Deletion of MCL-1 causes lethal cardiac failure and mitochondrial dysfunction

MCL-1 is an essential BCL-2 family member that promotes the survival of multiple cellular lineages, but its role in cardiac muscle has remained unclear. Here, we report that cardiac-specific ablation of Mcl-1 results in a rapidly fatal, dilated cardiomyopathy manifested by a loss of cardiac contractility, abnormal mitochondria ultrastructure, and defective mitochondrial respiration. Strikingly, genetic ablation of both proapoptotic effectors (Bax and Bak) could largely rescue the lethality and impaired cardiac function induced by Mcl-1 deletion. However, while the overt consequences of Mcl-1 loss were obviated by combining with the loss of Bax and Bak, mitochondria from the Mcl-1-, Bax-, and Bak-deficient hearts still revealed mitochondrial ultrastructural abnormalities and displayed deficient mitochondrial respiration. Together, these data indicate that merely blocking cell death is insufficient to completely overcome the need for MCL-1 function in cardiomyocytes and suggest that in cardiac muscle, MCL-1 also facilitates normal mitochondrial function. These findings are important, as specific MCL-1-inhibiting therapeutics are being proposed to treat cancer cells and may result in unexpected cardiac toxicity.     

Pilot Study Evaluating Regulatory T Cell–Promoting Immunosuppression and Nonimmunogenic Donor Antigen Delivery in a Nonhuman Primate Islet Allotransplantation Model

The full potential of islet transplantation will only be realized through the development of tolerogenic regimens that obviate the need for maintenance immunosuppression. Here, we report an immunotherapy regimen that combines 1‐ethyl‐3‐(3′‐dimethylaminopropyl)‐carbodiimide (ECDI)‐treated donor lymphoid cell infusion (ECDI‐DLI) with thymoglobulin, anti‐interleukin‐6 receptor antibody and rapamycin to achieve prolonged allogeneic islet graft survival in a nonhuman primate (NHP) model. Prolonged graft survival is associated with Treg expansion, donor‐specific T cell hyporesponsiveness and a transient absence of donor‐specific alloantibody production during the period of graft survival. This regimen shows promise for clinical translation.     

Effect of hyperglycaemia on inflammatory and stress responses and clinical outcome of pneumonia in non-critical-care inpatients: results from an observational cohort study

Aims/hypothesis

Despite the condition’s high prevalence, the influence of hyperglycaemia on clinical outcomes in non-critical-care inpatients with infections remains ill defined. In this study, we analysed associations of glucose levels at admission and during initial inpatient treatment with the inflammatory response and clinical outcome in community-acquired pneumonia (CAP) patients.

Methods

This secondary observational analysis included 880 confirmed CAP patients. We used severity-adjusted multivariate regression models to investigate associations of initial and 96 h mean glucose levels with serially measured biomarker levels over 7 days (C-reactive protein [CRP], procalcitonin, white blood cell count [WBC], pro-adrenomedullin [ProADM]) and adverse clinical course (death and intensive-care unit admission).

Results

In the 724 non-diabetic patients (82.3% of the study population), moderate or severe hyperglycaemia (glucose 6–11 mmol/l and >11 mmol/l, respectively) was associated with increased risk for adverse clinical course (adjusted OR [95% CI] 1.4 [0.8, 2.4] and 3.0 [1.1, 8.0], respectively) and with higher CRP, WBC and ProADM levels over 7 days (p?<?0.05, ANOVA, all days). In diabetic patients (n?=?156), no similar associations were found for initial hyperglycaemia, although mean 96 h glucose levels ?≥?9 mmol/l were associated with adverse clinical course (adjusted OR 5.4 [1.1, 25.8]; p?=?0.03). No effect modification by insulin treatment was detected (interaction terms p?>?0.2 for all analyses).

Conclusions/interpretation

Initial hyperglycaemia in non-diabetic CAP patients, and prolonged hyperglycaemia in diabetic or non-diabetic CAP patients, are associated with a more pronounced inflammatory response and CAP-related adverse clinical outcome. Optimal glucose targets for insulin treatment of hyperglycaemia in non-critical-care settings should be defined.     

Role of procalcitonin in managing adult patients with respiratory tract infections

Respiratory infections remain the most common reason why patients seek medical care in ambulatory and hospital settings, and they are the most frequent precursor of sepsis. In light of the limitations of clinical signs and symptoms and traditional microbiologic diagnostics for respiratory infections, blood biomarkers that correlate with the presence and extent of bacterial infections may provide additional useful information to improve diagnostic and prognostic efforts and help with therapeutic decisions in individual patients. A growing body of evidence supports the use of procalcitonin (PCT) to differentiate bacterial from viral respiratory diagnoses, to help risk stratify patients, and to guide antibiotic therapy decisions about initial need for, and optimal duration of, therapy. Although still relatively new on the clinical frontier, a series of randomized controlled trials have evaluated PCT protocols for antibiotic-related decision making and have included patients from different clinical settings and with different severities of respiratory infection. In these trials, initial PCT levels were effective in guiding decisions about the initiation of antibiotic therapy in lower-acuity patients, and subsequent measurements were effective for guiding duration of therapy in higher-acuity patients, without apparent harmful effects. Recent European respiratory infection guidelines now also recognize this concept. As with any other laboratory test, PCT should not be used on a stand-alone basis. Rather, it must be integrated into clinical protocols, together with clinical, microbiologic data and with results from clinical risk scores. The aim of this review is to summarize recent evidence about the usefulness of PCT in patients with lower respiratory tract infections and to discuss the potential benefits and limitations of this marker when used for clinical decision making.     

The Role of Procalcitonin in Respiratory Infections

Accurate diagnosis, risk stratification, and decisions about the need for and optimal duration of antibiotic therapy are cornerstones of the management of patients with respiratory infections. A growing body of evidence supports the use of procalcitonin, a marker of bacterial infection, in addition to conventional clinical parameters to improve diagnostic and prognostic assessment in patients with suspicion of respiratory infections. In addition, several randomized controlled trials indicate that procalcitonin may be used for clinical decision making about initiation and optimal duration of antibiotic therapy. For patients with respiratory infections, procalcitonin-guided antibiotic therapy resulted in less antibiotic use without any apparent adverse patient outcome. For other infections outcome studies are currently lacking. This review summarizes the results of recent investigations of procalcitonin in respiratory infections to provide physicians an overview of the utility and limitations of procalcitonin when used for bedside decision making.     

Prognostic Value of Disseminated Tumor Cells in the Bone Marrow of Patients with Operable Primary Breast Cancer: A Long-term Follow-up Study

Background

Detection of disseminated tumor cells (DTC) in primary breast cancer (BC) patients’ bone marrow (BM) seems to be a surrogate marker of tumor spread and an independent prognostic factor for disease-free and overall survival.

Methods

Here we present the largest single-center cohort of patients (n = 1378) with the longest observation time (median 82.0 months). Immunocytochemical staining was performed using murine monoclonal antibody 2E11 with the avidin–biotin complex technique.

Results

At primary surgery, 49 % of patients showed MUC-1 positive cells inside their BM. Patients without BM DTC had significantly more often T1-tumors (P = 0.007) with less often affected axillary lymph nodes (P < 0.001). We observed a significantly higher incidence of distant metastases in DTC positive patients (P < 0.001). This leads to a reduced disease-free survival (P < 0.0001). Furthermore, in DTC positive patients there was a higher mortality rate and, accordingly, a reduced overall survival (P < 0.0001).

Conclusions

Due to the presence of BM DTC, patients with a clinically poorer outcome can be identified at primary surgery. We therefore suggest that DTC analysis can be used as a prognostic factor and monitoring tool in clinical trials. Future study concepts relating to DTC should aim at identification of BC patients who may profit from adjuvant systemic therapy.     

Bone Regeneration Based on Tissue Engineering Conceptions — A 21st Century Perspective

The role of Bone Tissue Engineering in the field of Regenerative Medicine has been the topic of substantial research over the past two decades. Technological advances have improved orthopaedic implants and surgical techniques for bone reconstruction. However, improvements in surgical techniques to reconstruct bone have been limited by the paucity of autologous materials available and donor site morbidity. Recent advances in the development of biomaterials have provided attractive alternatives to bone grafting expanding the surgical options for restoring the form and function of injured bone. Specifically, novel bioactive (second generation) biomaterials have been developed that are characterised by controlled action and reaction to the host tissue environment, whilst exhibiting controlled chemical breakdown and resorption with an ultimate replacement by regenerating tissue. Future generations of biomaterials (third generation) are designed to be not only osteoconductive but also osteoinductive, i.e. to stimulate regeneration of host tissues by combining tissue engineering and in situ tissue regeneration methods with a focus on novel applications. These techniques will lead to novel possibilities for tissue regeneration and repair. At present, tissue engineered constructs that may find future use as bone grafts for complex skeletal defects, whether from post-traumatic, degenerative, neoplastic or congenital/developmental “origin” require osseous reconstruction to ensure structural and functional integrity. Engineering functional bone using combinations of cells, scaffolds and bioactive factors is a promising strategy and a particular feature for future development in the area of hybrid materials which are able to exhibit suitable biomimetic and mechanical properties. This review will discuss the state of the art in this field and what we can expect from future generations of bone regeneration concepts.     

Accumulation of methotrexate polyglutamates in lymphoblasts is a determinant of antileukemic effects in vivo. A rationale for high-dose methotrexate.

Methotrexate (MTX) is one of the most widely used drugs for the treatment of childhood acute lymphoblastic leukemia (ALL) and is commonly given in high doses. However, the rationale for high-dose MTX (HDMTX) has been challenged recently. To determine whether higher MTX polyglutamate (MTXPG) concentrations in ALL blasts translate into greater antileukemic effects, 150 children with newly diagnosed ALL were randomized to initial treatment with either HDMTX (1,000 mg/m2 intravenously over 24 h) or lower-dose MTX (30 mg/m2 by mouth every 6 h x 6). ALL blasts accumulated higher concentrations of MTXPG and long-chain MTXPG (MTXPGLC) after HDMTX (P < 0.00001). Of 101 patients evaluable for peripheral blast cytoreduction, MTXPG concentrations were higher in patients whose blast count decreased within 24 h (P = 0.005) and in those who had no detectable circulating blasts within 4 days (P = 0.004). The extent of inhibition of de novo purine synthesis in ALL blasts was significantly related to the blast concentration of MTXPGLC (IC95% = 483 pmol/10(9) blasts). The percentage of patients with 44-h MTXPGLC exceeding the IC95% was greater after HDMTX (81%) than LDMTX (46%, P < 0.0001). These data indicate that higher blast concentrations of MTXPG are associated with greater antileukemic effects, establishing a strong rationale for HD-MTX in the treatment of childhood ALL.