Heart Pump Devices May Quietly Damage Your Immune System Over Time

When doctors implant a left ventricular assist device (LVAD)—a mechanical pump that helps a failing heart—they're buying patients precious time. But a new study reveals these life-saving devices may quietly erode immune defenses the longer they stay in place, potentially explaining why infections become increasingly common in patients relying on them for years.

What Happens to Your Immune System With a Heart Pump?

Researchers at the Heart Center Leipzig in Germany compared immune function in 110 patients with the HeartMate 3 device. They divided them into two groups: 53 people who had the pump for 12 to 18 months (short-term), and 57 people who had it for at least 36 months (long-term). The findings were striking.

The mechanical pumps create constant, unnatural shearing forces on blood cells as they circulate through the device. Over months and years, this physical stress appears to wear down several critical immune cell populations. Patients with long-term LVAD support showed significant declines in:

• Dendritic cells: Specialized immune cells that alert your body to threats and coordinate immune responses, with total dendritic cell counts dropping significantly in long-term patients
• Natural killer (NK) cells: Frontline defenders against infected and cancerous cells, with immunoregulatory NK cells declining by a meaningful margin in the long-term group
• B cells: Antibody-producing cells essential for fighting infections, showing reduced percentages in patients with 3+ years of device support

The damage goes beyond simple cell loss. NK cells in long-term LVAD patients showed signs of advanced aging and exhaustion, measured by higher CD57 expression—a marker of cellular senescence. This suggests these immune cells aren't just fewer in number; they're also more worn out.

Why Does This Matter for Infection Risk?

The timing is telling. Infections are already a known complication of LVAD implantation, but they become increasingly common as patients live longer with the device. The new research suggests the immune system's progressive deterioration may explain this troubling trend. When dendritic cells, NK cells, and B cells all decline simultaneously, your body loses multiple layers of defense against bacteria, viruses, and other pathogens.

The study included 110 patients total, making it one of the first to examine immune changes beyond the first year of LVAD support. Previous research had documented immune changes in the first 12 months, but long-term effects remained a mystery until now.

A Different Angle: Zinc's Surprising Role in Controlling Inflammation

While LVAD patients face immune challenges from their devices, separate research points to an unexpected ally in fighting chronic inflammation: zinc. Scientists at Cincinnati Children's Hospital discovered that zinc can suppress runaway inflammatory cytokine production—the cellular messengers that fuel chronic diseases.

The research focused on adipocytes (fat cells), which produce large amounts of interleukin-6 (IL-6), a key inflammatory cytokine. When researchers treated these cells with zinc pyrithione, a form of zinc, something remarkable happened: the cells stopped amplifying their own inflammatory signals. Zinc blocked a feedback loop where IL-6 activates a pathway called Stat3, which then triggers more IL-6 production. By interrupting this cycle, zinc essentially hit the brakes on inflammation.

This matters because adipocytes contribute up to 35% of circulating IL-6 in the bloodstream. Chronic elevation of IL-6 is linked to obesity, metabolic disorders, liver inflammation, and even autoimmune conditions like systemic lupus erythematosus. The finding suggests that zinc's role in immune regulation extends beyond immune cells themselves to include the non-immune cells that fuel chronic inflammation.

Zinc deficiency is already prevalent in obesity and chronic inflammatory diseases. Previous supplementation trials have shown that boosting zinc intake can reduce inflammatory markers like C-reactive protein and IL-6 levels, along with improvements in weight and insulin sensitivity. This new mechanism—zinc's ability to suppress Stat3-driven IL-6 production—provides a biological explanation for why these benefits occur.

For LVAD patients facing immune challenges, and for anyone dealing with chronic inflammation, these findings highlight how different aspects of immune health interconnect. While mechanical heart support saves lives, understanding its immunological costs helps doctors monitor and potentially mitigate infection risks. And emerging research on zinc and other immune regulators offers complementary strategies for controlling the inflammatory processes that underlie many chronic diseases.