Is it Time to Migrate to Liquid Chromatography Automated Platforms in the Clinical Laboratory? A Brief Point of View.

Liquid chromatography coupled to mass spectrometry already started to surpass the major drawbacks in terms of sensitivity, specificity and cross-reactivity that some analytical methods used in the clinical laboratory exhibit. This hyphenated technique is already preferred for specific applications while finding its own place in the clinical laboratory setting. However, large-scale usage, high-throughput analysis and lack of automation emerge as shortcomings that liquid chromatography coupled to mass spectrometry still has to overrun in order to be used on a larger scale in the clinical laboratory. The aim of this review article is to point out the present-day position of the liquid chromatography coupled to mass spectrometry technique while trying to understand how this analytical method relates to the basic working framework of the clinical laboratory. This paper offers insights about the main regulation and traceability criteria that this coupling method has to align and comply to, automation and standardization issues and finally the critical steps in sample preparation workflows all related to the high-throughput analysis framework. Further steps are to be made toward automation, speed and easy-to-use concept; however, the current technological and quality premises are favorable for chromatographic coupled to mass spectral methods.

Observational study of the bisphosphonate-related osteonecrosis of jaws.

INTRODUCTION: The bisphosphonate-related osteonecrosis of the jaw was first referred to in 2003. Bisphosphonates action is focused on the osteoclasts. The drastic inhibition of the osteoclastic function is harmful for the jaws which are the only bones of the human skeleton in relative contact with the external environment. The adverse effects of the bisphosphonate-related therapy include the pathology for which they are prescribed, the atypical fractures in pathological bone. METHOD: The aim of this research was to analyze the risk factors and the treatment methods in case of osteonecrosis of the jaws. To achieve these goals, the author analyzed the observation sheets of the patients admitted to the Oral and Maxillofacial Surgery Clinic during the period 2010-2015. The inclusion criteria were as follows: treatment with bisphosphonates, current or previous; the lesions of the mucous gingiva of the maxillaries followed by exposed necrotic bone, older than 8 weeks, with no tendency of healing; specific radiological image showing extended osteolysis with diffuse outline or radiopacity surrounded by radio-transparence, representing the necrotic bone sequestered; no metastasis in the necrotic maxillary bone; patient with no medical background of cervical-facial radiations. The patients who met these criteria were admitted in the study after signing the informed consent. Afterwards, the information found in the notes of the observational sheet (anamnesis, general examination and the imagistic investigation, treatment, postoperative recovery, prescription, postoperative recommendations) were gathered and submitted for statistic analysis. RESULTS: Of the 20 patients in total, 13 were women and 7 men, of ages ranging from 43 to 83. The most numerous cases were registered in the seventh age decade. All patients included in the study had lesions of the gingival maxillary mucosal areas with exposure of the subjacent necrotic bone. 60% of them were under intravenous treatment with zoledronic acid (Zometa®). A single patient was under oral treatment with bisphosphonates. 19 of these 20 patients developed osteonecrosis following a dental extraction while one case was due to the instability of the mandibular mobile prosthesis. 61% of the patients included in the study developed a necrotic process in the mandibular bone, 80% of the localizations were in the posterior area. As first intention, the choice of treatment was represented by local lavages with antiseptic solutions, general antibiotics and sequestrectomy. Of these patients, a third had relapsed and needed radical surgery treatment. CONCLUSIONS: Prevention of the bisphosphonate-related osteonecrosis of the jaw represents the best method of treatment. The development of bone sequesters damages the volume of the maxillary bone as such, reducing the chances for prosthetic functional rehabilitation of the dento-maxillary system. An increase in the quality of life by oral restoration of these patients may represent a challenge.

Elevated Serum Levels of Sclerostin are Associated with High Disease Activity and Functional Impairment in Patients with Axial Spondyloarthritis.

BACKGROUND: Recent research suggests that biomarkers may be useful in assessing disease activity, structural damage, and response to therapy in axial spondyloarthritis (axSpA). Our study aims at evaluating the relationship between inflammation and bone remodeling markers and variables assessing disease activity and functional disability in patients with axSpA. METHODS: Serum levels of sclerostin, matrix metalloproteinase-3 (MMP-3), interleukin-17 (IL-17), and IL-23 were measured in 60 patients with axSpA and 20 healthy controls. Disease activity was evaluated using Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Ankylosing Spondylitis Disease Activity Score (ASDAS), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). Functional status was assessed by Bath Ankylosing Spondylitis Function Index (BASFI) and measures of spinal mobility. RESULTS: Sclerostin levels were more elevated in axSpA patients with high disease activity than in those with low disease activity and in controls. They were significantly correlated with BASFI values (r = 0.29, p = 0.03) and measures of spinal mobility, but not with the classical markers of disease activity (BASDAI, ASDAS, CRP, and ESR). Although both MMP-3 and IL-17 levels were elevated in patients with active disease, they were not correlated with markers of disease activity or with functional disability. The levels of sclerostin, MMP-3, IL-17, and IL-23 were similar in axSpA patients and healthy controls. CONCLUSIONS: Elevated levels of sclerostin, MMP-3, and IL-17 were observed in axSpA patients with active disease, suggesting their potential role in assessing disease activity. In axSpA patients, sclerostin levels might be equally influenced by inflammation and level of physical activity. Further studies are required to confirm our findings in order to understand their clinical value.

Bone mineral content in patients with congenital generalized lipodystrophy is unaffected by metreleptin replacement therapy.

CONTEXT: Leptin alters bone and mineral metabolism in rodents, but this has not been verified in humans. PATIENTS with congenital generalized lipodystrophy (CGL) have low leptin due to deficient adipose mass and serve as models of leptin deficiency and replacement. OBJECTIVE: To study the effects of recombinant human methionyl leptin (metreleptin) on bone mineral content (BMC) and mineral metabolism. DESIGN AND SETTING: An open-label nonrandomized study at the National Institutes of Health. PATIENTS: Thirty-one patients with CGL (ages 4.3 to 46.7 y). INTERVENTION: Metreleptin (0.06 to 0.24 mg/kg/d) for 6 months to 11 years. OUTCOME MEASURES: BMC was assessed by dual-energy x-ray absorptiometry. SD scores (SDS) for BMC were calculated based on height, race, sex, and age using population normative data. Calcium, phosphorus, PTH, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were measured at baseline and follow-up. RESULTS: At baseline, patients demonstrated significantly increased total body less head BMC (mean SDS, 1.8 ± 0.7), height (mean SDS, 1.3 ± 1.3), and lean mass index, defined as lean body mass per height squared (mean SDS, 1.5 ± 0.83), vs population normative data. No change in total body less head BMC was observed after metreleptin. Lean mass index decreased with metreleptin. Serum calcium decreased with metreleptin, but remained within normal limits. No changes were seen in phosphorus, PTH, or vitamin D. CONCLUSIONS: In contrast to rodent models, CGL patients have increased BMC in the leptin-deficient state, which does not change with leptin replacement. The high BMC in these patients is partially explained by high lean mass and tall stature.

The role of proinsulin and insulin in the diagnosis of insulinoma: a critical evaluation of the Endocrine Society clinical practice guideline.

CONTEXT: An end of fast insulin ≥ 3 µIU/mL and a proinsulin concentration ≥ 5 pmol/L have been suggested as useful cutoffs for the diagnosis of insulinoma. OBJECTIVE: The main objective was to evaluate the diagnostic performance of an end of fast insulin concentration ≥ 3 µIU/mL and an end of fast proinsulin concentration ≥ 5 pmol/L. DESIGN: The design was a case-control series. SETTING: The setting was a tertiary-care center. PATIENTS: Fifty-six subjects with a positive 48-hour supervised fast had an insulinoma between June 2000 and April 2011. During this same time period, a diagnosis of insulinoma was excluded in 29 subjects who underwent a supervised fast. INTERVENTION: 48-hour supervised fast. MAIN OUTCOME MEASURE: The main outcome measures were serum insulin concentration and plasma proinsulin concentration. RESULTS: Ninety-one percent of the patients with an insulinoma had a measured insulin concentration ≥5 µIU/mL at the end of fast. The sensitivity increased to 98% if the threshold to define inadequate insulin suppression was lowered to ≥3 µIU/mL. The median (interquartile range) end of fast proinsulin was 100 (53-270) pmol/L for cases and 6.8 (4.2-12.0) pmol/L for controls. An end of fast proinsulin value of ≥ 5 pmol/L could not distinguish cases from controls (59% false positive rate). All patients with an insulinoma (sensitivity 100%) and none of the control subject (specificity 100%) had end of fast proinsulin concentration ≥ 27 pmol/L. CONCLUSIONS: Using a current insulin assay 9% of insulinoma cases end the supervised fast with an insulin concentration below 5 µIU/mL. Inadequate insulin suppression defined using a threshold of ≥ 3 µIU/mL increases the sensitivity of the test. The value of the proinsulin test lies in its unique ability to distinguish cases from controls. A proinsulin concentration of ≥22 pmol/L best discriminates cases from controls. Reliance on an end of fast proinsulin cutoff value of 5 pmol/L does not augment sensitivity but greatly reduces specificity of the test.

Ultrasonography of the non-traumatic lesions of the fingers. Pictorial essay.

The purpose of this pictorial essay is to illustrate the ultrasonographic aspects of the non-traumatic lesions of the fingers. Diffuse (especially dactylitis) and localized (tumors, tophi, calcinosis, etc) lesions of the digits are discussed and illustrated. For a better understanding, the US images are compared with the clinical aspect of the pathological fingers.

The liver diseases of lipodystrophy: the long-term effect of leptin treatment.

BACKGROUND & AIMS: Lipodystrophies are hypoleptinemic conditions characterized by fat loss, severe insulin resistance, hypertriglyceridemia, and ectopic fat accumulation. Non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) are also features of this condition. We studied the spectrum of liver disease in lipodystrophy and the effects of leptin replacement. METHODS: This was an open-label, prospective study of leptin therapy in patients with inherited and acquired lipodystrophy at the National Institutes of Health. Liver biopsies were performed at baseline (N=50) and after leptin replacement (N=27). NASH activity was assessed using the NASH Clinical Research Network (CRN) scoring system. Fasting blood glucose, triglyceride, hemoglobin A1c and liver enzymes were measured at baseline and at the time of the final liver biopsy. RESULTS: In leptin-treated patients, 86% met criteria for NASH at baseline, while only 33% had NASH after leptin replacement for 25.8 ± 3.7 months (mean ± SE, p=0.0003). There were significant improvements in steatosis grade (reduction of mean score from 1.8 to 0.9) and ballooning injury scores (from 1.2 to 0.4), with a 44.2% reduction in mean NAFLD activity score (p<0.0001). Patients who already had fibrosis remained stable on leptin replacement. We observed significant improvement in metabolic profile, ALT and AST. In addition to NASH, four patients with acquired generalized lipodystrophy (AGL) had autoimmune hepatitis. CONCLUSIONS: The fundamental liver disease of lipodystrophy is NASH, although autoimmune hepatitis was observed in some patients with AGL. Leptin appears to be a highly effective therapy for NASH in hypoleptinemic lipodystrophic patients.

Insulin resistance is a sufficient basis for hyperandrogenism in lipodystrophic women with polycystic ovarian syndrome.

CONTEXT: The lipodystrophies (LD) are characterized by metabolic abnormalities (insulin resistance, hypertriglyceridemia, and diabetes) and a polycystic ovarian syndrome (PCOS) phenotype. Therapeutic administration of leptin improves insulin sensitivity and the metabolic features. OBJECTIVE: The objective of the study was to investigate whether the PCOS features are corrected by increasing insulin sensitivity as a function of leptin treatment. DESIGN: This was a prospective, open-label trial using leptin replacement in various forms of lipodystrophy. SETTING: The study was performed at the Clinical Center at the National Institutes of Health. PATIENTS OR OTHER PARTICIPANTS: Twenty-three female patients with LD were enrolled in a leptin replacement trial from 2000 to the present. Different parameters were assessed at baseline and after 1 yr of therapy. INTERVENTION(S): Patients were treated with leptin for at least 1 yr. MAIN OUTCOME MEASURE(S): We evaluated free testosterone, SHBG, and IGF-I at baseline and after 1 yr of leptin. RESULTS: Testosterone levels decreased from 3.05 ±0.6 ng/ml at baseline to 1.7 ±0.3 ng/ml (P = 0.02). SHBG increased from 14.5 ±2 to 25 ±3.5 nmol/liter after 1 yr of leptin therapy. There were no significant changes in the levels of gonadotropins and ovarian size as a result of leptin replacement therapy. IGF-I increased significantly after leptin therapy from 150 ±14 to 195 ±17. There was a significant decrease in triglycerides and glycosylated hemoglobin in the context of reduced insulin requirements. CONCLUSIONS: In the present study, we show that LD may be a model for the common forms of PCOS and that the endocrine features are corrected by leptin therapy, which reduces insulin resistance.

Cardiomyopathy in congenital and acquired generalized lipodystrophy: a clinical assessment.

Lipodystrophy is a rare disorder characterized by loss of adipose tissue and low leptin levels. This condition is characterized by severe dyslipidemia, insulin resistance, diabetes mellitus, and steatohepatitis. Another phenotypic feature that occurs with considerable frequency in generalized lipodystrophy is cardiomyopathy. We report here the cardiac findings in a cohort of patients with generalized congenital and acquired lipodystrophy, and present a literature review of the cardiac findings in patients with generalized lipodystrophy. We studied 44 patients with generalized congenital and acquired lipodystrophy, most of them enrolled in a clinical trial of leptin therapy. Patients underwent electrocardiograms and transthoracic echocardiograms to evaluate their cardiac status. We followed these patients for an extended time period, some of them up to 8 years. Evaluation of our cohort of patients with generalized lipodystrophy shows that cardiomyopathy is a frequent finding in this population. Most of our patients had hypertrophic cardiomyopathy, and only a small number had features of dilated cardiomyopathy. Hypertrophic cardiomyopathy was more frequent in patients with seipin mutation, a finding consistent with the literature. The underlying mechanism for cardiomyopathy in lipodystrophy is not clear. Extreme insulin resistance and the possibility of a "lipotoxic cardiomyopathy" should be entertained as possible explanations.

Cyclosporin A inhibits flow-mediated activation of endothelial nitric-oxide synthase by altering cholesterol content in caveolae.

Fluid shear stress generated by blood flowing over the endothelium is a major determinant of arterial tone, vascular remodeling, and atherogenesis. Nitric oxide (NO) produced by endothelial NO synthase (eNOS) plays an essential role in regulation of vascular function and structure by blood flow. Although cyclosporin A (CsA), an inhibitory ligand of cyclophilin A, is a widely used immunosuppressive drug, it causes arterial hypertension in part by impairing eNOS-dependent vasodilation. Here we show that CsA inhibits fluid shear stress-mediated eNOS activation in endothelial cells via decreasing cholesterol content in caveolae. Exposure of cultured bovine aortic endothelial cells to 1 mum CsA for 1 h significantly inhibited NO production and eNOS phosphorylation at Ser-1179 induced by flow (shear stress=dynes/cm2). The effect of CsA was not related to inhibition of two known eNOS kinases, protein kinase B (Akt) and protein kinase A, because CsA did not affect Akt or protein kinase A activation. In rabbit aorta perfused ex vivo, CsA also significantly inhibited flow-induced eNOS phosphorylation at Ser-1179 but had no effect on Akt measured by phosphorylation at Ser-473. However, CsA treatment decreased cholesterol content in caveolae and displaced eNOS from caveolae, which may be caused by CsA disrupting the association of caveolin-1 and cyclophilin A. The magnitude of the cholesterol depleting effect was similar to that of beta-cyclodextrin, a cholesterol-binding molecule, and beta-cyclodextrin had a similar inhibitory effect on flow-mediated eNOS activation. Treating bovine aortic endothelial cells for 24 h with 30 mug/ml cholesterol blocked the CsA effect and restored eNOS phosphorylation in response to flow. These data suggest that decreasing cholesterol content in caveolae by CsA is a potentially important pathogenic mechanism for CsA-induced endothelial dysfunction and hypertension.

Cyclophilin A is a proinflammatory cytokine that activates endothelial cells.

OBJECTIVE: Cyclophilin A (CyPA) is an abundant intracellular protein that is considered to be the main target of the immunosuppressive drug cyclosporine A. We and others showed that CyPA is secreted from smooth muscle cells and macrophages in response to oxidative stress and lipopolysaccharide, suggesting a role for CyPA in inflammation. We therefore studied the proinflammatory effects of CyPA on vascular endothelium. METHODS AND RESULTS: Because atherosclerosis is an inflammatory disease, we studied expression of CyPA in atherosclerotic plaques from the ApoE-/- mouse. Using immunohistochemistry, we showed that CyPA was highly expressed in these plaques. Because endothelial cells (EC) are important mediators of inflammation, we next studied the ability of CyPA to activate EC. Human recombinant CyPA activated mitogen-activated protein kinases, including ERK1/2, JNK, and p38 in cultured human umbilical vein EC. CyPA also stimulated IkappaB-alpha phosphorylation and NF-kappaB activation, and induced expression of adhesion molecules including E-selectin and vascular cell adhesion molecule-1. Furthermore, the combination of CyPA and cycloheximide induced EC apoptosis similar to the proapoptotic effect of tumor necrosis factor-alpha. CONCLUSIONS: Our data indicate that CyPA has proinflammatory effects on EC and may play an important role in the pathogenesis of inflammatory diseases, such as atherosclerosis.

Sphingosine 1-phosphate transactivates the platelet-derived growth factor beta receptor and epidermal growth factor receptor in vascular smooth muscle cells.

Sphingosine 1-phosphate (S1P) is a bioactive lipid generated during vascular injury that regulates cell growth, differentiation, survival, and motility via endothelial differentiation gene (EDG) family G protein-coupled receptors. Although several G protein-coupled receptor ligands transactivate receptor tyrosine kinases, such as the epidermal growth factor receptor (EGFR), S1P-stimulated receptor tyrosine kinase transactivation has not been well studied. We show that platelet-derived growth factor beta receptor (PDGFbetaR) and EGFR are tyrosine phosphorylated in response to S1P in rat aortic vascular smooth muscle cells (VSMCs). S1P-stimulated transactivation of PDGFbetaR and EGFR was mediated via Gi-coupled EDG receptors. S1P-stimulated transactivation of EGFR and PDGFbetaR was dependent on Src, reactive oxygen species, and cholesterol-rich membranes. A phosphoinositide 3-kinase-Akt pathway was activated by S1P and blocked by AG1296 and AG1478. Activation of extracellular signal-regulated kinase (ERK) 1 and ERK2 pathway by S1P was blocked only by AG1478. In Chinese hamster ovary cells that expressed exogenous EDG-1, activation of Akt and ERK1/2 in response to S1P was observed and was enhanced by coexpression of PDGFbetaR or EGFR. S1P-mediated VSMC proliferation was shown to be secondary to transactivation, because it was suppressed by AG1296 and AG1478. These data establish S1P as an important stimulus for EGFR and PDGFbetaR activation in VSMCs that may have important implications for the vessel response to injury.

Ligand-independent activation of vascular endothelial growth factor receptor 2 by fluid shear stress regulates activation of endothelial nitric oxide synthase.

Fluid shear stress generated by blood flowing over the endothelium is a major determinant of arterial tone, vascular remodeling, and atherogenesis. Nitric oxide (NO) produced by endothelial NO synthase (eNOS) plays an essential role in regulation of vascular function and structure by blood flow, but the molecular mechanisms that transduce mechanical force to eNOS activation are not well understood. In this study, we found that laminar flow (shear stress=12 dyne/cm2) rapidly activates vascular endothelial growth factor receptor 2 (VEGFR2) in a ligand-independent manner and leads to eNOS activation in cultured endothelial cells. Flow-stimulated VEGFR2 recruits phosphoinositide 3-kinase and mediates activation of Akt and eNOS. Inhibiting VEGFR2 kinase with selective inhibitors blocks flow-induced activation of Akt and eNOS and production of NO. Decreasing VEGFR2 expression with antisense VEGFR2 oligonucleotides significantly attenuates activation of Akt and eNOS. Furthermore, Src kinases are involved in flow-stimulated VEGFR2 because inhibiting Src kinases by PP2, a selective inhibitor for Src kinases, abolishes flow-induced VEGFR2 tyrosine phosphorylation and downstream signaling. Finally, we show that inhibiting VEGFR2 kinase significantly reduces flow-mediated NO-dependent arteriolar dilation in vivo. These data identify VEGFR2 as a key mechanotransducer that activates eNOS in response to blood flow.