As 2023 draws to a close, we once again present our selection of the most important scientific milestones of the past year. Not all of them represent new discoveries, nor are they all good news, but at least there are some first steps towards long-needed progress.
A step for the climate, but forwards or backwards?
Although there are still a few days to go before the curtain falls on 2023, the data confirm that we have just experienced the warmest year in recorded history. Average temperatures from January to November were 1.46°C above pre-industrial levels, already very close to the strict 1.5°C limit set by the 2015 Paris Agreement, although the more lenient 2°C limit was exceeded for the first time on two days in November. In the face of such alarming data, there were high expectations for possible progress at the COP28 climate conference in Dubai. However, as with previous summits, the results were disappointing: although a commitment to transition away from fossil fuels was made for the first time, experts criticised the lukewarm language used, with some describing it as a “step backwards”.
RNA vaccines
While few could have imagined a pandemic like the one that emerged in 2020, perhaps even fewer could have predicted what it would mean for the take-off of a new biomedical technology: RNA vaccines. Among the few positive legacies of a global catastrophe, new vaccines stand out. Before the pandemic, they had been extensively tested on animals, but had yet to make the leap to humans. With the great success of immunisations against COVID-19—which led to a Nobel Prize in Physiology or Medicine in 2023 for Katalin Karikó and Drew Weissman—several vaccines based on the same principle are under development or being tested against various diseases, and successes have already been achieved, for example against pancreatic cancer and melanoma.
Curing obesity with pills
It is unusual for Science magazine to award its Breakthrough of the Year honour to a drug, especially when it is not really a discovery of the current year. But new results for a group of anti-obesity drugs are exceeding expectations. These drugs mimic the action of glucagon-like peptide type 1 (GLP-1), a hormone in the body that stimulates insulin production. Originally targeted at diabetes, these compounds have shown great efficacy not only in obesity, but also in cardiovascular disease, and are now also being tested against addiction, Alzheimer’s and Parkinson’s disease.
NASA looks for UFOs, but fails to find them
Although it’s not a new discovery, it is a change of course. For decades, the phenomenon of UFOs, now renamed Unidentified Anomalous Phenomena, or UAP, has been ignored by mainstream science and scientists, after repeated failures by those attempting to prove its reality. This year, for the first time, NASA commissioned a study team to analyse the available data in order to establish a scientific case study methodology. We have no new evidence of alien life, but the Pentagon has also officially joined the search, which many believe is necessary.
The first synthetic embryos
The stem cell field is slowly realising its potential, with a new step being taken each year. In 2023, at least two teams published on the creation of synthetic early human embryos from stem cells, an achievement that was greeted with much media coverage, but also with alarm about the ethical implications. These are not actually viable whole embryos, but sufficiently similar structures to reveal crucial new insights into early embryonic development and the effects of genetic diseases, a field otherwise inaccessible to science. However, ethical oversight of such research remains essential.
Figuring out morning sickness
It is often said that this is one of those cases that would have received much more attention if it affected men. Around 70% of pregnant women suffer from discomfort and nausea, which in 0.3-2% of cases becomes disabling, known as hyperemesis gravidarum. Among those who have suffered from this severe form, which can lead to hospitalisation or even death, is geneticist Marlena Fejzo, first author of the study that has finally identified the cause: a hormone called GDF15, secreted by the foetus, which causes these symptoms in particularly sensitive women. The finding opens the door to prevention and treatment.
COVID-19, still present and long-lasting
In May, the World Health Organisation declared an end to the global health emergency, the term used for the pandemic. Officially, it has been with us for three and a half years, and restrictions and lockdowns have now been abandoned worldwide. But the virus is still with us, generating new variants and causing hospitalisations and deaths, especially in unvaccinated people. The origin of the SARS-CoV-2 virus has yet to be definitively identified, but the concern of organisations, authorities and the scientific community has been raised by persistent or long COVID, the consequences of which may become a major public health problem in the years to come. Although hypotheses about the causes vary, evidence has emerged this year that a reduction in the levels of the neurotransmitter serotonin may be a key element in this syndrome.
Gene editing comes to the hospital
Since 2012, when Emmanuelle Charpentier, Jennifer Doudna and others developed the CRISPR gene-editing system, based on a discovery by the Spanish scientist Francisco Mojica, the new DNA cut-and-paste tool has become an indispensable tool in laboratories. In parallel, CRISPR has been making strides towards its use in the clinic to repair faulty genes. In 2023, the first gene therapy using CRISPR was approved in the US, UK and Europe: CASGEVY, its commercial name, will treat sickle cell anaemia and beta thalassaemia—two blood diseases—by gene editing bone marrow stem cells taken from patients and then returned to their bodies. It joins some 30 other conventional gene therapies already approved.
A digital bionic bridge to walk again
In recent years, advances in bionics have led to increasingly sophisticated prostheses for amputees and systems designed to restore mobility to patients with spinal cord injuries. Among the most notable developments in this field is the system tested this year by Swiss researchers, which consists of a digital bridge that connects the brain to the spinal cord in people who have lost this connection, and is able to send commands from the patient’s brain to the spinal cord, converting them into electrical impulses that move the legs. We are still a long way from putting quadriplegia behind us for good, but we are getting there.Â
First drugs against Alzheimer’s disease
Neurodegenerative diseases are one of the great unresolved issues in medicine today, especially when the increase in life expectancy translates into a greater number of cases. Although a complete halt to the progression of these diseases remains elusive, the first specific drug has been approved this year: Leqembi (lecanemab) is an antibody that targets the beta-amyloid protein that accumulates in the diseased brain. Studies suggest that early treatment can slow cognitive decline by 27% after 18 months, although there are concerns about possible side effects. Another similar drug, donanemab, is undergoing clinical trials with similar results.
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