Promotion of ABCG2 gene expression by neolignans from Piper longum L.

We focused on Piper longum L., a herbal drug produced in Myanmar, which has a renoprotective effect. Thus, we attempted to isolate and identify compounds that enhance the expression of the ABCG2 gene from the aerial parts of the plant except for the fruit. Among the various P. longum extracts, we isolated and identified the components. Using Caco-2 cells, the hABCG2 mRNA expression-enhancing effects of the isolated compounds were compared with the positive reference compound (3-methylcholanthrene [3MC]) using real-time polymerase chain reaction. Six compounds were isolated and identified from the methanol extract of P. longum. Among the isolated compounds, licarin A and neopomatene had lower toxicity and higher hABCG2 mRNA expression-enhancing effects in Caco-2 cells. Suppression of hAhR expression by siRNA reduced the activity of licarin A and neopomatene, as well as the hAhR agonist 3MC, suggesting that these 2 compounds may act as hAhR agonists to promote hABCG2 expression.

Physiological effects of food ingredients on intestinal epithelial cell function.

Understanding the physiological effects of food ingredients on bodily functions is crucial for the development of foods for specified health use (FoSHU) and functional foods. To investigate this, intestinal epithelial cells (IECs) have been widely studied as they are most frequently exposed to the highest concentrations of food ingredients. Among the various functions of IECs, in this review, we have discussed glucose transporters and their involvement in preventing metabolic syndromes such as diabetes. Phytochemicals are also discussed, as they significantly inhibit glucose and fructose absorption via sodium-dependent glucose transporter 1 (SGLT1) and glucose transporter 5 (GLUT5), respectively. Additionally, we have focused on the barrier functions of IECs against xenobiotics. Phytochemicals induce detoxification of metabolizing enzymes via pregnane X receptor or aryl hydrocarbon receptor activation, which suggests that food ingredients can enhance barrier function. This review will provide insights into the role of food ingredients and glucose transporters, as well as detoxification metabolizing enzymes in IECs, and help guide future research on these aspects.

Phosphoglyceride Crystal Deposition Disease of the Scapula: A Case Report and Literature Review.

CASE: A 76-year-old woman presented with a 2-month history of right shoulder pain with no apparent cause. Radiography revealed an ill-defined osteolytic lesion in the right scapular spine with a pathological fracture. Malignant bone tumor was suspected, and a biopsy was performed. Pathological examination with gold hydroxamic acid staining revealed phosphoglyceride crystal deposition. Lesion curettage was performed, and her symptoms improved. No recurrence was observed at the 3-year postoperative follow-up. CONCLUSION: Phosphoglyceride crystal deposition in the bone is an extremely rare disease. The gold hydroxamic acid staining method might be useful for the diagnosis of this condition.

Chemogenetic Disconnection between the Orbitofrontal Cortex and the Rostromedial Caudate Nucleus Disrupts Motivational Control of Goal-Directed Action.

The orbitofrontal cortex (OFC) and its major downstream target within the basal ganglia-the rostromedial caudate nucleus (rmCD)-are involved in reward-value processing and goal-directed behavior. However, a causal contribution of the pathway linking these two structures to goal-directed behavior has not been established. Using the chemogenetic technology of designer receptors exclusively activated by designer drugs with a crossed inactivation design, we functionally and reversibly disrupted interactions between the OFC and rmCD in two male macaque monkeys. We injected an adeno-associated virus vector expressing an inhibitory designer receptor, hM4Di, into the OFC and contralateral rmCD, the expression of which was visualized in vivo by positron emission tomography and confirmed by postmortem immunohistochemistry. Functional disconnection of the OFC and rmCD resulted in a significant and reproducible loss of sensitivity to the cued reward value for goal-directed action. This decreased sensitivity was most prominent when monkeys had accumulated a certain amount of reward. These results provide causal evidence that the interaction between the OFC and the rmCD is needed for motivational control of action on the basis of the relative reward value and internal drive. This finding extends the current understanding of the physiological basis of psychiatric disorders in which goal-directed behavior is affected, such as obsessive-compulsive disorder.SIGNIFICANCE STATEMENT In daily life, we routinely adjust the speed and accuracy of our actions on the basis of the value of expected reward. Abnormalities in these kinds of motivational adjustments might be related to behaviors seen in psychiatric disorders such as obsessive-compulsive disorder. In the current study, we show that the connection from the orbitofrontal cortex to the rostromedial caudate nucleus is essential for motivational control of action in monkeys. This finding expands our knowledge about how the primate brain controls motivation and behavior and provides a particular insight into disorders like obsessive-compulsive disorder in which altered connectivity between the orbitofrontal cortex and the striatum has been implicated.

Risk factors for interstitial lung disease induced by gemcitabine plus albumin-bound paclitaxel therapy in pancreatic ductal adenocarcinoma patients.

BACKGROUND: Gemcitabine plus nab-paclitaxel (GnP) therapy is used for unresectable pancreatic ductal adenocarcinoma, but may cause interstitial lung disease (ILD) as a serious side effect. However, the risk factors for ILD in patients receiving GnP therapy are not well established. Here, we retrospectively investigated the incidence of GnP-induced ILD in pancreatic ductal adenocarcinoma patients, and the risk factors. METHODS: We investigated the patients' background, laboratory data, previous treatment history, concomitant medications, number of doses of GnP, cumulative dosage and administration period, and occurrence of side effects. RESULTS: Of the 105 patients included in this study, ILD occurred in 10 (9.5%). Patients with ILD had a significantly higher frequency of concomitant treatment with Kampo medicines, especially goshajinkigan, which is considered to help prevent chemotherapy-induced peripheral neuropathy (CIPN) (odds ratio: 11.5, 95% confidence interval: 2.67-49.38). No significant differences were observed in other clinical characteristics. Notably, the severity of CIPN in patients who used goshajinkigan for prevention was not significantly different from that in patients who did not use goshajinkigan in this study. CONCLUSIONS: These results suggest that administration of goshajinkigan to patients receiving GnP therapy for prevention of CIPN may need to be reconsidered.

Anatomical variability, multi-modal coordinate systems, and precision targeting in the marmoset brain.

Localising accurate brain regions needs careful evaluation in each experimental species due to their individual variability. However, the function and connectivity of brain areas is commonly studied using a single-subject cranial landmark-based stereotactic atlas in animal neuroscience. Here, we address this issue in a small primate, the common marmoset, which is increasingly widely used in systems neuroscience. We developed a non-invasive multi-modal neuroimaging-based targeting pipeline, which accounts for intersubject anatomical variability in cranial and cortical landmarks in marmosets. This methodology allowed creation of multi-modal templates (MarmosetRIKEN20) including head CT and brain MR images, embedded in coordinate systems of anterior and posterior commissures (AC-PC) and CIFTI grayordinates. We found that the horizontal plane of the stereotactic coordinate was significantly rotated in pitch relative to the AC-PC coordinate system (10 degrees, frontal downwards), and had a significant bias and uncertainty due to positioning procedures. We also found that many common cranial and brain landmarks (e.g., bregma, intraparietal sulcus) vary in location across subjects and are substantial relative to average marmoset cortical area dimensions. Combining the neuroimaging-based targeting pipeline with robot-guided surgery enabled proof-of-concept targeting of deep brain structures with an accuracy of 0.2 mm. Altogether, our findings demonstrate substantial intersubject variability in marmoset brain and cranial landmarks, implying that subject-specific neuroimaging-based localization is needed for precision targeting in marmosets. The population-based templates and atlases in grayordinates, created for the first time in marmoset monkeys, should help bridging between macroscale and microscale analyses.

Five-year outcomes after coronary artery bypass grafting and percutaneous coronary intervention in octogenarians with complex coronary artery disease.

OBJECTIVE: We assessed the clinical effectiveness of coronary artery bypass grafting (CABG) in comparison with that of percutaneous coronary intervention (PCI) in octogenarians with triple-vessel disease (TVD) or left main coronary artery (LMCA) disease. METHODS: From the CREDO-Kyoto registry cohort-2, 527 patients, who were ≥ 80 years of age and underwent the first coronary revascularization for TVD or LMCA disease, were divided into the CABG group (N = 151) and the PCI group (N = 376). RESULTS: The median and interquartile range of patient's age was 82 (81-84) in the CABG group and 83 (81-85) in the PCI group (P = 0.10). Patients > = 85 years of age accounted for 19% and 31% in the CABG and PCI groups, respectively (P = 0.01). The cumulative 5-year incidence of all-cause death was similar between CABG and PCI groups (35.8% vs. 42.9%, log-rank P = 0.18), while CABG showed a lower rate of the composite of cardiac death/MI than PCI (21.7% vs. 33.9%, log-rank P = 0.005). After adjusting for confounders, the lower risk of CABG relative to PCI was significant for all-cause death (HR 0.61, 95% CI 0.43-0.86, P = 0.005), any coronary revascularization (HR 0.25, 95% CI 0.14-0.43, P < 0.001) and the composite of cardiac death/MI (HR 0.52, 95% CI 0.32-0.85, P = 0.009). CONCLUSIONS: CABG compared with PCI was associated with a lower adjusted risk for all-cause death, any coronary revascularization, and a composite of cardiac death/MI in very elderly patients with TVD or LMCA disease. CABG seemed an acceptable option for selected octogenarians with severe coronary artery disease.

Surgical treatment for a pulmonary artery aneurysm with stenosis of the quadricuspid pulmonary valve.

We report a case of pulmonary artery aneurysm and pulmonary stenosis with a quadricuspid pulmonary valve in a 64-year-old woman. While pulmonary artery disease had been found as a child, she needed no treatment because of the absence of symptoms and her normal physical development. She began experiencing dyspnoea on exertion 3 years ago. Echocardiography showed pulmonary artery aneurysm and severe pulmonary stenosis with a quadricuspid valve. Computed tomography showed a pulmonary artery aneurysm extending from its main trunk to the bilateral branches. The pulmonary valve was replaced, and the pulmonary trunk and its bilateral branch were reconstructed. The patient's postoperative course was uneventful.

Cerebral blood flow and metabolism associated with cerebral microbleeds in small vessel disease.

OBJECTIVE: Cerebral microbleeds (CMBs), probably reflecting microangiopathy, have not yet sufficiently been examined in association with cerebral blood flow (CBF) and metabolism. We investigated the relationships between CMBs, and CBF and metabolism in symptomatic small vessel disease. METHODS: We enrolled 22 patients with symptomatic small vessel disease without severe stenosis (>50 %) in major cerebral arteries. Volumes of white matter lesions (WMLs) and number of CMBs were assessed on images of fluid-attenuated inversion recovery and gradient-echo T2*-weighted magnetic resonance imaging, respectively. Patients were divided into two groups according to the median number of CMBs (group I <5, n = 10; group II ≥5, n = 12). Parametric images of CBF, cerebral metabolic rate of oxygen (CMRO2), oxygen extraction fraction and cerebral blood volume were estimated using positron emission tomography and (15)O-labeled gases. The functional values in the cortex-subcortex, basal ganglia, and centrum semiovale were compared between the two groups. RESULTS: Volumes of WMLs of group II were larger than those of group I (median: 38.4; range: 25.1-91.5 mL vs. median: 11.3; range: 4.2-73.4 mL, p = 0.01). In the centrum semiovale, the mean CBF of group II was significantly lower than that of group I (12.6 ± 2.6 vs. 15.6 ± 3.3 mL/100 g/min, p = 0.04). In the other regions, there were no significant differences in either CBF or CMRO2 between the two groups. CONCLUSIONS: Our study indicated that increases in the number of CMBs with larger volumes of WMLs were associated with cerebral ischemia in the deep white matter in patients with symptomatic small vessel disease.

Sexual Differences in Chemical Composition and Aroma-active Compounds of Essential Oil from Flower Buds of Eurya japonica.

This study was conducted to determine the composition of essential oil from buds of male and female Eurya japonica flowers and to determine the aroma-active compounds of this plant by gas chromatography-mass spectrometry (GC-MS), sensory evaluation, and odor activity values (OAV). The oils contained eighty-five compounds. We identified for the first time forty-four compounds in E. japonica. Through sensory evaluation, nineteen aroma-active compounds were identified by gas chromatography-olfactometry (GC-O). Because the chemical composition can affect the interaction between plants and herbivorous insects, our results suggest that essential oils from male and female flower buds of E. japonica differently affect herbivores. Sexual differences in essential oils deserve further investigations in this plant-insect system.

Quantification of myocardial blood flow using (201)Tl SPECT and population-based input function.

OBJECTIVES: Thallium-201 ((201)Tl) single photon emission computed tomography (SPECT) is an important tool in the diagnosis of ischemic heart disease. Absolute quantification of myocardial blood flow (MBF) has the potential to provide more useful information on myocardial perfusion than semi-quantitative assessments. This study aimed to validate the quantification of MBF using (201)Tl cardiac SPECT based on a population-averaged input function (STD-IF) and one-point blood sample technique. METHODS: (201)Tl emission and computed tomography (CT)-based attenuation scans were performed on 11 healthy volunteers at rest using a SPECT/CT scanner. Individual input functions (IND-IFs) during the emission scans were based on arterial blood samples. The STD-IF technique was validated as follows: (1) optimal time to calibrate a STD-IF was determined to minimize differences between the calibrated STD-IF and the IND-IFs. (2) Tissue time-activity curves (TTACs) were generated based on a single-tissue compartment model for MBFtrue = 0.5, 1.0, 1.5, and 2.0 mL/min/g, a constant distribution volume of 45 mL/mL, and IND-IFs. The pseudo STD-IF for each subject was generated using the leave-one-out technique. Using the optimal calibration time and the pseudo STD-IFs, MBF values were estimated on the TTACs with an autoradiography method. Optimal mid-scan time (MST) with a fixed duration of 20 min was determined to minimize intersubject variation in estimated MBF errors, and (3) Global and regional MBF values estimated with pseudo STD-IFs were compared to those with IND-IFs using the optimal calibration time and MST. RESULTS: The optimal calibration time and MST were both 20 min after (201)Tl injection. Global MBF determined using both IND-IFs and pseudo STD-IF showed significant correlations with rate-pressure products, R (2) = 0.645; p < 0.01 and R (2) = 0.303; p < 0.05, respectively. The mean percent error in regional MBF using pseudo STD-IFs was 0.69 ± 7.80 % (-12.80 to 14.25 %). No significant difference was observed between regional MBF values using IND-IFs and pseudo STD-IFs. CONCLUSION: This study demonstrated that the proposed technique based on a STD-IF and one-point blood sample provided hemodynamically reasonable global MBF values and the regional MBF values comparable to those with IND-IFs.

[Aortic and mitral valve replacement via right thoracotomy in the case of a patient with severe heart failure following right pneumonectomy].

We report a case of aortic valve replacement (AVR) and mitral valve replacement (MVR) in a patient with severe left ventricular dysfunction who had undergone right pneumonectomy for lung cancer 14 years previously. A 64-year-old man had cathecolamine-dependent heart failure due to bicuspid aortic valve stenosis, functional mitral valve regurgitation and impaired left ventricular function (left ventricular ejection fraction 13%)because of dilated cardiomyopathy. AVR and MVR were performed using St. Jude Medical mechanical valves with right thoracotomy because the heart had shifted to the right side. Poor left ventricular function and postoperative atrial fibrillation made it difficult to control low-output syndrome, but prolonged use of intra-aortic balloon pumping improved it gradually. Intraaortic balloon pumping( IABP) was removed 34 days after the operation, the respirator was removed with tracheotomy 63 days postoperatively, and the patient was discharged on the 177th postoperative day. Careful preoperative assessment and perioperative control of heart failure are important components of successful clinical management.

[Total aortic arch replacement for severe atherosclerotic aortic aneurysms;consecutive 135 cases study].

OBJECTIVE: We study the validity of surgical procedure for total aortic arch replacement according to the atherosclerosis in the aortic arch. METHODS: From 2007 to June 2013, Consecutive 185 patients underwent total aortic arch replacement for thoracic aortic anuerysm. We studied 135 patients[96 males 72.1 year(38~89year)]except emergency operation. We assessed the atherosclerosis in the aortic arch by preoperative enhanced computed tomography (CT)scan and intraoperative epiaortic echocardiography. Based on the degree of atherosclerosis in the aortic arch, we divided into 2 groups:group 1(G1)included 97 patients with mild or moderate atherosclerosis and group 2 (G2) 38 patients with severe atherosclerosis. We used ascending aorta as arterial cannulation site in G1 and axillary artery with 8 mm graft in G2 .We compared with both groups for preoperative comorbidities and outcomes( mortality and stroke). RESULTS: Three patients died in the hospital (2%). In-hospital neurological events occurred in 12 patients, including major stroke in 4 patients, minor stroke in 4 patients and asymptomatic convulsion in 4 patients, although they were transient and clear before discharge except major stroke. There were no statistically significant differences in preoperative characteristics, cardiopulmonary bypass, brain protection, mortality, and neurological events between the 2 groups. There was a statistically difference in operation time( 388.8 minutes vs 448.5 minutes, p<0.01), intensive care unit( ICU) stay( 3.1 day vs 6.5 days, p<0.05) and hospital stay( 19.2 days vs 28.0 days, p<0.05). CONCLUSIONS: We selected surgical procedure for total aortic arch replacement (TAR) according to atherosclerosis in the aortic arch. Although the rate of stroke was largely acceptable, we much need to be improved in prevention of stroke.

Direct imaging of hyperpolarized 129Xe alveolar gas uptake in a mouse model of emphysema.

MRI of hyperpolarized (129)Xe dissolved in pulmonary tissues, and blood has the potential to offer a new tool for regional evaluation of pulmonary gas exchange and perfusion; however, the extremely short T2* and low magnetization density make it difficult to acquire the image. In this study, an ultrashort echo-time sequence was introduced, and its feasibility to quantitatively assess emphysema-like pulmonary tissue destruction by a combination of dissolved- and gas-phase (129)Xe lung MRI was investigated. The ultrashort echo-time has made it possible to acquire dissolved (129)Xe images with reasonably high spatial resolution of 0.625 × 0.625 mm(2) and to obtain T2* of 0.67 ± 0.30 ms in a spontaneously breathing mouse at 9.4 T. The regional dynamic alveolar gas uptake as well as subsequent transport by pulmonary blood flow was also visualized. The ratio of (129)Xe magnetization that diffused into the septa relative to the gas-phase magnetization F was regionally evaluated. The mean F value of elastase-treated mice was 2.28 ± 0.46%, which was significantly reduced from that of control mice 3.41 ± 0.48% (P = 0.0052). This reflects the reduced uptake efficiency due to alveolar tissue destruction and is correlated with the histologically derived alveolar surface-to-volume ratio.

Quantitative assessment of regional cerebral blood flow by dynamic susceptibility contrast-enhanced MRI, without the need for arterial blood signals.

In dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI), an arterial input function (AIF) is usually obtained from a time-concentration curve (TCC) of the cerebral artery. This study was aimed at developing an alternative technique for reconstructing AIF from TCCs of multiple brain regions. AIF was formulated by a multi-exponential function using four parameters, and the parameters were determined so that the AIF curves convolved with a model of tissue response reproduced the measured TCCs for 20 regions. Systematic simulations were performed to evaluate the effects of possible error sources. DSC-MRI and positron emission tomography (PET) studies were performed on 14 patients with major cerebral artery occlusion. Cerebral blood flow (CBF) images were calculated from DSC-MRI data, using our novel method alongside conventional AIF estimations, and compared with those from (15)O-PET. Simulations showed that the calculated CBF values were sensitive to variations in the assumptions regarding cerebral blood volume. Nevertheless, AIFs were reasonably reconstructed for all patients. The difference in CBF values between DSC-MRI and PET was -2.2 ± 7.4 ml/100 g/min (r = 0.55, p < 0.01) for our method, versus -0.2 ± 8.2 ml/100 g/min (r = 0.47, p = 0.01) for the conventional method. The difference in the ratio of affected to unaffected hemispheres between DSC-MRI and PET was 0.07 ± 0.09 (r = 0.82, p < 0.01) for our method, versus 0.07 ± 0.09 (r = 0.83, p < 0.01) for the conventional method. The contrasts in CBF images from our method were the same as those from the conventional method. These findings suggest the feasibility of assessing CBF without arterial blood signals.

Durability of aortic valve preservation with root reconstruction for acute type A aortic dissection.

OBJECTIVES: We evaluated the durability of aortic valve preservation with root reconstruction for acute type A aortic dissection (AAAD). METHODS: From January 2002 to March 2011, 140 patients [70 males, 68 ± 12 (SD) years] underwent emergency operation for AAAD. The aortic valve was preserved and one or more Valsalva sinuses were reconstructed. Techniques used for reconstruction were valve resuspension and additional reinforcement of the aortic root with Teflon felt patches, and gelatin-resorcinol-formaldehyde-glue (GRF-glue) was used for mending the dissection. The mean follow-up period was 44.0 ± 26.2 months. We classified the degree of aortic regurgitation (AR) into four grades (0, 1+, 2+ and 3+) using echocardiography. Based on a retrospective analysis of pre-operative echocardiographic findings, the 127 survivors were divided into two groups: group 1 (G1) included 98 patients with 0 or 1+ AR, and group 2 (G2) 29 patients with 2+ or 3+ AR. In addition, we measured the post-operative native aortic root dimension of AAAD patients with use of echocardiography or CT scan. RESULTS: The operative mortality rate was 9.3% (13/140). Freedom from aortic root re-operation was 100%. Aortic root pseudoaneurysm formation and severe AR requiring aortic valve replacement did not occur. Pre-operative AR of 0.2 ± 0.4 in G1 did not deteriorate (0.5 ± 0.5 at discharge, 0.4 ± 0.4 at follow-up). Meanwhile, pre-operative AR of 2.4 ± 0.5 in G2 improved to 0.6 ± 0.5 (P < 0.05) at discharge and 1.0 ± 0.6 (P < 0.05) at follow-up. The native aortic root dimension in G2 at follow-up was significantly larger than G1 (36.0 ± 4.7 vs. 33.9 ± 5.0 mm). CONCLUSIONS: Aortic valve preservation and root reconstruction appear to be an appropriate surgical approach to AAAD.

Engulfing tumors with synthetic extracellular matrices for cancer immunotherapy.

Local immunotherapies are under investigation for the treatment of unresectable tumors and sites of solid tumor resection to prevent local recurrence. Successful local therapy could also theoretically elicit systemic immune responses against cancer. Here we explored the delivery of therapeutic dendritic cells (DCs), cytokines, or other immunostimulatory factors to tumors via the use of 'self-gelling' hydrogels based on the polysaccharide alginate, injected peritumorally around established melanoma lesions. Peritumoral injection of alginate matrices loaded with DCs and/or an interleukin-15 superagonist (IL-15SA) around 14-day established ova-expressing B16F0 murine melanoma tumors promoted immune cell accumulation in the peritumoral matrix, and matrix infiltration correlated with tumor infiltration by leukocytes. Single injections of IL-15SA-carrying gels concentrated the cytokine in the tumor site approximately 40-fold compared to systemic injection and enabled a majority of treated animals to suppress tumor growth for a week or more. Further, we found that single injections of alginate matrices loaded with IL-15SA and the Toll-like receptor ligand CpG or two injections of gels carrying IL-15SA alone could elicit comparable anti-tumor activity without the need for exogenous DCs. Thus, injectable alginate gels offer an attractive platform for local tumor immunotherapy, and facilitate combinatorial treatments designed to promote immune responses locally at a tumor site while limiting systemic exposure to potent immunomodulatory factors.

Modular injectable matrices based on alginate solution/microsphere mixtures that gel in situ and co-deliver immunomodulatory factors.

Biocompatible polymer solutions that can crosslink in situ following injection to form stable hydrogels are of interest as depots for sustained delivery of therapeutic factors or cells, and as scaffolds for regenerative medicine. Here, injectable self-gelling alginate formulations obtained by mixing alginate microspheres (as calcium reservoirs) with soluble alginate solutions were characterized for potential use in immunotherapy. Rapid redistribution of calcium ions from microspheres into the surrounding alginate solution led to crosslinking and formation of stable hydrogels. The mechanical properties of the resulting gels correlated with the concentration of calcium-reservoir microspheres added to the solution. Soluble factors such as the cytokine interleukin-2 were readily incorporated into self-gelling alginate matrices by simply mixing them with the formulation prior to gelation. Using alginate microspheres as modular components, strategies for binding immunostimulatory CpG oligonucleotides onto the surface of microspheres were also demonstrated. When injected subcutaneously in the flanks of mice, self-gelling alginate formed soft macroporous gels supporting cellular infiltration and allowing ready access to microspheres carrying therapeutic factors embedded in the matrix. This in situ gelling formulation may thus be useful for stimulating immune cells at desired locales, such as solid tumors or infection sites, as well as for other soft tissue regeneration applications.

Injectable dendritic cell-carrying alginate gels for immunization and immunotherapy.

Dendritic cell vaccines, in which antigen-loaded dendritic cells (DCs) are injected directly into patients to trigger immune responses, are in development as a treatment for cancer and some infectious diseases. In this study, we tested the concept of delivering DCs in an injectable hydrogel matrix, with the aim of harboring dendritic cells for prolonged time periods at a defined site and trapping/concentrating factors secreted by DCs to establish an inflammatory milieu in situ. To achieve these goals, a self-gelling formulation of alginate was developed, obtained by mixing calcium-loaded alginate microspheres with soluble alginate solution and dendritic cells, a formulation that rapidly gelled in vivo. When injected subcutaneously in mice, these alginate 'vaccination nodes' containing activated DCs attracted both host dendritic cells and a large number of T cells to the injection sites over a week in vivo, while some of the inoculated DCs trafficked to the draining lymph nodes. Using an adoptive transfer model to track a defined population of T cells responding to immunization with antigen-loaded DCs, we show that DC/alginate immunization led to recruitment of activated antigen-specific T cells to the alginate matrix, in a manner dependent on the presence of the DCs. This gel/DC immunization system may thus be of interest for immunotherapy to direct the accumulation of immune cells at solid tumors or infection sites in the presence of supporting factors co-delivered by the hydrogel matrix.

Lymphoid tissue engineering: invoking lymphoid tissue neogenesis in immunotherapy and models of immunity.

The plasticity of the immune system is evident in the reorganization of secondary lymphoid organs during immune responses, lymphoid tissue neogenesis occurring during chronic inflammation or graft rejection, and the engineered lymphoid tissue formation induced by ectopic expression of single lymphoid tissue-associated genes. Approaches seeking to harness this plasticity for immunotherapy are under investigation, particularly by controlling immune cell recruitment and lymphoid tissue formation at tumor sites. By combining strategies from ectopic tissue induction models with methods from tissue engineering, new approaches for studying lymphoid tissue development and immunotherapy may be possible.