Human Stem Cells Converted to Functional Lung Cells

Possibility of generating lung tissue for transplant using a patient’s own cells

NEW YORK, NY — For the first time, scientists have succeeded in transforming human stem cells into functional lung and airway cells. The advance, reported by Columbia University Medical Center (CUMC) researchers, has significant potential for modeling lung disease, screening drugs, studying human lung development, and, ultimately, generating lung tissue for transplantation. The study was published today in the journal Nature Biotechnology.

Human embryonic stem cells differentiated into type II alveolar lung epithelial cells (green). A large portion of these transformed cells express surfactant protein B (red), which indicates that they are functional type II cells. Image credit: Sarah Xuelian Huang, PhD at the Columbia Center for Translational Immunology at CUMC.

“Researchers have had relative success in turning human stem cells into heart cells, pancreatic beta cells, intestinal cells, liver cells, and nerve cells, raising all sorts of possibilities for regenerative medicine,” said study leader Hans-Willem Snoeck, MD, PhD, professor of medicine (in microbiology & immunology) and affiliated with theColumbia Center for Translational Immunology and the Columbia Stem Cell Initiative. “Now, we are finally able to make lung and airway cells. This is important because lung transplants have a particularly poor prognosis. Although any clinical application is still many years away, we can begin thinking about making autologous lung transplants—that is, transplants that use a patient’s own skin cells to generate functional lung tissue.”

The research builds on Dr. Snoeck’s 2011 discovery of a set of chemical factors that can turn human embryonic stem (ES) cells or human induced pluripotent stem (iPS) cells into anterior foregut endoderm—precursors of lung and airway cells. (Human iPS cells closely resemble human ES cells but are generated from skin cells, by coaxing them into taking a developmental step backwards. Human iPS cells can then be stimulated to differentiate into specialized cells—offering researchers an alternative to human ES cells.)

In the current study, Dr. Snoeck and his colleagues found new factors that can complete the transformation of human ES or iPS cells into functional lung epithelial cells (cells that cover the lung surface). The resultant cells were found to express markers of at least six types of lung and airway epithelial cells, particularly markers of type 2 alveolar epithelial cells. Type 2 cells are important because they produce surfactant, a substance critical to maintain the lung alveoli, where gas exchange takes place; they also participate in repair of the lung after injury and damage.

The findings have implications for the study of a number of lung diseases, including idiopathic pulmonary fibrosis (IPF), in which type 2 alveolar epithelial cells are thought to play a central role. “No one knows what causes the disease, and there’s no way to treat it,” says Dr. Snoeck. “Using this technology, researchers will finally be able to create laboratory models of IPF, study the disease at the molecular level, and screen drugs for possible treatments or cures.”

“In the longer term, we hope to use this technology to make an autologous lung graft,” Dr. Snoeck said. “This would entail taking a lung from a donor; removing all the lung cells, leaving only the lung scaffold; and seeding the scaffold with new lung cells derived from the patient. In this way, rejection problems could be avoided.” Dr. Snoeck is investigating this approach in collaboration with researchers in the Columbia University Department of Biomedical Engineering.

“I am excited about this collaboration with Hans Snoeck, integrating stem cell science with bioengineering in the search for new treatments for lung disease,” said Gordana Vunjak-Novakovic, PhD, co-author of the paper and Mikati Foundation Professor of Biomedical Engineering at Columbia’s Engineering School and professor of medical sciences at Columbia University College of Physicians and Surgeons.

The paper is titled, “Highly efficient generation of airway and lung epithelial cells from human pluripotent stem cells.”

The other contributors are Sarah X.L. Huang, Mohammad Naimul Islam, John O’Neill, Zheng Hu, Yong-Guang Yang, Ya-Wen Chen, Melanie Mumau, Michael D. Green, and Jahar Bhattacharya (all at CUMC).

Columbia University has filed for a patent relating to the generation of lung and airway epithelium from human pluripotent stem cells and uses thereof. The authors declare no other financial or other conflicts of interests.

The study was supported by startup funds from CUMC and the New York Stem Cell Foundation.

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Columbia University Medical Center provides international leadership in basic, preclinical, and clinical research; medical and health sciences education; and patient care. The medical center trains future leaders and includes the dedicated work of many physicians, scientists, public health professionals, dentists, and nurses at the College of Physicians and Surgeons, the Mailman School of Public Health, the College of Dental Medicine, the School of Nursing, the biomedical departments of the Graduate School of Arts and Sciences, and allied research centers and institutions. Columbia University Medical Center is home to the largest medical research enterprise in New York City and State and one of the largest faculty medical practices in the Northeast. For more information, visit cumc.columbia.edu or columbiadoctors.org.

ORIGINAL: Columbia University

December 1, 2013

Greasy Sponge Slurps Up Oil

ORIGINAL: Chemical & Engineering News - ACS

By Erika Gebel

June 26, 2013

Materials Science: A chemical treatment makes a household sponge thirsty for oil instead of water

Waterproof Sponge. Water droplets rest on top of a superhydrophobic sponge coated in a thin layer of polypyrrole. Credit: Ind. Eng. Chem. Res.

Picking Up Petrol.
Researchers mixed petroleum with water in a petri dish (a)
and then added a superhydrophobic sponge (black, b).
After five minutes, the sponge had absorbed most of the oil from the water (c).
Credit: Ind. Eng. Chem. Res.

A sponge that can’t absorb a single drop of water may seem like a dud. But if it readily soaks up oil, it could help purify chemical syntheses or clean up oil spills on water. Researchers now report a simple chemical method for turning a household sponge into a water-blocking oil absorber (Ind. Eng. Chem. Res. 2013, DOI: 10.1021/ie400942t).

In response to oil spills on water, cleanup crews often turn to sorbent materials, such as wool, straw, cotton, and synthetic sponges, to separate oil from the water. Sponges are the best choice for the job, say Zhaozhu Zhang and colleagues at the Chinese Academy of Science. The materials can absorb a lot of liquid in a short time, and they can float. However, they suck up water as well as oil, so the sponges’ soaking capacity isn’t fully used to remove oil. To make the materials more efficient, Zhang and colleagues decided to make an oil-specific sponge.

The researchers purchased polyurethane sponges at a local furniture store and coated its entire surface with a thin layer of polypyrrole. This polymer is well known for being water-repellent and having a strong affinity for oil, says Paul L. Edmiston, a chemist at the College of Wooster, who was not involved in this study.

To prepare the sponge for its polypyrrole coating, the researchers first dipped it into ferric chloride and 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PTES). They then put the PTES-coated sponge into a sealed chamber over a pool of volatile pyrrole, which vaporized and infused the sponge. The PTES helped the pyrrole adhere to the sponge surface. Meanwhile, the iron from the ferric chloride helped to catalyze the polymerization of the pyrrole into a thin coating over the sponge’s pores.

When the scientists added droplets of water to the surface of the revamped sponge, the water stayed in a bead and wasn’t absorbed. Droplets of oil, however, disappeared into the sponge immediately. The researchers also dipped the sponge into a variety of oils, including motor oil and soybean oil. The sponge sopped up more than 20 times its dry weight for each of the oils. The team tested how the sponge fared after reuse: They sopped up oil with the sponge and then wrung out the absorbed oil. After repeating those steps five times, the sponge could absorb at least 17 times its weight in oil.

Other groups have modified meshlike materials to absorb oil, Edmiston says. But he likes the idea of an oil-absorbing sponge, because it has “lots of room to pick up the oil.”

Edmiston is concerned that the cost of making these sponges would be prohibitive in the case of a large-scale oil-spill cleanup operation. Although the sponges themselves are cheap, the chemicals used in the treatment are expensive. The superhydrophobic sponges, though may find a place in certain industrial operations, Edmiston says, like removing hydrophobic solvents during chemical syntheses. Such small-scale applications would probably be the first uses for the revamped sponges, he says.

Chemical & Engineering News
ISSN 0009-2347
Copyright © 2013 American Chemical Society

Hallan microalgas que devoran contaminantes

ORIGINAL: UNPeriódico

Fernando García Ardila, Unimedios

May. 12 de 2012

Las algas ayudan a disminuir el contenido de materia orgánica (aceites y grasas), y son más efectivas cuando trabajan en asocio con hongos y bacterias. - Foto: Víctor Manuel Holguín/Unimedios

Chlorella vulgaris es un pequeño y prodigioso organismo que absorbe los residuos sólidos de las aguas impuras. Biólogos e ingenieros comprobaron que puede eliminar entre un 20% y un 30% del material indeseable de un litro de líquido. Esta podría ser una solución viable y económica de descontaminación hídrica para fábricas y pequeñas localidades.

El profundo universo de las algas y sus prolíficas virtudes son el objeto de estudio de un grupo de investigadores que no ha parado de sumergirse, desde hace cinco años, en los secretos de este singular organismo. Ahora descubrieron lo que puede hacer la diminuta Chlorella vulgaris, una variedad propia de aguas dulces.

Este espécimen verde, de forma esférica, mide entre 2 y 10 micras (milésimas de milímetro) y tiene una capacidad enorme para atraer grasas y aceites inmersos en aguas residuales. Para el caso del estudio, se utilizaron las aguas procedentes de una empresa de cebos, que son tratadas con diferentes técnicas físico–químicas para luego devolverlas al medio.

Esta microalga se halla en ríos, lagos, humedales e incluso en suelos húmedos. Una de las razones para utilizarla es su fácil adaptación y supervivencia en fuentes hídricas con altos grados de contaminación. Además, tiene la capacidad de consumir materia orgánica.

El biólogo Luis Carlos Montenegro y el ingeniero químico Rubén Darío Godoy, de la Universidad Nacional de Colombia, y Alejandro Herrera, ingeniero químico de la Universidad de América, pudieron comprobar en el Laboratorio de Cultivos de Algas que, en un litro de agua con cebo, las microalgas “devoran” entre el 20% y el 30% de este.

En primer lugar, se tuvieron que identificar las condiciones adecuadas para su cultivo. Luego se efectuó la toma de muestras y su caracterización (demanda química de oxígeno –DQO–, oxígeno disuelto, aceites, grasas y pH) antes del tratamiento.

Posteriormente, se llevaron a cabo experimentos que incluyeron dos factores:

• disolución de grasas y 
• pretratamiento. 

Gracias a estos, se determinó qué concentración máxima de materia oleaginosa podían degradar las algas y si estas trabajan mejor solas o en compañía de otros microorganismos.

“Introdujimos las algas en botellas llenas de agua cargada de grasa, con buenas condiciones de luz y temperatura; esperamos ocho días y observamos que el contenido de cebo disminuía ostensiblemente”, recuerda Montenegro, experto en esta variedad de seres vivos que, aunque parecen plantas, no lo son.

El estudio determinó que la unión de microalgas y microorganismos (como bacterias y hongos) redunda en una remoción de contaminantes orgánicos más eficiente. Según el biólogo, la microalga se encarga de hacer fotosíntesis y producir oxígeno, el cual es consumido por otras bacterias que también degradan la materia orgánica presente en estos desechos.

De esta manera, la disminución de la demanda química de oxígeno, para estos tratamientos, se registró entre el 35% y el 76%, con respecto al comienzo del proceso: “Una medición que muestra la reducción de materia orgánica presente en los líquidos contaminados”.

En cuanto a las grasas y aceites, estos se reducen hasta 80%. Y, adicionalmente, se presenta una oxigenación hasta diez veces mayor que al comienzo de estos procedimientos.

Complemento estratégico

Los científicos destacan que trabajar con C. vulgaris tiene ventajas enormes para la preservación del medioambiente, así como para las compañías colombianas que producen desechos, pues su utilización abaratará los costos de tratamiento por el hecho de ser un organismo de fácil consecución y aplicación.

Los expertos aseguran que, en la actualidad, las técnicas para tratar el agua no son del todo eficientes, porque son sistemas muy básicos que dejan contaminantes; por ejemplo, las lagunas de sedimentación y oxidación no tienen la capacidad de disminuir las concentraciones de materia orgánica y metales pesados (cromo, cadmio, plomo).

El profesor Montenegro aclara que el tratamiento desarrollado por la UN complementará los usados comúnmente por las empresas para refinar la purificación del agua. Consistiría en la instalación de una piscina tratada con microalgas y microorganismos. Lo más interesante es que este método se adaptaría a municipios y veredas con plantas de tratamiento deficientes o inexistentes.

“En estos lugares las aguas residuales están contaminadas principalmente con materia orgánica. Es un proceso extremadamente económico y fácil de llevar a cabo, para liberar agua más limpia a los ríos”, asegura.

Potencial

La rica biodiversidad con la que cuenta Colombia incluye a las fuentes hídricas, cuya oferta superficial alcanza los 71.800 m³ al año, a ella se suman las reservas de aguas subterráneas, que se extienden por 5.848 km². Estos lugares pueden constituirse en el hábitat de la benéfica Chlorella vulgaris.

Se estima, además, que la demanda hídrica total en el país es de 35.877 mm³ anuales, de los cuales

• el 54% va al sector agrícola; 
• el 19%, al sector energético; 
• el 7%, a la actividad doméstica; 
• el 7%, a la acuícola; 
• el 6%, a la pecuaria; 
• el 4%, a la industrial; y 
• el 1,4%, al sector de servicios. 

Dichas esferas necesitan métodos de descontaminación de las aguas.

Tras el proceso de absorción del material residual, las micro-algas no sufren daño, ya que permanecen vivas. De manera que existe la posibilidad de reutilizarlas en la producción de

• combustibles, 
• pigmentos, 
• antioxidantes (para evitar enfermedades) y 
• alimento para peces. 

¡Unas pequeñas pero efectivas máquinas naturales!

Edición: 

UN Periodico Impreso No. 155