Intrauterine stress impairs growth and metabolism in the fetus and offspring. We recently found that sustained maternofetal inflammation resulted in intrauterine growth restricted fetuses (MI-IUGR) with asymmetric body composition, impaired muscle glucose metabolism, and β-cell dysfunction near term. These fetuses also exhibited heightened inflammatory tone, which we postulated was a fetal programming mechanism for the IUGR phenotype. Thus, the objective of this study was to determine whether poor growth and metabolism persisted in MI-IUGR lambs after birth. Polypay ewes received serial lipopolysaccharide or saline injections in the first 2 wk of the 3 rd trimester of pregnancy to produce MI-IUGR (n = 13) and control (n = 12) lambs, respectively. Lambs were catheterized at 25 d of age. β cell function was assessed at 29 d, hindlimb glucose metabolism at 30 d, and daily blood parameters from d 26 to 31. Glucose metabolism was also assessed in flexor digitorum superficialis (FDS) muscle isolated at necropsy on d 31. Asymmetric body composition persisted in MI-IUGR neonates, as these lambs were lighter (P < 0.05) than controls at birth and 31 d, but body and cannon bone lengths did not differ at either age. FDS muscles from MI-IUGR lambs were smaller (P < 0.05) and exhibited reduced (P < 0.05) glucose oxidation and Akt phosphorylation but similar glucose uptake compared to controls when incubated in basal or insulin-spiked media. Similarly, hindlimb glucose oxidation was reduced (P < 0.05) in MI-IUGR lambs under basal and hyperinsulinemic conditions, but hindlimb glucose utilization did not differ from controls. Circulating urea nitrogen and cholesterol were reduced (P < 0.05) and triglycerides, high density lipoprotein-cholesterol, and glucose-to-insulin ratios were increased (P < 0.05) in MI-IUGR lambs. Glucose and insulin concentrations did not differ between groups during basal or hyperglycemic conditions. Although circulating monocyte and granulocyte concentrations were greater (P < 0.05) in MI-IUGR lambs, plasma TNFα was reduced (P < 0.05). FDS muscle contained greater (P < 0.05) TNFR1 and IκBα protein content. These findings indicate that maternofetal inflammation in late pregnancy results in fetal programming that impairs growth capacity, muscle glucose oxidation, and lipid homeostasis in offspring. Inflammatory indicators measured in this study appear to reflect heightened cytokine sensitivity in muscle and compensatory systemic responses to it.
In humans and animals, intrauterine growth restriction (IUGR) results from fetal programming responses to poor intrauterine conditions. Chronic fetal hypoxemia elevates circulating catecholamines, which reduces skeletal muscle β2 adrenoceptor content and contributes to growth and metabolic pathologies in IUGR-born offspring. Our objective was to determine whether intermittent maternofetal oxygenation during late gestation would improve neonatal growth and glucose metabolism in IUGR-born lambs. Pregnant ewes were housed at 40°C from the 40 th to 95 th d of gestational age (dGA) to produce IUGR-born lambs (n = 9). A 2 nd group of IUGR-born lambs received prenatal O2 supplementation via maternal O2 insufflation (100% humidified O2, 10 L/min) for 8 h/d from dGA 130 to parturition (IUGR+O2, n = 10). Control lambs (n = 15) were from pair-fed thermoneutral ewes. All lambs were weaned at birth, hand-reared, and fitted with hindlimb catheters at d 25. Glucose-stimulated insulin secretion (GSIS) and hindlimb hyperinsulinemic-euglycemic clamp (HEC) studies were performed at d 28 and 29, respectively. At d 30, lambs were euthanized and ex vivo HEC studies were performed on isolated muscle. Without maternofetal oxygenation, IUGR lambs were 40% lighter (P < 0.05) at birth and maintained slower (P < 0.05) growth rates throughout the neonatal period compared to controls. At 30 d of age, IUGR lambs had lighter (P < 0.05) hindlimbs and flexor digitorum superficialis (FDS) muscles. IUGR+O2 lambs exhibited improved (P < 0.05) birthweight, neonatal growth, hindlimb mass, and FDS mass compared to IUGR lambs. Hindlimb insulin-stimulated glucose utilization and oxidation rates were reduced (P < 0.05) in IUGR but not IUGR+O2 lambs. Ex vivo glucose oxidation rates were less (P < 0.05) in muscle from IUGR but not IUGR+O2 lambs. Surprisingly, β2 adrenoceptor content and insulin responsiveness were reduced (P < 0.05) in muscle from IUGR and IUGR+O2 lambs compared to controls. In addition, glucose-stimulated insulin secretion was reduced (P < 0.05) in IUGR lambs and only modestly improved (P < 0.05) in IUGR+O2. Insufflation of O2 also increased (P < 0.05) acidosis and hypercapnia in dams, perhaps due to the use of 100% O2 rather than a gas mixture with a lesser O2 percentage. Nevertheless, these findings show that intermittent maternofetal oxygenation during late gestation improved postnatal growth and metabolic outcomes in IUGR lambs without improving muscle β2 adrenoceptor content.
Intrauterine growth restriction (IUGR) is linked to lifelong reductions in muscle mass due to intrinsic functional deficits in myoblasts, but the mechanisms underlying these deficits are not known. Our objective was to determine if the deficits were associated with changes in inflammatory and adrenergic regulation of IUGR myoblasts, as was previously observed in IUGR muscle. Primary myoblasts were isolated from IUGR fetal sheep produced by hyperthermia-induced placental insufficiency (PI-IUGR; n = 9) and their controls (n = 9) and from IUGR fetal sheep produced by maternofetal inflammation (MI-IUGR; n = 6) and their controls (n = 7). Proliferation rates were less (P < 0.05) for PI-IUGR myoblasts than their controls and were not affected by incubation with IL-6, TNF-α, norepinephrine, or insulin. IκB kinase inhibition reduced (P < 0.05) proliferation of control myoblasts modestly in basal media but substantially in TNF-α-added media and reduced (P < 0.05) PI-IUGR myoblast proliferation substantially in basal and TNF-α-added media. Proliferation was greater (P < 0.05) for MI-IUGR myoblasts than their controls and was not affected by incubation with TNF-α. Insulin increased (P < 0.05) proliferation in both MI-IUGR and control myoblasts. After 72-h differentiation, fewer (P < 0.05) PI-IUGR myoblasts were myogenin+ than controls in basal and IL-6 added media but not TNF-α-added media. Fewer (P < 0.05) PI-IUGR myoblasts were desmin+ than controls in basal media only. Incubation with norepinephrine did not affect myogenin+ or desmin+ percentages, but insulin increased (P < 0.05) both markers in control and PI-IUGR myoblasts. After 96-h differentiation, fewer (P < 0.05) MI-IUGR myoblasts were myogenin+ and desmin+ than controls regardless of media, although TNF-α reduced (P < 0.05) desmin+ myoblasts for both groups. Differentiated PI-IUGR myoblasts had greater (P < 0.05) TNFR1, ULK2, and TNF-α-stimulated TLR4 gene expression, and PI-IUGR semitendinosus muscle had greater (P < 0.05) TNFR1 and IL6 gene expression, greater (P < 0.05) c-Fos protein, and less (P < 0.05) IκBα protein. Differentiated MI-IUGR myoblasts had greater (P < 0.05) TNFR1 and IL6R gene expression, tended to have greater (P = 0.07) ULK2 gene expression, and had greater (P < 0.05) β-catenin protein and TNF-α-stimulated phosphorylation of NFκB. We conclude that these enriched components of TNF-α/TNFR1/NFκB and other inflammatory pathways in IUGR myoblasts contribute to their dysfunction and help explain impaired muscle growth in the IUGR fetus.
Objectives Iron depletion is common around the world and among certain risk groups in developed countries. The overall purpose was to test the suitability of a novel plasma collection card for minimally invasive iron status assessment. Methods Twenty participants (10 f/10 m) participated in this cross‐sectional study. Ferritin and hemoglobin were measured from blood collected from a forearm vein, serving as reference method. Blood was also collected from the fingertip using the NoviplexTM Plasma Prep Card as well as capillary collection tubes. Results There was substantial concordance between ferritin measured from samples collected via NoviplexTM and venous ferritin (concordance correlation coefficient (CCC) = 0.96) with a mean bias of −0.8 ng/mL. Storing NoviplexTM cards at room temperature for 2 weeks resulted in slightly lower but good concordance when compared to venous ferritin (CCC = 0.95). Capillary hemoglobin (CCC = 0.42) and hematocrit (CCC = 0.25) were in poor agreement with venous data. Conclusions NoviplexTM cards offer a suitable alternative for a minimally invasive ferritin screening in the field when compared to capillary collection tubes. Despite overall substantial concordance with the reference method, findings indicative of iron status abnormalities should be confirmed in venous samples.
Systemic lupus erythematosus (SLE) is an autoimmune disease predominantly affecting women and often leading to lupus nephritis and kidney damage. Endoplasmic reticulum (ER) stress has been implicated in several forms of kidney disease, but whether ER stress contributes to renal injury in SLE is unknown. To investigate this, a small molecule chaperone, sodium 4-phenylbutyrate (4-PBA), was administered to the New Zealand Black x New Zealand White F1 hybrid (NZBWF1) mouse model of SLE. In a prevention study, treatment with 4-PBA from 20 weeks of age (prior to the development of renal injury) delayed the onset of albuminuria and significantly reduced additional indices of renal injury compared with vehicle-treated NZBWF1 mice at 36 weeks of age, including collagen deposition, tubular casts, renal cell apoptosis, and blood urea nitrogen (BUN) concentration. To test whether ER stress contributes to the progression of renal injury once albuminuria has developed, mice were monitored for the onset of albuminuria (3+ or ≥300 mg/dl by dipstick measurement of 24-h urine sample) and once established, were either killed (onset group), or underwent 4-PBA or vehicle treatment for 4 weeks. Treatment with 4-PBA blocked the worsening of glomerular injury, reduced the number of dilated or cast-filled tubules, and reduced the number of apoptotic cells compared with vehicle-treated mice. BUN and left ventricle to bodyweight ratio (LV:BW) were also reduced by 4-PBA treatment. Renal expression of the endogenous chaperones, protein disulphide isomerase (PDI), and 78 kDa glucose-regulated protein (GRP78, also known as binding Ig protein (BiP)), were increased in 4-PBA-treated mice. Together, these results suggest a therapeutic potential for agents like 4-PBA in combating renal injury in SLE.
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