Intergenerational transmission of glucose intolerance and obesity by in utero undernutrition in mice

Abstract

Objective: Low birth weight (LBW) is associated with increased risk of obesity, diabetes, and cardiovascular disease during adult life. Moreover, this programmed disease risk can progress to subsequent generations. We previously described a mouse model of LBW, produced by maternal caloric undernutrition (UN) during late gestation. LBW offspring (F(1)-UN generation) develop progressive obesity and impaired glucose tolerance (IGT) with aging. We aimed to determine whether such metabolic phenotypes can be transmitted to subsequent generations in an experimental model, even in the absence of altered nutrition during the second pregnancy.

Research design and methods: We intercrossed female and male F(1) adult control (C) and UN mice and characterized metabolic phenotypes in F(2) offspring.

Results: We demonstrate that 1) reduced birth weight progresses to F(2) offspring through the paternal line (Cfemale -Cmale = 1.64 g; Cfemale -UNmale = 1.57 g, P < 0.05; UNfemale -Cmale = 1.64 g; UNfemale -UNmale = 1.60 g, P < 0.05), 2) obesity progresses through the maternal line (percent body fat: Cfemale -Cmale = 22.4%; Cfemale -UNmale = 22.9%; UNfemale -Cmale = 25.9%, P < 0.05; UNfemale -UNmale = 27.5%, P < 0.05), and 3) IGT progresses through both parental lineages (glucose tolerance test area under curve Cfemale -Cmale = 100; Cfemale -UNmale = 122, P < 0.05; UNfemale -Cmale = 131, P < 0.05; UNfemale -UNmale = 151, P < 0.05). Mechanistically, IGT in both F(1) and F(2) generations is linked to impaired beta-cell function, explained, in part, by dysregulation of Sur1 expression.

Conclusions: Maternal undernutrition during pregnancy (F(0)) programs reduced birth weight, IGT, and obesity in both first- and second-generation offspring. Sex-specific transmission of phenotypes implicates complex mechanisms including alterations in the maternal metabolic environment (transmaternal inheritance of obesity), gene expression mediated by developmental and epigenetic pathways (transpaternal inheritance of LBW), or both (IGT).

FIG. 1.

Experimental design, birth weight, and growth curves. A: Experimental design, including breeding scheme for second-generation (F₂) offspring. Circles designate females and squares designate males. Note that mating pairs were nonsiblings. Metabolic analysis was performed in males only. B: Body weight at birth for F₂ offspring. C: Postnatal growth curves for F₂ male mice. For all panels, values are means ± SE (n ≥ 15 mice/group). *P < 0.05; **P < 0.01 vs. C♀-C♂ (ANOVA).

FIG. 2.

Random fed blood glucose (A) and serum insulin (B) levels from 2 to 8 months of age in F₂ male mice. Values are means ± SE (n ≥ 8 mice/group). *P < 0.05 vs. C♀-C♂ (ANOVA).

FIG. 3.

Glucose and insulin tolerance tests in 6-month-old male mice. A: Intraperitoneal glucose tolerance test (2 g glucose/kg body wt) was performed after an overnight fast. B: Intraperitoneal insulin tolerance test (1 unit insulin/kg body wt) was performed after a 4-h fast. Results are expressed as means ± SE (n ≥ 6 mice/group). #P < 0.05; ***P < 0.001 vs. C♀-C♂ (repeated-measures ANOVA).

FIG. 4.

Islet physiology. A: In vivo: insulin levels during an intraperitoneal glucose tolerance test in 4-month-old male mice. Data are provided as the fold increase in serum insulin (over basal) at 30 min after the glucose bolus injection (n ≥ 8 mice/group). B: Ex vivo glucose-stimulated insulin secretion in islets isolated from 4-month-old mice (n ≥ 4 replicates/group in at least 2 independent isolations). □, 1 mmol/l; , 5.5 mmol/l; , 16.7 mmol/l. C: Intraperitoneal tolbutamide tolerance test (1 mg tolbutamide/kg body wt) was performed after a 4-h fast on 4-month-old mice (n ≥ 8 mice/group). □, 0 min; 30 min tolbutamide. D: Tolbutamide stimulation (200 μmol/l) of insulin release from isolated islets ex vivo (n ≥ 4 replicates/group in at least 2 independent isolations). □, none; tolbutamide. E: Sur1 gene expression was assessed by quantitative PCR in islets from 4-month-old mice (n ≥ 5 replicates/group). F: Kir6.2 gene expression was assessed by quantitative PCR in islets from 4-month-old mice (n ≥ 5 replicates/group). For all panels, results are expressed as means ± SE. *P < 0.05 vs. C♀-C♂; **P < 0.01 vs. C♀-C♂ (ANOVA).

FIG. 5.

Characterization of the obese phenotype. A: Total and visceral fat mass by dual-energy X-ray absorptiometry in 4-month-old males (n ≥ 6 mice/group). B: Serum leptin levels in 4-month-old males (n ≥ 6/group). C and D: Expression of imprinted genes assessed by quantitative PCR in epididymal fat from 4-month-old F₁ males (C) (n = 6/group) and 4-month-old F₂ males (D) (n = 6/group). Results are expressed as means ± SE. *P < 0.05 vs. C♀-C♂; **P < 0.01 vs. C♀-C♂ (ANOVA).