Category: Medical Research & Technology

Categories : Medical Research & TechnologyTags :

Microscopic Robots Kill Pneumonia Bacteria in Lungs

On By ModernMedia
Pseudomonas
Scanning Electron Micrograph of Pseudomonas aeruginosa. Credit: CDC/Janice Carr

Nanoengineers have developed microscopic robots, called microrobots, that can swim around in the lungs, deliver medication and be used to clear up life-threatening cases of bacterial pneumonia.

In mice, the microrobots safely eliminated Pseudomonas aeruginosa in the lungs of infected mice, resulting in a 100% survival rate. By contrast, untreated mice all died within three days after infection. The scientists describe the technology in Nature Materials.

The microrobots are not actually made of metal and plastic: instead they are algae cells armed with antibiotic-filled nanoparticles on their surfaces. The algae provide movement, which allows the microrobots to swim around and deliver antibiotics directly to more bacteria in the lungs. The nanoparticles are also coated with the neutrophil cell membranes, which absorb and neutralise inflammatory molecules produced by bacteria and the body’s immune system. This gives the microrobots a powerful anti-inflammatory tool, and the algae are biodegradable in the body, leaving no toxic traces.

The work is a joint effort between the labs of nanoengineering professors Joseph Wang and Liangfang Zhang, both at the UC San Diego Jacobs School of Engineering, both world leaders in nanoengineering.

“Our goal is to do targeted drug delivery into more challenging parts of the body, like the lungs. And we want to do it in a way that is safe, easy, biocompatible and long lasting,” said Prof Zhang. “That is what we’ve demonstrated in this work.”

The team used the microrobots to treat mice with an acute and potentially fatal form of pneumonia caused by P. aeruginosa. This is commonly seen in mechanically ventilated ICU patients. The researchers administered the microrobots to the lungs of the mice through a tube inserted in the windpipe. The infections fully cleared up after one week. All mice treated with the microrobots survived past 30 days, while untreated mice died within three days.

The microrobots enabled targeted drug delivery of only 500 nanograms of antibiotics per mouse, while an IV injection provided 1.644 milligrams of antibiotics per mouse.

“These results show how targeted drug delivery combined with active movement from the microalgae improves therapeutic efficacy,” said Wang.

“With an IV injection, sometimes only a very small fraction of antibiotics will get into the lungs. That’s why many current antibiotic treatments for pneumonia don’t work as well as needed, leading to very high mortality rates in the sickest patients,” said Professor Victor Nizet, co-author on the study and a physician-scientist collaborator of Profs Wang and Zhang. “Based on these mouse data, we see that the microrobots could potentially improve antibiotic penetration to kill bacterial pathogens and save more patients’ lives.”

The work is still at the proof-of-concept stage. The team plans to do more basic research to understand exactly how the microrobots interact with the immune system. Next steps also include studies to validate the microrobot treatment and scaling it up before testing it in larger animals and eventually, in humans.

“We’re pushing the boundary further in the field of targeted drug delivery,” said Zhang.

Source: University of California – San Diego

Categories : Medical Research & TechnologyTags :

Long-standing Theory of Hearing Turned on its Ear

On By ModernMedia

The sensory cells of hearing, outer and inner hair cells, are located in the cochlea, where the arrival sound waves cause the ‘hairs’ of the inner hair cells to bend, sending a signal through the nerves to the brain, which interprets the sound we hear.

For the past century, scientific belief was that each sensory cell has its own ‘optimal frequency’, to which the hair cell responds most strongly. This idea means that a sensory cell with an optimal frequency of 1000Hz would be much less responsive to sounds of slightly lower or higher frequency. It has also been assumed that all parts of the cochlea work in the same way. Now, however, researchers have discovered that this is not so for sensory cells that process sound with frequencies under 1000Hz, considered to be low-frequency sound, where the vowel sounds in human speech lie.

“Our study shows that many cells in the inner ear react simultaneously to low-frequency sound. We believe that this makes it easier to experience low-frequency sounds than would otherwise be the case, since the brain receives information from many sensory cells at the same time,” said Professor Anders Fridberger at Linköping University, senior author of the study published in Science Advances.

The scientists believe that this construction of our hearing system makes it more robust. If some sensory cells are damaged, many others remain that can send nerve impulses to the brain.

As well as the vowel sounds of human speech, many of the sounds that go to make up music also lie in this low-frequency area. Middle C on a piano, for example, has a frequency of 262Hz.

These results may eventually be significant for people with severe hearing impairments. The most successful treatment currently available in such cases is a cochlear implant, in which electrodes are placed into the cochlea.

“The design of current cochlear implants is based on the assumption that each electrode should only give nerve stimulation at certain frequencies, in a way that tries to copy what was believed about the function of our hearing system. We suggest that changing the stimulation method at low frequencies will be more similar to the natural stimulation, and the hearing experience of the user should in this way be improved,” says Anders Fridberger.

The researchers now plan to examine how their new knowledge can be applied in practice. One of the projects they are investigating concerns new methods to stimulate the low-frequency parts of the cochlea.

These results come from experiments on the cochlea of guinea pigs, whose hearing in the low-frequency region is similar to that of humans.

Source: Linköping University

Categories : Medical Research & TechnologyTags :

Simple, Painless Microneedle Tattoos

On By ModernMedia
Photo by Benjamin Lehman on Unsplash

Researchers from the Georgia Institute of Technology have developed a low-cost patch of microneedles that can be applied just by pressing it into the skin, with none of the pain and blood of traditional tattooing. The team development presented their research in the journal iScience.

These tattoos, which can be self-administered, have many potential applications, from medical alerts to tracking neutered animals to cosmetics. 

“We’ve miniaturised the needle so that it’s painless, but still effectively deposits tattoo ink in the skin,” said principal investigator Mark Prausnitz “This could be a way not only to make medical tattoos more accessible, but also to create new opportunities for cosmetic tattoos because of the ease of administration.” 

Medical applications of tattoos include covering up scars, guiding radiotherapy, or restoring nipples after breast surgery. Tattoos also serve instead of bracelets as medical alerts to communicate serious medical conditions such as diabetes, epilepsy, or allergies.  

<p>Medical alert tattoo: microneedle patch (above) and tattoo on skin (below).</p><p>Credit: Song Li, Georgia Tech</p>
Medical alert tattoo: microneedle patch (above) and tattoo on skin (below). Credit: Song Li, Georgia Tech

Various cosmetic products using microneedles are already on the market – mostly for anti-ageing – but developing microneedle technology for tattoos is new. Prausnitz, a veteran in this area, has studied microneedle patches for years to painlessly administer drugs and vaccines to the skin without the need for hypodermic needles. 

“We saw this as an opportunity to leverage our work on microneedle technology to make tattoos more accessible,” Prausnitz said. “While some people are willing to accept the pain and time required for a tattoo, we thought others might prefer a tattoo that is simply pressed onto the skin and does not hurt.”   

Transforming tattooing 

Tattoos typically use large needles to puncture repeatedly into the skin to get a good image, a time-consuming and painful process. The Georgia Tech team has developed microneedles that are smaller than a grain of sand and are made of tattoo ink encased in a dissolvable matrix.  

“Because the microneedles are made of tattoo ink, they deposit the ink in the skin very efficiently,” said former Georgia Tech postdoctoral fellow Song Li, the lead author of the study. 

In this way, the microneedles can be pressed into the skin just once and then dissolve, leaving the ink in the skin after a few minutes without bleeding.   

Creating the tattoo 

Although most microneedle patches for pharmaceuticals or cosmetics have dozens or hundreds of microneedles arranged in a square or circle, microneedle patch tattoos imprint a design that can include letters, numbers, symbols, and images. By arranging the microneedles in a specific pattern, each microneedle acts like a pixel to create a tattoo image in any shape or pattern.  

The researchers start with a mold containing microneedles in a pattern that forms an image. They fill the microneedles in the mold with tattoo ink and add a patch backing for convenient handling. The resulting patch is then applied to the skin for a few minutes, during which time the microneedles dissolve and release the tattoo ink. Tattoo inks of various colors can be incorporated into the microneedles, including black-light ink that can only be seen when illuminated with ultraviolet light.  

Prausnitz’s lab has been researching microneedles for vaccine delivery for years and realised they could be equally applicable to tattoos. Prausnitz’s team started working on tattoos to identify spayed and neutered pets, but then realised the technology could be effective for people, too. 

The tattoos were also designed with privacy in mind. The researchers even created patches sensitive to environmental factors such as light or temperature changes, where the tattoo will only appear with ultraviolet light or higher temperatures. This provides patients with privacy, revealing the tattoo only when desired. 

The study showed that the tattoos could last for at least a year and are likely to be permanent, which also makes them viable cosmetic options for people who want an aesthetic tattoo without risk of infection or the pain associated with traditional tattoos. Microneedle tattoos could alternatively be loaded with temporary tattoo ink to address short-term needs in medicine and cosmetics.  

Microneedle patch tattoos can also be used to encode information in the skin of animals. Rather than clipping the ear or applying an ear tag to animals to indicate sterilisation status, a painless and discreet tattoo can be applied instead.  

However, the technology does not aim to put tattoo artists out of business.

“The goal isn’t to replace all tattoos, which are often works of beauty created by tattoo artists,” Prausnitz said. “Our goal is to create new opportunities for patients, pets, and people who want a painless tattoo that can be easily administered.”  

Source: Georgia Institute of Technology

Categories : Medical Research & TechnologyTags :

Smartphones Could Serve as Pulse Oximeters in the Home

On By ModernMedia
Photo by Asterfolio on Unsplash

Researchers have demonstrated that smartphones are capable of detecting blood oxygen saturation levels down to 70% – the lowest value that pulse oximeters should be able to measure, as recommended by the US Food and Drug Administration. The team published these results in npj Digital Medicine.

The technique involves participants placing their finger over the camera and flash of a smartphone, which uses a deep-learning algorithm to decipher the blood oxygen levels. When the team delivered a controlled mixture of nitrogen and oxygen to six subjects to artificially bring their blood oxygen levels down, the smartphone correctly predicted whether the subject had low blood oxygen levels 80% of the time.

“Other smartphone apps that do this were developed by asking people to hold their breath. But people get very uncomfortable and have to breathe after a minute or so, and that’s before their blood-oxygen levels have gone down far enough to represent the full range of clinically relevant data,” said co-lead author Jason Hoffman, a UW doctoral student in the Paul G. Allen School of Computer Science & Engineering. “With our test, we’re able to gather 15 minutes of data from each subject. Our data shows that smartphones could work well right in the critical threshold range.”

Another benefit of measuring blood oxygen levels on a smartphone is that almost everyone has one.

“This way you could have multiple measurements with your own device at either no cost or low cost,” said co-author Dr. Matthew Thompson, professor of family medicine in the UW School of Medicine. “In an ideal world, this information could be seamlessly transmitted to a doctor’s office. This would be really beneficial for telemedicine appointments or for triage nurses to be able to quickly determine whether patients need to go to the emergency department or if they can continue to rest at home and make an appointment with their primary care provider later.”

The team recruited six participants ranging in age from 20 to 34. Three identified as female, three identified as male. One participant identified as being African American, while the rest identified as being Caucasian.

To gather data to train and test the algorithm, the researchers had each participant wear a standard pulse oximeter on one finger and then place another finger on the same hand over a smartphone’s camera and flash. Each participant had this same set up on both hands simultaneously.

“The camera is recording a video: Every time your heart beats, fresh blood flows through the part illuminated by the flash,” said Assistant Professor Edward Wang, who started this project as a doctoral student.

“The camera records how much that blood absorbs the light from the flash in each of the three color channels it measures: red, green and blue,” said Wang, who also directs the UC San Diego DigiHealth Lab. “Then we can feed those intensity measurements into our deep-learning model.”

Each participant breathed in a controlled mixture of oxygen and nitrogen to slowly reduce oxygen levels. For all six participants, the team acquired more than 10 000 blood oxygen level readings between 61% and 100%.

The researchers used data from four of the participants to train a deep learning algorithm to extract the blood oxygen levels, and the rest of the data was used to validate the method and then test it to see how well it performed on new subjects.

“Smartphone light can get scattered by all these other components in your finger, which means there’s a lot of noise in the data that we’re looking at,” said co-lead author Varun Viswanath. “Deep learning is a really helpful technique here because it can see these really complex and nuanced features and helps you find patterns that you wouldn’t otherwise be able to see.”

The team hopes to continue this research by testing the algorithm on more people.

“One of our subjects had thick calluses on their fingers, which made it harder for our algorithm to accurately determine their blood oxygen levels,” Hoffman said. “If we were to expand this study to more subjects, we would likely see more people with calluses and more people with different skin tones. Then we could potentially have an algorithm with enough complexity to be able to better model all these differences.”

But, the researchers said, this is a good first step toward developing biomedical devices that are aided by machine learning.

“It’s so important to do a study like this,” Wang said. “Traditional medical devices go through rigorous testing. But computer science research is still just starting to dig its teeth into using machine learning for biomedical device development and we’re all still learning. By forcing ourselves to be rigorous, we’re forcing ourselves to learn how to do things right.”

Source: University of Washington

Categories : Medical Research & Technology Substance UseTags :

Opioid Respiratory Depression Reversed with Electrical Pulses

On By ModernMedia
Source: Pixabay CC0

Opioid use is a significant cause of premature death, caused by supressing respiratory activity. New research, published in The Journal of Physiology, points to a novel treatment for respiratory depression associated with opioid use that administers electrical pulses to the back of the neck, helping patients regain respiratory control following high dosage opioid use.

Breathing problems can occur after opioid use or post-operative complications from anaesthesia because opioids desensitise the brain stem to rises in carbon dioxide. This can cause respiratory failure, which can be fatal. Current treatments, such as manual lung inflation and medication, can work in the short term to combat breathing problems following opioid use, but getting patients to breathe independently remains a challenge. Therefore, this new research, which administers epidural electrical stimulation (EES) offers an alternative, non-pharmacological treatment.

EES administered at the cervical spinal cord, which is located at the back of the neck, activates a network of neurons in the brainstem that stimulates and coordinates respiratory muscles and improves the rate and depth of breathing.

Researchers from the University of California, Los Angeles (UCLA), targeted sensory-motor circuits in the cervical spinal cord of 18 patients with degenerative spine diseases who were anaesthetised for surgical treatment. They delivered 30 Hertz of EES to the cervical spinal cord continuously for no longer than 90 seconds.

They found that short periods of continuous low-intensity EES not only increased the volume of breath but also actively controlled the frequency and rhythm during opioid-induced breathing problems. The rhythmic breathing pattern was sustained briefly after the EES stopped in the presence of high-dose opioids.

Senior author Dr Daniel Lu, UCLA professor and vice chair of neurosurgery, said: “Our results provide proof of principle that cervical EES could improve respiration following opioid use. We can compare the human body to a car, our goal is to jump start the body so it can run by itself without periodic pushes. We hope to use EES to provide novel approaches to restore breathing for healthcare providers as we are now using defibrillation devices for restoring cardiac activities.”

Future human trials with larger cohorts will be conducted to further assess the practical application and impact of EES to determine whether EES can alleviate or reduce the need for ventilator support in acute pathological conditions such as OIRD, stroke, and traumatic brain, brain stem or spinal cord injury. Experimental studies in mice will be carried out to further investigate the role specific neurons play in response to EES.

Source: Physiological Society

Categories : Medical Research & Technology Respiratory DiseasesTags :

‘Alveoli on a Chip’ Reveals Respiration Secrets

On By ModernMedia
Schematic diagram of the alveolar chip (upper left), photograph of the chip (upper middle), CAD drawing of the multi-generation alveolar structure (upper right), and two typical flow patterns in the alveolar chip (bottom). CREDIT: Yonggang Zhu

Understanding how air and particulates through the alveoli is important to better treat respiratory disease. In Biomicrofluidics, researchers detail a model alveolar system that they built to mimic the breathing action of the human lung and allows visualisation of flow patterns within the alveoli. They observed that flow changes after the 20th branching of the alveoli.

The scientists, from Harbin Institute of Technology in China, designed a chip that includes tubes arranged like the structure of a bifurcation point in the bronchial network. The upper layer of the chip is made of a flexible polymer moulded into small tubes that mimic the alveolar structure. The lower layer is glass, which allows the authors to visualise fluid flow through the tubes.

To mimic inhalation and exhalation, the scientists devised a system in which gas was pressurised in a sinusoidal fashion and pumped around the flexible tubes. Small red polystyrene spheres were added to the fluid flowing through tubes. These spheres allowed them to photograph movement of the fluid as it was pushed through the tubes by the artificial breathing apparatus.

Subsequent branches in the bronchial network are termed ‘generations’, and the team found different flow patterns for different generations. In the human lung, alveoli appear at the 15th generation and remain present for generations up to 23. The researchers found a change in flow pattern between the 19th–20th and the 21st–22nd generations.

“The alveolar flow pattern of the 19th generation is dominated by vortex flow,” author Yonggang Zhu said. “Alveolar flow patterns in the 20th generation are similar to those in the 19th, but somewhat compressed.”

The investigators observed a change in the next generation.

“The alveolar flow pattern in the 21st generation has both vortex flow and radial flow. The vortex region is much smaller than the radial flow region. By the time the flow reaches the 22nd generation, vortex flow disappears completely, and we observe only radial flow,” Zhu said.

The authors also found evidence of chaotic behaviour near the vortex centre. They said more research is needed to fully understand this, but they felt the current study provides a good baseline for deeper investigations.

With the model, researchers will be able to study changes in flow patterns in the alveoli due to diseases such as emphysema and COPD.

Source: American Institute of Physics

Categories : Medical Research & Technology Metabolic DisordersTags :

Breakthrough in Development of an Oral Insulin Tablet

On By ModernMedia
Source: Danilo Alvesd on Unsplash

A team of researchers working on developing oral insulin tablets as a replacement for daily insulin injections have made a game-changing discovery, which they published in Scientific Reports. The University of British Columbia team found that it’s not so much the composition of the pill so much as where it’s absorbed.

Researchers have discovered that insulin from the latest version of their oral tablets is absorbed by rats in the same way that injected insulin is.

“These exciting results show that we are on the right track in developing an insulin formulation that will no longer need to be injected before every meal, improving the quality of life, as well as mental health, of more than nine million Type 1 diabetics around the world.” said Professor Anubhav Pratap-Singh, the principal investigator.

He said the inspiration behind the search for a non-injectable insulin comes from his diabetic father, who has had to inject insulin for the past 15 years.

According to Dr Alberto Baldelli, they are now seeing nearly 100% of the insulin from their tablets go straight into the liver. In previous attempts to develop a drinkable insulin, most of the insulin would accumulate in the stomach.

“Even after two hours of delivery, we did not find any insulin in the stomachs of the rats we tested. It was all in the liver and this is the ideal target for insulin – it’s really what we wanted to see,” said PhD candidate Yigong Guo, first author of the study.

Changing the mode of delivery

When it comes to insulin delivery, injections are not the most comfortable or convenient for diabetes patients. But with several other oral insulin alternatives also being tested and developed, the UBC team worked to solve where and how to facilitate a higher absorption rate.

The team instead developed a different kind of tablet that isn’t made for swallowing, but instead dissolves when placed between the gum and cheek.

This method makes use of the buccal mucosa to deliver all the insulin to the liver without wasting or decomposing any insulin along the way.

“For injected insulin we usually need 100iu per shot. Other swallowed tablets being developed that go to the stomach might need 500iu of insulin, which is mostly wasted, and that’s a major problem we have been trying to work around,” explained Yigong.

Most swallowed insulin tablets in development tend to release insulin slowly over two to four hours, while fast-release injected insulin can be fully released in 30–120 minutes.

“Similar to the rapid-acting insulin injection, our oral delivery tablet absorbs after half an hour and can last for about two to four hours long,” said Dr Baldelli.

Potential broad benefits

The study is yet to go into human trials, and for this to happen Prof Pratap-Singh says they will require more time, funding and collaborators. But beyond the clear potential benefits to diabetics, he says the tablet they are developing could also be more sustainable, cost-effective and accessible.

“More than 300 000 Canadians have to inject insulin multiple times per day,” Prof Pratap-Singh said. “That is a lot of environmental waste from the needles and plastic from the syringe that might not be recycled and go to landfill, which wouldn’t be a problem with an oral tablet.”

He explains that their hope is to reduce the cost of insulin per dose since their oral alternative could be cheaper and easier to make. Pills would be easier for diabetics as well, since currently their doses need to be kept cool.

Source: University of British Columbia

Categories : Medical Research & TechnologyTags :

Spider Silk Woven into New Biomedical Applications

On By ModernMedia
Photo by Anthony Ievlev on Unsplash

Researchers have discovered that spider silk proteins can be fused to biologically active proteins and then converted into a gel at body temperature. This could allow for injectable protein solutions that form a gel inside the body, which could be used in tissue engineering and for drug release. Their study is published in Nature Communications.

“We have developed a completely new method for creating a three-dimensional gel from spider silk that can be designed to deliver different functional proteins,” says Anna Rising, research group leader at the Department of Biosciences and Nutrition, Karolinska Institutet (KI) and professor at the Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences (SLU). “The proteins in the gel are very close together and the method is so mild that it can be used even for sensitive proteins.”

An injectable protein solution

In the future, the researchers hope to develop an injectable protein solution that forms a gel inside the body. The ability to design hydrogels with specific functions opens up for a range of possible applications, for example, achieving a controlled release of drugs into the body. In the chemical industry, it could be fused to enzymes, a form of proteins used to speed up various chemical processes.

“In the slightly longer term, I think injectable gels can become very useful in regenerative medicine,” says the study’s first author Tina Arndt, PhD student in Prof Rising’s research group at Karolinska Institutet. “We have a long way to go, but the fact that the protein solution quickly forms a gel at body temperature and that the spider silk has been shown to be well tolerated by the body is promising.”

Mimics spider silk spinning

The researchers have been particularly interested in the spiders’ ability to keep proteins soluble so that they do not clump together before the spinning of the spider silk. They have previously developed a method for the production of valuable proteins which mimics the process the spider uses to produce and store its silk proteins.

“We have previously shown that a specific part of the spider silk protein called the N-terminal domain is produced in large quantities and can keep other proteins soluble, and we can exploit this for medical applications,” said Anna Rising. “We have let bacteria produce this part of the protein linked to functional proteins, including various drugs and enzymes.”

Transformed into a gel

The new study shows that the N-terminal domain also has the ability to change shape and transition to small fibrils that cause the protein solution to be converted into a gel if incubated at 37 °C. In addition, it can be fused to functional proteins that preserve their function in the gel.

Source: Karolinska Institutet

Categories : Genetics Medical Research & TechnologyTags :

Quantum Leap for Genetic Disease Therapy with Baculovirus DNA Repair Kit

On By ModernMedia
DNA repair
Source: Pixabay/CC0

Genetic mutations behind a genetic kidney disease affecting children and young adults have been fixed in patient-derived kidney cells with a high-capacity DNA ‘repair kit’. The advance, developed by University of Bristol scientists, is published in Nucleic Acids Research.

In this new study, the international team describe how they created a DNA repair vehicle to genetically fix faulty podocin, a common genetic cause of inheritable Steroid Resistant Nephrotic Syndrome (SRNS).

Podocin is a protein normally located on the surface of specialised kidney cells and is essential for kidney function. Faulty podocin, however, remains stuck inside the cell and never makes it to the surface, terminally damaging the podocytes. Since the disease cannot be cured with medications, gene therapy which repairs the genetic mutations causing the faulty podocin offers hope for patients.

Typically, human viruses have been utilised in gene therapy applications to carry out genetic repairs. These are used as a ‘Trojan Horse’ to enter cells carrying the errors. Currently dominating systems include lentivirus (LV), adenovirus (AV) and adeno-associated virus (AAV), which are all relatively harmless viruses that readily infect humans. Their viral shells however restrict the amount of cargo they can carry and deliver, namely the DNA kit necessary for efficient genetic repair. This limits the scope of their application in gene therapy.

By applying synthetic biology techniques, the team led by Dr Francesco Aulicino and Professor Imre Berger, re-engineered baculovirus, a insect virus which has a nearly unlimited cargo capacity.

“What sets apart baculovirus from LV, AV, and AAV is the lack of a rigid shell encapsulating the cargo space.” said Dr Francesco Aulicino, who led the study. The shell of baculovirus resembles a hollow stick, simply lengthening when the cargo increases. This allows a much more sophisticated tool-kit can be delivered by the baculovirus.

First, baculovirus had to be equipped to penetrate human cells which it normally would not do. “We decorated the baculovirus with proteins that enabled it to enter human cells very efficiently.” explained Dr Aulicino. The scientists then used their engineered baculovirus to deliver much larger DNA pieces than was previously possible, and build these into the genomes of a whole range of human cells.

The DNA in the human genome comprises 3 billion base-pairs making up ~25,000 genes, which encode for the proteins that are essential for cellular functions. If faulty base-pairs occur in our genes, faulty proteins are made which can make us ill, resulting in hereditary disease. Gene therapy promises repair of hereditary disease at its very root, by rectifying such errors in our genomes. Gene editing approaches, in particular CRISPR/Cas-based methods, have greatly advanced the field by enabling genetic repair with base-pair precision.

The team used patient-derived podocytes carrying the disease-causing error in the genome to demonstrate the aptitude of their technology. By creating a DNA repair kit, comprising protein-based scissors and the nucleic acid molecules that guide them – and the DNA sequences to replace the faulty gene, the team delivered with a single engineered baculovirus a healthy copy of the podocin gene concomitant with the CRISPR/Cas machinery to insert it with base-pair precision into the genome. This was able to reverse the disease-causing phenotype and restore podocin to the cell surface.

Professor Imre Berger explained: “We had previously used baculovirus to infect cultured insect cells to produce recombinant proteins for studying their structure and function.” This method, called MultiBac, has been highly successful to make very large multiprotein complexes with many subunits, in laboratories world-wide. “MultiBac already exploited the flexibility of the baculovirus shell to deliver large pieces of DNA into the cultured insect cells, instructing them to assemble the proteins we were interested in.” When the scientists realised that the same property could potentially transform gene therapy in human cells, they created this new DNA repair kit.

Dr Aulicino added: “There are many avenues to utilise our system. In addition to podocin repair, we could show that we can simultaneously correct many errors in very different places in the genome efficiently, by using our single baculovirus delivery system and the most recent editing techniques available.”

Source: University of Bristol

Categories : Medical Research & TechnologyTags :

Why Some Cells Move Faster in Thicker Mediums

On By ModernMedia
Lung cancer metastasising. Photo by National Cancer Institute on Unsplash

Researchers have discovered that, counterintuitively, certain cells move faster in thicker fluid – such as mucus as opposed to blood – because their ruffled edges sense the viscosity of their environment and adapt to increase their speed.

The researchers’ combined results in cancer and fibroblast cells suggest that the viscosity of a cell’s surrounding environment is an important contributor to disease. The findings, published in Nature Physics, may help explain tumour progression, scarring in mucus-filled lungs affected by cystic fibrosis, and the wound-healing process.

“This link between cell viscosity and attachment has never been demonstrated before,” noted Sergey Plotnikov, assistant professor at the University of Toronto and a co-corresponding author of the study. “We found that the thicker the surrounding environment, the stronger the cells adhere to the substrate and the faster they move – much like walking on an icy surface with shoes that have spikes, versus shoes with no grip at all.”

Understanding why cells behave in this surprising way is important because cancer tumours create a viscous environment, which means spreading cells can move into tumours faster than non-cancerous tissues. Since the researchers observed that cancer cells speed up in a thickened environment, they concluded that the development of ruffled edges in cancer cells may contribute to cancer spreading to other areas of the body.

Targeting the spreading response in fibroblasts, on the other hand, may reduce tissue damage in the mucus-filled lungs affected by cystic fibrosis. Because ruffled fibroblasts move quickly, they are the first type of cells to move through the mucus to the wound, contributing to scarring rather than healing. These results also imply that cell movement might be controlled by changing the viscosity of the lung’s mucus.

“By showing how cells respond to what’s around them, and by describing the physical properties of this area, we can learn what affects their behaviour and eventually how to influence it,” says Ernest Iu, PhD student at the University of Toronto and study co-author.

Plotnikov added, “For example, perhaps if you put a liquid as thick as honey into a wound, the cells will move deeper and faster into it, thereby healing it more effectively.”

Asst Prof Plotnikov and Iu used advanced microscopy techniques to measure the traction that cells exert to move, and changes in structural molecules inside the cells. They compared cancer and fibroblast cells, which have ruffled edges, to cells with smooth edges. They determined that ruffled cell edges sense the thickened environment, triggering a response that allows the cell to pull through the resistance – the ruffles flatten down, spread out and latch on to the surrounding surface.

The experiment originated at Johns Hopkins, where assistant professor Yun Chen, lead author of the study, and Matthew Pittman, PhD student and first author, were first examining the movement of cancer cells. Pittman created a viscous, mucus-like polymer solution, deposited it on different cell types, and saw that cancer cells moved faster than non-cancerous cells when migrating through the thick liquid. To further probe this behaviour, Asst Prof Chen collaborated with U of T’s Plotnikov, who specialises in the push and pull of cell movement.

Plotnikov was amazed at the change in speed going into thick, mucus-like liquid. “Normally, we’re looking at slow, subtle changes under the microscope, but we could see the cells moving twice as fast in real time, and spreading to double their original size,” he explained.

Typically, cell movement depends on myosin proteins, which help muscles contract. Asst Prof Plotnikov and Iu reasoned that stopping myosin would prevent cells from spreading, however were surprised when evidence showed the cells still sped up despite this action. They instead found that columns of the actin protein inside the cell, which contributes to muscle contraction, became more stable in response to the thick liquid, further pushing out the edge of the cell.   

The teams are now investigating how to slow the movement of ruffled cells through thickened environments, which may open the door to new treatments for people affected by cancer and cystic fibrosis.

Source: EurekAlert!