ORCID Profile
0000-0001-5782-6303
Current Organisations
The Liggins Institute, University of Auckland
,
The University of Auckland
,
University College Dublin
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Publisher: Springer Science and Business Media LLC
Date: 17-07-2017
DOI: 10.1038/S41598-017-05793-0
Abstract: We examined whether maternal fish oil supplementation during pregnancy could prevent development of insulin resistance in adult male offspring of rat dams fed a high-fat diet. Time-mated Sprague-Dawley rat dams were randomised into four treatment groups: Con-Con, dams fed a control diet (fat: 15% kcal) and administered water by gavage Con-FO, control diet with unoxidised fish oil by gavage HF-Con, high-fat diet (fat: 45% kcal) and water by gavage and HF-FO, high-fat diet and unoxidised fish oil by gavage. Dams were fed the allocated diet ad libitum during pregnancy and lactation, but daily gavage occurred only during pregnancy. After weaning, male offspring consumed a chow diet ad libitum until adulthood. Maternal high-fat diet led to increased food consumption, adiposity, systolic blood pressure, and triglycerides and plasma leptin in adult HF-Con offspring. HF-Con offspring also exhibited lower insulin sensitivity than Con-Con rats. Male offspring from HF-FO group were similar to HF-Con regarding food consumption and most metabolic parameters. However, insulin sensitivity in the HF-FO group was improved relative to the HF-Con offspring. Supplementation with unoxidised n-3 PUFA rich oils in the setting of a maternal obesogenic diet improved insulin sensitivity, but had no impact on body composition of adult male offspring.
Publisher: American Physiological Society
Date: 09-2016
DOI: 10.1152/AJPREGU.00005.2016
Abstract: Fish oil is commonly taken by pregnant women, and supplements sold at retail are often oxidized. Using a rat model, we aimed to assess the effects of supplementation with oxidized fish oil during pregnancy in mothers and offspring, focusing on newborn viability and maternal insulin sensitivity. Female rats were allocated to a control or high-fat diet and then mated. These rats were subsequently randomized to receive a daily gavage treatment of 1 ml of unoxidized fish oil, a highly oxidized fish oil, or control (water) throughout pregnancy. At birth, the gavage treatment was stopped, but the same maternal diets were fed ad libitum throughout lactation. Supplementation with oxidized fish oil during pregnancy had a marked adverse effect on newborn survival at day 2, leading to much greater odds of mortality than in the control (odds ratio 8.26) and unoxidized fish oil (odds ratio 13.70) groups. In addition, maternal intake of oxidized fish oil during pregnancy led to increased insulin resistance at the time of weaning (3 wks after exposure) compared with control dams (HOMA-IR 2.64 vs. 1.42 P = 0.044). These data show that the consumption of oxidized fish oil is harmful in rat pregnancy, with deleterious effects in both mothers and offspring.
Publisher: American Physiological Society
Date: 08-2022
DOI: 10.1152/AJPREGU.00042.2022
Abstract: Fish oil (FO) supplements are consumed during pregnancy to increase dietary omega-3. However, FO is often oxidized past recommended limits. In rats, a large dose of highly oxidized FO substantially increased newborn mortality, but the effects of human-relevant doses of less oxidized oil are unknown. A dose-response study in rats was conducted to estimate the safe level of oxidation during pregnancy. Sprague-Dawley rat dams were mated, then in idually housed and provided with a gel treatment on each day of pregnancy. Treatment groups differed only in the FO content of the gel control (no oil), PV5, PV10, and PV40 [0.05 mL of FO oxidized to a peroxide value (PV) of 5, 10, or 40 meq/kg], or PV40(1 mL) (1 mL of PV40). A subset of dams was culled on gestational day 20 to enable s ling, and the remainder were allowed to give birth. Newborn mortality was recorded. Offspring were s led on postnatal days 2 and 21, and dams on day 21. There were no signs of unwellness during pregnancy. However, there was markedly increased neonatal mortality affecting the PV40(1 mL) (12.8%) and PV40 (6.3%) groups, but not the control, PV5, or PV10 groups (1%–1.4%). Dietary-oxidized FO altered the expression of placental genes involved in antioxidant pathways and the production of free radicals. Highly oxidized FO was toxic in rat pregnancy leading to a marked increase in mortality even at a human-relevant dose. We observed no toxic effects of FOs with PV ≤10 meq/kg, suggesting that this is an appropriate maximum limit.
Publisher: American Physiological Society
Date: 10-2013
DOI: 10.1152/AJPENDO.00297.2013
Abstract: Emerging evidence has demonstrated that saturated fatty acids prime pro-IL-1β production and inflammasome-mediated IL-1β activation is critical in obesity-associated insulin resistance (IR). Nonetheless, IL-1 receptor I-deficient (IL-1RI −/− ) mice develop mature-onset obesity despite consuming a low-fat diet (LFD). With this apparent contradiction, the present study evaluated whether IL-1RI −/− mice were protected against long-term (6 mo) high-fat diet (HFD)-induced IR. Male wild-type and IL-1RI −/− mice were fed LFD or HFD for 3 or 6 mo, and glucose and insulin tolerance tests were performed. Adipose insulin sensitivity, cytokine profiles, and adipocyte morphology were assessed. The adipogenic potential of stromal vascular fraction was determined. Hepatic lipid accumulation and insulin sensitivity were characterized. IL-1RI −/− mice developed glucose intolerance and IR after 6 mo HFD compared with 3 mo HFD, coincident with enhanced weight gain, hyperinsulinemia, and hyperleptinemia. The aggravated IR phenotype was associated with loss of adipose functionality, switch from adipocyte hyperplasia to hypertrophy and hepatosteatosis. Induction of adipogenic genes was reduced in IL-1RI −/− preadipocytes after 6 mo HFD compared with 3 mo HFD. Obese LFD-IL-1RI −/− mice exhibited preserved metabolic health. IL-1RI −/− mice develop glucose intolerance and IR after 6 mo HFD intervention. While mature-onset obesity is evident in LFD-IL-1RI −/− mice, the additional metabolic insult of HFD was required to drive adipose inflammation and systemic IR. These findings indicate an important interaction between dietary fat and IL-1, relevant to optimal metabolic health.
Publisher: American Diabetes Association
Date: 27-01-2015
DOI: 10.2337/DB14-1098
Abstract: Saturated fatty acid (SFA) high-fat diets (HFDs) enhance interleukin (IL)-1β–mediated adipose inflammation and insulin resistance. However, the mechanisms by which different fatty acids regulate IL-1β and the subsequent effects on adipose tissue biology and insulin sensitivity in vivo remain elusive. We hypothesized that the replacement of SFA for monounsaturated fatty acid (MUFA) in HFDs would reduce pro-IL-1β priming in adipose tissue and attenuate insulin resistance via MUFA-driven AMPK activation. MUFA-HFD–fed mice displayed improved insulin sensitivity coincident with reduced pro-IL-1β priming, attenuated adipose IL-1β secretion, and sustained adipose AMPK activation compared with SFA-HFD–fed mice. Furthermore, MUFA-HFD–fed mice displayed hyperplastic adipose tissue, with enhanced adipogenic potential of the stromal vascular fraction and improved insulin sensitivity. In vitro, we demonstrated that the MUFA oleic acid can impede ATP-induced IL-1β secretion from lipopolysaccharide- and SFA-primed cells in an AMPK-dependent manner. Conversely, in a regression study, switching from SFA- to MUFA-HFD failed to reverse insulin resistance but improved fasting plasma insulin levels. In humans, high-SFA consumers, but not high-MUFA consumers, displayed reduced insulin sensitivity with elevated pycard-1 and caspase-1 expression in adipose tissue. These novel findings suggest that dietary MUFA can attenuate IL-1β–mediated insulin resistance and adipose dysfunction despite obesity via the preservation of AMPK activity.
No related grants have been discovered for Clare Reynolds.