Dental pulp stem cells transformed by 'bad breath' chemical

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Japanese scientists have found that the odorous compound responsible for halitosis – otherwise known as bad breath – is ideal for harvesting stem cells taken from human dental pulp.

In a study published today, Monday 27 February, in IOP Publishing's Journal of Breath Research, researchers showed that hydrogen sulphide (H2S) increased the ability of adult stem cells to differentiate into hepatic (liver) cells, furthering their reputation as a reliable source for future liver-cell therapy.

This is the first time that liver cells have been produced from human dental pulp and, even more impressively, have been produced in high numbers of high purity.

"High purity means there are less 'wrong cells' that are being differentiated to other tissues, or remaining as stem cells. Moreover, these facts suggest that patients undergoing transplantation with the hepatic cells may have almost no possibility of developing teratomas or cancers, as can be the case when using bone marrow stem cells," said lead author of the study Dr. Ken Yaegaki.

The remarkable transforming ability of stem cells has led to significant focus from research groups around the world and given rise to expectations of cures for numerable diseases, including Parkinson's and Alzheimer's.

In this study, Dr. Ken Yaegaki and his group, from Nippon Dental University, Japan, used stem cells from dental pulp – the central part of the tooth made up of connective tissue and cells – which were obtained from the teeth of dental patients who were undergoing routine tooth extractions.

Once the cells were sufficiently prepared, they were separated into two batches (a test and a control) and the test cells incubated in a H2S chamber. They were harvested and analysed after 3, 6 and 9 days to see if the cells had successfully transformed into liver cells.

To test if the cells successfully differentiated under the influence of H2S, the researchers carried out a series of tests looking at features that were characteristic of liver cells. In addition to physical observations under the microscope, the researchers investigated the cell's ability to store glycogen and then recorded the amount of urea contained in the cell.

"Until now, nobody has produced the protocol to regenerate such a huge number of hepatic cells for human transplantation. Compared to the traditional method of using fetal bovine serum to produce the cells, our method is productive and, most importantly, safe" continued Dr. Yaegaki.

Hydrogen sulphide (H2S) has the characteristic smell of rotten eggs and is produced throughout the body in the tissues. Although its exact function is unknown, researchers have been led to believe that it plays a key role in many physiological processes and disease states.

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Injectable progesterone contraceptives may be associated with poor periodontal health

Injectable progesterone contraceptives may be associated with poor periodontal health, according to research in the Journal of Periodontology. The study found that women who are currently taking depotmedroxyprogesterone acetate (DMPA) injectable contraceptive, or have taken DMPA in the past, are more likely to have indicators of poor periodontal health, including gingivitis and periodontitis, than women who have never taken the injectable contraceptive. DMPA is a long-lasting progestin-only injectable contraceptive administered intermuscularly every three months.

Periodontal disease is a chronic inflammatory disease that affects the gum tissue and bone that supports the teeth. Gingivitis, the mildest form of gum disease, causes the gums to become red, swollen, and bleed easily. Periodontitis is the most severe form of gum disease and can lead to tooth loss. Additionally, research has associated gum disease with other chronic inflammatory diseases such as diabetes, cardiovascular disease, and rheumatoid arthritis.

The data for this study were obtained from the NHANES 1999-2004 public use datasets. The participants chosen were non-pregnant, premenopausal women aged 15-44 who had provided complete DMPA usage data, indicating current usage of DMPA, past usage of DMPA, or no usage of DMPA at all. All participants received a dental examination that noted clinical attachment (CA) loss, periodontal pocket assessment at two or three sites per tooth, and presence of gingival bleeding.

After adjusting for age, race, education, poverty income level, and smoking status, the study found that current and past DMPA users had significantly increased periodontal pockets, gingival bleeding, and CA loss than women who have never used DMPA. Current DMPA users were more likely to have gingivitis, while past DMPA users were more likely to have periodontitis.

According to Dr. Pamela McClain, President of the American Academy of Periodontology (AAP) and a practicing periodontist in Aurora, Colorado, women currently taking DMPA or that have used DMPA in the past should pay careful attention to their teeth and gums. "Hormones can play a role in woman's periodontal health. These findings suggest that women that use, or have used, a hormone-based injectable contraception such as DMPA may have increased odds of poor periodontal health. I would encourage women that use or previously used this form of contraception to maintain excellent oral care, and to be sure to see a dental professional for a comprehensive periodontal evaluation on an annual basis."