COVID-19 has continued to claim lives in 2023, killing more than 50 thousand patients in the United States alone and bringing the global death toll to almost seven million people. The pandemic has also created an epidemic of survivors who continue to suffer from long COVID. But it wasn’t all bad news in 2023.
With more people becoming immune against the virus, the World Health Organization decided, on May 5, that COVID-19 no longer constitutes a public health emergency of international concern. Updated boosters of existing vaccines helped reduce the number of cases, hospitalizations, and deaths, and a new COVID vaccine from Novavax was approved this year.
Aside from COVID-19 vaccines, there were many other interesting and groundbreaking discoveries made this year, some of which are especially notable for their potential impact on health and medicine.
1. The world’s first CRISPR-based gene therapy becomes available
The world’s first CRISPR-based gene therapy was approved by drug regulators in the United Kingdom on November 16, and the U.S. on December 8. It treats sickle cell disease and beta thalassemia, genetic disorders that affect the red blood cells. Hemoglobin, found in red blood cells, carries oxygen around the body. The errors in hemoglobin genes create fragile red blood cells that cause a shortage of oxygen in the body, a condition known as anemia. Patients with sickle cell disease also suffer from infections and severe pain when sickled cells form clots and impede blood flow, while patients with beta thalassemia must receive blood transfusion every three to four weeks.
The newly approved gene therapy, named CASGEVY, corrects faulty hemoglobin genes in a patient’s bone marrow stem cells so they can produce functioning hemoglobin. A patient’s stem cells are harvested from their bone marrow, edited in a laboratory, and then infused back into the patient. A single treatment can potentially cure some patients for life.
Two inventors who fine-tuned CRISPR (short for “clustered regularly interspaced short palindromic repeats”) to work as a precise gene-editing tool, Emmanuelle Charpentier and Jennifer Doudna, were awarded the Nobel Prize in Chemistry just three years ago in 2020.
2. The first drug that slows down Alzheimer’s disease gets approved
The U.S. Food and Drug Administration approved the first drug for Alzheimer’s that targets one underlying cause of the disease. While the drug, Leqembi, isn’t a cure or improve symptoms in late-stage disease, after 18 months of treatment it slows declines in memory and thinking by about 30 percent if the medicine is given in the early stage of disease.
Leqembi is a monoclonal antibody that works by targeting amyloid plaques in the brain that are a defining feature of Alzheimer’s disease. When abnormal levels of a naturally occurring protein, called beta amyloid, clump together to form sticky plaques in brain, they trigger inflammation and damage neuronal connections. Accumulation of amyloid plaques leads to loss of memory and thinking causing Alzheimer’s disease.
Clinical trials indicate that Leqembi removes amyloid plaques from the brain, which slows the progression of the disease.
3. Researchers produce healthy mice pups from two fathers; no female required
Yes, you read that right. Researchers from Japan presented evidence at a scientific conference that it is possible to produce healthy, fertile mice without an egg from a female mouse.
First, eggs were made from the stem cells derived from the skin cells of a male mouse. These eggs were fertilized with sperm of another male and then the fertilized egg was transferred into a female mouse where it grew and matured.
Although just seven out of more than 600 implanted embryos developed into baby mice, the pups grew normally and were fertile as adults.
It is not yet known if the mouse pups will develop exactly like those born through conventional breeding. These findings have not yet been published in a peer reviewed journal and similar preliminary steps have so far failed in humans.
4. Scientists map all the connections in an insect brain
Scientists have produced the first complete brain-wiring diagram of an insect brain. This may not sound impressive but the brain, even that of a fruit fly, contains vast networks of interconnected neurons called the connectome.
Until now, only the brains of a roundworm, a sea squirt, and a marine worm have been completely mapped; each of which contains just a couple of hundred connections.
But a complete map of the connectome of a fruit fly larva reveals it contains more than 3,000 neurons and more than half a million connections between them. Developing this map took an international team of scientists more than five years. Although a fruit fly brain is much simpler than that of humans, the techniques developed will help map more complex brains in the future.
The neural circuits In the fruit fly brain look similar to neural networks used in machine learning. Understanding the similarities and complexities of the fly brain connectome can help to decipher how the human brain works and how neurological diseases develop. It can also lead to the development of new machine learning methods and more efficient artificial intelligence systems.
5. Pigment-producing cells get “stuck” causing gray hairs
Scientists show that when pigment-producing cells, called melanocytes, get stuck in an immature state, they fail to develop their blonde, brown, red, or black, hair color. This arrested state leads to graying hairs. New hair grows from follicles, found in the skin, where melanocytes also reside.
The scientists at New York University observed single melanocyte stem cells migrate up and down the individual hair folicle of mice over two years. To their surprise, they found that melanocyte stem cells can switch back and forth from gray immature stem cells to mature colored cells as they traverse up and down during the life cycle of the hair. But as hair ages, the melanocyte stem cells get sluggish after multiple cycles and become trapped near the base of the hair as immature melanocytes. With no pigment being produced, the hair turns gray.
6. Bacteria shown to help cancer cells spread more aggressively
Scientists have found that some bacteria that are frequently found in many gastrointestinal tract tumors directly help cancer cells evade the body’s immune response.
Not only do these bacteria cooperate with tumor cells to promote cancer progression, they also help them spread more rapidly by breaking down anticancer drugs and causing the treatment to fail.
This research suggests that some anticancer drugs are effective because they also kill the tumor dwelling bacteria. Understanding how the tumor’s microenvironment affects its survival and progression can open new doors of treating cancer.
7. AI identifies people at the highest risk of pancreatic cancer
A new artificial intelligence (AI) tool can predict pancreatic cancer up to three years before actual diagnosis, by identifying specific patterns of conditions that occurred in patients’ health records.
Pancreatic cancer is rare but it is the third largest cause of cancer-related deaths. It is so deadly because it is generally detected in the late stages when the disease has already spread to other areas of body.
Symptoms of early stage pancreatic cancer are easily misdiagnosed, but many patients could live longer if the cancer was detected early. That led scientists to train an AI algorithm on the medical records of 6.2 million people from Denmark spanning 41 years to detect the patterns hidden in the records of 24,000 patients who later developed pancreatic cancer.
In the medical records, each disease is recorded with a code. The AI model analyzed the combinations of these disease codes and the timing of their occurrence. By comparing specific sequences of conditions that preceded a diagnosis of pancreatic cancer, the AI model learned to identify those at greatest risk for the disease.
The scientists then tested the AI tool by analyzing the records of nearly 3 million U.S. veterans spanning 21 years. The computer algorithm correctly identified almost 4,000 individuals, up to three years before they were actually diagnosed with pancreatic cancer. The study shows that AI models can be as accurate as genetic testing in predicting the risk of pancreatic cancer. Because pancreatic cancer is so rare, genetic screening is currently recommended only for high risk individuals, or with those with a family history of the disease.
Editor’s Note: This story has been updated to include news that the FDA approved gene therapies for sickle cell disease.