Jeff Weitz

Jeff Weitz


Professor of Medicine & Biochemisty and Biomedical Sciences, McMaster University

Executive Director, Thrombosis & Atherosclerosis Research Institute

Recent publications   



TaARI is made up of four programs: the Experimental Thrombosis and Atherosclerosis Program, the Comparative Medicine program, Biometrics program, and the Clinical Thromboembolism program.  “Our research at the program goes right from basic research to animal models to clinical trials so we really can do true bench to bedside work,” he says.

As Executive Director, Dr Jeffrey Weitz says his job is making sure everything runs smoothly.  “My role is to make sure the trainees are getting the proper education, that the new faculty are getting mentored, that their careers are blossoming, that they’re getting the recognition that the need and they’re making advances,” he lists on his fingers.

In the end, Dr Weitz says he works to ensure they bring recognition to McMaster University and Hamilton Health Sciences through their research and educational activities.

In terms of his research, Dr. Weitz says he chose to focus on clotting problems because they can lead heart disease and stroke, which is the number one cause of death and morbidity in Canada and world-wide.

Clots can be good, bad or ugly Dr. Weitz says. Good clots stop bleeding by plugging holes in blood vessels. “As we age, small leaks occur in the blood vessels that need to be plugged. The clotting system is designed to form small clots to fill these holes,” he says. Those are the good clots, Dr Weitz explains.

Bad clots, he continues, develop inside either arteries or veins. In arteries, these clots often form on top of fat-filled lesions that are a hallmark of atherosclerosis. These clots become ugly clots if they grow to fill the blood vessel and block blood flow, he says, adding that in heart arteries, this leads to heart attacks and in the brain, causes a stroke.

Dr Weitz says clots can also form in the veins, particularly the deep veins of the leg - a process is known as deep vein thrombosis. The clot blocks outflow of blood form the leg and produces pain and swelling. These can then break off from the leg and travel up to the lungs, he says, describing these also as “ugly clots,” because they can cause sudden death by blocking delivery of blood from the heart to the lungs.

Because he isn’t always in the lab, Dr. Weitz says he has a number of people there who can instruct at different levels. “Everybody needs somebody with more experience to provide advice,” he explains.

While research is a large portion of his job, Dr. Weitz says he also enjoys seeing patients and working with the students. “Helping students to define their questions, design their experiments, interpret their results, write their papers, get their degrees and find a career of their own. It’s very rewarding to see these people grow,” he says proudly.

Research Interests  

“My own research spans that spectrum from basic bench research . . . to animal models of clotting, to studies in patients,” Dr. Weitz explains. Dr. Weitz says that most of the questions that they take to the bench focus on common clinical problems. “We start with a clinical problem or a clinical question and we go first to the bench, to first principles, to try and tackle that question, and then go into animal models to explore it even further,” he explains.

Jim Fredenburgh, who oversees the day-to-day work in the lab, says the main focus of the lab is to understand how and why blood clots form so as to develop new methods for prevention and treatment. Often, this means working with pharmaceutical companies to develop and test new drugs. The lab is also performing primary research to discover new drugs, Fredenburgh says.

Dr Ji Zhou also works in laboratory, where she performs her own research under guidance from Dr Weitz. Dr Zhou says her first project in the Weitz lab was to develop an animal model of DVT. Using this model, she can begin to identify the factors that trigger clot formation and growth, she explains. It is well known, she says, that tissue factor, a substance exposed at sites of blood vessel injury, triggers clotting through factors VII and X. However, Dr. Zhou says her work suggests that factors XII and XI also play a part in this process, which is an important finding because it identifies new targets for DVT prevention and treatment.

Factors XII and XI are particularly interesting targets because patients with hereditary deficiency of these clotting proteins don’t suffer from bleeding. This means blood thinning medications directed against these factors may be safer than current blood thinners. This is an example of bench research that can hopefully one day be taken to the bedside, a transition that the Weitz lab prides itself in being able to perform.

”There are very few people who do research that spans the spectrum from basic, biochemical research right through to clinical trials,” Dr Weitz says about his lab.

Lab Profiles

Nima Vaezzadeh, PhD Candidate
Ran Ni, PhD Candidate
Shana Aadl Shaya, MSc Candidate

Lab Profiles

Kim Nagel, Clinical Research Coordinator
Helen Atkinson, Research Assistant
Netnapha Paredes, Research Assistant
Laura Calvert, MSc Candidate
Gabriela Chang, MSc Candidate
Sajjad Afraz, MSc Candidate