Single-Photon Emission Computed Tomography/Computed Tomography Imaging in a Rabbit Model of Emphysema Reveals Ongoing Apoptosis In Vivo.

Evaluation of lung disease is limited by the inability to visualize ongoing pathological processes. Molecular imaging that targets cellular processes related to disease pathogenesis has the potential to assess disease activity over time to allow intervention before lung destruction. Because apoptosis is a critical component of lung damage in emphysema, a functional imaging approach was taken to determine if targeting apoptosis in a smoke exposure model would allow the quantification of early lung damage in vivo. Rabbits were exposed to cigarette smoke for 4 or 16 weeks and underwent single-photon emission computed tomography/computed tomography scanning using technetium-99m-rhAnnexin V-128. Imaging results were correlated with ex vivo tissue analysis to validate the presence of lung destruction and apoptosis. Lung computed tomography scans of long-term smoke-exposed rabbits exhibit anatomical similarities to human emphysema, with increased lung volumes compared with controls. Morphometry on lung tissue confirmed increased mean linear intercept and destructive index at 16 weeks of smoke exposure and compliance measurements documented physiological changes of emphysema. Tissue and lavage analysis displayed the hallmarks of smoke exposure, including increased tissue cellularity and protease activity. Technetium-99m-rhAnnexin V-128 single-photon emission computed tomography signal was increased after smoke exposure at 4 and 16 weeks, with confirmation of increased apoptosis through terminal deoxynucleotidyl transferase dUTP nick end labeling staining and increased tissue neutral sphingomyelinase activity in the tissue. These studies not only describe a novel emphysema model for use with future therapeutic applications, but, most importantly, also characterize a promising imaging modality that identifies ongoing destructive cellular processes within the lung.

Therapeutic efficacy of 166Holmium siloxane in microbrachytherapy of induced glioblastoma in minipig tumor model.

Glioblastoma is considered the most common malignant primary tumor of central nervous system. In spite of the current standard and multimodal treatment, the prognosis of glioblastoma is poor. For this reason, new therapeutic approaches need to be developed to improve the survival time of the glioblastoma patient. In this study, we performed a preclinical experiment to evaluate therapeutic efficacy of 166Ho microparticle suspension administered by microbrachytherapy on a minipig glioblastoma model. Twelve minipigs were divided in 3 groups. Minipigs had injections into the tumor, containing microparticle suspensions of either 166Ho (group 1; n = 6) or 165Ho (group 2; n = 3) and control group (group 3; n = 3). The survival time from treatment to euthanasia was 66 days with a good state of health of all minipigs in group 1. The median survival time from treatment to tumor related death were 8.6 and 7.3 days in groups 2 and control, respectively. Statistically, the prolonged life of group 1 was significantly different from the two other groups (p < 0.01), and no significant difference was observed between group 2 and control (p=0.09). Our trial on the therapeutic effect of the 166Ho microparticle demonstrated an excellent efficacy in tumor control. The histological and immunohistochemical analysis showed that the efficacy was related to a severe 166Ho induced necrosis combined with an immune response due to the presence of the radioactive microparticles inside the tumors. The absence of reflux following the injections confirms the safety of the injection device.

The Association between Vitamin D and Gut Microbiota: A Systematic Review of Human Studies.

Recent evidence has shown a number of extra-skeletal functions of Vitamin D (VD), primarily involving the immune system. One of these functions is mediated by the modulation of gut microbiota, whose alterations are linked to many diseases. Our purpose is to contribute to the understanding of existing evidence on the association between VD and gastrointestinal microbiota alterations. A systematic review of studies with human subjects has been conducted up to January 2021. We included publications reporting the association between gut microbiota and VD, including VD supplementation, dietary VD intake and/or level of 25(OH)D. We identified 25 studies: 14 were interventional and 11, observational. VD supplementation was found to be associated with a significant change in microbiome composition, in particular of Firmicutes, Actinobacteria and Bacteroidetes phyla. Furthermore, Firmicutes were found to be correlated with serum VD. Concerning alpha and beta diversity, a high nutritional intake of VD seems to induce a shift in bacterial composition and/or affects the species' richness. Veillonellaceae and Oscillospiraceae families, in the Firmicutes phylum, more frequently decreased with both increasing levels of 25(OH)D and vitamin D supplementation. We found evidence of an association, even though the studies are substantially heterogeneous and have some limitations, resulting sometimes in conflicting results. To further understand the role of VD on the modulation of the gastrointestinal microbiota, future research should be geared toward well-designed animal-based studies or larger randomized controlled trials (RCTs).

Vitamin D Supplementation and Cancer Mortality: Narrative Review of Observational Studies and Clinical Trials.

Several studies have investigated the beneficial effects of vitamin D on survival of cancer patients. Overall evidence has been accumulating with contrasting results. This paper aims at narratively reviewing the existing articles examining the link between vitamin D supplementation and cancer mortality. We performed two distinct searches to identify observational (ObS) studies and randomized clinical trials (RCTs) of vitamin D supplementation (VDS) in cancer patients and cohorts of general population, which included cancer mortality as an outcome. Published reports were gathered until March 2021. We identified 25 papers published between 2003 and 2020, including n. 8 RCTs on cancer patients, n. 8 population RCTs and n. 9 ObS studies. There was some evidence that the use of VDS in cancer patients could improve cancer survival, but no significant effect was found in population RCTs. Some ObS studies reported evidence that VDS was associated with a longer survival among cancer patients, and only one study found an opposite effect. The findings do not allow conclusive answers. VDS may have the potential as treatment to improve survival in cancer patients, but further investigations are warranted. We strongly support investment in well-designed and sufficiently powered RCTs to fully evaluate this association.

An engineered monomer of CCL2 has anti-inflammatory properties emphasizing the importance of oligomerization for chemokine activity in vivo.

We demonstrated recently that P8A-CCL2, a monomeric variant of the chemokine CCL2/MCP-1, is unable to induce cellular recruitment in vivo, despite full activity in vitro. Here, we show that this variant is able to inhibit CCL2 and thioglycollate-mediated recruitment of leukocytes into the peritoneal cavity and recruitment of cells into lungs of OVA-sensitized mice. This anti-inflammatory activity translated into a reduction of clinical score in the more complex inflammatory model of murine experimental autoimmune encephalomyelitis. Several hypotheses for the mechanism of action of P8A-CCL2 were tested. Plasma exposure following s.c. injection is similar for P8A-CCL2 and wild-type (WT) CCL2, ruling out the hypothesis that P8A-CCL2 disrupts the chemokine gradient through systemic exposure. P8A-CCL2 and WT induce CCR2 internalization in vitro and in vivo; CCR2 then recycles to the cell surface, but the cells remain refractory to chemotaxis in vitro for several hours. Although the response to P8A-CCL2 is similar to WT, this finding is novel and suggests that despite the presence of the receptor on the cell surface, coupling to the signaling machinery is retarded. In contrast to CCL2, P8A-CCL2 does not oligomerize on glycosaminoglycans (GAGs). However, it retains the ability to bind GAGs and displaces endogenous JE (murine MCP-1) from endothelial surfaces. Intravital microscopy studies indicate that P8A-CCL2 prevents leukocyte adhesion, while CCL2 has no effect, and this phenomenon may be related to the mechanism. These results suggest that oligomerization-deficient chemokines can exhibit anti-inflammatory properties in vivo and may represent new therapeutic modalities.

The use of chemokine antagonists in EAE models.

Multiple sclerosis is believed to be an autoimmune disease with an end-point of neuro-degeneration, but in which inflammation plays a predominant role. Therefore therapies which target inhibition of the excessive recruitment of leukocytes into the central nervous system (CNS) are actively sought after by medical research. Drug discovery relies heavily on animal models used for such research, called Experimental Autoimmune Encephalomyelitis (EAE). Several chemokines and their receptors have been shown to play a role in this recruitment into the CNS, and we have investigated several strategies which antagonize this system in EAE models. We will discuss these strategies and their successes and failures to prevent disease symptoms and the insights they have provided.

Knockout mice reveal a role for protein tyrosine phosphatase H1 in cognition.

BACKGROUND: The present study has investigated the protein tyrosine phosphatase H1 (PTPH1) expression pattern in mouse brain and its impact on CNS functions. METHODS: We have previously described a PTPH1-KO mouse, generated by replacing the PTP catalytic and the PDZ domain with a LacZ neomycin cassette. PTPH1 expression pattern was evaluated by LacZ staining in the brain and PTPH1-KO and WT mice (n = 10 per gender per genotype) were also behaviorally tested for CNS functions. RESULTS: In CNS, PTPH1 is expressed during development and in adulthood and mainly localized in hippocampus, thalamus, cortex and cerebellum neurons. The behavioral tests performed on the PTPH1-KO mice showed an impact on working memory in male mice and an impaired learning performance at rotarod in females. CONCLUSION: These results demonstrate for the first time a neuronal expression of PTPH1 and its functionality at the level of cognition.

Fish oil and mental health: the role of n-3 long-chain polyunsaturated fatty acids in cognitive development and neurological disorders.

Epidemiological and experimental studies have indicated that consumption of more n-3 long-chain polyunsaturated fatty acids may reduce the risk for a variety of diseases, including cardiovascular, neurological and immunological disorders, diabetes and cancer. This article focuses on the role of marine n-3 long-chain polyunsaturated fatty acids in brain functions, including the development of the central nervous system and neurological disorders. An overview of the major animal studies and clinical trials is provided here, focusing on fatty acid supplementation during pregnancy and infancy, and prevention and management of Alzheimer's disease, schizophrenia, depression and attention deficit hyperactive disorder. Although an optimal balance in n-3/n-6 long-chain polyunsaturated fatty acid ratio is important for proper neurodevelopment and cognitive functions, results from randomized controlled trials are controversial and do not confirm any useful effect of supplementation on development of preterm and term infants. The relationship between fatty acid status and mental disorders is confirmed by reduced levels of n-3 long-chain polyunsaturated fatty acids in erythrocyte membranes of patients with central nervous system disorders. Nevertheless, there are very little data supporting the use of fish oil in those patients. The only way to verify whether n-3 long-chain polyunsaturated fatty acids are a potential therapeutic option in the management and prevention of mental disorders is to conduct a large definitive randomized controlled trials similar to those required for the licensing of any new pharmacological treatment.

Single photon emission computed tomography imaging of cerebral blood flow, blood-brain barrier disruption, and apoptosis time course after focal cerebral ischemia in rats.

BACKGROUND: Cerebral ischemia is a leading cause of disability worldwide and no other effective therapy has been validated to date than intravenous thrombolysis. In this context, many preclinical models have been developed and recent advances in preclinical imaging represent promising tools. Thus, we proposed here to characterize in vivo time profiles of cerebral blood flow, blood-brain barrier disruption and apoptosis following a transient middle cerebral artery occlusion in rats using SPECT/CT imaging. METHODS: Rats underwent a 1-h middle cerebral artery occlusion followed by reperfusion. Cerebral blood flow, blood-brain barrier disruption and apoptosis were evaluated by SPECT/CT imaging using respectively (99m)Tc-HMPAO, (99m)Tc-DTPA and the experimental (99m)Tc-Annexin V-128, up to 14 days after middle cerebral artery occlusion. Histological evaluation of apoptosis has been performed using TUNEL method to validate the (99m)Tc-Annexin V-128 uptake. RESULTS: (99m)Tc-HMPAO cerebral blood flow evaluation showed hypoperfusion during occlusion, partially restored on days 4 and 7 and sustained up to 14 days after middle cerebral artery occlusion. (99m)Tc-DTPA SPECT/CT showed a blood-brain barrier disruption starting on day 1 post-middle cerebral artery occlusion, peaking on day 2, with barrier integrity totally restored on day 7. (99m)Tc-Annexin V-128 SPECT/CT imaging showed significant positive correlation with TUNEL immunohistochemistry and allowed ischemic-induced apoptosis to be detected from day 2 to day 7, peaking on day 3 after middle cerebral artery occlusion. CONCLUSIONS: Using SPECT/CT imaging, we showed that after transient middle cerebral artery occlusion in rat there was a sustained decrease in cerebral blood flow followed by blood-brain barrier disruption preceding meanwhile apoptosis. Rodent SPECT/CT imaging of cerebral blood flow, blood-brain barrier disruption and apoptosis appears to be an efficient tool for evaluating neuroprotective drugs and regenerative therapies against cerebral ischemia and time-windows for therapeutic intervention.

BDNF binding to truncated trkB.T1 does not affect gene expression.

Truncated trkB.T1 is a splice variant of the neurotrophin receptor trkB. In spite of its abundance, and ability to bind and internalize BDNF, it is not clear whether it can transmit BDNF signaling. We tested this hypothesis by searching for proteins binding the evolutionarily conserved cyto-domain of trkB.T1, and by studying BDNF-induced changes of gene expression through DNA microarrays. Cells bearing trkB.T1 receptors presented morphological changes. However, no cytoplasmic interactors of trkB.T1 were found. In addition, BDNF-dependent modulation of gene expression was detected in cells bearing trkB.TK but not trkB.T1 receptors. These results suggest that the main function of trkB.T1 is to regulate local availability of neurotrophins and that it is unable to sense changes in BDNF availability.

Synthesis and preliminary evaluation in tumor bearing mice of new (18)F-labeled arylsulfone matrix metalloproteinase inhibitors as tracers for positron emission tomography.

New fluorinated, arylsulfone-based matrix metalloproteinase (MMP) inhibitors containing carboxylate as the zinc binding group were synthesized as radiotracers for positron emission tomography. Inhibitors were characterized by Ki for MMP-2 in the nanomolar range and by a fair selectivity for MMP-2/9/12/13 over MMP-1/3/14. Two of these compounds were obtained in the (18)F-radiolabeled form, with radiochemical purity and yield suitable for preliminary studies in mice xenografted with a human U-87 MG glioblastoma. Target density in xenografts was assessed by Western blot, yielding Bmax/Kd = 14. The biodistribution of the tracer was dominated by liver uptake and hepatobiliary clearance. Tumor uptake of (18)F-labeled MMP inhibitors was about 30% that of [(18)F]fluorodeoxyglucose. Accumulation of radioactivity within the tumor periphery colocalized with MMP-2 activity (evaluated by in situ zimography). However, specific tumor uptake accounted for only 18% of total uptake. The aspecific uptake was ascribed to the high binding affinity between the radiotracer and serum albumin.

Characterization of protein tyrosine phosphatase H1 knockout mice in animal models of local and systemic inflammation.

BACKGROUND: PTPH1 is a protein tyrosine phosphatase expressed in T cells but its effect on immune response is still controversial. PTPH1 dephosphorylates TCRzeta in vitro, inhibiting the downstream inflammatory signaling pathway, however no immunological phenotype has been detected in primary T cells derived from PTPH1-KO mice. The aim of the present study is to characterize PTPH1 phenotype in two in vivo inflammatory models and to give insights in possible PTPH1 functions in cytokine release. METHODS: We challenged PTPH1-KO mice with two potent immunomodulatory molecules, carrageenan and LPS, in order to determine PTPH1 possible role in inflammatory response in vivo. Cytokine release, inflammatory pain and gene expression were investigated in challenged PTPH1-WT and KO mice. RESULTS: The present study shows that carrageenan induces a trend of slightly increased spontaneous pain sensitivity in PTPH1-KO mice compared to WT (wild-type) littermates, but no differences in cytokine release, induced pain perception and cellular infiltration have been detected between the two genotypes in this mouse model. On the other hand, LPS-induced TNFalpha, MCP-1 and IL10 release was significantly reduced in PTPH1-KO plasma compared to WTs 30 and 60 minutes post challenge. No cytokine release modulation was detectable 180 minutes post LPS challenge. CONCLUSION: In conclusion, the present study points out a slight potential role for PTPH1 in spontaneous pain sensitivity and it indicates that this phosphatase might play a role in the positive regulation of the LPS-induced cytokines release in vivo, in contrast to previous reports indicating PTPH1 as potential negative regulator of immune response.

New antirheumatic drugs: any real added value? A critical overview of regulatory criteria for their marketing approval.

OBJECTIVE: Rheumatoid arthritis (RA) is a systemic autoimmune disorder causing chronic polyarticular synovial inflammation and progressive joint damage. New anti-rheumatic drugs, such as leflunomide, infliximab, etanercept, adalimumab and anakinra, have recently become available. The aim of this paper is to summarize and critically evaluate the type of studies and clinical endpoints accepted by the European Medicines Agency (EMEA) to approve these new drugs. MATERIALS AND METHODS: Information regarding the approval of antirheumatic drugs was obtained from European Public Assessment Reports (EPARs) and published pivotal studies. RESULTS: Leflunomide is the only non-biological disease-modifying anti-rheumatic drug (DMARD) to receive recent approval for RA treatment, but strong evidence of its superiority over conventional therapies is lacking. Anakinra in combination with methotrexate received approval as a DMARD for RA on the basis of two pivotal trials in which American College of Rheumatology response criteria (ACR 20 response) were used as the sole primary endpoint. For easier demonstration of efficacy, studies leading to first approval of etanercept, infliximab and adalimumab were carried out on non-responders to DMARDs. Once on the market, these drugs gained an extension of the indication to methotrexate-naïve patients. Studies that provided the basis for approval were not adequately designed, given the lack of an active control and the choice of ACR response as the only clinical endpoint. Consequently, only a weak proof of efficacy emerged for the treatment of signs and symptoms of RA, and these drugs failed to show real benefit in slowing radiographic progression. Serious infections, changes in blood cell counts, severe skin and hepatic infections were the main adverse events that emerged from the clinical studies. Therefore, the unconvincing benefit of the new antirheumatic drugs can scarcely outweigh the risk associated with their use. Moreover, the monthly costs in Italy of the new biological preparations are several fold higher than those of the reference drugs. CONCLUSIONS: Recently approved anti-RA products should be a therapeutic option only for patients refractory to conventional drugs.

Motor evoked potentials in a mouse model of chronic multiple sclerosis.

We tested cortical motor evoked potentials (cMEPs) as a quantitative marker for in vivo monitoring of corticospinal tract damage in a murine multiple sclerosis model (experimental autoimmune encephalomyelitis, EAE). The cMEPs, previously standardized in naive C57BL/6 developing and adult mice, were studied longitudinally in adult EAE mice. Central conduction times (CCTs) increased significantly shortly before the earliest clinical signs developed (10 days postimmunization, dpi), with peak delay in acute EAE (20-40 dpi). In clinically stable disease (80 dpi), CCTs did not increase further, but cMEP amplitude declined progressively, with complete loss in >80% of mice at 120 dpi. Increase in CCT correlated with presence of inflammatory infiltrates and demyelination in acute EAE, whereas small or absent cMEPs were associated with continuing axonal damage in clinically-stabilized disease and beyond (>80 dpi). These results demonstrate that cMEPs are a useful method for monitoring corticospinal tract function in chronic-progressive EAE, and provide insight into the pathological substrate of the condition.

Interference with heparin binding and oligomerization creates a novel anti-inflammatory strategy targeting the chemokine system.

A hallmark of autoimmunity and other chronic diseases is the overexpression of chemokines resulting in a detrimental local accumulation of proinflammatory immune cells. Chemokines play a pivotal role in cellular recruitment through interactions with both cell surface receptors and glycosaminoglycans (GAGs). Anti-inflammatory strategies aimed at neutralizing the chemokine system have to-date targeted inhibition of the receptor-ligand interaction with receptor antagonists. In this study, we describe a novel strategy to modulate the inflammatory process in vivo through mutation of the essential heparin-binding site of a proinflammatory chemokine, which abrogates the ability of the protein to form higher-order oligomers, but retains receptor activation. Using well-established protocols to induce inflammatory cell recruitment into the peritoneal cavity, bronchoalveolar air spaces, and CNS in mice, this non-GAG binding variant of RANTES/CCL5 designated [44AANA47]-RANTES demonstrated potent inhibitory capacity. Through a combination of techniques in vitro and in vivo, [44AANA47]-RANTES appears to act as a dominant-negative inhibitor for endogenous RANTES, thereby impairing cellular recruitment, not through a mechanism of desensitization. [44AANA47]-RANTES is unable to form higher-order oligomers (necessary for the biological activity of RANTES in vivo) and importantly forms nonfunctional heterodimers with the parent chemokine, RANTES. Therefore, although retaining receptor-binding capacity, altering the GAG-associated interactive site of a proinflammatory chemokine renders it a dominant-negative inhibitor, suggesting a powerful novel approach to generate disease-modifying anti-inflammatory reagents.