Even with blood glucose under control, people with diabetes still face a high risk of heart attack and stroke. The reason is not yet fully understood, but researchers from the Extracellular Matrix Laboratory (ECM Lab) at UNICAMP believe that a possible key piece is glycated collagen. They are investigating whether this alteration may make blood vessels stiffer and favor thrombus formation.
We spoke with the leading researcher of the laboratory, Prof. Dr. Renato Simões Gaspar, and some of his trainees: undergraduate research student Beatriz Scardua da Silva; master’s student Natália Silva Oliveira; and PhD students M.Sc. Tatiana Alves Toledo (also a biologist in the lab), M.Sc. Rômulo Brênno Lopes Fróes, and Samuel Duarte Maia.
Investigating whether what happens outside the cell can define cardiovascular risk
Leading the ECM Lab is Prof. Dr. Renato, a faculty member in the Graduate Program in Pharmacology at UNICAMP. With a medical degree from the Federal University of Maranhão, a PhD from the University of Reading (United Kingdom), and postdoctoral training at InCor-USP, he also currently serves as an editor of the journal Circulation Research.
His academic trajectory is marked by investigating mechanisms that increase cardiovascular risk. In this line of research, his studies focus especially on the role of extracellular matrix proteins, as well as the modifications they may undergo: oxidation, reduction, and post-translational modifications (irreversible chemical changes in their structure). He seeks to understand how platelets, endothelial cells, and smooth muscle cells “sense” and respond to the modified proteins.
From this perspective, the Extracellular Matrix Laboratory (ECM Lab) is dedicated to investigating what happens outside the cell. In this space are very important matrix proteins, such as collagen, fibronectin, and fibrinogen. The group starts from the idea that chronic diseases, such as diabetes, promote long-lasting alterations in these proteins. Thus, they study how cells perceive these changes, especially in the cardiovascular context.
To unravel these processes, the laboratory integrates approaches ranging from molecular and biophysical analysis of proteins and their interactions to studies with cells, animal models, and patient samples. In this way, it is possible to search for new therapeutic targets for cardiovascular diseases.
Why does diabetes increase the risk of cardiovascular diseases so much?
Patients with diabetes have a high risk of developing cardiovascular diseases. Prof. Renato comments: “We conducted an epidemiological study that showed that, for the Brazilian population, when we look at risk factors for mortality from cardiovascular diseases, diabetes is by far the leading risk factor. Its magnitude is two to three times greater than that of other factors, such as smoking and hypertension.”
There are several factors involved in this increased risk. “Diabetes never comes alone. Usually, a person is diabetic, but may also be dyslipidemic, obese, sedentary, or a smoker. So there are associated risk factors,” explains Prof. Renato.
In addition, diabetes itself directly affects other mechanisms involved in the risk of experiencing an ischemic event. Prof. Renato highlights that an important mechanism is platelet activation: “Platelets in people with diabetes tend to be hyperreactive. As a result, they form larger thrombi. This increases the likelihood of affecting an organ such as the heart or brain.”
Platelets circulate in the blood and are essential for stopping bleeding. When a blood vessel is damaged (causing bleeding), platelets act quickly by becoming activated and aggregating to form a clot, which prevents hemorrhage. You have probably noticed that a wound stops bleeding after a short time. This happens precisely because platelets form a clot to stop the bleeding.
However, platelets in people with diabetes may react far more than normal. As a result, they do not respond only to injuries in blood vessels that cause bleeding. Much smaller stimuli can trigger a reaction, such as microlesions in the vessels and changes in blood flow.
This can lead to the formation of clots within blood vessels, known as thrombi. In people with diabetes, these thrombi can become large enough to obstruct small vessels in the heart or brain, leading to myocardial infarction and stroke, respectively. In other words, once the vessel is “blocked,” blood can no longer circulate and deliver oxygen to that area, resulting in cell death.
The enigma of persistent risk in diabetes
However, a mystery has puzzled researchers for decades. It is known that even after glycemic control is achieved, cardiovascular risk often remains elevated. Prof. Renato comments: “Diabetic patients are usually prescribed metformin. However, we still do not have robust studies showing that metformin will reduce the likelihood of a person having a heart attack.”
In recent years, so-called “weight-loss pens,” such as Ozempic and Mounjaro, have revolutionized diabetes treatment. Prof. Renato notes: “If you look at these medications, they reduce mortality by approximately 15%. […] So even these more modern drugs may not provide very efficient protection.”
The reason why cardiovascular risk remains high even after glycemic control is still unclear. For this reason, the ECM Lab decided to investigate this relationship (Funding: São Paulo Research Foundation – FAPESP, grant no. 22/05750-7). One of the hypotheses points to the role of glycated collagen. This is a modified form of collagen that accumulates damage over years of hyperglycemia. This process is known as glycation.
In glycation, sugar molecules bind to other molecules, such as proteins. In the case of collagen, when glycated, it forms larger and stiffer fibers than normal. This reaction cannot be reversed, as it involves covalent bonds, that is, the sharing of electrons between atoms within a molecule. It is as if glucose were bound to collagen with concrete, making them inseparable.
Doctoral student and laboratory technician M.Sc. Tatiana Toledo explains the rationale behind investigating collagen: “Between the onset of hyperglycemia and the diagnosis of diabetes, there is a gap of around five years. Collagen is a long half-life protein.” This means that the same collagen molecule can remain in the body for more than 10 years without being replaced.
M.Sc. Tatiana adds: “Because it is a protein exposed to everything that happens inside the body, it can undergo modifications such as glycation. We can draw a parallel with glycated hemoglobin, which is used as a parameter for diabetes diagnosis. However, hemoglobin is replaced within 120 days. Collagen is not. So, over time, there is an accumulation of modifications in collagen.”
Due to its long half-life, collagen functions as a kind of “molecular memory” of the disease, potentially retaining alterations caused by hyperglycemia even after it has been treated. This process has already been shown to play a role in impaired wound healing in diabetes. Currently, the ECM Lab is investigating whether collagen glycation may contribute to increased cardiovascular risk, for example, by making blood vessels stiffer or by altering platelet reactivity.
Doctoral students M.Sc. Rômulo Fróes and Samuel Maia were drawn to the group precisely because of the study’s unique approach. M.Sc. Rômulo explains: “The innovation factor is what attracted me. There are very few studies linking glycated collagen to cardiovascular diseases.”
Samuel adds: “What sparked my curiosity to work on this project was learning that there is this subgroup of diabetes patients who remain susceptible to very serious cardiovascular outcomes. The project focuses on a group that is often overlooked and may even help us find ways to address this issue.”
How to study glycation in practice
The project is quite ambitious and involves the participation of several students. Prof. Renato explains: “The idea is to work from the isolated protein, through the cell, all the way to the patient. So far, we have managed to study the isolated protein, cells, and animal models. Soon, we will begin working with patients.”
In animal models, the researchers use two drugs to induce collagen glycation: streptozotocin and methylglyoxal. Streptozotocin leads to the destruction of pancreatic β (beta) cells, which are responsible for insulin production. Insulin is an essential hormone for glycemic control, as it allows glucose in the bloodstream to enter cells, thereby lowering blood glucose levels.
Thus, after the administration of streptozotocin, insulin production decreases and, consequently, hyperglycemia develops. This condition closely resembles type 1 diabetes, in which the individual has little or no insulin production. With hyperglycemia, collagen glycation occurs.
The other drug used is methylglyoxal, a byproduct of glucose produced by our body. In the process known as metabolism, the body chemically modifies glucose to facilitate its excretion, generating methylglyoxal and other molecules. Methylglyoxal does not cause hyperglycemia, but it is highly reactive, leading to the glycation of several molecules in the body, such as collagen.
Master’s student Natália Oliveira, who works exclusively with animals treated with methylglyoxal, highlights the importance of this approach: “I measured the blood glucose levels of my animals. They were not diabetic. With methylglyoxal, I can observe something much more specific: only collagen glycation. Just this final product that would result from hyperglycemia, without actually inducing hyperglycemia itself. The diabetes condition.”
Teamwork to understand how thrombi form
Several students work on the same project, but each has a specific role. Each one is responsible for uncovering a different part of the story. Prof. Renato explains: “Since I am at the beginning of setting up my lab, I designed projects that are highly interconnected. Each student has their own project, but they also have a counterpart working on something similar. So I always encourage students to collaborate with one another.”
At the ECM Lab, students at different academic levels work with glycated collagen: undergraduate researcher Beatriz da Silva (FAPESP grant no. 25/23132-7); master’s student Natália Silva Oliveira (FAPESP grant no. 24/00842-6); and doctoral students M.Sc. Rômulo Fróes (FAPESP grant no. 24/07470-7) and Samuel Maia (FAPESP grant no. 24/02620-0).
Beatriz and M.Sc. Rômulo focus on platelet response. M.Sc. Rômulo explains: “My hypothesis is that, in a scenario of chronic hyperglycemia (as in diabetes), collagen undergoes glycation, which alters platelet response, leading to the development of cardiovascular diseases, especially thrombotic ones.”
And this is exactly what has been observed, as M.Sc. Rômulo explains: “Glycated collagen increases both platelet aggregation and platelet adhesion.” This finding is particularly relevant. If glycated collagen makes platelets more prone to aggregation and adhesion, it facilitates thrombus formation and, consequently, the occurrence of myocardial infarction or stroke.
Between relaxing and contracting: how glycated collagen alters vessel function
Doctoral student Samuel also investigates platelet function, but his focus is endothelial dysfunction in diabetes, which is essential for proper vascular function. He therefore conducts animal experiments to assess vascular reactivity.
Understanding endothelial dysfunction is key to unraveling cardiovascular risk in diabetes. The endothelium is a layer of cells that lines the inner surface of blood vessels. These cells play a central role in regulating vascular tone, blood flow, and the balance between procoagulant and anticoagulant factors. When the endothelium does not function properly, there is impaired vessel dilation, increased inflammation, and a higher likelihood of thrombus formation.
Master’s student Natália also investigates vascular reactivity. She explains: “My focus is the thoracic aorta. This allows me to investigate how much glycated collagen is associated with vascular events.”
While Samuel induces diabetes using streptozotocin, Natália focuses solely on collagen glycation through the use of methylglyoxal. Natália notes that, despite the different drugs used, their results are directly comparable: “Even so, we obtained identical results regarding vessel stiffness.” Samuel adds: “We observed that the damage was very similar between the two models, such as vascular remodeling damage.”
Prof. Renato further comments on the findings: “We observed that the aorta relaxes just as much as a control aorta, both in methylglyoxal-treated animals and in diabetic animals. In other words, endothelial function is preserved. However, the contraction of this vessel is increased. So perhaps the long-term impact of this glycation is more prominent in the vascular smooth muscle than in the endothelium.”
This result is important because it helps identify exactly where the problem lies in the blood vessels. Vessels need both to relax and to contract in order to regulate blood flow. The researchers observed that relaxation remains normal. Since the endothelium is primarily responsible for relaxation, they concluded that it is not affected by collagen glycation.
On the other hand, vessel contraction is increased, which may cause vessels to become more “constricted” than they should be. This suggests that glycated collagen primarily affects the vascular smooth muscle, which is responsible for regulating contraction.
When treatment does not erase the damage
An interesting aspect of Natália’s project is that she performs a “washout” period in her animals, as explained by Prof. Renato: “We administered methylglyoxal for 12 weeks and then withdrew it for 4 weeks. The idea was to observe the long-term effects of methylglyoxal on vascular reactivity in these animals.” This approach is based on the assumption that collagen becomes glycated during exposure to methylglyoxal and remains so even after the drug is withdrawn.
In addition, Natália treats some animals with metformin after this period. This is one of the most commonly prescribed drugs for the treatment of diabetes. Metformin reduces glucose production in the liver and improves insulin sensitivity, thereby helping to control blood glucose levels.
By using metformin, Natália is able to assess whether a widely used diabetes medication can attenuate the effects of collagen glycation. However, the researcher notes that this treatment appears to have no effect.
This finding closely parallels clinical reality. We observe that cardiovascular risk persists even after patients have achieved glycemic control and are receiving pharmacological treatment. This highlights the importance of developing new therapeutic strategies.
Hypotheses do not always hold, but that is where science advances
Having multiple students working on parallel yet interconnected projects makes the ECM Lab a highly collaborative environment. Prof. Renato explains that he consistently encourages students to work together: “We have meetings every Friday. During these, students share what they have done throughout the week.”
Prof. Renato also has a very insightful perspective on work within the lab: “Science is a creative process. Sometimes you have an idea at night. Sometimes you don’t feel like working the next day. Of course, you need some structure to support a productive creative process, but sometimes it just doesn’t happen.” This environment gives students room to grow while developing their projects.
The ECM Lab is also where Beatriz, an undergraduate Pharmacy student at UNICAMP, chose to carry out her first scientific initiation project. She shares what it is like to be involved in such an ambitious project early in her academic journey: “I won’t deny that it is quite challenging and requires a lot of mental energy, but it is very rewarding to see the outcomes of the research and realize how much knowledge I have gained from my experience in the lab.”
Beatriz explains that the main challenges of engaging in research include assimilating undergraduate content at a much deeper level and constantly learning new experimental techniques. She also shares what motivated her to join the ECM Lab team: “I had always been curious about doing a research project. At the time, I was taking a pharmacology class and became interested in Prof. Renato’s research line. I decided to visit the lab and loved it.”
By investigating glycated collagen, researchers at the ECM Lab are helping to uncover how cardiovascular risk develops in diabetes. Long-lasting molecular changes, accumulated over time, may continue to affect vascular function even after treatment. These findings highlight the need for new therapeutic approaches that go beyond blood glucose control.
Learn more:
Risk factors for cardiovascular diseases in Brazil (DOI: 10.1371/journal.pone.0269549)
Diabetes and cardiovascular disease (DOI: 10.29277/cardio.36.1.4)
Treatment of cardiovascular disease in diabetes (DOI: 10.1016/j.repc.2018.03.013)
Collagen glycation in diabetes (DOI: 10.2337/diab.45.3.s67)
Glycated collagen in arterial and myocardial stiffness (DOI: 10.1097/00004872-200301000-00002)
Written by:
Mia Schezaro Ramos
Pharmacist. Ph.D. in Pharmacology. Science journalist, illustrator, trans, Nintendo enthusiast, K-pop fan, and dependent on physical exercise to stay sane.