Nanogels For Heart Attack Patients

Heart disease and heart-related illnesses are a leading cause of death around the world, but treatment options are limited. Now, one group reports in ACS Nano that encapsulating stem cells in a nanogel could help repair damage to the heart.

Myocardial infarction, also known as a heart attack, causes damage to the muscular walls of the heart. Scientists have tried different methods to repair this damage. For example, one method involves directly implanting stem cells in the heart wall, but the cells often don’t take hold, and sometimes they trigger an immune reaction. Another treatment option being explored is injectable hydrogels, substances that are composed of water and a polymer. Naturally occurring polymers such as keratin and collagen have been used but they are expensive, and their composition can vary between batches. So Ke Cheng, Hu Zhang, Jinying Zhang and colleagues wanted to see whether placing stem cells in inexpensive hydrogels with designed tiny pores that are made in the laboratory would work.

The team encapsulated stem cells in nanogels, which are initially liquid but then turn into a soft gel when at body temperature. The nanogel didn’t adversely affect stem cell growth or function, and the encased stem cells didn’t trigger a rejection response. When these enveloped cells were injected into mouse and pig hearts, the researchers observed increased cell retention and regeneration compared to directly injecting just the stem cells. In addition, the heart walls were strengthened. Finally, the group successfully tested the encapsulated stem cells in mouse and pig models of myocardial infarction.


Liver Cancer: Hope Is Coming From Plants

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-associated death worldwide. Also called malignant hepatoma, HCC is the most common type of liver cancer. Most cases of HCC are secondary to either a viral hepatitis infection (hepatitis B or C) or cirrhosis (alcoholism being the most common cause of hepatic cirrhosis). These regrettably poor prognoses are due to the difficulty in treating this cancer using conventional chemotherapeutic drugs such as doxorubicin, epirubicin, cisplatin, 5-fluorouracil, etoposide or combinations therein. This may be attributed to that the conventional medicines are not able to reach in a sufficient concentration in the liver tumor cells at levels that are not harmful to the rest of the body.

Now a team of scientists, led by Prof. Taeghwan Hyeon at the Institute for Basic Science (IBS)/Seoul National University and Prof. Kam Man Hui at the National Cancer Center Singapore, has screened a library containing hundreds of natural products against a panel of HCC cells to search a better drug candidate. The screen uncovered a compound named triptolide, a traditional Chinese medicine isolated from the thunder god vine (Tripterygium wilfordii (Latin) or lei gong teng (Chinese)) which was found to be far more potent than current therapies. Studies from other researchers corroborate the findings as triptolide has also found to be very effective against several other malignant cancers including; pancreatic, neuroblastoma and cholangiocarcinoma. However this excitement was tempered when the drug was administered to mice as the increased potency was coupled with increased toxicity as well. Prof. Hyeon et al. endeavoured to alleviate the toxic burden by increasing the specific delivery of the drug to the tumor using a nanoformulation. The designed formulation was a pH-sensitive nanogel coated with the nucleotide precursor, folate.

Nanogel Against Lupus

Systemic lupus erythematosus (SLE) is disease in which the immune system mistakenly attacks healthy tissues, resulting in inflammation and tissue damage. Current treatments are focused on suppression of the immune system, but these therapies can leave patients vulnerable to infection. Michael Look, Tarek Fahmy, and colleagues developed a nanogel-based delivery system that delivers an immunosuppressive drug (mycophenolic acid) directly to tissues associated with immune cells. A nanogel is composed of a polymer containing pores that can be loaded with drug compounds. Look and colleagues tested the mycophenolic acid-loaded nanogel in a mouse model of lupus. Mice treated with the nanogel lived longer than untreated mice or mice treated with mycophenolic acid alone. Additionally, the onset of kidney damage, a common complication of lupus, was delayed in nanogel-treated mice.
Nanoparticles (white spheres) are loaded with a toxic drug, mycophenolic acid (yellow-green molecule), and treat disease (in mice) with greater potency and less toxicity than conventional regimens that do not use nanoparticles. The particles are engulfed by dendritic cells (violet cell on the left) or bind CD4 T cells (purple cell on the right).