Urinary biomarker links diet-associated DCM to phospholipidosis

Lisa Freeman, DVM, PhD, DACVIM (Nutrition), and her team have opened a new line of inquiry into diet-associated dilated cardiomyopathy (DCM). Results from their research have shown that dogs eating pulse-rich diets (peas, lentils, chickpeas, beans) who develop DCM have significantly elevated concentrations of a urinary biomarker linked to phospholipidosis.¹

The discovery offers a biologically plausible mechanism to study further and a way for veterinarians to prioritize early detection, referral, and reporting. Freeman’s work is a finalist for the American Kennel Club’s Canine Health Discovery of the Year Award, recognition that highlights the potential clinical impact of this finding.¹

Your January 2025 study identified a urinary biomarker linked to phospholipidosis in dogs with DCM eating pulse-rich diets. Clinically speaking, what does that biomarker tell us about the disease mechanism. Do you view phospholipidosis as a likely causal pathway, a downstream effect, or a marker of exposure? What additional evidence would be needed to establish causality?

Freeman: Dilated cardiomyopathy, or DCM, is a relatively common genetic cardiac disease that affects certain dog breeds like Doberman Pinschers. However, for approximately the last 10 years, dogs of many different breeds have been developing a specific form of DCM that appears to be associated with diets high in pulses (pulses include peas, lentils, chickpeas, and beans). Our team and others have been working to identify what it is about these ingredients that may cause this disease and there are now numerous peer-reviewed publications on this issue. Earlier this year, our team identified a potential mechanism for diet-associated DCM—higher levels of a urine biomarker in dogs with diet-associated DCM— suggesting phospholipidosis, an abnormal metabolism of phospholipid that could potentially affect the heart. We’re now investigating this possible mechanism further to explain how and why the disease develops, as well as to find better treatments for dogs that have been affected by diet-associated DCM.

How should practicing veterinarians use this finding today? Is urinary biomarker testing available for clinicians or still research-only? If available, what sample type/handling and interpretation should we use; if not, what diagnostic steps do you recommend for suspicious cases in the meantime?

Freeman: This recent issue with DCM has emphasized to me the importance of doing a nutritional assessment on every patient at every visit: weight, body condition score, muscle condition score, and diet history. There’s so much misinformation about pet nutrition circulating now, so knowing exactly what a pet is eating can help the veterinary healthcare team determine whether it’s really the best possible diet for that dog or cat or if it could potentially be harmful to a pet’s health. This urine biomarker is not intended to be a test for clinical use in dogs, but it’s an important piece of the puzzle for our research.

From a nutrition/advice standpoint, what specific guidance should we be giving owners who are worried about diet-associated DCM (ingredient types, processing concerns, label reading tips, or particular diet categories to prefer or avoid)?

Freeman: I think it’s important for owners to know that diet-associated DCM can affect many dog breeds, not just the breeds commonly associated with the genetic form of DCM, like Doberman Pinschers or Great Danes. Our research suggests that cats might also be susceptible to this problem. Also, while this disease was initially associated with grain-free diets, some grain-inclusive diets include pulses too.

For dogs already diagnosed with diet-associated DCM, what treatment and monitoring protocol do you currently recommend (diet change, cardiac meds, supplements, recheck schedule, imaging/biomarker follow-up)? What clinical or test findings predict recovery versus persistent cardiac dysfunction

Freeman: Pet owners should work with their pets’ veterinarians, veterinary cardiologists, and veterinary nutritionists to determine the best treatment for their individual pet, including cardiac medications, diet and dietary supplements, and monitoring (a searchable directory of veterinary cardiologists, veterinary nutritionists, and other ACVIM specialists can be found at www.vetspecialists.com).

What are the next research priorities and most useful ways veterinarians can help (case reporting, sample submission, referring patients for trials, etc.)? Are there registries or ongoing studies clinicians should be aware of and how can they get involved?

Freeman: This discovery has helped to focus our research on a potential mechanism that we’re studying further now so we can identify the cause of diet-associated DCM as quickly as possible. I hope that this research also will help to advance our knowledge about dog and cat nutrition in general. Performing a nutritional assessment on all patients, as noted above, is an important step veterinarians can take to ensure individual patients are getting the best diet for their needs.

Reference

1. Freeman LM, Rush JE, Berridge BR, et al. Dogs with diet-associated dilated cardiomyopathy have higher urine di-docosahexaenoyl (22:6)-bis(monoacylglycerol)phosphate, a biomarker of phospholipidosis. Am J Vet Res. 2024 Oct 28;86(1):ajvr.24.07.0211. doi: 10.2460/ajvr.24.07.0211. PMID: 39467380.