Metabolic signature shift in type 2 diabetes mellitus revealed by mass spectrometry-based metabolomics

OBJECTIVE

Metabolic profiling of small molecules offers a snapshot of physiological processes. To identify metabolic signatures associated with type 2 diabetes and impaired fasting glucose (IFG) beyond differences in glucose, we used mass spectrometry-based metabolic profiling.

RESEARCH DESIGN AND METHODS

Individuals attending an institutional health screen were enrolled. IFG (n = 24) was defined as fasting glucose (FG) of 6.1 to 6.9 mmol/L and 2-hour post glucose load <11.1 mmol/L or glycosylated hemoglobin <6.5%, type 2 diabetes (n = 27), FG ≥7.0 mmol/L, or 2-hour post glucose load ≥11.1 mmol/L, or glycosylated hemoglobin ≥6.5%, and healthy controls (n = 60), FG <6.1 mmol/L. Fasting serum metabolomes were profiled and compared using gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry.

RESULTS

Compared to healthy controls, those with IFG and type 2 diabetes had significantly raised fructose, α-hydroxybutyrate, alanine, proline, phenylalanine, glutamine, branched-chain amino acids (leucine, isoleucine, and valine), low carbon number lipids (myristic, palmitic, and stearic acid), and significantly reduced pyroglutamic acid, glycerophospohlipids, and sphingomyelins, even after adjusting for age, gender, and body mass index.

CONCLUSIONS

Using 2 highly sensitive metabolomic techniques, we report distinct serum profile change of a wide range of metabolites from healthy persons to type 2 diabetes mellitus. Apart from glucose, IFG and diabetes mellitus are characterized by abnormalities in amino acid, fatty acids, glycerophospholipids, and sphingomyelin metabolism. These early broad-spectrum metabolic changes emphasize the complex abnormalities present in a disease defined mainly by elevated blood glucose levels.

Elevation of a novel angiogenic factor, leucine-rich-α2-glycoprotein (LRG1), is associated with arterial stiffness, endothelial dysfunction, and peripheral arterial disease in patients with type 2 diabetes

CONTEXT

Increased arterial stiffness and endothelial dysfunction are associated with peripheral arterial disease (PAD). Leucine-rich-α2-glycoprotein (LRG1) is a proangiogenic factor involved in regulation of the TGFβ signaling pathway.

OBJECTIVE

This study in patients with type 2 diabetes mellitus explored the associations of plasma LRG1 with arterial stiffness, endothelial function, and PAD.

DESIGN

Based on the ankle brachial index (ABI), patients were classified as having PAD (ABI ≤ 0.9) or as being borderline abnormal (ABI, 0.91-0.99) or normal (ABI, 1.00-1.40). LRG1 was measured by immunoassay; arterial stiffness, by carotid-femoral pulse-wave velocity and augmentation index; and endothelial function, by laser Doppler flowmetry.

RESULTS

A total of 2058 patients with type 2 diabetes mellitus were recruited. Mean age (1 SD) was 57.4 (0.2) years. Patients with PAD (n = 258) had significantly higher LRG1 compared to patients with borderline ABI and patients without PAD (19.00 [13.50] vs 17.35 [13.30] and 15.28 [10.40] μg/mL, respectively; P < .0001). Multiple regression analysis revealed that female gender (P < .0001), non-Chinese ethnicity (P < .0001), higher waist circumference (P = .017), lower estimated glomerular filtration rate (P < .0001), higher urine albumin-creatinine ratio (P = .009), lower ABI (P < .0001), higher pulse wave velocity (P = .040), and poorer endothelium-dependent vasodilation (P = .007) were independent significant predictors of higher plasma LRG1 levels. A generalized linear model showed that a 1-SD increase in log LRG1 was associated with an odds ratio of 4.072 (95% confidence interval, 1.889-8.777; P < .0001) for prevalence of PAD, after adjustment for traditional risk factors.

CONCLUSIONS

Higher LRG1 is a significant predictor for arterial stiffness, endothelial function, and PAD. The pathobiological basis and the temporal relationships of these associations need to be explored by further mechanistic and prospective studies to understand the clinical significance of these findings.

The role of intrathecal baclofen in the management of primary and secondary dystonia in children

Intrathecal baclofen (ITB) is a well-established method of treating spasticity in children with cerebral palsy. In our series, eight children with primary or dystonia secondary to cerebral palsy have benefited from ITB. The observations in this paper are subjective and based on the carer's impressions, but have confirmed the role of ITB in dystonia. Children with dystonia secondary to cerebral palsy benefited most and ITB can be used in these as a single treatment modality. The approach is different in dystonia secondary to cerebral palsy, where ITB can be used to palliate the spastic component, but other methods are necessary to treat the primary disease. We currently have three children in our series, where ITB in conjunction with deep brain stimulation (DBS) was used with satisfactory results.

MicroRNAs as biomarkers of hepatotoxicity in a randomized placebo-controlled study of simvastatin and ubiquinol supplementation

Statins are potent cholesterol-lowering drugs and are generally well tolerated. Hepatotoxicity is a rare but serious adverse effect of statins; however, its mechanisms are not clear. Coenzyme Q10 deficiency has been suggested, and supplementation of reduced coenzyme Q10 (ubiquinol) has been shown to have hepatoprotective effects. MicroRNAs (miRNAs) are small nucleotides that have been shown to be up-regulated in drug-induced liver injury. We hypothesized that circulating miRNAs may be differentially regulated after simvastatin treatment and by comparing with that of simvastatin and ubiquinol supplementation could potentially uncover signatory miRNA profile for simvastatin-induced liver injury. In this double-blind, prospective, randomized-controlled trial, miRNA profiles and liver enzymes were compared between simvastatin-treated patients, with and without ubiquinol supplementation, over 12 weeks compared to baseline. miRNA expression was further validated in HepG2 liver cell lines by real-time PCR. Changes in miR-192, miR-146a, miR-148a, miR-15a, and miR-21 were positively correlated (p<0.05) with alanine aminotransferase in simvastatin-only treated patients. In ubiquinol supplementation group, alanine aminotransferase and alkaline phosphatase were significantly down-regulated after 12 weeks and changes in miR-15a, miR-21 and miR-33a were negatively correlated with alkaline phosphatase (p < 0.05). Bioinformatics analyses predicted that miRNA regulation in simvastatin group was related to reduce proliferation and adenosine triphosphate-binding cassette transporters. Ubiquinol supplementation additionally regulated miRNAs that inhibit apoptotic and inflammatory pathways, suggesting potential hepatoprotective effects. Our results suggest that 20 mg/day of simvastatin does not have significant risk of hepatotoxicity and ubiquinol supplementation may, at the miRNA level, provide potential beneficial changes to reduce the effects of coenzyme Q10 deficiency in the liver.

Niacin results in reduced monocyte adhesion in patients with type 2 diabetes mellitus

BACKGROUND AND AIM

Patients with type 2 diabetes have increased expression of cell adhesion molecules (CAMs). CAMs and monocyte adhesion mediate essential processes in atherogenesis. It remains unclear if monocytes from patients on niacin have reduced adhesion function.

METHODS

We studied the variation of monocyte adhesion in patients with type 2 diabetes and low HDL-cholesterol, taking either extended release niacin (Niaspan®, Abbott Laboratories) or controls not on niacin. Biochemical parameters including adiponectin, CAMs and fresh monocytes from whole blood for adhesion assays, were studied at baseline and 12-weeks.

RESULTS

Niacin 1500 mg daily raised HDL-cholesterol from 0.8 mmol/l (95% CI: 0.7-0.9) to 0.9 mmol/l (95% CI: 0.8-1.1), p=0.10, and significantly reduced PECAM-1 by 24.9% (95% CI: 10.9-39.0; p<0.05), increased adiponectin by 30.5% (95% CI: 14.1-47.0; p<0.05), with monocyte adhesion reduced by 9.2% (95%CI: 0.7-17.7; p<0.05) in endothelial cells treated in basal conditions, and 7.8% (95% CI: 3.1-12.5; p<0.05) after TNF-α stimulation.

CONCLUSIONS

Monocytes isolated from patients on niacin had reduced adhesion to endothelial cells. Our findings suggest niacin has broad range of effects apart from lipid-modification, and these could be important in cardiovascular risk reduction.

Comparative outcomes of ulnar nerve transposition versus neurolysis in patients with entrapment neuropathy at the cubital tunnel: a 20-year analysis

BACKGROUND

Entrapment neuropathy of the ulnar nerve at the level of the elbow is the shared domain of multiple surgical specialties. A wide variety of operative methods for its surgical management have been reported. Our hospital utilizes neurolysis (NL) and subcutaneous transposition (AST). The aim of this paper was to compare the clinical outcomes in patients treated by ulnar nerve transposition versus neurolysis over a 20-year period.

METHODS

We included patients who underwent either neurolysis or an ulnar nerve transposition. A retrospective analysis was performed which included 480 patients at our institution between January 1992 and December 2012. In total, physical and electronic records for 480 patients were reviewed. Three-hundred and one underwent ulnar nerve transposition and 179 underwent ulnar nerve neurolysis .

RESULTS

In the AST group 201/301 patients suffered from parasthesiae pre-operatively and 156/301 had pain at and around the cubital tunnel. Paresis of the ulnar nerve innervated muscles was present in 99/301 patients. At the 3-month follow-up appointment, 187/201 patients with parasthesiae and 113/156 patients with local pain had resolution of their symptoms. In the NL group 151/179 patients had parasthesiae pre-operatively and 126/179 had pain at and around the cubital tunnel. Paresis of the ulnar nerve innervated muscles was present in 56/179 patients. At the 3-month follow-up appointment, 141/151 patients with parasthesiae and 117/126 patients with local pain had resolution of their symptoms.

CONCLUSIONS

In cases of ulnar nerve compression at the cubital tunnel, both neurolysis and transposition are effective in improving clinical outcome. The only statistically significant advantage of neurolysis over transposition seems to be relief of localized elbow pain. We recommend neurolysis as the preferred procedure.

'Scapula alata' as a consequence of park bench position for a retro-mastoid craniectomy

We report on a patient who developed winged scapula on the contralateral side to the approach for a cerebellopontine tumour excision, an unreported complication following this procedure. We think this was due to damage of the long thoracic nerve in the dependant side, while in the park bench position.

Molecular Signatures of Natural Killer Cells in CMV-Associated Anterior Uveitis, A New Type of CMV-Induced Disease in Immunocompetent Individuals

Cytomegalovirus (CMV) causes clinical issues primarily in immune-suppressed conditions. CMV-associated anterior uveitis (CMV-AU) is a notable new disease entity manifesting recurrent ocular inflammation in immunocompetent individuals. As patient demographics indicated contributions from genetic background and immunosenescence as possible underlying pathological mechanisms, we analyzed the immunogenetics of the cohort in conjunction with cell phenotypes to identify molecular signatures of CMV-AU. Among the immune cell types, natural killer (NK) cells are main responders against CMV. Therefore, we first characterized variants of polymorphic genes that encode differences in CMV-related human NK cell responses (Killer cell Immunoglobulin-like Receptors (KIR) and HLA class I) in 122 CMV-AU patients. The cases were then stratified according to their genetic features and NK cells were analyzed for human CMV-related markers (CD57, KLRG1, NKG2C) by flow cytometry. KIR3DL1 and HLA class I combinations encoding strong receptor–ligand interactions were present at substantially higher frequencies in CMV-AU. In these cases, NK cell profiling revealed expansion of the subset co-expressing CD57 and KLRG1, and together with KIR3DL1 and the CMV-recognizing NKG2C receptor. The findings imply that a mechanism of CMV-AU pathogenesis likely involves CMV-responding NK cells co-expressing CD57/KLRG1/NKG2C that develop on a genetic background of KIR3DL1/HLA-B allotypes encoding strong receptor–ligand interactions.

Associations between pigment epithelium-derived factor, insulin resistance and high density lipoprotein

AIMS

To measure serum pigment epithelium-derived factor in control subjects with normal fasting glucose, and in subjects with impaired fasting glucose and those with newly diagnosed Type 2 diabetes, before treatment initiation, and to measure pigment epithelium-derived factor prospectively in patients being treated with HDL-raising therapy, niacin.

METHODS

We enrolled 89 individuals attending an institutional health screen. Biochemical indices including lipids, homeostasis model assessment-insulin resistance, high-sensitivity C-reactive protein and pigment epithelium-derived factor were analysed in fasting blood. To validate the association between HDL and pigment epithelium-derived factor, we analysed samples from a separate study cohort with low HDL, followed up for 12-weeks while on niacin treatment. Secreted pigment epithelium-derived factor from 3T3-L1 adipocytes, after HDL treatment (24-h), was measured using Western blot analysis.

RESULTS

Mean (± sd) serum pigment epithelium-derived factor was significantly higher in subjects with impaired fasting glucose [13.99 (± 3.06) μg/ml] and Type 2 diabetes [12.94 (± 2.61)] μg/ml, compared with control subjects [11.83 (± 2.85) μg/ml (P = 0.014)]. In multivariate analyses, serum pigment epithelium-derived factor concentration was associated with BMI (β = 0.32, 0.007), homeostasis model assessment-insulin resistance (β = 0.33, P = 0.01) and HDL (β = -0.24, P = 0.05), after adjustment for age, gender and high-sensitivity C-reactive protein. In the niacin study, on-treatment HDL was an independent determinant of pigment epithelium-derived factor (β = -0.439, P = 0.033), after adjusting for age, homeostasis model assessment-insulin resistance and treatment. Adipocytes treated with HDL were found to have reduced pigment epithelium-derived factor secretion [24.8% (50 μg/ml), 28.4% (100 μg/ml) HDL; P < 0.05)], compared with the control samples.

CONCLUSION

Serum pigment epithelium-derived factor is positively associated with homeostasis model assessment-insulin resistance and negatively associated with HDL. Further studies are needed to understand the mechanism of low HDL and raised pigment epithelium-derived factor and to determine if they are causally related to the pathobiology of insulin resistance.

Spontaneous umbilical CSF fistula in an adult as a complication of a ventriculoperitoneal shunt

Ventriculoperitoneal (VP) shunt is the most commonly used CSF shunt in the modern era and widely accepted for the management of hydrocephalus. Numerous abdominal complications have been reported in the literature. Spontaneous umbilical fistula from VP shunt, although uncommon, has been reported previously in children, but never in an adult. This is a case report on an adult who was treated for spontaneous umbilical fistula at our unit.

In Vivo Profiling of a Natural Alkaloid, Anatabine, in Rodents: Pharmacokinetics and Anti-Inflammatory Efficacy

Natural alkaloids, a large class of plant-derived substances, have attracted considerable interest because of their pharmacological activities. In this study, the in vivo pharmacokinetics and anti-inflammatory profile of anatabine, a naturally occurring alkaloid, were characterized in rodents. Anatabine was found to be bioavailable and brain-penetrant following systemic administration. Following intraperitoneal (i.p.) administration (1, 2, and 5 mg/kg), anatabine caused a dose-dependent reduction in carrageenan-induced paw edema in rats; in mice, it inhibited the production of pro-inflammatory cytokines and simultaneously elevated the levels of an anti-inflammatory cytokine in a dose-dependent manner 2 h after lipopolysaccharide challenge. Furthermore, anatabine (∼10 and ∼20 mg/kg/day for 4 weeks; inhalation exposure) had effects in a murine model of multiple sclerosis, reducing neurological deficits and bodyweight loss. Comparative studies of the pharmacokinetics and anti-inflammatory activity of anatabine demonstrated its bioequivalence in rats following i.p. administration and inhalation exposure. This study not only provides the first detailed profile of anatabine pharmacokinetics in rodents but also comprehensively characterizes the anti-inflammatory activities of anatabine in acute and chronic inflammatory models. These findings provide a basis for further characterizing and optimizing the anti-inflammatory properties of anatabine.

Metabolic signature shift in type 2 diabetes mellitus revealed by mass spectrometry-based metabolomics

OBJECTIVE

Metabolic profiling of small molecules offers a snapshot of physiological processes. To identify metabolic signatures associated with type 2 diabetes and impaired fasting glucose (IFG) beyond differences in glucose, we used mass spectrometry-based metabolic profiling.

RESEARCH DESIGN AND METHODS

Individuals attending an institutional health screen were enrolled. IFG (n = 24) was defined as fasting glucose (FG) of 6.1 to 6.9 mmol/L and 2-hour post glucose load <11.1 mmol/L or glycosylated hemoglobin <6.5%, type 2 diabetes (n = 27), FG ≥7.0 mmol/L, or 2-hour post glucose load ≥11.1 mmol/L, or glycosylated hemoglobin ≥6.5%, and healthy controls (n = 60), FG <6.1 mmol/L. Fasting serum metabolomes were profiled and compared using gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry.

RESULTS

Compared to healthy controls, those with IFG and type 2 diabetes had significantly raised fructose, α-hydroxybutyrate, alanine, proline, phenylalanine, glutamine, branched-chain amino acids (leucine, isoleucine, and valine), low carbon number lipids (myristic, palmitic, and stearic acid), and significantly reduced pyroglutamic acid, glycerophospohlipids, and sphingomyelins, even after adjusting for age, gender, and body mass index.

CONCLUSIONS

Using 2 highly sensitive metabolomic techniques, we report distinct serum profile change of a wide range of metabolites from healthy persons to type 2 diabetes mellitus. Apart from glucose, IFG and diabetes mellitus are characterized by abnormalities in amino acid, fatty acids, glycerophospholipids, and sphingomyelin metabolism. These early broad-spectrum metabolic changes emphasize the complex abnormalities present in a disease defined mainly by elevated blood glucose levels.