Physiology of aging among healthy, older bottlenose dolphins (Tursiops truncatus): comparisons with aging humans

Abstract

Changes in hematological and serum chemistry values have been identified among older compared to younger humans. We hypothesized that healthy bottlenose dolphins (Tursiops truncatus) 30 years and older may demonstrate similar clinicopathological changes with increasing age. Retrospective hematological and serum chemistry data generated from routine, fasted blood samples collected over 10 to 20 years among six healthy dolphins that lived at least 40 years were analyzed to (1) assess linear trends in blood variable values with increasing age, (2) compare mean blood values by older age categories (30-35 years, 36-40 years, and >40 years), and (3) compare the prevalence of clinically high or low blood values by older age categories. Absolute lymphocytes, serum globulins, and mean platelet volume increased linearly with increasing old age. Mean white blood cells, neutrophils, serum globulins, erythrocyte sedimentation rates, serum cholesterol, and serum triglycerides; and the prevalence of neutrophilic leukocytosis, hyperglobulinemia, and hypercholesterolemia, were more likely to be higher as geriatric dolphins got older. A linear decrease in serum albumin with increasing age was present for five of six animals. Serum creatinine decreased among dolphins older than 40 years compared to when they were 30-40 years old. Our study demonstrates that older dolphins have changes in hematological and serum chemistry values similar to those found in older humans. As such, bottlenose dolphins may serve as a useful comparative model for aging in humans. Further studies are needed to assess whether these changes are associated with negative health outcomes and whether targeted therapeutics can help improve quality of life among aging dolphins.

Relationship between brain and liver oxidative state and maximum lifespan potential of different fish species

“…This result would support data from previous studies in which no obvious changes were detected in hepatic tissue during the process of ageing (Schmucker et al, 1984;Kitani, 1991;Venn-Watson et al, 2011).…”

Normal Glucose Metabolism in Carnivores Overlaps with Diabetes Pathology in Non-Carnivores

“…Mean basal insulin in this group was ∼12 μIU/ml but mean insulin 2 h-post-prandial was lower (∼9 μIU/ml) (1). These data are difficult to interpret because insulin levels in this small group showed substantial variability, particularly the post-prandial measurements, possibly due to influences of gender and age, as noted for other hematologic and biochemical parameters (103). Further study with larger groups and uniform populations is needed to place these initial findings into context.…”

“…In three separate studies, fasting glucose in captive bottlenose dolphins was determined to be between 108 and 194 mg/dL (1, 2, 103). The largest study measured serum glucose in 1161 samples from 52 captive bottlenose dolphins and reported mean serum glucose concentrations of 108 and 112 mg/dL in fed and fasted conditions, respectively (2).…”

Adipose-Derived Stem Cell Collection and Characterization in Bottlenose Dolphins (Tursiops truncatus)

“…Several dolphin diseases have similar human counterparts, including type 2 diabetes [8], urate nephrolithiasis with renal failure [33], and iron overload with liver disease [9,34]. The dolphin may serve as a human model for several disease processes, as was recently proposed for type 2 diabetes [10] and aging studies [35], where new treatment modalities using stem cells could be realized.…”