BACKGROUND Although progenitor cells have been described in distinct anatomical regions of the lung, description of resident stem cells has remained elusive. METHODS Surgical lung-tissue specimens were studied in situ to identify and characterize human lung stem cells. We defined their phenotype and functional properties in vitro and in vivo. RESULTS Human lungs contain undifferentiated human lung stem cells nested in niches in the distal airways. These cells are self-renewing, clonogenic, and multipotent in vitro. After injection into damaged mouse lung in vivo, human lung stem cells form human bronchioles, alveoli, and pulmonary vessels integrated structurally and functionally with the damaged organ. The formation of a chimeric lung was confirmed by detection of human transcripts for epithelial and vascular genes. In addition, the self-renewal and long-term proliferation of human lung stem cells was shown in serial-transplantation assays. CONCLUSIONS Human lungs contain identifiable stem cells. In animal models, these cells participate in tissue homeostasis and regeneration. They have the undemonstrated potential to promote tissue restoration in patients with lung disease. (Funded by the National Institutes of Health.)

We report a lung-on-a-chip array that mimics the pulmonary parenchymal environment, including the thin alveolar barrier and the three-dimensional cyclic strain induced by breathing movements. The micro-diaphragm used to stretch the alveolar barrier is inspired by the in vivo diaphragm, the main muscle responsible for inspiration. The design of this device aims not only at best reproducing the in vivo conditions found in the lung parenchyma but also at making the device robust and its handling easy. An innovative concept, based on the reversible bonding of the device, is presented that enables accurate control of the concentration of cells cultured on the membrane by easily accessing both sides of the membranes. The functionality of the alveolar barrier could be restored by co-culturing epithelial and endothelial cells that form tight monolayers on each side of a thin, porous and stretchable membrane. We showed that cyclic stretch significantly affects the permeability properties of epithelial cell layers. Furthermore, we also demonstrated that the strain influences the metabolic activity and the cytokine secretion of primary human pulmonary alveolar epithelial cells obtained from patients. These results demonstrate the potential of this device and confirm the importance of the mechanical strain induced by breathing in pulmonary research.

Objective: To determine whether nutrient intake and academic and psychosocial functioning improve after the start of a universal-free school breakfast program (USBP). Methods: Information was gathered from 97 inner city students prior to the start of a USBP and again after the program had been in place for 6 months. Students who had total energy intakes of <50% of the recommended daily allowance (RDA) and/or 2 or more micronutrients of <50% of RDA were considered to be at nutritional risk. Results: Prior to the USBP, 33% of all study children were classified as being at nutritional risk. Children who were at nutritional risk had significantly poorer attendance, punctuality, and grades at school, more behavior problems, and were less likely to eat breakfast at school than children who were not at nutritional risk. Six months after the start of the free school breakfast programs, students who decreased their nutritional risk showed significantly greater: improvements in attendance and school breakfast participation, decreases in hunger, and improvements in math grades and behavior than children who did not decrease their nutritional risk. Conclusion: Participation in a school breakfast program enhanced daily nutrient intake and improvements in nutrient intake were associated with significant improvements in student academic performance and psychosocial functioning and decreases in hunger.

The use of mesenchymal stromal cells (MSCs) for treatment of bacterial infections, including systemic processes like sepsis, is an evolving field of investigation. The present study was designed to investigate the potential use of MSCs, harvested from compact bone, and their interactions with the innate immune system, during polymicrobial sepsis induced by cecal ligation and puncture (CLP). We also wanted to elucidate the role of endogenous HO-1 in MSCs during a systemic bacterial infection. MSCs harvested from the bones of heme oxygenase (HO)-1 deficient (−/−) and wild-type (+/+) mice improved the survival of HO-1−/− and HO-1+/+ recipient mice when administered after the onset of polymicrobial sepsis induced by cecal ligation and puncture (CLP), compared with the administration of fibroblast control cells. The MSCs, originating from compact bone in mice, enhanced the ability of neutrophils to phagocytize bacteria in vitro and in vivo, and to promote bacterial clearance in the peritoneum and blood after CLP. Moreover, after depleting neutrophils in recipient mice, the beneficial effects of MSCs were entirely lost, demonstrating the importance of neutrophils for this MSC response. MSCs also decreased multiple organ injury in susceptible HO-1−/− mice, when administered after the onset of sepsis. Taken together, these data demonstrate that the beneficial effects of treatment with MSCs after the onset of polymicrobial sepsis is not dependent on endogenous HO-1 expression, and that neutrophils are crucial for this therapeutic response.

Cancer is responsible for millions of deaths worldwide and the variability in disease patterns calls for patient-specific treatment. Therefore, personalized treatment is expected to become a daily routine in prospective clinical tests. In addition to genetic mutation analysis, predictive chemosensitive assays using patient's cells will be carried out as a decision making tool. However, prior to their widespread application in clinics, several challenges linked to the establishment of such assays need to be addressed. To best predict the drug response in a patient, the cellular environment needs to resemble that of the tumor. Furthermore, the formation of homogeneous replicates from a scarce amount of patient's cells is essential to compare the responses under various conditions (compound and concentration). Here, we present a microfluidic device for homogeneous spheroid formation in eight replicates in a perfused microenvironment. Spheroid replicates from either a cell line or primary cells from adenocarcinoma patients were successfully created. To further mimic the tumor microenvironment, spheroid co-culture of primary lung cancer epithelial cells and primary pericytes were tested. A higher chemoresistance in primary co-culture spheroids compared to primary monoculture spheroids was found when both were constantly perfused with cisplatin. This result is thought to be due to the barrier created by the pericytes around the tumor spheroids. Thus, this device can be used for additional chemosensitivity assays (e.g. sequential treatment) of patient material to further approach the personalized oncology field.

SummaryHeme oxygenase (HO)-1 is a cytoprotective enzyme that plays a critical role in defending the body against oxidant-induced injury during inflammatory processes. HO catalyzes the degradation of heme to carbon monoxide (CO), biliverdin, and ferrous iron. Biliverdin is converted to bilirubin, a potent endogenous antioxidant. CO has a number of biological functions, including anti-inflammatory properties. In various models of disease, HO-1 is known to play a critical role by ameliorating the pathological consequences of injury. In many of these models, the beneficial effects of HO-1 and its products of heme catabolism are by suppressing an inflammatory response. However, when investigating diseases due to microbial infections, inhibition of the inflammatory response could disrupt the ability of the immune system to eradicate an invading pathogen. Thus, questions remain regarding the role of HO-1 in microbial host defense. This microreview will address our present understanding of HO-1 and its functional significance in a variety of microbial infections.

Background-The striated preferentially expressed gene (Speg) generates 4 different isoforms through alternative promoter use and tissue-specific splicing. Depending on the cell type, Speg isoforms may serve as markers of striated or smooth muscle differentiation. Methods and Results-To elucidate function of Speg gene isoforms, we disrupted the Speg gene locus in mice by replacing common exons 8, 9, and 10 with a lacZ gene. ␤-Galactosidase activity was detected in cardiomyocytes of the developing heart starting at day 11.5 days post coitum (dpc). ␤-Galactosidase activity in other cell types, including vascular smooth muscle cells, did not begin until 18.5 dpc. In the developing heart, protein expression of only Speg␣ and Speg␤ isoforms was present in cardiomyocytes. Homozygous Speg mutant hearts began to enlarge by 16.5 dpc, and by 18.5 dpc, they demonstrated dilation of right and left atria and ventricles. These cardiac abnormalities in the absence of Speg were associated with a cellular hypertrophic response, myofibril degeneration, and a marked decrease in cardiac function. Moreover, Speg mutant mice exhibited significant neonatal mortality, with increased death occurring by 2 days after birth. Conclusions-These findings demonstrate that mutation of the Speg locus leads to cardiac dysfunction and a phenotype consistent with a dilated cardiomyopathy. Key Words: cardiomyopathy Ⅲ hypertrophy Ⅲ myocytes Ⅲ genes M yosin light chain kinases (MLCK) are a family of proteins that are important for myocyte function, including structure and regulation of the actin-based cytoskeleton. 1,2 One member of this family, striated preferentially expressed gene (Speg), has isoforms in both striated and smooth muscle cells. 3 The Speg locus contains 2 transcriptional start sites, and through alternative promoter use and splicing in a tissue-specific manner, it generates 4 different isoforms. 3 Speg␣ and Speg␤ are expressed in striated muscle (cardiac and skeletal), aortic preferentially expressed gene (Apeg-1) is expressed in smooth muscle (predominantly vascular), and brain preferentially expressed gene (Bpeg) is expressed in the brain and aorta. [3][4][5] Speg␣ and Speg␤ share homology with MLCK family members. Specifically, the Speg isoforms, along with obscurin-MLCK, are unique members of the MLCK family, because they contain 2 tandemly arranged serine/threonine kinase (MLCK) domains. 2 Beyond the MLCK domains, Speg␣ and Speg␤ also contain immunoglobulin and fibronectin domains that are characteristic of the MLCK family of proteins. Prior investigations in our laboratory revealed that Speg␣ and Speg␤ are sensitive markers of striated muscle differentiation and that Speg colocalizes with desmin in the sarcomeric Z disc 3 ; however, the functional significance of Speg isoforms is yet to be elucidated. Editorial p 213 Clinical Perspective p 268In contrast to smooth muscle cells, striated muscle cells of both cardiac and skeletal origin undergo terminal differenti- Received June 15, 2008; accepted October 14, 2008. From Pulmona...

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