at initial staging in lymphoma patients. Forty-seven newly diagnosed patients were evaluated. PET/CT was superior compared with CT and PET in nodal evaluation and detection of extranodal disease. Using a staging algorithm with PET/CT resulted in the disease stage being increased in 11 of 47 patients (10 NHL and 1 HL) (McNemar test P = 0.012). Therefore, a different treatment strategy based on PET/CT findings was suggested for seven patients (14.8%). PET/CT markedly improves accuracy in the diagnostic work-up of patients with lymphoma.