Tag Archives: blood vessel

One of the lab-grown blood vessels. Credit: Science Translational Medicine.

Scientists implant lab-grown blood vessels in patients who need dialysis

One of the lab-grown blood vessels. Credit: Science Translational Medicine.

One of the lab-grown blood vessels. Credit: Science Translational Medicine.

Not only have researchers grown blood vessels in the lab, but they also implanted them into the circulatory systems of patients undergoing dialysis. Since the blood vessels were grown from cells collected from the recipient’s own tissue, there are no biocompatibility issues. In time, these blood vessels grew cells of their own and became indistinguishable from other blood vessels.

The blood vessels were developed at Humacyte, a biotech company in Durham, North Carolina. Researchers grew the blood vessels using smooth muscles cells collected from the walls of arteries and veins. In the lab, the cells were placed inside a scaffold filled with a fluid that provides nutrients. Over the course of two months, this setup produced 3D networks of proteins that led to the formation of blood vessels.

In the final step, the researchers removed proteins from the newly grown vessels that might have been recognized as foreign by a recipient’s immune system. The blood vessels grew on average to 42 centimeters in length and 6 millimeters in diameter.

These blood vessels were implanted into the upper arms of 60 people with kidney failure who were undergoing dialysis. In order to connect a dialysis machine, doctors normally have to merge an artery to a vein in order to create a wider vessel that can transfer blood. However, all of the recipients were not able to undergo this procedure since their blood vessels were too narrow, which is why they were selected for blood vessel implants in the first place.

Four years after the implant, the blood vessels developed into self-healing, multi-layered tissues that looked and behaved like the recipient’s own vessels. The lab-grown vessels had no cells of their own when they were first implanted but became populated with different types of the recipient’s own cells, the authors reported in the journal Science Translational Medicine.

Blood vessels have to be replaced in many other situations such as in the event of trauma or cardiovascular disease. Usually, doctors implant synthetic tubes but these can cause scarring or lead to inflammatory reactions.

The researchers at Humacyte hope to scale their process in order to grow tens of thousands of blood vessels per year.

Energy drinks.

Energy drinks have a profound effect on our blood vessels, new research shows

Just have a coffee instead. Or, ideally, a good night’s rest!

Energy drinks.

Image credits Simon Desmarais.

Energy drinks have been associated with a host of health problems, including conditions that relate to heart, stomach, and nerve function. New research comes to explain how such beverages interact with our cardiovascular systems. According to the findings, consuming just one energy drink leads to notably diminished blood vessel capacity — an effect that lasts at least 90 minutes.

“As energy drinks are becoming more and more popular, it is important to study the effects of these drinks on those who frequently drink them and better determine what, if any, is a safe consumption pattern,” authors noted.

The team was led by John Higgins, M.D., M.B.A., of McGovern Medical School at UTHealth, Houston. Together with his colleagues, Higgins studied the endothelial (blood vessel) function of 44 healthy, non-smoking students in their 20s. Afterward, the students were given a 24-ounce (710 milliliters) energy drink. Blood vessel function was then re-analyzed, 90 minutes after the participants finished their drink.

The students experienced notably diminished blood vessel function after consuming the beverage, the team reports.

Before consuming the drink (and one and a half hours afterward), the team tested the students’ artery flow-mediated dilation. This basically involves taking an ultrasound measurement of an artery to gauge the overall health of a patient’s blood vessels. The team reports that vessel dilation was, on average, 5.1% in diameter at the start of the test, but dropped to 2.8% in diameter after the drink was consumed. This measurement is consistent with an acute impairment of vascular function, they add.

Higgins and his team say that the change in vessel dilation may be produced by the blend of ingredients that go into making an energy drink. These components — usually caffeine, taurine, sugar, and other herbal components — may act on the endothelium (lining of the blood vessels) to make it constrict. The results are still preliminary and the team will need to perform further tests to see exactly which ingredients cause this effect.

The findings will be presented at the American Heart Association’s Scientific Sessions 2018 conference in Chicago.

Scientists hack a $40 cotton candy maker to spin artificial blood vessels

Creating artificial blood vessels is a pivotal aspect of reconstructive medicine. However, time and time again this has proven very tricky to accomplish. Now, a researcher believes he has found the key: weaving blood vessels with cotton candy machines.

Three-dimensional slab of gelatin that contains a microvascular network. (Bellan Lab / Vanderbilt)

Traditionally, researchers would allow cultured cells to spontaneously develop capillary systems of their own. This process can be very lengthy, taking weeks or months, and is very delicate. Leon Bellan, assistant professor of mechanical engineering at Vanderbilt University, wanted to try something different so he went for a top-bottom approach, finding help in an unexpected area: cotton candy.

“So far the other top-down approaches have only managed to create networks with microchannels larger than 100 microns, about ten times the size of capillaries,” he said. In addition, many of these other techniques are not able to form networks as complex as the cotton candy approach.

In an article published online on Feb. 4 by the Advanced Healthcare Materials journal, Bellan and colleagues report that they have finally succeeded in their unorthodox technique, creating a three-dimensional artificial capillary system that can keep living cells viable and functional for more than a week – a great breakthrough, especially when considering today’s alternatives.

“Some people in the field think this approach is a little crazy,” said Bellan, “But now we’ve shown we can use this simple technique to make microfluidic networks that mimic the three-dimensional capillary system in the human body in a cell-friendly fashion. Generally, it’s not that difficult to make two-dimensional networks, but adding the third dimension is much harder; with this approach, we can make our system as three-dimensional as we like.”

Microvascular network perfused with liquid. Figure B is magnification of the area in Figure A outlined in white. (Bellan Lab / Vanderbilt)

Like many other artificial tissues, this relies on a class of materials called hydrogels. A hydrogel is a network of polymer chains that are hydrophilic, they don’t absorb water because they are saturated with it. Hydrogels are very interesting because their properties can be tuned to closely mimic those of the natural extracellular matrix that surrounds cells in the body.

However, even when you have the right technique, creating bio-materials from hydrogels isn’t easy. Especially when designing materials for blood vessels, you encounter a specific paradox, something that Bellan calls the “Catch 22“:

“First, the material has to be insoluble in water when you make the mold so it doesn’t dissolve when you pour the gel. Then it must dissolve in water to create the microchannels because cells will only grow in aqueous environments,” he explained.

So he and his team worked with many materials before they got the right fit. They finally developed one that somehow satisfied this condition: it’s insoluble at temperatures above 32 degrees Celsius and soluble below that temperature, so it can be developed outside the human body at lower temperatures, and inside the human body it becomes insoluble. It gets even better, because this material has already been proven to be compatible with the human body.

So far so good – now they’re working on improving the method and making it available to as many people as possible.

“Our goal is to create a basic ‘toolbox’ that will allow other researchers to use this simple, low-cost approach to create the artificial vasculature needed to sustain artificial livers, kidneys, bone and other organs,” Bellan said.

See a video of how it works here:

Eye blood vessels linked to IQ and cognitive functions – in other words, the back of your eye may indicate brain health

According to a new research published in Psychological Science, the width of blood vessels in the retina may indicate your brain health.

human eye

Previous studies have already shown that younger people who score relatively low on IQ tests tend to be poorer and have a shorter lifespan — however, it’s still a matter of debate if this has a physiological cause, or if the lifestyle associated with the lower IQ is simple less healthier. However, in the current study, psychological scientists led by Dr Idan Shalev of Duke University wondered whether intelligence might directly indicate the health of the brain – specifically the health of the system of blood vessels which provide nutrients and oxygen to your brain. In order to investigate this relation, they studied a rather unexpected domain: ophtalmology.

The researchers examined data from participants taking part in the Dunedin Multidisciplinary Health and Development Study, a large health and behavior investigation that takes place in New Zealand and studies over 1000 people. They used a technique called digital retinal imaging. In digital retinal imaging, high-resolution imaging systems are used to take pictures of the inside of your eye, enabling doctors to estimate the health of your retina and helps them to detect and manage such eye and health conditions as glaucoma, diabetes, and macular degeneration.

The findings were intriguing: lower IQ scores were associated with wider retina venules (the very small blood vessel at the back of your eye), even after researchers compensated for other factors, such as lifestyle, general health and environmental risks.

“It’s remarkable that venular caliber in the eye is related, however modestly, to mental test scores of individuals in their 30s, and even to IQ scores in childhood,” Dr Idan Shalev and colleagues said.

The study doesn’t explain why vascular health and cognitive functioning are connected, but researchers are fairly sure that it is somehow connected to the oxygen in the brain.

“Increasing knowledge about retinal vessels may enable scientists to develop better diagnosis and treatments to increase the levels of oxygen into the brain and by that, to prevent age-related worsening of cognitive abilities,” the scientists concluded.

Journal Reference.

Blood vessels in the eye linked to IQ and cognitive functions

It’s not quite what scientists expected – the width of blood vessels in the eye, at the back of the retina, may indicate brain health risks, such as dementia and alzheimers years before they actually set in according to a new study published in Psychological Science.

Credit: © lightpoet / Fotolia

Credit: © lightpoet / Fotolia

It is already well known that young people who score very low at IQ tests are at a higher risk for poorer health and shorter lifespan which can’t be explained only by other factors. Psychological scientist Idan Shalev of Duke University and colleagues have tried to find out if there is a any connection between IQ score (I really prefer this term to intelligence in this case) and brain health.

To do this, they turned to opthalmology – the branch of medicine that deals with the eye. They used a technique called digital retinal imaging, which is relatively new and completely noninvasive.

“Digital retinal imaging is a tool that is being used today mainly by eye doctors to study diseases of the eye,” Shalev notes. “But our initial findings indicate that it may be a useful investigative tool for psychological scientists who want to study the link between intelligence and health across the lifespan.”

Basically, you can get a pretty good idea of what happens in the blood vessels in the brain by looking at the blood vessels in the retina – it’s the next best thing. Retinal blood vessels share similar size, structure, and function with blood vessels in the brain. Their results were rather intriguing.

Having wider retinal venules was linked with lower IQ scores at age 38, even after researchers eliminated all the other likely causes, like health, lifestyle, and environmental risk factors that might have played a role.

People who had wider retinal venules had noticeable cognitive deficits, scoring lower on numerous tests of neuropsychological functioning, verbal comprehention, memory, and many more. But what was even more surprising, is that people who had wider blood vessels at age 38 also had lower IQ in childhood, a full 25 years earlier.

“It’s remarkable that venular caliber in the eye is related, however modestly, to mental test scores of individuals in their 30s, and even to IQ scores in childhood,” the researchers observe.

They believe that there is not really a distinct mechanism between retinal vessels and cognitive functioning, but is rather connected to oxygenation of the brain.

“Increasing knowledge about retinal vessels may enable scientists to develop better diagnosis and treatments to increase the levels of oxygen into the brain and by that, to prevent age-related worsening of cognitive abilities,” they conclude.