Characterization of a Par j 1/Par j 2 mutant hybrid with reduced allergenicity for immunotherapy of Parietaria allergy

BACKGROUND

Parietaria pollen is one of the major cause of pollinosis in the southern Europe. Specific immunotherapy is the only treatment able to modify the natural outcome of the disease restoring a normal immunity against allergens.

METHODS

We designed a recombinant molecule (PjEDloop1) comprised of genetic-engineered variants of the major allergens of the Parietaria pollen (Par j 2/Par j 1). Purity and chemical-physical properties of the derivative were analysed by RP-HPLC chromatography and Photon Correlation Spectroscopy. Immunological activity was evaluated by means of Western blotting, ELISA inhibition and PBMC proliferation assay in 10 Parietaria allergic patients. Basophil activation was studied in six subjects. The immunogenicity of the hybrid was studied looking at the immune responses induced in a mouse model of sensitization.

RESULTS

The PjEDloop1 hybrid was produced as a purified recombinant protein with high stability in solution. Western blot, ELISA inhibition and basophil activation test showed that the PjEDloop1 displays a remarkable reduced IgE binding and anaphylactic activity. CD3 reactivity was conserved in all patients. Mice immunization with the rPjEDloop1 induced antibodies and T cell responses comparable to that obtained by the wild type allergens. Such antibodies shared the specificities to rPar j 1 and rPar j 2 with human IgE antibodies.

CONCLUSION

Our results demonstrated that a mutant hybrid expressing genetically engineered forms of the major P. judaica allergens displayed reduced allergenicity and retained T cell reactivity for the induction of protective antibodies in vaccination approaches for the treatment of Parietaria pollinosis.

Complete pathologic response after combined-modality treatment for rectal cancer and long-term survivals: A meta-analysis

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Background: Recent literature suggests that a complete pathologic response (CPR) following neoadjuvant chemoradiotherapy (combined modality treatment, CMT) for rectal cancer is associated with improved survivals compared to partial or no response (NPR). However, previous reports have been limited by small sample size and single-institution design. To overcome these limitations, we performed a meta- analysis of studies evaluating the prognostic value of CPR.

Methods: A systematic literature review was conducted to detect studies comparing long-term results of patients with CPR or NPR after CMT for rectal cancer. Variables were pooled only if evaluated by 3 or more studies. Both qualitative and quantitative data were pooled using a random-effects model. Study endpoints included rates of complete pathological response, local recurrence (LR), distant recurrence (DR), as well as 5-year overall (OS) and disease-free survival (DFS).

Results: There were 13 studies suitable for the meta-analysis, that overall reported on outcomes of 2030 patient with rectal cancer treated with CMT. CPR was achieved in 332 patients (16.4%). CPR and NPR patients groups were similar with respect to age, male gender, tumor size, distance of tumor from the anus and pre- treatment stage (p > 0.3 for all comparisons). Median follow-up ranged from 23.5 to 46 months. CPR patients had lower rates of LR (0.7% vs. 2.6%; odds ratio [OR]=0.45, 95% CI 0.22–0.90), DR (5.3% vs. 24.1%; OR=0.15, 95% CI 0.07–0.31) and LR+DR (0.7% vs. 4.8%; OR=0.32, 95% CI 0.13–0.79). OS was 92.6% for CPR vs. 73.2% for NPR (OR=3.6, 95% CI 1.84–7.06), and DFS was 89.1% vs. 64.3% (OR=4.3, 95% CI 1.8-10.1).

Conclusions: Our meta-analysis confirms that a CPR following CMT for rectal cancer is associated with an improved local and distal control as well enhanced OS and DFS.

No significant financial relationships to disclose.

Outcomes associated with T4 esophageal cancer

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Background: Esophageal cancer often presents as locally advanced disease with 15% of patients having T4 tumors upon diagnosis. Esophagectomy was often reserved for palliation given the dismal survival rates and high rates of R1/R2 resections. However, neoadjuvant therapy (NT) has the potential to significantly downstage esophageal cancers and thus increase complete resection rates. We report our experience with surgically resected T4 cancers of the esophagus.

Methods: Using a comprehensive esophageal cancer database, we identified patients who underwent an esophagectomy for T4 tumors between 1994 and 2008. Neoadjuvant therapy and pathologic response were recorded and denoted as complete (pCR), partial (pPR), and non-response (NR). Clinical and pathologic data were compared using Fisher's exact and chi-square when appropriate while Kaplan Meier estimates were used for survival analysis.

Results: We identified 39 patients with T4 tumors who underwent esophagectomy of which 38 (97%) underwent NT. The median age was 61 (31-79) years with a median follow-up of 32 (5-97) months. There were 3 (7.9%) pCR, 17 (44.7%) pPR, and 18 (47.4%) NR. R0 resections were accomplished in 37 (94.9%). Two patients had incomplete resections. One patient had a R2 resection after NT and was deemed as NR. An additional patient had a R1 resection after NT and was a pPR with a residual 0.2 cm tumor on permanent pathology. There were 14 (35.9%) recurrences with a median time to recurrence of 19.5 (4-71) months. Complete pathologic response represented 1 (7.1%), whereas pPR and NR represented 6 (42.9%), and 7 (50%) respectively of all recurrences. The overall and disease free survival for all patients with T4 tumors was 28% and 34% respectively. Patients achieving a pCR had a 5-year overall and disease free survival of (43% and 47%), compared to pPR (30% and 21%) while there were no 5-year survivors in the NR cohort.

Conclusions: T4 esophageal cancer often portends a dismal prognosis even after surgical resection. Historical incomplete resections and dismal survival rates often make surgery palliative rather then curative. However, we have demonstrated that neoadjuvant therapy and down staging of T4 tumors leads to increased R0 resections and improvements in overall and disease free survival.

No significant financial relationships to disclose.

From surface to nuclear receptors: the endocannabinoid family extends its assets

Peroxisome proliferator-activated receptors (PPARs) have long been known as mediators of several physiological functions, among which the best characterized are lipid metabolism, energy balance and anti-inflammation. Their rather large and promiscuous ligand binding site has been recently discovered to accommodate, among a plethora of lipid molecules and metabolic intermediates, endocannabinoids and their cognate compounds, specifically belonging to the Nacylethanolamine group. In fact, oleoylethanolamide, palmitoylethanolamide and probably anandamide bind with relatively high affinity to PPARs and have now been included among their endogenous ligands. Through activation of PPARs these molecules exert a variety of physiological processes. Particularly, both long-term effects via genomic mechanisms and rapid non-genomic actions have been described, which in several instances are opposite to those evoked by activation of "classical" surface cannabinoid receptors. In this review, we describe how these effects are relevant under diverse physiological and pathophysiological circumstances, such as lipid metabolism and feeding behaviour, neuroprotection and epilepsy, circadian rhythms, addiction and cognition. A picture is emerging where nuclear receptors are involved in anorexiant, anti-inflammatory, neuroprotective, anti-epileptic, wakefulness- and cognitive-enhancing, and anti-addicting properties of endocannabinoid-like molecules. Further studies are necessary to fully understand cellular mechanisms underlying the interactions between endocannabinoids and PPARs, but also between their surface and nuclear receptors, and to exploit their potential therapeutic applications.

Endocannabinoid signaling in midbrain dopamine neurons: more than physiology?

Different classes of neurons in the CNS utilize endogenous cannabinoids as retrograde messengers to shape afferent activity in a short- and long-lasting fashion. Transient suppression of excitation and inhibition as well as long-term depression or potentiation in many brain regions require endocannabinoids to be released by the postsynaptic neurons and activate presynaptic CB1 receptors. Memory consolidation and/or extinction and habit forming have been suggested as the potential behavioral consequences of endocannabinoid-mediated synaptic modulation. HOWEVER, ENDOCANNABINOIDS HAVE A DUAL ROLE: beyond a physiological modulation of synaptic functions, they have been demonstrated to participate in the mechanisms of neuronal protection under circumstances involving excessive excitatory drive, glutamate excitotoxicity, hypoxia-ischemia, which are key features of several neurodegenerative disorders. In this framework, the recent discovery that the endocannabinoid 2-arachidonoyl-glycerol is released by midbrain dopaminergic neurons, under both physiological synaptic activity to modulate afferent inputs and pathological conditions such as ischemia, is particularly interesting for the possible implication of these molecules in brain functions and dysfunctions. Since dopamine dysfunctions underlie diverse neuropsychiatric disorders including schizophrenia, psychoses, and drug addiction, the importance of better understanding the correlation between an unbalanced endocannabinoid signal and the dopamine system is even greater. Additionally, we will review the evidence of the involvement of the endocannabinoid system in the pathogenesis of Parkinson's disease, where neuroprotective actions of cannabinoid-acting compounds may prove beneficial.The modulation of the endocannabinoid system by pharmacological agents is a valuable target in protection of dopamine neurons against functional abnormalities as well as against their neurodegeneration.

Biochemical, immunological and clinical characterization of a cross-reactive nonspecific lipid transfer protein 1 from mulberry

BACKGROUND

Mulberry (Morus spp.) is a genus comprising several species of deciduous trees whose fruits are commonly eaten in southern Europe. Subjects with severe systemic reaction have been described. The aim of this study was to isolate the allergens of this species.

METHODS

A nonspecific lipid transfer protein 1 (ns-LTP1) was purified from black mulberry by ion exchange and reverse phase high-performance liquid chromatography, and the primary structure was elucidated by direct protein sequencing. Its allergenic activity was evaluated in vivo by skin prick test and in vitro by Western Blot, CD203c basophil activation assay and high throughput multiplex inhibition method on immunosolid-phase allergen chip (ISAC).

RESULTS

Mulberry ns-LTP (Mor n 3) comprises 91 amino acids producing a molecular mass of 9246 Da. This protein shows high sequence identity with several allergenic ns-LTP1. Immunoblot analysis and CD203c activation assay demonstrated its allergenic activity in symptomatic subjects and in ns-LTP allergic patients who are not mulberry consumers. Immunological co-recognition was studied in vivo on a selected group of well-characterized ns-LTP allergic patients showing a high percentage of nMor n 3(+) subjects (88.46%) even in patients who have never eaten mulberry before. IgE inhibition on ISAC micro-array demonstrated an almost complete cross-reactivity to nArt v 3, rCor a 8 and a very high percentage of inhibition to nPru p 3.

CONCLUSIONS

Mor n 3 is the first allergen isolated in black mulberry and immunologically characterized. It displayed allergenic activity among symptomatic and nonconsumer patients and a pattern of cross-reactivity to other plant-derived LTPs.

Optimised labeling, preclinical and initial clinical aspects of CCK-2 receptor-targeting with 3 radiolabeled peptides

Medullary thyroid carcinoma (MTC) expresses CCK-2 receptors. (111)In-labeled DOTA-DGlu-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH(2) (DOTA-MG11), DOTA-DAsp-Tyr-Nle-Gly-Trp-Nle-Asp-Phe-NH(2) (DOTA-CCK), and (99m)Tc-labeled N(4)-Gly-DGlu-(Glu)(5)-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH(2) ((99m)Tc-Demogastrin 2) are analogs developed for CCK-2 receptor-targeted scintigraphy. All 3 radiolabeled analogs were selected on the basis of their high CCK-2 receptor affinity and their good in vitro serum stability, with in vitro serum t(1/2) values of several hours. Radiolabeling of DOTA-peptides with (111)In requires a heating procedure, typically in the range of 80 degrees -100 degrees C up to 30 min. Following this procedure with DOTA-MG11 resulted in a >98 % incorporation of (111)In, however, with a radiochemical purity (RCP) of <50 %. The decrease in RCP was found to be due to oxidation of the methionine residue in the molecule. Moreover, this oxidized compound lost its CCK-2 receptor affinity. Therefore, conditions during radiolabeling were optimised: labeling of DOTA-MG11 and DOTA-CCK with (111)In involved 5 min heating at 80 degrees C and led to an incorporation of (111)In of >98 %. In addition, all analogs were radiolabeled in the presence of quenchers to prevent radiolysis and oxidation resulting in a RCP of >90 %. All 3 radiolabeled analogs were i.v. administered to 6 MTC patients: radioactivity cleared rapidly by the kidneys, with no significant differences in the excretion pattern of the 3 radiotracers. All 3 radiolabeled analogs exhibited a low in vivo stability in patients, as revealed during analysis of blood samples, with the respective t(1/2) found in the order of minutes. In patient blood, the rank of radiopeptide in vivo stability was: (99m)Tc-Demogastrin 2 (t(1/2) 10-15 min)>(111)In-DOTA-CCK (t(1/2) approximately 5-10 min)>(111)In-DOTA-MG11 (t(1/2)<5 min).

Molecular Imaging and Magnetic Resonance Imaging in Early Diagnosis of Alzheimer's Disease

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is the most common cause of dementia in the elderly. Magnetic resonance (MR) or computed tomography (CT) imaging is recommended for routine evaluation of dementias. The development of molecular imaging agents and the new techniques of MR for AD are critically important for early diagnosis, neuropathogenesis studies and assessing treatment efficacy in AD. Neuroimaging using nuclear medicine techniques such as SPECT, PET and MR spectroscopy has the potential to characterize the biomarkers for Alzheimer's disease. The present review summarizes the results of radionuclide imaging and MR imaging in AD.

Acetaldehyde mediates alcohol activation of the mesolimbic dopamine system

Ethanol (EtOH), the main psychoactive ingredient of alcoholic drinks, is widely considered to be responsible for alcohol abuse and alcoholism through its positive motivational properties, which depend, at least partially, on the activation of the mesolimbic dopaminergic system. However, acetaldehyde (ACD), the first metabolite of EtOH, has been classically considered to be aversive and useful in the pharmacological therapy of alcoholics. Here we show that EtOH-derived ACD is necessary for EtOH-induced place preference, a pre-clinical test with high predictive validity for reward liability. We also found that ACD is essential for EtOH-increased microdialysate dopamine (DA) levels in the rat nucleus accumbens and that this effect is mimicked by intra-ventral tegmental area (VTA) ACD administration. Furthermore, in vitro, ACD enhances VTA DA neuronal firing through action on two ionic currents: reduction of the A-type K+ current and activation of the hyperpolarization-activated inward current. EtOH-stimulating properties on DA neurons are prevented by pharmacological blockade of local catalase, the main metabolic step for biotransformation of EtOH into ACD in the central nervous system. These results provide in-vivo and in-vitro evidence for a key role of ACD in the motivational properties of EtOH and its activation of the mesolimbic DA system. Additionally, these observations suggest that ACD, by increasing VTA DA neuronal activity, would oppose its well-known peripherally originating aversive properties. Careful consideration of these findings could help in devising new effective pharmacological therapies aimed at reducing EtOH intake in alcoholics.

Sixty-four-section CT cerebral perfusion evaluation in patients with carotid artery stenosis before and after stenting with a cerebral protection device

BACKGROUND AND PURPOSE

Brain tissue viability depends on cerebral blood flow (CBF) that has to be kept within a narrow range to avoid the risk of developing ischemia. The aim of the study was to evaluate by 64-section CT (VCT) the cerebral perfusion modifications in patients with severe carotid stenosis before and after undergoing carotid artery stent placement (CAS) with a cerebral protection system.

MATERIALS AND METHODS

Fifteen patients with unilateral internal carotid stenosis (>or=70%) underwent brain perfusional VCT (PVCT) 5 days before and 1 week after the stent-placement procedure. CBF and mean transit time (MTT) values were measured.

RESULTS

Decreased CBF and increased MTT values were observed in the cerebral areas supplied by the stenotic artery as compared with the areas supplied by the contralateral patent artery (P < .001). A significant normalization of the perfusion parameters was observed after the stent-placement procedure (mean pretreatment MTT value, 5.3 +/- 0.2; mean posttreatment MTT value, 4.3 +/- 0.18, P < .001; mean pretreatment CBF value, 41.2 mL/s +/- 2.1; mean posttreatment CBF value, 47.9 mL/s +/- 2.9, P < .001).

CONCLUSIONS

PVCT is a useful technique for the assessment of the hemodynamic modifications in patients with severe carotid stenosis. The quantitative evaluation of cerebral perfusion makes it a reliable tool for the follow-up of patients who undergo CAS.

Up-regulation of somatostatin receptor density on rat CA20948 tumors escaped from low dose [177Lu-DOTA0,Tyr3]octreotate therapy

AIM

Peptide receptor radionuclide therapy using the somatostatin analogue [(177)Lu-DOTA(0),Tyr(3)]octreotate is a convincing treatment modality for metastasized neuroendocrine tumors. Therapeutic doses are administered in 4 cycles with 6-10 week intervals. A high somatostatin receptor density on tumor cells is a prerequisite at every administration to enable effective therapy. In this study, the density of the somatostatin receptor subtype 2 (sst2) was investigated in the rat CA20948 pancreatic tumor model after low dose [(177)Lu-DOTA(0), Tyr(3)]octreotate administration resulting in approximately 20 Gy tumor radiation absorbed dose, whereas 60 Gy is needed to induce complete tumor regression in these and the majority of tumors.

METHODS

Sixteen days after inoculation of the CA20948 tumor, male Lewis rats were injected with 185 MBq [(177)Lu-DOTA(0),Tyr(3)]octreotate to initiate a decline in tumor size. Approximately 40 days after injection, tumors re-grew progressively after initial response. Quantification of sst2 expression was performed using in vitro autoradiography on frozen sections of three groups: control (not-treated) tumors, tumors in regression and tumors in re-growth. Histology and proliferation were determined using HE- and anti-Ki-67-staining.

RESULTS

The sst2 expression on CA20948 tumor cells decreased significantly after therapy to 5% of control level. However, tumors escaping from therapy showed an up-regulated sst2 level of 2-5 times higher sst2 density compared to control tumors.

CONCLUSION

After a suboptimal therapeutic dose of [(177)Lu-DOTA(0),Tyr(3)]octreotate, escape of tumors is likely to occur. Since these cells show an up-regulated sst2 receptor density, a next therapeutic administration of radiolabelled sst2 analogue can be expected to be highly effective.

Five-year follow-up of temporomandibular disorders and other musculoskeletal symptoms in dental students

AIM

The aim of this epidemiologic study was to evaluate the intensity and variation of temporomandibular disorders and other musculoskeletal symptoms in a population of dental students during the five years of Dental School.

METHODS

A 0-to-3 numeric scale questionnaire (0=absence of the symptom, 1=mild intensity, 2=moderate intensity, 3=severe intensity) was submitted to all the students enrolled in the first year of the Dental School at the University of Saint Joseph (Beirut, Lebanon). The same questionnaire was filled out by the same students every year until they reached the fifth (last) year.

RESULTS

Temporomandibular disorders and musculoskeletal symptoms were generally of mild intensity and fluctuating in time. No significant differences were found among years in the intensity of earache, headache, face pain, arm symptoms, neck pain, and toothache. Ear stuffiness decreased from the first to the third and fifth year. Temporomandibular joint pain, temporomandibular joint sounds, upper back pain, and lower back pain showed a similar trend generally increasing from the first and second years to the third year, and then decreasing until the fourth and fifth years.

CONCLUSION

A higher risk of developing such symptoms associated with dental work in the laboratory can be hypothesized in case of improper ergonomics.

Localization of MTT formazan in lipid droplets. An alternative hypothesis about the nature of formazan granules and aggregates

MTT (3-(4, 5-dimethyl-2-thiazolyl)-2, 5-dihphenyltetrazolium bromide) assay is a widely used method to assess cell viability and proliferation. MTT is readily taken up by cells and enzymatically reduced to formazan, a dark compound which accumulates in cytoplasmic granules. Formazan is later eliminated by the cell by a mechanisms often indicated as exocytosis, that produces characteristic needle-like aggregates on the cell surface. The shape of formazan aggregates and the rate of exocytosis change in the presence of bioactive amyloid beta peptides (Abeta) and cholesterol. Though the cellular mechanisms involved in MTT reduction have been extensively investigated, the exact nature of formazan granules and the process of exocytosis are still obscure. Using Nile Red, which stains differentially neutral and polar lipids, and a fluorescent analog of cholesterol (NBD-cholesterol), we found that formazan localized in lipid droplets, consistent with the lipophilic nature of formazan. However, formazan granules and aggregates were also found to form after killing cells with paraformaldehyde fixation. Moreover, formazan aggregates were also obtained in cell-free media, using ascorbic acid to reduce MTT. The density and shape of formazan aggregates obtained in cell-free media was sensitive to cholesterol and Abeta. In cells, electron microscopy failed to detect the presence of secretory vesicles, but revealed unusual fibers of 50 nm of diameter extending throughout the cytoplasm. Taken together, these findings suggest that formazan efflux is driven by physico-chemical interactions at molecular level without involving higher cytological mechanisms.

A hybrid expressing genetically engineered major allergens of the Parietaria pollen as a tool for specific allergy vaccination

BACKGROUND

Allergy is an immunological disorder affecting about 25% of the population living in the industrialized countries. Specific immunotherapy is the only treatment with a long-lasting relief of allergic symptoms and able to reduce the risk of developing new allergic sensitizations and inhibiting the development of clinical asthma in children treated for allergic rhinitis.

METHODS

By means of DNA recombinant technology, we were able to design a head to tail dimer expressing disulphide bond variants of the major allergen of the Parietaria pollen. IgE binding activity was studied by Western blot, ELISA inhibition assays and the skin prick test. T cell recognition was studied by peripheral blood mononuclear cell proliferation. The immunogenicity of the hybrid was studied in a mouse model of sensitization.

RESULTS

In vitro and in vivo analysis showed that the disruption of specific cysteine residues in both allergens caused a strong reduction in IgE binding activity of the PjEDcys hybrid. In addition,we were able to show that a reduction in the IgE epitope content profoundly reduced the anaphylactic activity of the hybrid (from 100 to 1,000 times less than wild-type allergens) without interfering with the T cell recognition. Sera from BALB/c mice immunized with the hybrid were able to bind the natural Parietaria allergens and to inhibit the binding of human IgE to wild-type Par j 1 and Par j 2 allergens up to 90%.

CONCLUSION

Our results demonstrate that hybrid-expressing disulphide bond variants of the major allergens of the Parietaria pollen displayed reduced allergenicity and maintained T cell reactivity for induction of protective antibodies.