Login with your Social Account

Mouse brain tissue kept alive for several weeks in laboratory

Mouse brain tissue kept alive for several weeks in laboratory

Researchers from Japan have kept small portions of mouse brain tissue alive and viable for a period of 25 days, isolating in a culture. This has highly increased the timeline in which the isolated brain tissue can keep the functions intact extending days to weeks. This can affect the research in therapeutic drugs in a positive way. The findings have been published in the Analytical Sciences journal.

The key to success was a new technique that combines a special kind of membrane with an improved microfluidic device. Microfluidic devices use small channels for delivery of fluid into tissues and are better than the normal culture dishes specially for ex vivo tissue experiments. They can also be customized highly and mimic certain kinds of cell behaviors. They also require small volume samples thus making it easy to study the cell interactions. 

However, only a few days is not sufficient to understand how body systems react to various things. The main problem is to keep a balance. Tissues dry quickly so the system has to be kept moist along with nutrients in a wet culture medium. Too much moisture prevents cells to exchange gases which the tissue needs thus drowning it finally. This problem had to be tackled by the researchers. 

This device has a semi-permeable microfluidic channel that is surrounded by an artificial membrane and solid walls. These are made from polydimethylsiloxane, a polymer mainly used in microfluidic devices. The tissue does not sit in the bath consisting of the culture medium but instead, the fluid circulates through the channel, passing by the membrane to keep the tissues most while still maintaining the exchange of gases between cells. 

Nobutoshi Ota, a biochemist at RIKEN Center for Biosystems Dynamics Research said that the medium flow was difficult to be controlled as the microchannel between the porous membrane and PDMS walls were not normal. The team got success after repeated trials and modifications to the membrane while adjusting the flow rates of the inlet and outlet.

A small part of the brain named suprachiasmatic nucleus(SCN)  was used which is responsible for keeping the circadian and biological rhythms intact in mammals. Neuronal cells in SCN exchange information by keeping the motion of peptides and molecules between cells intact. This is ideal for studying cell interactions. 

The mice from where the SCNs were harvested had been edited genetically such that the circadian rhythm in the brain was connected to the production of a fluorescent protein indicating if everything was working properly. 

The fluorescence was active for 25 days compared to that of a normal culture dish where after 10 hours the activity control reduced by 6 percent. The experiment lasted for only 25 days since it was the cutoff time for this experiment. It could have lasted well beyond 100 days. 

Researchers believe that this can also be used for remaining organ tissues with the possibility for human organs that are grown in the laboratory. This will improve the research in organogenesis by culturing and observation which is needed for the growth of organs and tissue. 

Journal Reference: Analytical Sciences

8-cell human embryo

Researchers in pursuit of creation of human-monkey embryos in laboratory

In a controversial move, scientists have created embryos that are partially human and partially monkey. According to Spanish daily El País, Juan Carlos Izpisúa Belmonte, a Spanish biologist operates a lab at Salk Institute, California, has been collaborating with researchers in China to conduct this controversial research. Their main goal is to produce “human-animal chimeras”, where human cells are added to the monkey embryos. Just a few days back, the Japanese government also approved experiments to be conducted on human-animal embryos.

The main motive behind this research is to create animals which possess organs such as liver or kidney that are composed of human cells. As a result, these animals could be used for sources for organ transplantation. The technique for creating chimeras is that human embryonic stem cells are injected into the embryos of another species which are a day-old. Researchers hope that with this addition the growth of human cells would take place with the embryo.

Previously, Izpisúa Belmonte tried to create human-animal chimeras with the addition of human cells to the pig embryos however, in that case, human cells did not take an effective hold. However as monkeys are closer to humans genetically, chances are more for the experiment to succeed. Researchers are using gene-editing technology so that the formation of certain kinds of cells can be disabled in the animal embryos and as a result, the human cells have a better chance of taking hold.

However, this is highly controversial in the United States. According to the National Institutes of Health, federal funds can never be used for the creation of mixed monkey-human embryos. Although China does not have such a rule which facilitates the research in that country.

Till now, a part-human and part-monkey has not taken birth. Estrella Núñez, an administrator and biologist at the Catholic University of Murcia, Spain told that the mixed embryos are only allowed to develop for a week or two in the laboratory, where they can be studied. Catholic University of Murcia is helping to fund this research. There have been no comments from the Salk Institute about this and Núñez has refused to comment till the final results are published.

Pablo Ross, a veterinary researcher at University of California, Davis, worked previously with Salk on pig-human chimeras. He said that it does not make any sense to try to grow human organs in the monkeys. As they are quite small, it takes a long time for their development. He thinks that the injection of human cells into the monkey embryos could resolve questions of evolutionary distance and interspecies barriers.

Situs Inversus Totalis

Bizarre case study reveals man with his body organs on the wrong side

A medical emergency room with the patient turned into a tale of an unexpected tale in the case of a 66-year-old man who turned up at the hospital with coughs and chest pains. Only for the doctors to realize that the internal organs of the patients were on the wrong side of the body like the heart was on the right, liver on the left, etc. The report was published in the New England Journal of Medicine.

This condition is named as Situs inversus totalis and it is not life changing as it sounds. This was discovered due to modern medical scanning tools and many people had lived their lives without any diagnosis. The doctors have said that the patient was migrated to the United States after being in a refugee camp for 20 years. The findings as shown by the chest radiograph were dextrocardia in which the heart is situated on the right rather than on the left and a mirror image transposition for the abdominal organs. The symptoms of the man included chest pain, congestion and coughing and a little pain on the left of the abdomen as seen on the medical reports.

This case is very rare but not unheard. Donny Osmond is a well-known case of Situs Inversus Totalis where all internal organs are flipped like a mirror image and this common type affects close to 1 in 10,000 people. Such people are generally seen wearing a bracelet that declares and signals the doctor of this disorder in case of an emergency surgery where the doctor might mistakenly open the wrong part of the body. The heart is the part where most of the complication occurs in the case of Situs Inversus and dextrocardia in which the key important arteries can end up lying in parallel rather than crisscrossing which makes the heart surgery and transplants very difficult to operate.

The name of this abnormality was coined by Matthew Baillie in 1788 which is “location” and “opposite” in Latin and this terminology is continued by doctors and scientists even today. One recent case was reported of Rose Marie Bentley who lived up to the age of 99 years and no one knew about this abnormal condition until her death report came. Her heart was on the correct side of the body which makes Situs Inversus much more dangerous.

Situs Inversus is often dismissed as an X-ray error after the reports when the baby is born and is the reason why people aren’t diagnosed until many years later.