Chronic kidney disease is associated with attenuated plasma metabolome response to oral glucose tolerance testing

Chronic kidney disease (CKD), a major public health problem, is associated with decreased anabolic response to insulin contributing to protein-energy wasting. Targeted metabolic profiling of the response to oral glucose tolerance testing (OGTT) may help identify metabolic pathways contributing to disruptions to insulin response in CKD. Using targeted metabolic profiling, we examined plasma metabolome in 41 moderate-to-severe non-diabetic CKD patients with estimated glomerular filtration rate (eGFR)<60ml/min per 1.73m2 (38.9+-12.7) and 20 healthy controls with normal eGFR (87.2+-17.7) before and after 2h of 75g oral glucose load. Compared to controls, CKD participants had higher lactate: pyruvate (L:P) ratio both at fasting and after oral glucose challenge. Total energy production estimated through GTP:GDP ratio was impaired during OGTT despite similar fasting GTP:GDP ratio. CKD group had sustained elevation of vitamin B family members, TCA cycle metabolites, and purine nucleotides in response to glucose challenge. Metabolic profiling in response to OGTT suggests a broad disruption of mitochondrial energy metabolism in CKD patients. These findings motivate further investigation into insulin sensitizers in patients with non-diabetic CKD and their impact on energy metabolism.

Lack of Offspring Nrf2 Does Not Exacerbate the Detrimental Metabolic Outcomes Caused by In Utero PCB126 Exposure

Human environmental exposures to toxicants, such as polychlorinated biphenyls (PCBs), increase oxidative stress and disease susceptibility. Such exposures during pregnancy and/or nursing have been demonstrated to adversely affect offspring health outcomes. Nuclear factor erythroid-2-related factor 2 (Nrf2) regulates the antioxidant response and is involved in the detoxification of coplanar PCBs, like PCB126. The purpose of this study was to investigate glucose tolerance and body composition in PCB-exposed offspring expressing or lacking Nrf2. We hypothesized that offspring lacking Nrf2 expression would be more susceptible to the long-term health detriments associated with perinatal PCB exposure. During gestation, whole-body Nrf2 heterozygous (Het) and whole-body Nrf2 knockout (KO) mice were exposed to vehicle or PCB126. Shortly after birth, litters were cross-fostered to unexposed dams to prevent PCB exposure during nursing. Offspring were weaned, and their body weight, body composition, and glucose tolerance were recorded. At two months of age, PCB exposure resulted in a significant reduction in the average body weight of offspring born to Nrf2 Het dams (p &lt; 0.001) that primarily arose from the decrease in average lean body mass in offspring (p &lt; 0.001). There were no differences in average body weight of PCB-exposed offspring born to Nrf2 KO dams (p &gt; 0.05), and this was because offspring of Nrf2 KO dams exposed to PCB126 during pregnancy experienced a significant elevation in fat mass (p = 0.002) that offset the significant reduction in average lean mass (p &lt; 0.001). Regardless, the lack of Nrf2 expression in the offspring themselves did not enhance the differences observed. After an oral glucose challenge, PCB-exposed offspring exhibited significant impairments in glucose disposal and uptake (p &lt; 0.05). Offspring born to Nrf2 Het dams exhibited these impairments at 30 min and 120 min, while offspring born to Nrf2 KO dams exhibited these impairments at zero, 15, 30, 60 and 120 min after the glucose challenge. Again, the interactions between offspring genotype and PCB exposure were not significant. These findings were largely consistent as the offspring reached four months of age and demonstrate that the lack of offspring Nrf2 expression does not worsen the metabolic derangements caused by in utero PCB exposure as we expected. Future directions will focus on understanding how the observed maternal Nrf2 genotypic differences can influence offspring metabolic responses to in utero PCB exposure.

The association between an oral glucose tolerance test performed at term pregnancy and obstetric outcomes

Aims Assessing the value of oral glucose tolerance test performed at term pregnancy in identifying obstetric complications. Methods Retrospective cohort study of women with a normal 50 g glucose challenge test who also had an oral glucose tolerance test at term (defined as at or after 37 weeks of gestation). Comparison between the pathological and normal oral glucose tolerance test groups was performed. Results The mean glucose in the glucose challenge test of women in the normal oral glucose tolerance test ( n = 256) group was lower than that in the pathological oral glucose tolerance test ( N = 16) group (105 ± 17 mg/dl (5.8 ± 0.9 mmol/l) vs 117 ± 13 mg/dl (6.5 ± 0.7 mmol/l), p = 0.007). Relevant obstetrical complications did not differ significantly between the groups. Of note, in the pathological oral glucose tolerance test group only one woman delivered a macrosomic infant. Conclusions A pathological oral glucose tolerance test performed at term was unable to identify women at risk for impaired glucose metabolism-related obstetric complications and is therefore of limited clinical value and seems to be unjustified.

Alcalase Potato Protein Hydrolysate-PPH902 Enhances Myogenic Differentiation and Enhances Skeletal Muscle Protein Synthesis under High Glucose Condition in C2C12 Cells

Sarcopenia is an aging associated disorder involving skeletal muscle atrophy and a reduction in muscle strength, and there are no pharmaceutical interventions available thus far. Moreover, conditions such as hyperglycaemia are known to further intensify muscle degradation. Therefore, novel strategies to attenuate skeletal muscle loss are essential to enhance muscle function and thereby improve the quality of life in diabetic individuals. In this study, we have investigated the efficiency of a potato peptide hydrolysate PPH902 for its cytoprotective effects in skeletal muscle cells. PPH902 treatment in C2C12 cells showed the dose-dependent activation of the Akt/mTOR signalling pathway that is involved in skeletal myogenesis. According to Western blotting analysis, PPH902 induced the phosphorylation of Akt, mTOR proteins and induced the myogenic differentiation of C2C12 myoblasts in a differentiation medium. The phosphorylation myogenic transcription factor Foxo3A was also found to be increased in the cells treated with PPH902. In addition, treatment with PPH902 ameliorated the high glucose induced reduction in cell viability in a dose-dependent manner. Moreover, the number of myotubes in a differentiation medium reduced upon high glucose challenge, but treatment with PPH902 increased the number of differentiated myotubes. Further, the phosphorylations of AMPK and mitochondrial-related transcription factors such as PGC-1α were suppressed upon high glucose challenge but PPH902 treatment restored the protein levels. We demonstrate, for the first time, that a specific potato peptide has a therapeutic effect against sarcopenia. In addition, PPH902 improved the myogenic differentiation and their mitochondrial biogenesis and further improved myogenic protein and inhibited muscle protein degradation in C2C12 cells challenged under a high glucose condition.