Characterization of perfluorocarbon relaxation times and their influence on the optimization of fluorine-19 MRI at 3 tesla.

PURPOSE: To characterize and optimize 19 F MRI for different perfluorocarbons (PFCs) at 3T and quantify the loss of acquisition efficiency as a function of different temperature and cellular conditions. METHODS: The T1 and T2 relaxation times of the commonly used PFCs perfluoropolyether (PFPE), perfluoro-15-crown-5-ether (PFCE), and perfluorooctyl bromide (PFOB) were measured in phantoms and in several different conditions (cell types, presence of fixation agent, and temperatures). These relaxation times were used to optimize pulse sequences through numerical simulations. The acquisition efficiency in each cellular condition was then determined as the ratio of the signal after optimization with the reference relaxation times and after optimization with its proper relaxation times. Finally, PFC detection limits were determined. RESULTS: The loss of acquisition efficiency due to parameter settings optimized for the wrong temperature and cellular condition was limited to 13%. The detection limits of all PFCs were lower at 24 °C than at 37 °C and varied from 11.8 ± 3.0 mM for PFCE at 24 °C to 379.9 ± 51.8 mM for PFOB at 37 °C. CONCLUSION: Optimizing 19 F pulse sequences with a known phantom only leads to moderate loss in acquisition efficiency in cellular conditions that might be encountered in in vivo and in vitro experiments. Magn Reson Med 77:2263-2271, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

CARMEN, a human super enhancer-associated long noncoding RNA controlling cardiac specification, differentiation and homeostasis.

Long noncoding RNAs (lncRNAs) are emerging as important regulators of developmental pathways. However, their roles in human cardiac precursor cell (CPC) remain unexplored. To characterize the long noncoding transcriptome during human CPC cardiac differentiation, we profiled the lncRNA transcriptome in CPCs isolated from the human fetal heart and identified 570 lncRNAs that were modulated during cardiac differentiation. Many of these were associated with active cardiac enhancer and super enhancers (SE) with their expression being correlated with proximal cardiac genes. One of the most upregulated lncRNAs was a SE-associated lncRNA that was named CARMEN, (CAR)diac (M)esoderm (E)nhancer-associated (N)oncoding RNA. CARMEN exhibits RNA-dependent enhancing activity and is upstream of the cardiac mesoderm-specifying gene regulatory network. Interestingly, CARMEN interacts with SUZ12 and EZH2, two components of the polycomb repressive complex 2 (PRC2). We demonstrate that CARMEN knockdown inhibits cardiac specification and differentiation in cardiac precursor cells independently of MIR-143 and -145 expression, two microRNAs located proximal to the enhancer sequences. Importantly, CARMEN expression was activated during pathological remodeling in the mouse and human hearts, and was necessary for maintaining cardiac identity in differentiated cardiomyocytes. This study demonstrates therefore that CARMEN is a crucial regulator of cardiac cell differentiation and homeostasis.

Fluorine MR Imaging of Inflammation in Atherosclerotic Plaque in Vivo.

PURPOSE: To preliminarily test the hypothesis that fluorine 19 ((19)F) magnetic resonance (MR) imaging enables the noninvasive in vivo identification of plaque inflammation in a mouse model of atherosclerosis, with histologic findings as the reference standard. MATERIALS AND METHODS: The animal studies were approved by the local animal ethics committee. Perfluorocarbon (PFC) emulsions were injected intravenously in a mouse model of atherosclerosis (n = 13), after which (19)F and anatomic MR imaging were performed at the level of the thoracic aorta and its branches at 9.4 T. Four of these animals were imaged repeatedly (at 2-14 days) to determine the optimal detection time. Repeated-measures analysis of variance with a Tukey test was applied to determine if there was a significant change in (19)F signal-to-noise ratio (SNR) of the plaques and liver between the time points. Six animals were injected with a PFC emulsion that also contained a fluorophore. As a control against false-positive results, wild-type mice (n = 3) were injected with a PFC emulsion, and atherosclerotic mice were injected with a saline solution (n = 2). The animals were sacrificed after the last MR imaging examination, after which high-spatial-resolution ex vivo MR imaging and bright-field and immunofluorescent histologic examination were performed. RESULTS: (19)F MR signal was detected in vivo in plaques in the aortic arch and its branches. The SNR was found to significantly increase up to day 6 (P < .001), and the SNR of all mice at this time point was 13.4 ± 3.3. The presence of PFC and plaque in the excised vessels was then confirmed both through ex vivo (19)F MR imaging and histologic examination, while no signal was detected in the control animals. Immunofluorescent histologic findings confirmed the presence of PFC in plaque macrophages. CONCLUSION: (19)F MR imaging allows the noninvasive in vivo detection of inflammation in atherosclerotic plaques in a mouse model of atherosclerosis and opens up new avenues for both the early detection of vulnerable atherosclerosis and the elucidation of inflammation mechanisms in atherosclerosis.

Functional importance of cardiac enhancer-associated noncoding RNAs in heart development and disease.

The key information processing units within gene regulatory networks are enhancers. Enhancer activity is associated with the production of tissue-specific noncoding RNAs, yet the existence of such transcripts during cardiac development has not been established. Using an integrated genomic approach, we demonstrate that fetal cardiac enhancers generate long noncoding RNAs (lncRNAs) during cardiac differentiation and morphogenesis. Enhancer expression correlates with the emergence of active enhancer chromatin states, the initiation of RNA polymerase II at enhancer loci and expression of target genes. Orthologous human sequences are also transcribed in fetal human hearts and cardiac progenitor cells. Through a systematic bioinformatic analysis, we identified and characterized, for the first time, a catalog of lncRNAs that are expressed during embryonic stem cell differentiation into cardiomyocytes and associated with active cardiac enhancer sequences. RNA-sequencing demonstrates that many of these transcripts are polyadenylated, multi-exonic long noncoding RNAs. Moreover, knockdown of two enhancer-associated lncRNAs resulted in the specific downregulation of their predicted target genes. Interestingly, the reactivation of the fetal gene program, a hallmark of the stress response in the adult heart, is accompanied by increased expression of fetal cardiac enhancer transcripts. Altogether, these findings demonstrate that the activity of cardiac enhancers and expression of their target genes are associated with the production of enhancer-derived lncRNAs.

Antibacterial role for natural killer cells in host defense to Bacillus anthracis.

Natural killer (NK) cells have innate antibacterial activity that could be targeted for clinical interventions for infectious disease caused by naturally occurring or weaponized bacterial pathogens. To determine a potential role for NK cells in immunity to Bacillus anthracis, we utilized primary human and murine NK cells, in vitro assays, and in vivo NK cell depletion in a murine model of inhalational anthrax. Our results demonstrate potent antibacterial activity by human NK cells against B. anthracis bacilli within infected autologous monocytes. Surprisingly, NK cells also mediate moderate antibacterial effects on extracellular vegetative bacilli but do not have activity against extracellular or intracellular spores. The immunosuppressive anthrax lethal toxin impairs NK gamma interferon (IFN-γ) expression, but neither lethal nor edema toxin significantly alters the viability or cytotoxic effector function of NK cells. Compared to human NK cells, murine NK cells have a similar, though less potent, activity against intracellular and extracellular B. anthracis. The in vivo depletion of murine NK cells does not alter animal survival following intranasal infection with B. anthracis spores in our studies but significantly increases the bacterial load in the blood of infected animals. Our studies demonstrate that NK cells participate in the innate immune response against B. anthracis and suggest that immune modulation to augment NK cell function in early stages of anthrax should be further explored in animal models as a clinical intervention strategy.

Progenitor cell therapy for heart disease.

Many cell types are currently being studied as potential sources of cardiomyocytes for cell transplantation therapy to repair and regenerate damaged myocardium. The question remains as to which progenitor cell represents the best candidate. Bone marrow-derived cells and endothelial progenitor cells have been tested in clinical studies. These cells are safe, but their cardiogenic potential is controversial. The functional benefits observed are probably due to enhanced angiogenesis, reduced ventricular remodeling, or to cytokine-mediated effects that promote the survival of endogenous cells. Human embryonic stem cells represent an unlimited source of cardiomyocytes due to their great differentiation potential, but each step of differentiation must be tightly controlled due to the high risk of teratoma formation. These cells, however, confront ethical barriers and there is a risk of graft rejection. These last two problems can be avoided by using induced pluripotent stem cells (iPS), which can be autologously derived, but the high risk of teratoma formation remains. Cardiac progenitor cells have the advantage of being cardiac committed, but important questions remain unanswered, such as what is the best marker to identify and isolate these cells? To date the different markers used to identify adult cardiac progenitor cells also recognize progenitor cells that are outside the heart. Thus, it cannot be determined whether the cardiac progenitor cells identified in the adult heart represent resident cells present since fetal life or extracardiac cells that colonized the heart after cardiac injury. Developmental studies have identified markers of multipotent progenitors, but it is unknown whether these markers are specific for adult progenitors when expressed in the adult myocardium. Cardiac regeneration is dependent on the stability of the cells transplanted into the host myocardium and on the electromechanical coupling with the endogenous cells. Finally, the promotion of endogenous regenerative processes by mobilizing endogenous progenitors represents a complementary approach to cell transplantation therapy.

Endophthalmitis after pars plana vitrectomy a 20- and 25-gauge comparison.

OBJECTIVE: Recent retrospective analyses have suggested that postoperative endophthalmitis may be more frequent with 25- than 20-gauge pars plana vitrectomy (PPV). Because the infection risk may depend on the suturing status of the sclerotomy, and the perioperative anti-infection protocol, we compared the incidence rate of endophthalmitis after sutureless 25-gauge versus sutured 20-gauge PPV on a large cohort of patients operated with a standardized perioperative anti-infection protocol. DESIGN: Retrospective comparative case series. PARTICIPANTS: Consecutive patients who underwent 20- or 25-gauge PPVs at a single center over a multi-year period. METHODS: We analyzed 3597 consecutive PPVs. Patients with a pre-PPV diagnosis of endophthalmitis, PPVs performed for implantation of drug delivery devices, or 25-gauge PPVs with all sclerotomies sutured closed were excluded. Patients with > or =1 week of follow-up were divided into 2 study groups by sclerotomy status at the end of surgery: the 20-gauge group had 3 sutured 20-gauge sclerotomies, and the 25-gauge group had > or =1 unsutured 25-gauge sclerotomy. Endophthalmitis was defined by clinical criteria independent of microbiological results. MAIN OUTCOME MEASURES: The incidence of endophthalmitis was compared between 25- versus 20-gauge groups. RESULTS: Of 3372 PPV surgeries meeting inclusion and exclusion criteria, 1948 and 1424 surgeries were 20- and 25-gauge PPVs, respectively. Average age (+/- standard deviation) of patients was 54.6 (+/- 22.6) and 64.4 (+/- 16.5) years in the 20- and 25-gauge PPV groups, respectively (P<0.0001). Median post-PPV follow-up time was not significantly different between the 2 groups (12.5 vs 13.0 months; P = 0.69). Endophthalmitis was observed in 1 patient (0.07%; 95% confidence interval, 0%-0.21%) from the 25-gauge group and none in the 20-gauge group (P = 0.42; Fisher exact test, 2-tailed). The use of air/gas endotamponade (P<0.0001) and intravitreal triamcinolone (P<0.001) was more common in 25- versus 20-gauge PPV. CONCLUSIONS: The incidence of endophthalmitis was low in both groups. We were unable to show a significant difference in the incidence of endophthalmitis between sutureless 25-gauge and sutured 20-gauge PPV, and conclude that a careful perioperative anti-infection protocol may reduce 25-gauge PPV endophthalmitis risk to that of 20-gauge PPV.

Submacular combination treatment for management of acute, massive submacular hemorrhage in age-related macular degeneration.

A surgical technique is described combining submacular anti-vascular endothelial growth factor (anti-VEGF) and recombinant tissue plasminogen activator (r-TPA) with pneumatic displacement of massive submacular hemorrhage in age-related macular degeneration. An 84-year-old man with a large, acute submacular hemorrhage secondary to age-related macular degeneration underwent combination vitrectomy, submacular anti-VEGF and r-TPA injection with pneumatic displacement of the hemorrhage. At the last follow-up visit, 7 months after surgery, visual acuity was 20/80 with a small fibrovascular pigment epithelial detachment and atrophic retinal pigment epithelial changes. A 77-year-old woman with known age-related macular degeneration underwent a similar surgical procedure for a similar acute, large submacular hemorrhage related to age-related macular degeneration. Nine months after surgery, the visual acuity was 20/70(-1). Combination submacular anti-VEGF therapy delivered at the time of pars plana vitrectomy and submacular tissue plasminogen activator assisted hemorrhage displacement may be a viable treatment strategy for the management massive submacular hemorrhage.

A Phase 1, Open-Label, Dose-Escalation Trial to Investigate Safety and Tolerability of Single Intravitreous Injections of ICON-1 Targeting Tissue Factor in Wet AMD.

BACKGROUND AND OBJECTIVE: This phase 1 study evaluated the safety and tolerability of single intravitreous injections (IVIs) of ICON-1 (Iconic Therapeutics, South San Francisco, CA) in patients with neovascular age-related macular degeneration (nAMD). ICON-1 is a modified factor VIIa protein linked with the Fc portion of a human immunoglobulin G1. The molecule binds tissue factor overexpressed on choroidal neovascularization (CNV) in AMD. PATIENTS AND METHODS: Open-label, interventional, dose-escalation trial in 18 patients with CNV due to AMD, with six patients per dose cohort. Patients received a single IVI of ICON-1 at baseline in one of three escalating doses: 60 µg, 150 µg, or 300 µg. Standard anti-vascular endothelial growth factor treatment was allowed at the investigator's discretion at least 2 weeks after the ICON-1 injection; patients were followed up to 24 weeks. Dose escalation was based on the absence of significant safety events. At each study visit, best-corrected visual acuity (BCVA), ophthalmic examination (intraocular pressure, slit-lamp, and dilated fundus examination), and ophthalmic imaging (color fundus photography, fluorescein angiography, and optical coherence tomography) assessments were performed. The systemic pharmacokinetics of ICON-1 and presence of anti-ICON-1 antibodies were also assessed. RESULTS: ICON-1 was safe and well-tolerated up to the highest dose administered, which was 300 µg. Commonly reported adverse events were considered related to the IVI procedure or to the underlying nAMD. No significant systemic levels of ICON-1 or anti-ICON-1 antibodies were detected. Preliminary evidence of biological activity (improved BCVA, reduced central retinal thickness, decreased CNV size, and leakage) was most evident with the 300 µg dose at 1 to 2 weeks after the single ICON-1 injection. CONCLUSION: Intravitreous administration of ICON-1 in single doses up to 300 µg in eyes with neovascular AMD was safe and well-tolerated. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:336-345.].

Familial exudative vitreoretinopathy and macular hole exhibited in same individual.

This observational case report is designed to report the first known occurrence of Familial Exudative Vitreoretinopathy (FEVR) and macular hole in the same individual. Clinical exams and fluorescein angiography were used to evaluate patient. Indirect laser panretinal photocoagulation was used to treat the right eye. A nine-year old male was diagnosed with familial exudative vitreoretinopathy in both eyes, as well as a full-thickness macular hole in his right eye. Medical histories indicated that the macular hole was not caused by trauma. Indirect laser panretinal photocoagulation was performed to treat an exudative process caused by FEVR in the right eye, and the exudative retinal detachment regressed. A vitrectomy was later also performed to treat traction retinal detachment as well as macular hole in the right eye. Our conclusion is that macular hole can be associated with familial exudative vitreoretinopathy.

Syphilitic scleritis and choroidal malignant melanoma of the same eye.

A 42-year-old Italian homosexual presented with a red painful eye associated with exudative retinal detachment that was subsequently attributed to syphilitic posterior scleritis. These findings all resolved with intravenous penicillin therapy. However, choroidal mass lesion persisted and subsequent ancillary imaging including B scan and ultrasonography confirmed the presence of a choroidal melanoma, which was treated with radioactive plaque therapy. This case report will describe the interesting findings of this unique presentation.

Suprachoroidal hemorrhage as an intraoperative complication of 25-gauge pars plana vitrectomy.

PURPOSE: To describe a case of suprachoroidal hemorrhage occurring during 25-gauge vitrectomy. METHODS: Retrospective case review. RESULTS: An 80-year old pseudophakic man developed intraoperative suprachoroidal hemorrhage during a vitreous biopsy procedure for chronic intraocular inflammation. Despite drainage of the choroidals, visual outcome was poor. CONCLUSIONS: 25-gauge vitrectomy is often referred to as a "less-invasive" procedure than 20-gauge vitrectomy, but it is not necessarily less risky and probably carries a similar risk profile.

Intravitreous vascular endothelial growth factor (VEGF) inhibitor therapy for tamoxifen induced macular edema.

A 59-year-old male patient with tamoxifen induced macular edema in both eyes was treated with intravitreous sodium pegaptanib. Follow-up clinical examination, OCT, and FA demonstrated reduced edema and leakage with improvement in visual acuity.

Changes in retinal neovascularization after pegaptanib (Macugen) therapy in diabetic individuals.

OBJECTIVE: To study effects of intravitreal pegaptanib (Macugen) on retinal neovascularization. DESIGN: Retrospective analysis of a randomized clinical trial. PARTICIPANTS, INTERVENTION, AND MAIN OUTCOME MEASURES: Individuals with retinal neovascularization identified from a multicenter, randomized, controlled trial evaluating pegaptanib for treatment of diabetic macular edema, with a best-corrected visual acuity letter score between 68 and 25 (approximate Snellen equivalent between 20/50 and 20/320) and receiving a sham injection or intravitreal pegaptanib (0.3 mg, 1 mg, 3 mg) administered at study entry, week 6, and week 12, with additional injections and/or focal photocoagulation as needed during the ensuing 18 weeks, up to a maximum of 6 pegaptanib/sham therapies, were evaluated. Scatter panretinal photocoagulation before study enrollment was permitted, but not within 6 months of randomization and study entry. Changes in retinal neovascularization were assessed on fundus photographs and fluorescein angiograms graded at a reading center in a masked fashion. RESULTS: Of 172 participants, 19 had retinal neovascularization in the study eye at baseline. Excluding 1 who had scatter photocoagulation 13 days before randomization and 2 with no follow-up photographs, 1 of the remaining 16 subjects had panretinal photocoagulation during study follow-up. Of these 16 subjects, 8 of 13 (62%) in a pegaptanib treatment group (including the one receiving panretinal photocoagulation), 0 of 3 in the sham group, and 0 of 4 fellow (nonstudy) eyes showed either regression of neovascularization on fundus photographs or regression or absence of fluorescein leakage from neovascularization (or both) at 36 weeks. In 3 of 8 with regression, neovascularization progressed at week 52 after cessation of pegaptanib at week 30. CONCLUSIONS: Most subjects with retinal neovascularization at baseline assigned to pegaptanib showed regression of neovascularization by week 36. These findings suggest a direct effect of pegaptanib upon retinal neovascularization in patients with diabetes mellitus.

Outcomes of vitrectomy with inferior retinectomy in patients with recurrent rhegmatogenous retinal detachments and proliferative vitreoretinopathy.

PURPOSE: To report the anatomic and functional outcomes of patients treated with vitrectomy and inferior retinectomy for recurrent, rhegmatogenous retinal detachment complicated by proliferative vitreoretinopathy (PVR). DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Fifty-six patients with recurrent, rhegmatogenous retinal detachments complicated by PVR who underwent an inferior retinectomy for repair. METHODS: Retrospective review over a 6-year period of patients treated with vitrectomy and inferior retinectomy. MAIN OUTCOME MEASURES: The primary outcome was anatomic success, defined as complete retinal reattachment. Secondary outcomes included change in visual acuity, the mean number of operations required for complete retinal reattachment, number of operations before retinectomy, use of silicone oil tamponade, location and extent of retinectomy, whether lensectomy was undertaken, and incidence of postoperative complications. RESULTS: Complete retinal reattachment was achieved in 52 of 56 patients (93%), with a mean follow-up of 25 months (range, 6-70 months). After retinal reattachment, visual acuity was improved or stabilized in 39 of 56 patients (70%). The mean number of operations for retinal detachment before diagnosis of PVR requiring retinectomy was 1.8 (range, 1-5). Patients undergoing radical anterior vitreous base dissection and lensectomy at the time of first retinectomy had a higher success rate than those who did not: 74% versus 38%, respectively (P = 0.011). Furthermore, tamponade with silicone oil had a higher success rate than tamponade with gas: 71% versus 18%, respectively (P = 0.002). Of the 56 patients, 9 (16%) had 1 or more of the following complications: keratopathy requiring penetrating keratoplasty (n = 4), glaucoma requiring aqueous shunt device (n = 3), and hypotony (n = 3). Silicone oil removal was performed in 26 of 45 patients (58%) before the last follow-up visit, with a 1 in 26 (4%) redetachment rate. CONCLUSIONS: When combined with anterior base dissection, inferior retinectomy may be useful in the surgical treatment of complex PVR-related retinal detachment. The authors show that with lensectomy, radical anterior base dissection, and inferior retinectomy, anatomic success rates are improved and visual function can be maintained. In addition, silicone oil offers an advantage over gas tamponade in these cases.

Severe steroid-induced glaucoma following intravitreal injection of triamcinolone acetonide.

PURPOSE: To report a case of severe corticosteroid-induced glaucoma after intravitreal injection of triamcinolone acetate in a 34-year-old man without a history of glaucoma. DESIGN: Observational case report. METHODS: Retrospective review of a clinical case. RESULTS: A 34-year-old man acquired visual field defects and severe vision loss in both eyes after intravitreal injection of triamcinolone for diabetic macular edema. CONCLUSIONS: Intravitreal injection of triamcinolone is a commonly performed treatment for many retinal conditions. This treatment has the potential to cause severe vision loss as a result of intractable corticosteroid-induced glaucoma.

Cardiomyocyte Lineage Specification in Adult Human Cardiac Precursor Cells Via Modulation of Enhancer-Associated Long Noncoding RNA Expression.

The mechanisms controlling differentiation in adult cardiac precursor cells (CPCs) are still largely unknown. In this study, CPCs isolated from the human heart were found to produce predominantly smooth muscle cells but could be redirected to the cardiomyocyte fate by transient activation followed by inhibition of NOTCH signaling. NOTCH inhibition repressed MIR-143/145 expression, and blocked smooth muscle differentiation. Expression of the microRNAs is under control of CARMEN, a long noncoding RNA associated with an enhancer located in the MIR-143/145 locus and target of NOTCH signaling. The CARMEN/MIR-145/143 axis represents, therefore, a promising target to favor production of cardiomyocytes in cell replacement therapies.

In-Vivo Detection and Tracking of T Cells in Various Organs in a Melanoma Tumor Model by 19F-Fluorine MRS/MRI.

BACKGROUND: 19F-MRI and 19F-MRS can identify specific cell types after in-vitro or in-vivo 19F-labeling. Knowledge on the potential to track in-vitro 19F-labeled immune cells in tumor models by 19F-MRI/MRS is scarce. AIM: To study 19F-based MR techniques for in-vivo tracking of adoptively transferred immune cells after in-vitro 19F-labeling, i.e. to detect and monitor their migration non-invasively in melanoma-bearing mice. METHODS: Splenocytes (SP) were labeled in-vitro with a perfluorocarbon (PFC) and IV-injected into non-tumor bearing mice. In-vitro PFC-labeled ovalbumin (OVA)-specific T cells from the T cell receptor-transgenic line OT-1, activated with anti-CD3 and anti-CD28 antibodies (Tact) or OVA-peptide pulsed antigen presenting cells (TOVA-act), were injected into B16 OVA melanoma-bearing mice. The distribution of the 19F-labelled donor cells was determined in-vivo by 19F-MRI/MRS. In-vivo 19F-MRI/MRS results were confirmed by ex-vivo 19F-NMR and flow cytometry. RESULTS: SP, Tact, and TOVA-act were successfully PFC-labeled in-vitro yielding 3x1011-1.4x1012 19F-atoms/cell in the 3 groups. Adoptively transferred 19F-labeled SP, TOVA-act, and Tact were detected by coil-localized 19F-MRS in the chest, abdomen, and left flank in most animals (corresponding to lungs, livers, and spleens, respectively, with highest signal-to-noise for SP vs TOVA-act and Tact, p<0.009 for both). SP and Tact were successfully imaged by 19F-MRI (n = 3; liver). These in-vivo data were confirmed by ex-vivo high-resolution 19F-NMR-spectroscopy. By flow cytometric analysis, however, TOVA-act tended to be more abundant versus SP and Tact (liver: p = 0.1313; lungs: p = 0.1073; spleen: p = 0.109). Unlike 19F-MRI/MRS, flow cytometry also identified transferred immune cells (SP, Tact, and TOVA-act) in the tumors. CONCLUSION: SP, Tact, and TOVA-act were successfully PFC-labeled in-vitro and detected in-vivo by non-invasive 19F-MRS/MRI in liver, lung, and spleen. The portion of 19F-labeled T cells in the adoptively transferred cell populations was insufficient for 19F-MRS/MRI detection in the tumor. While OVA-peptide-activated T cells (TOVA-act) showed highest infiltration into all organs, SP were detected more reliably by 19F-MRS/MRI, most likely explained by cell division of TOVA-act after injection, which dilutes the 19F content in the T cell-infiltrated organs. Non-dividing 19F-labeled cell species appear most promising to be tracked by 19F-MRS/MRI.

The neuropeptide Y Y1 receptor mediates NPY-induced inhibition of the gonadotrope axis under poor metabolic conditions.

Hypothalamic neuropeptide Y (NPY) plays a central role in the control of food intake, energy balance, and modulation of neuroendocrine functions. In particular, an increase in NPY expression participates in the inhibition of the reproductive activity under poor nutritional conditions. The present study was designed to evaluate further the involvement of the Y1 subtype of NPY receptors in these effects. Food intake, body weight gain, and the onset of puberty were studied in groups of wild-type and Y1 deficient mice that were either fed ad libitum or subjected to a 30% restriction in food intake. This moderate feeding restriction induced a similar deficit in body weight gain in wild-type and in Y1 knockout mice. However, although wild-type mice experienced the expected delay of puberty, all mice in the food restriction group and lacking Y1 could go through puberty over the time of the experiment despite decreases in circulating leptin levels and increases in hypothalamic NPY expression. This observation demonstrates that the absence of Y1 impairs the perception of decreasing energy stores by the gonadotrope axis, demonstrating a physiological role for Y1 in the sensing of endogenous metabolic parameters by the hypothalamus.

The neuropeptide Y Y1 receptor regulates leptin-mediated control of energy homeostasis and reproductive functions.

The orexigenic neurotransmitter neuropeptide Y (NPY) plays a central role in the hypothalamic control of food intake and energy balance. NPY also exerts an inhibition of the gonadotrope axis that could be important in the response to poor metabolic conditions. In contrast, leptin provides an anorexigenic signal to centrally control the body needs in energy. Moreover, leptin contributes to preserve adequate reproductive functions by stimulating the activity of the gonadotrope axis. It is of interest that hypothalamic NPY represents a primary target of leptin actions. To evaluate the importance of the NPY Y1 and Y5 receptors in the downstream pathways modulated by leptin and controlling energy metabolism as well as the activity of the gonadotrope axis, we studied the effects of leptin administration on food intake and reproductive functions in mice deficient for the expression of either the Y1 or the Y5 receptor. Furthermore, the role of the Y1 receptor in leptin resistance was determined in leptin-deficient ob/ob mice bearing a null mutation in the NPY Y1 locus. Results point to a crucial role for the NPY Y1 receptor in mediating the NPY pathways situated downstream of leptin actions and controlling food intake, the onset of puberty, and the maintenance of reproductive functions.