Amifostine analog, DRDE-30, alleviates radiation induced lung damage by attenuating inflammation and fibrosis

BACKGROUND

Radiotherapy of thoracic neoplasms and accidental radiation exposure often results in pneumonitis and fibrosis of lungs. Here, we investigated the potential of amifostine analogs: DRDE-07, DRDE-30, and DRDE-35, in alleviating radiation-induced lung damage.

METHODS

C57BL/6 mice were exposed to 13.5 Gy thoracic irradiation, 30 min after intraperitoneal administration of the analogs, and assessed for modulation of the pathological response at 12 and 24 weeks.

KEY FINDINGS

DRDE-07, DRDE-30 and DRDE-35 increased the survival of irradiated mice from 20% to 30%, 80% and 70% respectively. Reduced parenchymal opacity (X-ray CT) in the lungs of DRDE-30 pre-treated mice corroborated well with the significant decrease in Ashcroft score (p < 0.01). Two-fold increase in SOD and catalase activities (p < 0.05), coupled with a 50% increase in GSH content and a 60% decrease in MDA content (p < 0.05) suggested restoration of the antioxidant defence system. A 20% to 40% decrease in radiation-induced apoptotic and mitotic death in the lung tissue (micronuclei: p < 0.01), resulted in attenuated lung and vascular permeability (FITC-Dextran leakage) by 50% (p < 0.01), and a commensurate reduction (~50%) in leukocyte infiltration in the injured tissue (p < 0.05). DRDE-30 abrogated the activation of pro-inflammatory NF-κB and p38/MAPK signaling cascades, suppressing the release of pro-inflammatory cytokines (IL-1β: p < 0.05; TNF-α: p < 0.05; IL-6: p < 0.05) and up-regulation of CAMs on the endothelial cell surface. Reduction in hydroxyproline content (p < 0.01) and collagen suggested inhibition of lung fibrosis which was associated with attenuation of TGF-β/Smad pathway-mediated-EMT.

CONCLUSION

DRDE-30 could be a potential prophylactic agent against radiation-induced lung injury.

Quercetin: a savior of alveolar barrier integrity under hypoxic microenvironment

High altitude pulmonary edema (HAPE) is generally characterized by the loss of alveolar epithelial barrier integrity. The current study was undertaken to assess the noninvasive approaches of HAPE diagnosis and to evaluate the prophylactic potential of quercetin in preventing alveolar junction impairments. Male SD rats fed with quercetin 1 h prior to hypoxia (7,620 m, for 6 h) were selected. PET/CT imaging was performed to visualize the lung uptake of ¹⁸F-FDG in animals under hypoxia. Further, oxidant status, catalase activity, hematological & blood gas parameters were evaluated. Moreover, tight junction (TJ) proteins (ZO-1, JAM-C, Claudin-4, and occludin) expression analysis was accomplished using immune-blotting. The structural differences in lung epithelia were noted by TEM imaging. Quercetin prophylaxis has significantly reduced the FDG uptake in rat lungs under hypoxia. It has also dramatically alleviated the protein oxidation followed by an elevation in catalase activity in the lungs under hypoxia. The TJ protein expression in the lungs has also been restored to normal upon quercetin pre-treatment. Concomitantly, the quercetin preconditioning has elicited the stable blood gas and hematological parameters under hypoxia. The observations from TEM imaging have also implicated the normal lung epithelial structures in the quercetin pretreated animals under hypoxia. Quercetin prophylaxis has significantly restored alveolar epithelium integrity by abating oxidative stress in the lungs under hypoxia.Abbreviations: CT- Computed Tomography¹⁸F-FDG- Fluorodeoxyglucose (¹⁸FHAPE- High Altitude Pulmonary EdemaHb- HemoglobinHCT- HematocritHCO₃^- BicarbonateJAM- Junctional Adhesion MoleculeKBq- Killo BecquerelPaO₂- Partial pressure of arterial oxygenPaCO₂- Partial pressure of arterial carbon di-oxidePET- Positron Emission TomographyRBC- Red Blood CorpusclesSD- Sprague DawleyTJ- Tight JunctionsTEM- Transmission Electron MicroscopyWBC- White Blood CorpusclesZO- Zona Occludin.

Synthesis and biological evaluation of modified laminin peptide (N2S2-KDP) with enhanced affinity for neuronal growth and targeted molecular imaging (SPECT)

An analog of γ1 laminin (RDIAEIIKDI) decapeptide has been used to augment neuronal survival and regeneration after injuries, during aging and other CNS disorder. As a prime synthetic peptide, KDI, is responsible for the neurite outgrowth of human embryonic neurons. In this study, we have designed, modified a KDI derivative and synthesized by replacing isoleucine (I) with Pro (P) amino acid at C-terminal to enhance its potency towards neurite growth. -Cys-Gly-Cys (-CGC) N2S2 motif was also incorporated in the present design for peptide radiolabeling. The modified peptide showed a better binding with the desired 3T1M receptor for neurite growth. The peptide was synthesized using solid phase peptide synthesis and Fmoc-strategy with more than 80% yield. The receptor binding studies of 99mTc-N2S2-KDP in Neuro2A cell lines showed Kd value in 31 nM range and the complex showed appreciable brain uptake in mice. The results on human SH-SY5Y indicate that the unlabeled N2S2-KDP may perhaps be useful for neurite growth in neurodegenerative disorder.

The diagnostic performance of 99mTc-methionine single-photon emission tomography in grading glioma preoperatively: a comparison with histopathology and Ki-67 indices

OBJECTIVE

To characterize glioma preoperatively using quantitative 99mTc-methionine SPECT and comparison with MR-perfusion/spectroscopy and histopatholgical/Ki-67 scoring.

METHODS

Twenty-nine patients (21M: 8F; mean age 42.3 ± 10.5 years) with clinical and radiological suspicion of glioma assessed by 99mTc-MDM/SPECT and ceMRI. Additionally, 12/29 patients underwent dynamic susceptibility contrast-enhanced (DSCE) MRI and magnetic resonance spectroscopy (MRS) examination. Three patients with benign pathologies were recruited as controls. Histopathological tumor analysis was done in all (n = 29) the patients, and the Ki-67 index was evaluated in 20/29 patients. The target-to-nontarget (T/NT) methionine tumor uptake ratios, normalized cerebral blood volume (nCBV) and metabolites [choline/N-acetyl aspartate (Cho/NAA), Cho/creatine (Cr), Cr/NAA and Cr/Cho) ratios were measured in tumor areas.

RESULTS

On histopathological analysis, 26/29 patients had glioma (G IV-13; G III-04; G II-09). The mean T/NT ratio in G-II was significantly lower (2.46 ± 2.3) than in G-III (7.13 ± 2.2) and G-IV (5.16 ± 1.2). However, the mean ratio was highest (15.9 ± 6.8) in meningioma (n=3). The T/NT cutoff ratio of 3.08 provided 100% sensitivity, 87.5% specificity for discriminating high-grade glioma (HGG) from low-grade glioma (LGG) disease. Likewise, the nCBV cutoff of 2.43 offered 100% sensitivity and 80% specificity. Only the Cho/NAA cutoff value of greater than 3.34 provided reasonable sensitivity and specificity of 85.7% and 80.0% respectively for this differentiation. T/NT ratio correlated significantly with nCBV and Cho/NAA, Cho/Cr ratios but not with Ki-67.

CONCLUSION

Quantitative 99mTc-MDM -SPECT provided high sensitivity and specificity to differentiate HGG versus LGG preoperatively and demonstrated a potential role for the differential diagnosis of glial versus nonglial tumors.

[99mTc]-Bis-Methionine-DTPA Single-Photon Emission Computed Tomography Impacting Glioma Management: A Sensitive Indicator for Postsurgical/Chemoradiotherapy Response Assessment

Background: The present study evaluated the prognostic value of [^99mTc]MDM (bis-methionine-DTPA) follow-up single-photon emission computed tomography (SPECT) imaging for response assessment to chemoradiotherapy in glioma postoperatively. Materials and Methods: One hundred fourteen glioma patients (80 M:34 F) were followed postoperatively by sequential [^99mTc]MDM SPECT, dynamic susceptibility contrast-enhanced (DSCE)-MRI, and magnetic resonance spectroscopy (MRS) at baseline, 6, 12, and 22.5 months postchemoradiotherapy. The quantitative imaging results and the clinical outcome were used for response assessment and for the final diagnosis. The quantitative parameter of [^99mTc]MDM SPECT were also used for survival analysis. Results: A significantly (p = 0.001) lower target to nontarget (T/NT) ratio was observed in responders than in nonresponders. The sensitivity and specificity of [^99mTc]MDM-SPECT for identifying tumor recurrence from radiation necrosis at a cutoff ratio of 1.90 were estimated at 97.9% and 92%. Whereas, the sensitivity and specificity of DSCE-MRI with the normalized cerebral blood volume (nCBV) cutoff of 3.32 for this differentiation was found to be 84.6% and 93.0%. MRS intensity ratios of Cho/NAA and Cho/Cr provided comparatively lower sensitivity of 81.0% and 85.3% and specificity of 73.0% and 73.7%. T/NT ratios correlated with nCBV (r = 0.775, p < 0.001) and to a moderate extent with Cho/NAA ratios (r = 0.467, p = 0.001). [^99mTc]MDM SPECT and DSCE-MRI provided comparable results for predicting response assessment to chemoradiotherapy. There was a final diagnosis in 72 patients, of which 47 cases were tumor recurrence and 25 were radiation necrosis. The Kaplan-Meier analysis indicated that patients with T/NT ratio <1.9 showed prolonged survival (53.8 months) as compared (37.2 months) with those who demonstrated T/NT ratio >1.9 (p = 0.0001). Conclusion: Thus, this low-cost SPECT technique in combination with DSCE-MRI can be used accurately for mapping the disease activity, response assessment, and survival in glioma. [^99mTc]MDM SPECT and DSCE-MRI had the same diagnostic efficacy to detect recurrent/residual tumor and radiation necrosis while MRS was inferior to both the techniques.

Potential for differentiation of glioma recurrence from radionecrosis using integrated 18F-fluoroethyl-L-tyrosine (FET) positron emission tomography/magnetic resonance imaging: A prospective evaluation

PURPOSE

To assess the utility of 18F-fluoroethyl-L-tyrosine (FET) positron emission tomography/magnetic resonance imaging (PET/MRI) in distinguishing recurrence from radionecrosis.

MATERIALS AND METHODS

Thirty-two patients (25 males, 7 females) of glioma who had already undergone surgery/chemoradiotherapy and had enhancing brain lesions suspicious of recurrence were evaluated using integrated 18F-FET PET/MRI, and followed up with histopathology or clinical follow-up and/or MRI/PET/MRI imaging. Manually drawn regions of interest over areas of maximal enhancement or FET uptake were used to calculate tumor to background ratios [TBRmax, TBRmean], choline: creatine ratio [Cho: Cr ratio], normalized relative cerebral blood volume [N rCBVmean] and apparent diffusion coefficient [ADCmean]. Correlations were evaluated using Pearson's coefficient. Accuracy of each parameter was calculated using independent t-test and receiver operator curve (ROC) analysis while utility of all four parameters together using multivariate analysis of variance (MANOVA) for differentiating recurrence vs. radionecrosis was evaluated. Positive histopathology and imaging/clinical follow up served as the gold standard.

RESULTS

Twenty-four of the 32 patients were diagnosed with recurrent disease and 8 with radiation necrosis. Significant correlations were observed between TBRmaxand N rCBVmean (ρ =0.503; P = 0.003), TBRmean, and N rCBVmean (ρ =0.414; P = 0.018), TBRmaxand ADCmean (ρ = -0.52; P = 0.002), and TBRmeanand ADCmean(ρ = -0.518; P = 0.002). TBRmax, TBRmean, ADCmean, Cho: Cr ratios, and N rCBVmeanwere significant in differentiating recurrence from radiation necrosis with an accuracy of 94.1%, 88.2%, 80.4%, 96.4%, and 89.9%, respectively. MANOVA indicated that combination of all parameters demonstrated better evaluation of recurrence vs. necrosis than any single parameter. The diagnostic accuracy, sensitivity, and specificity using all MRI parameters were 93.75%, 96%, and 85.7%, and using all FET PET/MRI parameters was 96.87%, 100%, and 85.7%, respectively.

CONCLUSIONS

Synergetic effect of multiple MR parameters evaluated together in addition to FET PET uptake highlights the fact that integrated 18F-FET PET/MRI might have the potential to impact management of patients with glioma by timely and conclusive recognition of true recurrence from radiation necrosis.

Gemini Amphiphile-Based Lipoplexes for Efficient Gene Delivery: Synthesis, Formulation Development, Characterization, Gene Transfection, and Biodistribution Studies

Some quaternary gemini amphiphiles (GAs) were synthesized as nonviral gene delivery carriers. The critical miceller concentration values of these amphiphiles are indicative of their superior surface-active properties. All of the synthesized GAs, alone or along with lipids like cholesterol and/or dioleoylphosphatidyl ethanolamine (DOPE), were formulated as liposomes. Formulations of GAs with DOPE showed average particle diameters of 326-400 nm with positive ζ-potential (30.1-46.4 mV). The lipoplexes of theses formulations showed complete pDNA retention at the base at a N/P ratio higher than 1.0 in gel retardation study. The GAs were effective in condensing pDNA into a ψ-phase, as indicated by circular dichroism study, and provided complete protection of the pDNA against the enzyme DNase at a N/P ratio more than 1. In vitro cell line studies showed that GA liposomal formulations caused β-gal expression and offered a higher transfection efficiency than that of liposomes prepared with the help of N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate (DOTAP)/DOPE and dicyclocarbodiimide (DCC)/DOPE but comparable to those of Lipofectamine 2000 in A549 and HeLa cell lines. Modulation of head group polarity significantly affected the transfection efficacy of GAs. The cell viabilities of almost all of the formulations were comparable to those of the standards (DCC/DOPE and DOTAP/DOPE liposomes). Incorporation of cholesterol [GA/DOPE/cholesterol in the ratio of 1:1:1] further improved the serum compatibility of the formulations and improved the transfection efficacy when evaluated in A549 and HeLa cell lines. Fluorescence-assisted cell sorting studies showed comparable number of transfected cells to Lipofectamine 2000 in the HeLa cell line. Intracellular trafficking studies using confocal microscopy indicated transfection of the HeLa cells with the reporter gene within 30 min of lipoplex treatment. γ-Scintigraphy using ^99mTc-labeled lipoplexes showed higher concentrations of the lipoplexes in vital tissues like liver, spleen, lungs, and kidneys.

Amifostine Analog, DRDE-30, Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice

Bleomycin (BLM) is an effective curative option in the management of several malignancies including pleural effusions; but pulmonary toxicity, comprising of pneumonitis and fibrosis, poses challenge in its use as a front-line chemotherapeutic. Although Amifostine has been found to protect lungs from the toxic effects of radiation and BLM, its application is limited due to associated toxicity and unfavorable route of administration. Therefore, there is a need for selective, potent, and safe anti-fibrotic drugs. The current study was undertaken to assess the protective effects of DRDE-30, an analog of Amifostine, on BLM-induced lung injury in C57BL/6 mice. Whole body micro- computed tomography (CT) was used to non-invasively observe tissue damage, while broncheo-alveolar lavage fluid (BALF) and lung tissues were assessed for oxidative damage, inflammation and fibrosis. Changes in the lung density revealed by micro-CT suggested protection against BLM-induced lung injury by DRDE-30, which correlated well with changes in lung morphology and histopathology. DRDE-30 significantly blunted BLM-induced oxidative stress, inflammation and fibrosis in the lungs evidenced by reduced oxidative damage, endothelial barrier dysfunction, Myeloperoxidase (MPO) activity, pro-inflammatory cytokine release and protection of tissue architecture, that could be linked to enhanced anti-oxidant defense system and suppression of redox-sensitive pro-inflammatory signaling cascades. DRDE-30 decreased the BLM-induced augmentation in BALF TGF-β and lung hydroxyproline levels, as well as reduced the expression of the mesenchymal marker α-smooth muscle actin (α-SMA), suggesting the suppression of epithelial to mesenchymal transition (EMT) as one of its anti-fibrotic effects. The results demonstrate that the Amifostine analog, DRDE-30, ameliorates the oxidative injury and lung fibrosis induced by BLM and strengthen its potential use as an adjuvant in alleviating the side effects of BLM.

[68Ga]/[188Re] Complexed [CDTMP] Trans-1,2-Cyclohexyldinitrilotetraphosphonic Acid As a Theranostic Agent for Skeletal Metastases

Objective

Metastasis of the osseous tissue is one of the frequent and severe aggravations as a result of several neoplastic conditions, such as metabolic disorders, infections, and cancer. The objective of this study was to evaluate the pertinence of [⁶⁸Ga]-trans-1,2-cyclohexyldinitrilo tetramethylene phosphonic acid (CDTMP) as a potential bone imaging agent for positron emission tomography (PET) applications as well as to assess [¹⁸⁸Re]-CDTMP for bone pain palliation in metastatic skeletal disorders.

Methods

⁶⁸Ga complex of CDTMP was prepared at 80°C at pH 3.5, and ¹⁸⁸Re complex of CDTMP was prepared at room temperature. [⁶⁸Ga]-CDTMP complex was investigated as PET tracer while the therapeutic efficacy was assessed for [¹⁸⁸Re]-CDTMP. Labeling efficiency, biodistribution, myelotoxicity, and imaging studies were carried out for the complexes synthesized. Both PET and MicroPET imaging studies were performed for [⁶⁸Ga]-CDTMP whereas SPECT acquisitions were acquired for [¹⁸⁸Re]-CDTMP. Data were analyzed semiquantitatively for all the scintigraphic scans obtained.

Results

The radiolabeling efficiency was observed to be >70% for [⁶⁸Ga]-CDTMP. High bone uptake of [⁶⁸Ga]-CDTMP as compared to contralateral tissue was found in PET imaging in Balb/C mice and New Zealand rabbit; the similar result for bone uptake was correlated in the biodistribution study of the compound in BALB/c mice at different time intervals. Biodistribution experiments carried out in mice showed maximum uptake of 6.12 ± 1.22%ID/g at 45 min postinjection. For [¹⁸⁸Re]-CDTMP, total skeletal uptake was 8.12 ± 1.11%ID/g observed at 1 h postinjection from biodistribution data. High renal uptake confirms renal route of excretion. A good hydroxyapatite binding too was seen for both the complexes. No evidence of destruction or adverse functioning of vital organs was observed for the ¹⁸⁸Re complex.

Conclusion

[⁶⁸Ga]-CDTMP complex can be used as a promising PET bone imaging agent and [¹⁸⁸Re]-CDTMP as a surrogate moiety for therapeutic application. Owing to the short half-life of ⁶⁸Ga (68 min), cyclotron-independent radiopharmacy, fast clearance, and rapid renal excretion as evidenced in preclinical animal models. Very low myelotoxicity and highly selective bone uptake prove the potential of [¹⁸⁸Re]-CDTMP for therapeutic application.

Mapping neuroreceptors with metal-labeled radiopharmaceuticals

The growing epidemiological and economic burden of neurological diseases on society is tremendous. A correct and timely diagnosis can help in lowering the burden and improving the life quality of both the diseased person and the caretaker. Imaging of the brain (neuroimaging) using CT, MRI, and nuclear imaging methods can provide anatomical and functional information. Neuroreceptors are central to neurotransmission and neuromodulation in the CNS. In vivo imaging of receptors in the brain provides powerful tools for the functional study of the central nervous system (CNS) in normal or diseased states. Presently, PET imaging using non-metallic radiotracers dominates the imaging of neuroreceptors. Metal-based probes for SPECT and PET can be economical and logistically easier to use without compromising the information. This review focuses on the development of metallic radiotracers for (99mTc) SPECT and (68Ga) PET along with future directions based on the metallic probes developed for other imaging modalities namely MRI.

Evaluation of methionine and tryptophan derivatised vehicles: Met-ac-TE3A/Trp-ac-TE3A for tumor imaging

Two novel amino acid (methionine and tryptophan) appended 1,4,8,11-tetraazacyclotetradecane triacetate (TE3A) compounds Met-ac-TE3A and Trp-ac-TE3A were synthesized and evaluated for imaging applications.

(68)Ga-labeled bombesin analogs for receptor-mediated imaging

Targeted receptor-mediated imaging techniques have become crucial tools in present targeted diagnosis and radiotherapy as they provide accurate and specific diagnosis of disease information. Peptide-based pharmaceuticals are gaining popularity, and there has been vast interest in developing (68)Ga-labeled bombesin (Bn) analogs. The gastrin-releasing peptide (GRP) family and its Bn analog have been implicated in the biology of several human cancers. The three bombesin receptors GRP, NMB, and BRS-3 receptor are most frequently ectopically expressed by common, important malignancies. The low expression of Bn/GRP receptors in normal tissue and relatively high expression in a variety of human tumors can be of biological importance and form a molecular basis for Bn/GRP receptor-mediated imaging. To develop a Bn-like peptide with favorable tumor targeting and pharmacokinetic characteristics for possible clinical use, several modifications in the Bn-like peptides, such as the use of a variety of chelating agents, i.e., acyclic and macrocyclic agents with different spacer groups and with different metal ions (gallium), have been performed in recent years without significant disturbance of the vital binding scaffold. The favorable physical properties of (68)Ga, i.e., short half-life, and the fast localization of small peptides make this an ideal combination to study receptor-mediated imaging in patients.

Preliminary evaluation of technetium-99m-labeled ceftriaxone: infection imaging agent for the clinical diagnosis of orthopedic infection

OBJECTIVE

In this study we sought to assess the efficacy of a technetium-99m (Tc-99m)-labeled third-generation cephalosporin as an infection imaging agent in the accurate detection of the sites of bacterial infection in vivo.

DESIGN

Ceftriaxone (CRO) was formulated into a ready-to-use single-vial cold kit with a shelf-life of over 6 months and was successfully labeled with technetium. The radiolabeled drug, Tc-99m-CRO, was subjected to the following preclinical evaluations: radiochemical purity, in vitro and in vivo stability, bacterial binding assay, and pharmacokinetic studies in animals and in human patients.

RESULTS

The kit formulation exhibited excellent radiolabeling efficiency (∼99%) and high in vitro and in vivo stability. The radiolabeled drug exhibited slow blood clearance (12% at 4 h), and the high protein binding and excretion pattern of the labeled formulation mimics the reported pharmacokinetic profile of the drug alone. In the animal model, scintigraphy scans showed higher uptake of the radiopharmaceutical in infectious lesions, even at 1 h post-administration, in comparison to inflammatory lesions. The clinical evaluation of Tc-99m-labeled CRO showed a diagnostic accuracy of 83.3%, and a sensitivity and specificity of 85.2% and 77.8%, respectively.

CONCLUSIONS

This kit formulation has the potential for imaging bacterial infections with much higher sensitivity and specificity as compared to other Tc-99m-labeled antibiotics available as convenient ready-to-use kits in routine clinical practice.

Synthesis and evaluation of biodegradable PCL/PEG nanoparticles for neuroendocrine tumor targeted delivery of somatostatin analog

PURPOSE

Neuroendocrine tumors often present a diagnostic and therapeutic challenge. We have aimed to synthesize and develop biodegradable nanoparticles of somatostatin analogue, octreotide for targeted therapy of human neuroendocrine pancreatic tumor.

METHODS

Direct solid phase peptide synthesis of octreotide was done. Octreotide loaded PCL/PEG nanoparticles were prepared by solvent evaporation method and characterized for transmission electron microscopy, differential scanning calorimetery (DSC), Zeta potential measurement studies. The nanoparticles were evaluated in vitro for release studies and peptide content. For biological evaluations, receptor binding & cytotoxicity studies were done on BON-1 neuroendocrine tumor cell line. Biodistribution of radiolabeled peptide and nanoparticles, tumor regression studies were performed on tumor-bearing mouse models.

RESULTS

We have synthesized and purified octreotide with the purity of 99.96% in our laboratory. PEG/PCL nanoparticles with an average diameter of 130-195 nm having peptide loading efficiency of 66-84% with a negative surface charge were obtained with the formulation procedure. Octreotide nanoparticles have a negative action on the proliferation of BON-1 cells. In vivo biodistribution studies exhibited major accumulation of octreotide nanoparticles in tumor as compared to plain octreotide. Octreotide nanoparticles inhibited tumor growth more efficiently than free octreotide.

CONCLUSIONS

Thus, it was concluded that the PCL/PEG nanoformulation of octreotide showed high tumor uptake due to the enhanced permeation and retention (EPR) effect and then peptide ligand imparts targetability to the sst2 receptor and there by showing increase tumor growth inhibition. Selective entry of nanoparticles to the tumor also give the reduce side effects both in vivo and in vitro.