Polyunsaturated Fatty Acid EAB-277® Supplementation Improved Heart Rate Variability and Clinical Signs in Tracheal Collapse Dogs

Abstract

Canine tracheal collapse is a progressive disease in small breed dogs resulting from chronic inflammation of the tracheal mucosal lining. Polyunsaturated fatty acid EAB-277^® is one of the nutraceuticals that can alleviate inflammation and oxidative stress. Heart rate variability (HRV) is a prognostic tool related to sympathovagal balance and oxidative stress level, which is widely used with cardiorespiratory diseases. However, the effect of EAB-277^® on HRV in tracheal collapse dogs has rarely been investigated. In this study, 26 tracheal collapse dogs were divided into two groups. In the control group, the dogs received the standard treatment, whereas the dogs in the EAB-277^® group received standard treatment combined with EAB-277^®. After being treated for 5 weeks, changes in radiographic findings, blood profiles, serum malondialdehyde, inflammatory markers, and HRV were evaluated. This study found that clinical signs were improved in both groups (p < 0.05). However, serum malondialdehyde (MDA), Interleukin-6 (IL-6), and Tumor necrosis factor-alpha (TNF-α) were decreased only in the EAB-277^® group after treatment for five weeks (p < 0.05) and the mean percent change of MDA, IL-6, and TNF-α at week five compared to baseline in the EAB-277^® group was greater than in the control group (p < 0.05). Additionally, greater sympathovagal imbalance indicated by decreased standard deviation of all normal R-R intervals (SDNN) and standard deviation of the averaged R-R intervals for all 5-minutes segments (SDANN) was found in the control group at week five compared to baseline (P < 0.05), whereas EAB-277^® improved SDNN and SDANN and decreased low frequency/high-frequency component (LF/HF ratio) after being treated for five weeks (P < 0.05). This study demonstrates that EAB-277^® improves clinical signs and attenuates HRV impairment by reducing oxidative stress and inflammation in tracheal collapse dogs.

Keywords: dog; heart rate variability; inflammatory marker; malondialdehyde; polyunsaturated fatty acid EAB-277®; tracheal collapse.

Figure 1

Schematic representation of the study protocol. At pre-treatment, all dogs underwent chest X-ray, blood collection, Holter recording for 2-h. Then, dogs were divided into two groups to receive the standard treatment or standard treatment combined with polyunsaturated fatty acid EAB-277^® from Green-Lipped Mussel blend for the 5 weeks. At post-treatment, all dogs underwent the re-assessment of chest X-ray, blood collection, Holter recording for 2-h to investigate cardiac sympathovagal balance, plasma oxidative stress, and inflammatory marker measurement. MDA, Malondialdehyde.

Figure 2

Clinical signs of tracheal collapse at baseline and at week 5 were evaluated by questionnaire in the control and EAB-277^® groups. All clinical signs, (A) coughing frequency, (B) coughing duration, (C) activity-induced coughing, and (D) coughing during eating, at baseline were not different between the groups. After treatment for 5 weeks, the clinical signs as evaluated by questionnaire were improved in both the control group and the EAB-277^® group compared to baseline in the same group. ^†P ≤ 0.05 compared to baseline in the same group.

Figure 3

Effect of a standard treatment plus EAB-277^® on serum MDA levels in tracheal collapse dogs. Serum MDA level before and after treatment was not different in the control group, whereas serum MDA level was decreased at week 5 in the treatment group compared to the control group and compared to the treatment group at baseline (A). Moreover, the mean percent change of serum MDA at week 5 in the treatment group was greater than the mean percent change in the control group (B). *P ≤ 0.05 compared to the control group. ^†P ≤ 0.05 compared to baseline in the same group.

Figure 4

Effect of standard treatment and EAB-277^® on serum IL-6 and serum TNF-α in tracheal collapse dogs. (A) Serum IL-6 and (B) TNF-α were not different between groups at baseline, whereas serum IL-6 and TNF-α were decreased at week 5 in the EAB-277^® group compared to baseline in the same group. Moreover, the mean percent change of serum IL-6 and TNF-α at week 5 in the treatment group was greater than the control group (C,D). *P ≤ 0.05 compared to the control group. ^†P ≤ 0.05 compared to baseline in the same group.

Figure 5

Effect of standard treatment and EAB-277^® on time-domain heart rate variability in tracheal collapse dogs. Time-domain HRV demonstrated that (A) mean NN, (B) SDNN, (C) SDANN, (D) ASDNN, (E) rMSSD, and (F) pNN50 were not different in the two groups at baseline. In the control group, SDNN, SDANN, and ASDNN were decreased at week 5 compared to baseline. In the EAB-277^® group, (E) rMSSD was increased at week 5 compared to baseline, whereas mean NN, SDNN, SDANN, ASDNN, and pNN50 were not different before and after treatment. Mean NN, mean of N-N intervals; SDNN, standard deviation of all normal R-R intervals; SDANN, standard deviation of the averaged N-N intervals for all 5-min segments; ASDNN, average of the 5-min standard deviations of N-N intervals; rMSSD, Square root of the mean of successive N-N intervals differences and pNN5, the percentage of successive N-N intervals > 50 msec. ^†P ≤ 0.05 compared to baseline in the same group.

Figure 6

Effect of standard treatment and EAB-277^® on frequency-domain heart rate variability in tracheal collapse dogs. Frequency-domain HRV demonstrated that (A) VLF, (B) LF, (C) HF, and (D) LF/HF ratios were not different between groups at baseline. At week five, frequency-domain HRV in the control group (A–D) showed that (A) VLF parameter was decreased compared to baseline, whereas (B) LF, (C) HF, and (D) LF/HF ratio at week 5 were not different from baseline. In the EAB-277^® group, (C) the HF parameter was increased at week 5 compared to the control group, and (D) the LF/HF ratio at week 5 was decreased compared to baseline, whereas (A) VLF, (B) LF, and (C) HF were not different before and after treatment. VLF, Very low-frequency component; LF, Low frequency component; HF, High frequency component. LF/HF ratio, Low frequency/high-frequency component. *P ≤ 0.05 compared to baseline in the same group. ^†P ≤ 0.05 compared to baseline in the same group.