Localization of tissue transglutaminase in human carotid and coronary artery atherosclerosis: implications for plaque stability and progression

Although atherosclerosis progresses in an indolent state for decades, the rupture of plaques creates acute ischemic syndromes that may culminate in myocardial infarction and stroke. Mechanical forces and matrix metalloproteinase activity initiate plaque rupture, whereas tissue inhibitors of metalloproteinases have an important (albeit indirect) role in plaque stabilization. In this paper, an enzyme that could directly stabilize the plaque is described. Tissue transglutaminase (TG) catalyzes the formation of epsilon(gamma-glutamyl)lysine isopeptide bonds that are resistant to enzymatic, mechanical, and chemical degradation. We performed immunohistochemistry for TG in atherosclerotic human coronary and carotid arteries. TG was most prominent along the luminal endothelium and in the medium of the vessels with a distribution mirroring that of smooth muscle cells. Variable, often prominent, immunoreactivity for TG was also seen in the intima, especially in regions with significant neovascularization. Additionally, TG was detected in fibrous caps and near the "shoulder regions" of some plaques. A monoclonal antibody to the transglutaminase product epsilon(gamma-glutamyl)lysine isopeptide demonstrated co-localization with TG antigen. Transglutaminase activity was found in 6 of 14 coronary artery atherectomy samples. Cross-linking of TG substrates such as fibrinogen, fibronectin, vitronectin, collagen type I, and protease inhibitors stabilized the plaque. Furthermore, the activation of transforming growth factor-beta-1 by TG might be an additional mechanism for the promotion of plaque stabilization and progression by increasing the synthesis of extracellular matrix components.     

Enolase 1 of Candida albicans binds human CD4+ T cells and modulates naïve and memory responses

To obtain a better understanding of the biology behind life-threatening fungal infections caused by Candida albicans, we recently conducted an in silico screening for fungal and host protein interaction partners. We report here that the extracellular domain of human CD4 binds to the moonlighting protein enolase 1 (Eno1) of C. albicans as predicted bioinformatically. By using different anti-CD4 monoclonal antibodies, we determined that C. albicans Eno1 (CaEno1) primarily binds to the extracellular domain 3 of CD4. Functionally, we observed that CaEno1 binding to CD4 activated lymphocyte-specific protein tyrosine kinase (LCK), which was also the case for anti-CD4 monoclonal antibodies tested in parallel. CaEno1 binding to naïve human CD4⁺ T cells skewed cytokine secretion toward a Th2 profile indicative of poor fungal control. Moreover, CaEno1 inhibited human memory CD4⁺ T-cell recall responses. Therapeutically, CD4⁺ T cells transduced with a p41/Crf1-specific T-cell receptor developed for adoptive T-cell therapy were not inhibited by CaEno1 in vitro. Together, the interaction of human CD4⁺ T cells with CaEno1 modulated host CD4⁺ T-cell responses in favor of the fungus. Thus, CaEno1 mediates not only immune evasion through its interference with complement regulators but also through the direct modulation of CD4⁺ T-cell responses.     

Erythropoietin and erythropoietin receptor expression in head and neck cancer: relationship to tumor hypoxia.

PURPOSE: Erythropoietin, an oxygen-regulated glycoprotein hormone, is a hematopoietic cytokine that stimulates erythropoiesis by binding to its cellular receptor [erythropoietin receptor (EPOR)]. The recombinant form of human erythropoietin is used to prevent or treat anemia in cancer patients. However, in a recent randomized, placebo-controlled trial involving patients receiving curative radiotherapy for squamous cell carcinoma of the head and neck, erythropoietin treatment was associated with poorer locoregional progression-free survival. The purpose of our study was to determine whether EPOR and its ligand erythropoietin are expressed in primary head and neck cancer. We also investigated the hypothesis that erythropoietin expression in malignant cells may be associated with the presence of tumor hypoxia, an important factor involved in resistance to radiation treatment, tumor aggressiveness, and poor prognosis. EXPERIMENTAL DESIGN: Twenty-one patients received an i.v. infusion of the hypoxia marker pimonidazole hydrochloride before multiple tumor biopsies. Contiguous sections from 74 biopsies were analyzed by immunohistochemistry for EPOR and erythropoietin expression and pimonidazole binding. RESULTS: EPOR expression was present in tumor cells in 97% of the biopsies. Coexpression of erythropoietin was observed in 90% of biopsies. Erythropoietin and pimonidazole adduct staining did not always colocalize within tumors, but there was a significant positive correlation between levels of microregional erythropoietin expression and pimonidazole binding. CONCLUSIONS: The coexpression of erythropoietin and EPOR in tumor cells suggests that erythropoietin may potentially function as an autocrine or paracrine factor in head and neck cancer. The expression of the hypoxia-inducible protein erythropoietin in tumor cells correlates with levels of tumor hypoxia.     

Development and Characterizations of Pullulan and Maltodextrin-Based Oral Fast-Dissolving Films Employing a Box–Behnken Experimental Design

Migraine is a neurological disorder characterized by severe headaches, visual aversions, auditory, and olfactory disorders, accompanied by nausea and vomiting. Zolmitriptan (ZMT^®) is a potent 5HT1B/1D serotonin receptor agonist frequently used for the treatment of migraine. It has erratic absorption from the gastrointestinal tract (GIT), but its oral bioavailability is low (40–45%) due to the hepatic metabolism. This makes it an ideal candidate for oral fast dissolving formulations. Hence, the current study was undertaken to design and develop oral fast-dissolving films (OFDFs) containing ZMT for migraine treatment. The OFDFs were formulated by the solvent casting method (SCM) using Pullulan (PU) and maltodextrin (MDX) as film-forming agents and propylene glycol (PG) as a plasticizer. The strategy was designed using Box–Behnken experimental design considering the proportion of PU:MDX and percentage of PG as independent variables. The effectiveness of the OFDF’s was measured based on the following responses: drug release at five min, disintegration time (D-time), and tensile strength (TS). The influence of formulation factors, including percent elongation (%E), thickness, water content, moisture absorption, and folding endurance on ZMT-OFDFs, were also studied. The results showed a successful fabrication of stable ZMT-OFDFs, with surface uniformity and amorphous shape of ZMT in fabricated films. The optimized formulation showed a remarkable rapid dissolution, over 90% within the first 5 min, a fast D-time of 18 s, and excellent mechanical characteristics. Improved maximum plasma concentration (C max) and area under the curve (AUC 0–t) in animals (rats) treated with ZMT-OFDFs compared to those treated with an intra-gastric (i-g) suspension of ZMT were also observed. Copolymer OFDFs with ZMT is an exciting proposition with great potential for the treatment of migraine headache. This study offers a promising strategy for developing ZMT-OFDFs using SCM. ZMT-OFDFs showed remarkable rapid dissolution and fast D-time, which might endeavor ZMT-OFDFs as an auspicious alternative approach to improve patient compliance and shorten the onset time of ZMT in migraine treatment.     

Mixed germ cell tumor of the pineal gland in a pediatric patient

Tumors of the pineal region are a rare clinical entity, comprising approximately 3%-8% of pediatric tumors. Based on their histopathological features, they are typically classified as pineal parenchymal tumors and germ cell tumors, with the latter being more prevalent. Clinical presentation is heterogeneous, with symptoms arising either due to tumor invasion or compression of adjacent neurovascular structures and increased intracranial pressure. Imaging studies are paramount in evaluating pineal region lesions and establishing an accurate diagnosis, with MRI representing the gold standard. Herein, we present the case of a 16-year-old boy presented with recurrent headaches. A head MRI revealed a pineal gland lesion. Histopathological examination confirmed the diagnosis, and the patient underwent a successful gross total resection (GTR) of the tumor. This case report seeks to draw attention to the elusive clinical presentation and management of this infrequently encountered tumor, as well as emphasize the importance of considering pineal gland tumors in the differential diagnosis of recurrent, chronic headaches in pediatric patients.     

A novel predictor of clinical response to methotrexate in patients with rheumatoid arthritis: a pilot study of in vitro T cell cytokine suppression

OBJECTIVE: Methotrexate (MTX) is an important drug for treatment of rheumatoid arthritis; however, there is variation in the clinical response. MTX inhibits T cell cytokine production, with significant interindividual variability in the dose required. We investigated if the variability in clinical response was related to variability in the in vitro assay. METHODS:Patients with disease modifying antirheumatic drug-naive, active RA [1982 American College of Rheumatology (ACR) criteria] seen from September 2005 through January 2006 were enrolled. MTX was started at 10 mg/week and increased monthly by 2.5 mg/week. Baseline whole-blood cultures were set up with anti-CD3, anti-CD28, and increasing doses of MTX. Supernatants were harvested at 96 hours and tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and interleukin 10 (IL-10) concentrations were estimated by ELISA. The dose of MTX (ID50) required for 50% suppression of production of cytokines and the change in Disease Activity Score-28 (DeltaDAS) at 4 months were noted. RESULTS: T cell stimulation resulted in significant increase in cytokine release, and addition of MTX led to a dose-dependent suppression of all 3 cytokines. There was significant negative correlation of DeltaDAS with ID50 values for TNF-alpha (R = -0.62, p < 0.01) and IFN-gamma (R = -0.43, p = 0.04). At 4 months, EULAR moderate and ACR 20% responses were achieved by 13 and 16 patients, respectively. EULAR moderate response could be predicted using ROC curves for TNF-alpha (sensitivity 93%, specificity 86%) and IFN-gamma (60% specificity, 71% sensitivity). ACR response was correctly predicted in 14 of 16 ACR 20% responders and in all ACR 50% and ACR 70% responders. CONCLUSION: An in vitro TNF-alpha suppression assay may help predict clinical response to MTX in RA.     

All-inside meniscal repair surgery: factors affecting the outcome

BackgroundMeniscal injury is currently a well-recognized source of knee dysfunction. While it would be ideal to repair all meniscus tears, the failure rate is significantly high, although it may be reduced by careful selection of the patients. Our objective was to assess the outcome of meniscal repair surgery and the role of simultaneous reconstruction of the anterior cruciate ligament (ACL).Results136 Meniscal repairs were performed in 122 patients with a mean age of 26.8 years. Mean follow-up duration was 9 months. 63 % of the patients underwent medial and 37 % underwent lateral meniscal repair, with failure rates of 19 % for medial and 12 % for lateral menisci. Ligament injuries were found in 61 % of the patients (n = 83). Failure of meniscal repair occurred in 14.5 % (n = 12) of the patients who had early ACL reconstruction and in 27 % (n = 22) of the patients who had delayed ACL reconstruction (p = 0.0006). The failure rate was found to be 13 % in patients who were younger than 25 years (61 %) and 15 % in patients who were older than 25 years (39 %).ConclusionThe success rate of meniscal repair was found to be significantly better when ACL reconstruction was performed simultaneously with meniscal repair.

Level of evidence

Level IV.     

Rituximab as a first-line agent for the treatment of dermatomyositis

B cells may play a pivotal role in the pathophysiology of DM, and reports have claimed that targeting B cells is a viable treatment option in patients with dermatomyositis. A 20-year-old girl presented in October 2007, with few weeks’ history of proximal muscle weakness. Gottron’s papules were noted on her knuckles. She had normal inflammatory markers and negative autoantibody screen. Her CPK was 7,000 U/L (normal range 0–170) with an LDH of 1,300 U/L (normal range 266–500). EMG and muscle biopsy was consistent with active myositis. She had normal pulmonary function tests. HRCT showed no interstitial lung disease. She was started with 60 mg glucocorticoids (1 mg/kg), with a good clinical response. However, any attempt to taper down the steroid dose led to recurrence of her symptoms. The options of available immunosuppressive therapies, including the experimental usage of rituximab, were discussed with her; averse to long-term systemic treatments, she opted to try a course of rituximab. She had rituximab 1,000 mg on days 0 and 14, and her glucocorticoids were tapered in next few weeks. Now, 24 months since her rituximab infusions, she remains in complete clinical and biochemical remission and is na?ve to other immunosuppressive agents apart from glucocorticoids and rituximab. Depleting peripheral B cells with rituximab (one course) in our patient has led not only to complete resolution of muscle and skin disease (induction) but also remains off all immunosuppressives including glucocorticoids.