A mother's struggle, a daughter's mission

When PhD candidate Maryam Rahmani stood up to give her three-minute thesis presentation in an Auckland lecture theatre packed with students and academics, she began her talk with her mum, Leila. Her beloved mum.

Leila was diagnosed with gestational diabetes when she was pregnant with Rahmani’s younger brother and later developed type 2 diabetes. As a teenager, Rahmani remembers alarming changes to her mother’s health – sudden eyesight issues and gangrenous toes caused by glucose-related nerve damage.

Plus the ever-present threat of heart disease.

“Over 20 years, diabetes will damage different parts of your body – your brain, your kidneys, your eyes, but in particular your heart," says Rhahmani. 

Research shows that compared with healthy subjects, patients with diabetes are three times more likely to develop heart failure and twice as likely to die of heart-related causes.

The risks for women are particularly high. Women with diabetes have a two‑fold higher risk of developing coronary heart disease than men with the disease; they are also more likely to have a heart attack, and more likely to die as a result.

But scientists don’t know why.

Rahmani, an exceptional student through school, chose to study electrical engineering at university, but always intended to pivot towards science and biology.

“I remember telling my mum, ‘I want to be a doctor some day. I want to find a cure for your diabetes’.”

The opportunity to do a PhD at the Auckland Bioengineering Institute (ABI), part of Waipapa Taumata Rau, University of Auckland, allows her to turn her engineering skills towards something she hopes will help her mum – and other women like her.

“I have moved from applying engineering concepts to make power systems more stable and efficient to examining the efficiency of another adaptive system – the heart, particularly in the context of diabetes.”

Importantly, Rahmani is focusing on the female heart – something often neglected by researchers who have mostly developed tests and treatments using men as models.

“We know that diabetes-related damage manifests itself differently in men and women. Different parts of the cell are showing different dysfunction for men as opposed to women – they behave differently,” she says.

“We need to have more understanding of what’s happening in women’s hearts, so we can make sure the treatment is right. Clinicians might think women are okay because they are doing the wrong tests – tests designed for men. And then women don’t get treatment, or don’t get the right treatment.

“Tests and treatments need to be sex-specific.”

“There is something else happening”

Over the last three years at the ABI, Rahmani has delicately isolated muscle tissue, the width of a human hair and about three millimetres long, from healthy and diabetes-induced rats. These cardiac trabeculae form tiny vertical columns which give structure to heart walls. They contract and relax to make the heart beat.

With the aid of a work-loop calorimeter, a unique device developed at the ABI, Rahmani has been able to measure the efficiency of these minute muscles as they work outside of the heart.

“When a muscle contracts, there is a lot going on inside a cell,” she says. “Firstly, calcium ion cycling acts like the ‘on-off switch’ for your heart’s beat by signaling when to contract and relax. Crossbridge processes are the action part that explains how muscle fibres pull on each other to make the heart squeeze.”

“We expected that the diabetic female heart would have much-reduced energy efficiency in these two processes – but this was not what we saw."

Instead, Rahmani says their results have been “striking and unexpected”.

“Efficiency related to the calcium domain inside the cell was reduced in males and the efficiency related to the crossbridge domain inside the cell was reduced in females. The heart’s muscle cell is showing different dysfunction for male and female subjects but not in the way we expected.

“There is something else happening.”

A deeply personal mission

Recent studies point to possible sex-specific differences in how diabetes affects the heart’s energy metabolism, Rahmani says.

Women with diabetes may have trouble with the proteins involved in making the heartbeat, which can make them less efficient at producing energy.

Dr June-Chiew (JC) Han is an expert in heart disease and diabetes, and Rahmani’s main supervisor. “Energy efficiency is often overlooked, clinically, when it comes to understanding heart failure and sex‑differences," he says. "We are trying to understand how diabetes impacts the heart’s ability to function properly, and why women with diabetes are more likely to experience heart problems.” 

For Rahmani, her research goes beyond just the science – it’s a mission that is deeply personal.

“It’s about giving all women like my mum, who are often underrepresented in research, a better future when living with diabetes. I love my mum, and being far from her makes this mission even more meaningful to me.” 

Saturday March 8 is International Women's Day. The theme for 2025 is 'Accelerate Action'. It calls for increased momentum and urgency in addressing the systemic barriers and biases that women face, in their personal and work lives.