Posts tagged melanocytes

A new study from Karolinska Institutet shows that a part of the nervous system, the parasympathetic nervous system, is formed in a way that is different from what researchers previously believed. In this study, which is published in the journal Science, a new phenomenon is investigated within the field of developmental biology, and the findings may lead to new medical treatments for congenital disorders of the nervous system.

Almost all of the body’s functions are controlled by the autonomous, involuntary nervous system, for example the heart and blood vessels, liver and gastrointestinal system. At rest, the body is set up for energy saving functions, which is regulated by the parasympathetic part of the autonomous nervous system.

Current understanding is that many important types of cells, including the parasympathetic nerve cells in various organs, originate in early progenitor cells that move short distances while the embryo is still small. But this model does not explain how many of our organs – which develop relatively late, when the embryo is large – are furnished with cells that form the parasympathetic neurons.

This study alters a fundamental principal of our understanding of how the peripheral nervous system develops in the body. Researchers at Karolinska Institutet have made three-dimensional reconstructions of mouse embryos. These show that the parasympathetic neurons are formed from immature glial cells known as Schwann cell precursors that travel along the peripheral nerves out to the body’s tissues and organs. The immature cells have the properties of stem cells and may be the origin of several different types of cells. For example, the researchers behind this new study have previously demonstrated that the majority of our melanocytes (pigment cells) are born from these cells.

New principal of developmental biology

"Our study focuses on a new principal of developmental biology, a targeted recruitment of cells that are probably also used in the reconstruction of tissue. Despite the elegance, simplicity and beauty of this principal, it is still unclear how the number of parasympathetic neurons is controlled and why only some of the cells transported by nerves are transformed into that which becomes an important part of the nervous system", says Igor Adameyko at the Department of Physiology and Pharmacology who, together with Patrik Ernfors at the Department of Medical Biochemistry and Biophysics, is responsible for the study.

Somewhat surprisingly, the researchers found that the entire parasympathetic nervous system arises from these progenitor cells that travel along the peripheral nerves. The researchers hope that this discovery will open up the possibility of new ways to treat congenital disorders of the autonomous nervous system using regenerative medicine.

(Source: ki.se)

In a retrospective study, Saint Louis University researchers have found that patients with melanoma brain metastases can be treated with large doses of interleukin-2 (HD IL-2), a therapy that triggers the body’s own immune system to destroy the cancer cells.

The study that was recently published in Chemotherapy Research and Practice, reviews cases of eight patients who underwent this therapy at Saint Louis University.

John Richart, M.D., associate professor of internal medicine at SLU and principal investigator of the study, first treated a patient with the disease using the HD IL-2 treatment in 1999.

"Traditionally, melanoma patients with brain metastases have not been considered for HD IL-2 because treatment was thought to be futile," Richart said. "Our study shows that having this condition does not exclude a patient from getting this treatment and can in fact improve the length of their life."

Melanoma is the most dangerous form of skin cancer that begins in the melanin-producing cells called melanocytes. In some melanoma patients, the cancer spreads to the brain, causing multiple tumors that are difficult to treat. According to the CDC, melanoma is the third most common cancer causing brain metastases in the U.S. Richart said the median overall survival of patients with melanoma brain metastases is approximately four months whereas in the study, the median overall survival for patients was 8.7 months.

During the treatment, patients are given an IV medication - a chemical the body naturally makes that stimulates the immune system to recognize and destroy melanoma cells - for a period of six days while they are admitted to the hospital and are closely monitored by doctors and nurses. A patient requires four such six-day admission cycles in order to complete the course of the treatment.

To be eligible for HD IL-2 treatment, melanoma patients with brain metastases have to be in healthy shape with good brain function - that is they cannot have brain lesions that are growing rapidly or show any symptoms of brain lesions. In the past, melanoma patients with brain metastases have been considered ineligible for this treatment because doctors thought that the treatment would cause life-threatening cerebral edema, a complication that causes excess accumulation of fluids in the brain, and neurotoxicity, or irreversible damage to the brain or the nervous system.

"In this review, we found that there were no episodes of treatment-related mortality. Our findings demonstrate that HD IL-2 can be considered as an option for patients with melanoma brain metastases," said Melinda Chu, M.D., a first year dermatology resident at SLU and first author of the study.
SLU is the only medical center in the region that provides this treatment.

"We need a highly skilled nursing staff for the HD-IL-2 program to be successful," Richart said. "Our nursing team at SLU is with each patient every step of the way, 24 hours a day. They help patients get through and continue the treatment."