Effect of Bariatric Surgery on Adipose Tissue Glucose Metabolism in Different Depots in Patients With or Without Type 2 Diabetes

OBJECTIVE

We investigated fat distribution and tissue-specific insulin-stimulated glucose uptake (GU) in seven fat compartments (visceral and subcutaneous) and skeletal muscle in morbidly obese patients with (T2D) and without (ND) type 2 diabetes before and 6 months after bariatric surgery.

RESEARCH DESIGN AND METHODS

A total of 23 obese patients (BMI 43.0 ± 3.6 kg/m(2); 9 T2D and 14 ND) were recruited from a larger, randomized multicenter SLEEVEPASS study. MRI (for fat distribution) and [(18)F]-fluorodeoxyglucose PET (for GU) studies were performed for the obese patients before and 6 months postsurgery; 10 lean subjects served as control subjects and were studied once.

RESULTS

At baseline, visceral fat GU was 30 ± 7% of muscle GU in control subjects and 57 ± 5% in obese patients. Visceral and deep subcutaneous fat were more abundant (despite same total fat mass) and less insulin sensitive in T2D than ND; in both, GU was impaired compared with control subjects. Postsurgery, visceral fat mass decreased (∼40%) more than subcutaneous fat (7%). Tissue-specific GU was improved, but not normalized, at all sites in T2D and ND alike. The contribution of visceral fat to whole-body GU was greater in T2D than ND but decreased similarly with surgery. Subcutaneous fat made a fourfold greater contribution to whole-body GU in obese versus lean subjects (15% vs. 4%) both before and after surgery.

CONCLUSIONS

Bariatric surgery leads to sustained weight loss and improves tissue-specific glucose metabolism in morbidly obese patients. We conclude that 1) enhanced visceral fat accumulation is a feature of T2D, 2) severe obesity compromises muscle insulin sensitivity more than fat insulin sensitivity, and 3) fat mass expansion is a sink for plasma glucose.

Resistance training enhances insulin suppression of endogenous glucose production in elderly women

An altered prenatal environment during maternal obesity predisposes offspring to insulin resistance, obesity, and their consequent comorbidities, type 2 diabetes and cardiovascular disease. Telomere shortening and frailty are additional risk factors for these conditions. The aim of this study was to evaluate the effects of resistance training on hepatic metabolism and ectopic fat accumulation. Thirty-five frail elderly women, whose mothers' body mass index (BMI) was known, participated in a 4-mo resistance training program. Endogenous glucose production (EGP) and hepatic and visceral fat glucose uptake were measured during euglycemic hyperinsulinemia with [(18)F]fluorodeoxyglucose and positron emission tomography. Ectopic fat was measured using magnetic resonance spectroscopy and imaging. We found that the training intervention reduced EGP during insulin stimulation [from 5.4 (interquartile range 3.0, 7.0) to 3.9 (-0.4, 6.1) μmol·kg body wt(-1)·min(-1), P = 0.042] in the whole study group. Importantly, the reduction was higher among those whose EGP was more insulin resistant at baseline (higher than the median) [-5.6 (7.1) vs. 0.1 (5.4) μmol·kg body wt(-1)·min(-1), P = 0.015]. Furthermore, the decrease in EGP was associated with telomere elongation (r = -0.620, P = 0.001). The resistance training intervention did not change either hepatic or visceral fat glucose uptake or the amounts of ectopic fat. Maternal obesity did not influence the studied measures. In conclusion, resistance training improves suppression of EGP in elderly women. The finding of improved insulin sensitivity of EGP with associated telomere lengthening implies that elderly women can reduce their risk for type 2 diabetes and cardiovascular disease with resistance training.

Resistance training improves skeletal muscle insulin sensitivity in elderly offspring of overweight and obese mothers

AIMS/HYPOTHESIS

Maternal obesity predisposes offspring to adulthood morbidities, including type 2 diabetes. Type 2 diabetes and insulin resistance have been associated with shortened telomere length. First, we aimed to investigate whether or not maternal obesity influences insulin sensitivity and its relationship with leucocyte telomere length (LTL) in elderly women. Second, we tested whether or not resistance exercise training improves insulin sensitivity in elderly frail women.

METHODS

Forty-six elderly women, of whom 20 were frail offspring of lean/normal weight mothers (OLM, BMI ≤26.3 kg/m2) and 17 were frail offspring of overweight/obese mothers (OOM,BMI ≥28.1 kg/m2), were studied before and after a 4 month resistance training (RT) intervention. Muscle insulin sensitivity of glucose uptake was measured using 18F-fluoro-2-deoxyglucose and positron emission tomography with computed tomography during a hyperinsulinaemic–euglycaemic clamp. Muscle mass and lipid content were measured using magnetic resonance and LTL was measured using real-time PCR.

RESULTS

The OOM group had lower thigh muscle insulin sensitivity compared with the OLM group (p=0.048) but similar whole body insulin sensitivity. RT improved whole body and skeletal muscle insulin sensitivity in the OOM group only (p=0.004 and p=0.013, respectively), and increased muscle mass in both groups (p <0 .01). In addition, in the OOM group, LTL correlated with different thigh muscle groups insulin sensitivity (ρ ≥ 0.53; p ≤ 0.05). Individuals with shorter LTL showed a higher increase in skeletal muscle insulin sensitivity after training (ρ ≥ −0.61; p ≤ 0.05).

CONCLUSIONS/INTERPRETATION

Maternal obesity and having telomere shortening were associated with insulin resistance in adult offspring. A resistance exercise training programme may reverse this disadvantage among offspring of obese mothers. Trial registration: ClinicalTrials.gov NCT01931540.

Cognitive-Motor Related Brain Activity During Walking: Differences Between Men and Women With Multiple Sclerosis

OBJECTIVE

To determine if sex differences in glucose uptake, a marker of brain activity, are present in brain regions that facilitate walking performance in persons with multiple sclerosis (MS).

DESIGN

Cross-sectional, observational pilot.

SETTING

University laboratory.

PARTICIPANTS

Positron emission tomography with fluorine-18-labeled deoxyglucose (FDG) was performed on persons with MS and healthy controls (4 men and 4 women per group; N=16) after a 15-minute walking test.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Brain activity was quantified as the mean standardized uptake value (SUV).

RESULTS

The mean SUV was significantly lower in the thalamus (P=.029) and cerebellum (P=.029) for men with MS compared with women with MS, but not for the prefrontal (P=.057) or frontal (P=.057) cortices. Similar nonsignificant trends were found for healthy controls. No mean SUV group × sex interaction effects were found between the MS and healthy control groups (all P>.05).

CONCLUSIONS

To our knowledge, this is the first study of brain activity sex differences based on FDG uptake in persons with MS during walking. Significantly less FDG uptake in the thalamus and cerebellum brain regions important for walking performance was found in men with MS compared with women with MS; however, these comparisons were not significantly different in the healthy control group. No differences in FDG uptake were found between the MS and healthy control groups in any of the brain regions examined. Results from this study provide pilot data for larger studies aimed at identifying underlying mechanisms responsible for accelerated disability in men with MS.

The effects of acute hyperinsulinemia on bone metabolism

Insulin signaling in bone-forming osteoblasts stimulates bone formation and promotes the release of osteocalcin (OC) in mice. Only a few studies have assessed the direct effect of insulin on bone metabolism in humans. Here, we studied markers of bone metabolism in response to acute hyperinsulinemia in men and women. Thirty-three subjects from three separate cohorts (n=8, n=12 and n=13) participated in a euglycaemic hyperinsulinemic clamp study. Blood samples were collected before and at the end of infusions to determine the markers of bone formation (PINP, total OC, uncarboxylated form of OC (ucOC)) and resorption (CTX, TRAcP5b). During 4 h insulin infusion (40 mU/m(2) per min, low insulin), CTX level decreased by 11% (P<0.05). High insulin infusion rate (72 mU/m(2) per min) for 4 h resulted in more pronounced decrease (-32%, P<0.01) whereas shorter insulin exposure (40 mU/m(2) per min for 2 h) had no effect (P=0.61). Markers of osteoblast activity remained unchanged during 4 h insulin, but the ratio of uncarboxylated-to-total OC decreased in response to insulin (P<0.05 and P<0.01 for low and high insulin for 4 h respectively). During 2 h low insulin infusion, both total OC and ucOC decreased significantly (P<0.01 for both). In conclusion, insulin decreases bone resorption and circulating levels of total OC and ucOC. Insulin has direct effects on bone metabolism in humans and changes in the circulating levels of bone markers can be seen within a few hours after administration of insulin.

Outstanding effects on antithrombin activity of modified TBA diastereomers containing an optically pure acyclic nucleotide analogue

Herein, we report optically pure modified acyclic nucleosides as ideal probes for aptamer modification. These new monomers offer unique advantages in exploring the role played in thrombin inhibition by a single residue modification at key positions of the TBA structure.

Characterization of zofenoprilat as an inducer of functional angiogenesis through increased H2 S availability

BACKGROUND AND PURPOSE

Hydrogen sulfide (H2 S), an endogenous volatile mediator with pleiotropic functions, promotes vasorelaxation, exerts anti-inflammatory actions and regulates angiogenesis. Previously, the SH-containing angiotensin-converting enzyme inhibitor (ACEI), zofenopril, was identified as being effective in preserving endothelial function and inducing angiogenesis among ACEIs. Based on the H2 S donor property of its active metabolite zofenoprilat, the objective of this study was to evaluate whether zofenoprilat-induced angiogenesis was due to increased H2 S availability.

EXPERIMENTAL APPROACH

HUVECs were used for in vitro studies of angiogenesis, whereas the Matrigel plug assay was used for in vivo assessments.

KEY RESULTS

Zofenoprilat-treated HUVECs showed an increase in all functional features of the angiogenic process in vitro. As zofenoprilat induced the expression of CSE (cystathionine-γ-lyase) and the continuous production of H2 S, CSE inhibition or silencing blocked the ability of zofenoprilat to induce angiogenesis, both in vitro and in vivo. The molecular mechanisms underlying H2 S/zofenoprilat-induced angiogenesis were dependent on Akt, eNOS and ERK1/2 cascades. ATP-sensitive potassium (KATP ) channels, the molecular target that mediates part of the vascular functions of H2 S, were shown to be involved in the upstream activation of Akt and ERK1/2. Moreover, the up-regulation of fibroblast growth factor-2 was dependent on CSE-derived H2 S response to H2 S and KATP activation.

CONCLUSIONS AND IMPLICATIONS

Zofenoprilat induced a constant production of H2 S that stimulated the angiogenic process through a KATP channel/Akt/eNOS/ERK1/2 pathway. Thus, zofenopril can be considered as a pro-angiogenic drug acting through H2 S release and production, useful in cardiovascular pathologies where vascular functions need to be re-established and functional angiogenesis induced.

Walking Speed and Brain Glucose Uptake are Uncoupled in Patients with Multiple Sclerosis

Motor impairments of the upper and lower extremities are common symptoms of multiple sclerosis (MS). While some peripheral effects like muscle weakness and loss of balance have been shown to influence these symptoms, central nervous system activity has not been fully elucidated. The purpose of this study was to determine if alterations in glucose uptake were associated with motor impairments in patients with multiple sclerosis. Eight patients with multiple sclerosis (four men) and eight sex matched healthy controls performed 15 min of treadmill walking at a self-selected pace, during which ≈322 MBq of the positron emission tomography (PET) glucose analog [¹⁸F]-fluorodeoxyglucose (FDG) was injected. Immediately after the cessation of walking, participants underwent PET imaging. Patients with MS had lower FDG uptake in ≈40% of the brain compared to the healthy controls (p_FWE-corr < 0.001, q_FDR-corr < 0.001, k_e = 93851) and walked at a slower speed [MS, 1.1 (0.2), controls 1.4 (0.1), m/s, P = 0.014]. Within the area of lower FDG uptake 15 regions were identified. Of these 15 regions, 13 were found to have strong to moderate correlations to walking speed within the healthy controls (r > −0.75, P < 0.032). Within patients with MS only 3 of the 15 regions showed significant correlations: insula (r = −0.74, P = 0.036), hippocampus (r = −0.72, P = 0.045), and calcarine sulcus (r = −0.77, P = 0.026). This data suggest that walking impairments in patients with MS may be due to network wide alterations in glucose metabolism. Understanding how brain activity and metabolism are altered in patients with MS may allow for better measures of disability and disease status within this clinical population.

Identification of microRNAs 758 and 33b as potential modulators of ABCA1 expression in human atherosclerotic plaques

BACKGROUND AND AIM

Adenosine triphosphate (ATP)-binding cassette (ABC) transporters A1 and G1 are the main transporters involved in macrophage cholesterol efflux. The understanding of the molecular mechanism(s) of their regulation in atherosclerosis is crucial for potential therapeutic approaches. Preclinical studies support a role for microRNAs in the posttranscriptional regulation of these transporters; however, no evidence is still available on human atherosclerosis. Thus, the aim of this study was to investigate the modulation of the ABCA1 and ABCG1 pathway in human atherosclerotic plaques and microRNA involvement in its modulation.

METHODS AND RESULTS

Thirty-one human atherosclerotic plaques were obtained from patients undergoing carotid endarterectomy for high-grade (>70%) vessel stenosis, and divided into normocholesterolemic (n = 15) and hypercholesterolemic groups (n = 16) according to the presence/absence of hypercholesterolemia. Both ABCA1 and ABCG1 messenger RNAs (mRNAs) were significantly upregulated in carotid plaques from hypercholesterolemic patients as assessed by real-time polymerase chain reaction (RT-PCR). Despite this result, no difference was found at the protein levels analyzed by Western blot, thus suggesting a strong posttranscriptional modulation. MicroRNA microarray and subsequent validation by RT-PCR showed a significant upregulation of ABCA1-linked miR-758 and miR-33b in plaques from hypercholesterolemic patients.

CONCLUSION

We provide evidence of a strong posttranscriptional regulation of ABCA1 and ABCG1 expression in human atherosclerotic plaques from hypercholesterolemic patients. This effect is potentially due to the concomitant increase of miR-33b and miR-758, two well-established regulators of ABCA1 and ABCG1 expression. The identification of miR-33b and miR-758 as putative key regulators of ABCA1 protein expression within human atherosclerotic plaques provides further data for the realization of new anti-atherosclerotic drugs with specific targets based on anti-miRNA technologies.

MicroRNA profiling in migraine without aura: pilot study

BACKGROUND AND PURPOSE

MicroRNAs (miRNAs) are short, non-coding RNAs whose deregulation has been shown in several human diseases, including pain states and diseases associated with increased cardiovascular (CV) risk. This study aimed at identifying differentially expressed circulating miRNAs in patients with 'migraine without aura' (MO), a pain condition whose link with CV risk remains debated.

METHODS

Fifteen female MO patients and 13 matching healthy controls underwent a circulating microRNA expression profiling. MiR-22, miR-26a, miR-26b, miR-27b, miR-29b, let-7b, miR-181a, miR-221, miR-30b, and miR-30e were selected for validation by quantitative real-time polymerase chain reaction.

RESULTS

In migraineurs versus controls, four miRNAs were differentially expressed: miR-27b was significantly up-regulated (q < 0.004), while miR-181a, let-7b, and miR-22 were significantly down-regulated (q ≤ 0.01). MiR-22 and let-7b down-regulation was also confirmed in circulating blood monocytes. A logistic regression model based on microRNA expression profile showed a high accuracy for identifying migraine (AUC of ROC curve: 0.956; P < 0.001).

CONCLUSION

A specific circulating miRNAs profile is associated with migraine without aura. Remarkably, the same miRNAs are known to be modulated in the setting of atherosclerosis and stroke in humans. This study represents a first step towards further characterization of MO diagnosis/pathophysiology, also in relation to its link with cardiovascular risk.

Enhanced fatty acid uptake in visceral adipose tissue is not reversed by weight loss in obese individuals with the metabolic syndrome

AIMS/HYPOTHESIS

Obesity causes an imbalance in fat mass distribution between visceral and subcutaneous adipose tissue (AT) depots. We tested the hypothesis that this relates to increased NEFA uptake between these depots in obese compared with healthy participants. Second, we hypothesised that a diet very low in energy (very low calorie diet [VLCD]) decreases fat mass in obese participants and that this is associated with the decline in NEFA uptake.

METHODS

NEFA uptake in AT depots was measured with [(18)F]-fluoro-6-thia-heptadecanoic acid ((18)F-FTHA) and positron emission tomography (PET) in 18 obese participants with the metabolic syndrome before and after a 6 week VLCD. Whole body fat oxidation was measured using indirect calorimetry and [U-(13)C]palmitate. Sixteen non-obese participants were controls.

RESULTS

Obese participants had >100% higher (p < 0.0001) NEFA uptake in the visceral and subcutaneous abdominal AT depots than controls. VLCD decreased AT mass in all regions (12% to 21%), but NEFA uptake was decreased significantly (18%; p < 0.006) only in the femoral AT. Whole body carbohydrate oxidation decreased, while fat oxidation increased.

CONCLUSIONS/INTERPRETATION

The data demonstrate that weight loss caused by VLCD does not affect abdominal fasting NEFA uptake rates. We found that visceral fat takes up more NEFAs than subcutaneous AT depots, even after weight loss.

Megaprosthesis in post-traumatic and periprosthetic large bone defects: Issues to consider

INTRODUCTION

The recent evolution of prosthesis technology has enabled the surgeon to replace entire limbs. These special prostheses, or megaprostheses, were developed for the treatment of severe oncological bone loss; however, the indications and applications of these devices have expanded to other orthopaedic and trauma situations. For some years, surgeons have been implanting megaprostheses in non-oncological conditions, such as acute trauma in severe bone loss and poor bone quality; post-traumatic failures, both aseptic and septic (represented by complex non-unions and critical size bone defects); major bone loss in prosthetic revision, both aseptic and septic; periprosthetic fractures with component mobilisation and poor bone stock condition. The purpose of this study was to evaluate retrospectively the complications during and after the implantation of megaprosthesis of the lower limb in post-traumatic and prosthetic bone loss, and to propose tips about how to avoid and manage such complications.

MATERIALS AND METHODS

All the complications and difficulties we have encountered during or after the implantation of megaprosthesis in non-oncology patients were evaluated retrospectively. A total of 72 patients were treated with large resection mono-and bi-articular prostheses between January 2008 and January 2014.

RESULTS

The main critical problems found in the study were: restoration of the correct length and rotation of the limb; reconstruction of the knee extensor mechanism; trochanteric reconstruction; stability/dislocation of the implant; mobility/range of motion (ROM) of the implant; skin cover; sepsis, and bone quality.

CONCLUSION

Megaprosthesis in severe bone loss can be considered as an available solution for the orthopaedic surgeon in extreme, appropriately selected cases. This type of complex surgery must be performed in specialised centres where knowledge and technologies are present. Patients with severe bone loss should not be treated in the same way as oncology patients because life expectancy is definitely longer; therefore, the surgical technique and the system implantation must be extremely rigorous to ensure longevity of the prosthesis. The characteristics of the bone and soft tissue conditions in these patients are very different from those presented by oncology patients, which creates critical problems that the surgeon should be able to manage to avoid serious complications.

Plasma exosome microRNA profiling unravels a new potential modulator of adiponectin pathway in diabetes: effect of glycemic control

CONTEXT

Type 2 diabetes is a chronic disease characterized by inadequate β-cell response to the progressive insulin resistance. MicroRNAs (miRNAs) are short, endogenous, noncoding RNAs representing a class of powerful gene expression modulators. Previous population studies observed a modulation of circulating miRNAs in diabetic patients; however, few data are presently available on miRNA modulation in diabetic patients naïve to pharmacological treatment as well as the effect of glycemic control on this.

OBJECTIVE

We aimed at studying circulating miRNA expression in diabetic patients naïve to treatment and at investigating the influence on this of glycemic control.

DESIGN

This was a case-control study.

PARTICIPANTS

Eighteen treatment-naïve diabetic patients with poor metabolic control and 12 control patients participated in the study.

MAIN OUTCOME MEASURES

Wide miRNA expression profiling was performed, and the expression of miRNAs found to be dysregulated was then validated by quantitative RT-PCR. Finally, algorithm-identified putative miRNA targets were evaluated by quantitative RT-PCR and ELISA.

RESULTS

In diabetic patients, microarray analysis showed that four miRNAs are increased, whereas 21 miRNAs are decreased. Quantitative RT-PCR validation confirmed the significant up-regulation of miR-326 (P = .004) and down-regulation of let-7a (P < .001) and let-7f (P = .003). Notably, an inverse negative correlation was found between circulating miR-326 and its putative target adiponectin (p = -0.479, P = .009). After 12 months of antidiabetic treatment, quantitative RT-PCR data analysis showed that miR-326 levels were unaffected, whereas the levels of let-7a and let-7f were significantly increased.

CONCLUSIONS

Treatment-naïve, poorly controlled diabetic patients show a significant dysregulation of miRNAs involved in the regulation of the adiponectin pathway, a phenomenon that may be reversed, at least in part, by improved glycemic control.

Crucial role of androgen receptor in vascular H2S biosynthesis induced by testosterone

BACKGROUND AND PURPOSE

Hydrogen sulphide (H2S) is a gaseous mediator strongly involved in cardiovascular homeostasis, where it provokes vasodilatation. Having previously shown that H2 S contributes to testosterone-induced vasorelaxation, here we aim to uncover the mechanisms underlying this effect.

EXPERIMENTAL APPROACH

H2 S biosynthesis was evaluated in rat isolated aortic rings following androgen receptor (NR3C4) stimulation. Co-immunoprecipitation and surface plasmon resonance analysis were performed to investigate mechanisms involved in NR3C4 activation.

KEY RESULTS

Pretreatment with NR3C4 antagonist nilutamide prevented testosterone-induced increase in H2S and reduced its vasodilator effect. Androgen agonist mesterolone also increased H2S and induced vasodilatation; effects attenuated by the selective cystathionine-γ lyase (CSE) inhibitor propargylglycine. The NR3C4-multicomplex-derived heat shock protein 90 (hsp90) was also involved in this effect; its specific inhibitor geldanamycin strongly reduced testosterone-induced H2S production. Neither progesterone nor 17-β-oestradiol induced H2S release. Furthermore, we demonstrated that CSE, the main vascular H2S-synthesizing enzyme, is physically associated with the NR3C4/hsp90 complex and the generation of such a ternary system represents a key event leading to CSE activation. Finally, H2S levels in human blood collected from male healthy volunteers were higher than those in female samples.

CONCLUSIONS AND IMPLICATIONS

We demonstrated that selective activation of the NR3C4 is essential for H2S biosynthesis within vascular tissue, and this event is based on the formation of a ternary complex between cystathionine-γ lyase, NR3C4and hsp90. This novel molecular mechanism operating in the vasculature, corroborated by higher H2S levels in males, suggests that the L-cysteine/CSE/H2S pathway may be preferentially activated in males leading to gender-specific H2S biosynthesis.

Effects of aerobic training, resistance training, or combined resistance-aerobic training on the left ventricular myocardium in a rat model

This study follows the left ventricular (LV) hypertrophy in rats undergoing aerobic training alone (A), resistance training alone (R), or combined resistance and aerobic training (RA) (usually referred as concurrent training) program. A sedentary control group (C) was included. LV remodeling was evaluated using electron and light microscopy. The LV weight to body weight (LVW: BW) increased 11.4% in A group, 35% in the R group, and 18% in the RA group compared to the C group. The LV thickness increased 6% in the A group, 17% in the R group, and 10% in the RA group. The LV internal diameter increased 19% in the A group, 3% in the R group, and 8% in the RA group compared with the C group. The cross-sectional area of cardiomyocyte increased by 1% with the A group, 27% with R group, and 12% with RA training. The capillary density increased by 5.4% with A training, 11.0% with R training, and 7.7% with RA training compared with the C group. The volume fraction of interstitial collagen increased by 0.4% with training A, increased by 2.8% with R training, and 0.9% with RA training. In conclusion, except for the LV internal diameter, which increased more in the A group, the cardiac parameters increased more in the R group than in the other groups and in RA group than in A group. Collagen density increased from 5.4 ± 0.8% in the C group to 5.8 ± 0.6% in the A group (n. s.) (P > 0.05), to 8.2 ± 0.7% in the R group (P < 0.05), and to 6.3 ± 0.4% in the RA group (P < 0.05). These results demonstrate a significant increase for collagen content in the LV with R and RA exercise, but the increase was higher with R training alone than with RA training.

Megaprosthesis in large bone defects: opportunity or chimaera?

INTRODUCTION

The development of new megaprosthesis for the treatment of large bone defects provides important options to orthopaedic oncologic surgeons for the replacement of skeletal segments, such as the long bones of the upper and lower limbs and the relative joints. We implanted megaprosthesis using either a one-step or two-step technique depending on the patient's condition. The aim of this study was to evaluate retrospectively both clinical and radiological outcomes in patients who underwent lower limb megaprosthesis implant.

MATERIALS AND METHODS

A total of 32 patients were treated with mono- and bi-articular megaprosthesis subdivided as follows: proximal femur, distal femur, proximal tibia and total femur. The mean follow-up of patients was about 18 months (range 3 months to 5 years). Clinical and serial radiographic evaluations were conducted using standard methods (X-ray at 45 days, 3, 6, 12, 18 and 24 months) and blood parameters of inflammation were monitored for at least 2 months.

RESULTS

Although the mean length of follow-up was only 18 months, the first patients to enter the study were monitored for 5 years and showed encouraging clinical results, with good articulation of the segments, no somato-sensory or motor deficit and acceptable functional recovery. During surgery and, more importantly, in pre-operative planning, much attention should be given to the evaluation of the extensor apparatus, preserving it and, when necessary, reinforcing it with tendon substitutes.

DISCUSSION

Megaprosthesis in extreme cases of severe bone loss and prosthetic failure is a potential solution for the orthopaedic surgeon. In oncological surgery, the opportunity to restore functionality to the patient (although not ad integrum) is important for both the patient and the surgeon. The high mortality associated with cancer precludes long-term patient follow-up; therefore, there is a lack of certainty about the survival of this type of prosthesis and any medium- to long-term complications that may occur. Nevertheless, patients should be considered as an oncologic patient, not because of the disease, but because of the limited therapeutic options available.

CONCLUSIONS

Megaprosthesis provides a valuable opportunity to restore functionality to patients with highly disabling diseases.

Positron emission tomography detects greater blood flow and less blood flow heterogeneity in the exercising skeletal muscles of old compared with young men during fatiguing contractions

The purpose of this study was to investigate blood flow and its heterogeneity within and among the knee muscles in five young (26 ± 6 years) and five old (77 ± 6 years) healthy men with similar levels of physical activity while they performed two types of submaximal fatiguing isometric contraction that required either force or position control. Positron emission tomography (PET) and [(15)O]-H2O were used to determine blood flow at 2 min (beginning) and 12 min (end) after the start of the tasks. Young and old men had similar maximal forces and endurance times for the fatiguing tasks. Although muscle volumes were lower in the older subjects, total muscle blood flow was similar in both groups (young men: 25.8 ± 12.6 ml min(-1); old men: 25.1 ± 15.4 ml min(-1); age main effect, P = 0.77) as blood flow per unit mass of muscle in the exercising knee extensors was greater in the older (12.5 ± 6.2 ml min(-1) (100 g)(-1)) than the younger (8.6 ± 3.6 ml min(-1) (100 g)(-1)) men (age main effect, P = 0.001). Further, blood flow heterogeneity in the exercising knee extensors was significantly lower in the older (56 ± 27%) than the younger (67 ± 34%) men. Together, these data show that although skeletal muscles are smaller in older subjects, based on the intact neural drive to the muscle and the greater, less heterogeneous blood flow per gram of muscle, old fit muscle achieves adequate exercise hyperaemia.

Weight loss after bariatric surgery reverses insulin-induced increases in brain glucose metabolism of the morbidly obese

Obesity and insulin resistance are associated with altered brain glucose metabolism. Here, we studied brain glucose metabolism in 22 morbidly obese patients before and 6 months after bariatric surgery. Seven healthy subjects served as control subjects. Brain glucose metabolism was measured twice per imaging session: with and without insulin stimulation (hyperinsulinemic-euglycemic clamp) using [18F]fluorodeoxyglucose scanning. We found that during fasting, brain glucose metabolism was not different between groups. However, the hyperinsulinemic clamp increased brain glucose metabolism in a widespread manner in the obese but not control subjects, and brain glucose metabolism was significantly higher during clamp in obese than in control subjects. After follow-up, 6 months postoperatively, the increase in glucose metabolism was no longer observed, and this attenuation was coupled with improved peripheral insulin sensitivity after weight loss. We conclude that obesity is associated with increased insulin-stimulated glucose metabolism in the brain and that this abnormality can be reversed by bariatric surgery.

Cross-talk between toll-like receptor 4 (TLR4) and proteinase-activated receptor 2 (PAR(2) ) is involved in vascular function

BACKGROUND AND PURPOSE

Proteinase-activated receptors (PARs) and toll-like receptors (TLRs) are involved in innate immune responses. The aim of this study was to evaluate the possible cross-talk between PAR(2) and TLR4 in vessels in physiological condition and how it varies following stimulation of TLR4 by using in vivo and ex vivo models.

EXPERIMENTAL APPROACH

Thoracic aortas were harvested from both naïve and endotoxaemic rats for in vitro studies. Arterial blood pressure was monitored in anaesthetized rats in vivo. LPS was used as a TLR4 agonist while PAR(2) activating peptide (AP) was used as a PAR(2) agonist. Aortas harvested from TLR4(-/-) mice were also used to characterize the PAR(2) response.

KEY RESULTS

PAR(2) , but not TLR4, expression was enhanced in aortas of endotoxaemic rats. PAR(2) AP-induced vasorelaxation was increased in aortic rings of LPS-treated rats. TLR4 inhibitors, curcumine and resveratrol, reduced PAR(2) AP-induced vasorelaxation and PAR(2) AP-induced hypotension in both naïve and endotoxaemic rats. Finally, in aortic rings from TLR4(-/-) mice, the expression of PAR(2) was reduced and the PAR(2) AP-induced vasodilatation impaired compared with those from wild-type mice and both resveratrol and curcumine were ineffective.

CONCLUSIONS AND IMPLICATIONS

Cross-talk between PAR(2) and TLR4 contributes to vascular homeostasis.

Moderate alcohol use and health: a consensus document

AIMS

The aim of this consensus paper is to review the available evidence on the association between moderate alcohol use, health and disease and to provide a working document to the scientific and health professional communities.

DATA SYNTHESIS

In healthy adults and in the elderly, spontaneous consumption of alcoholic beverages within 30 g ethanol/d for men and 15 g/d for women is to be considered acceptable and do not deserve intervention by the primary care physician or the health professional in charge. Patients with increased risk for specific diseases, for example, women with familiar history of breast cancer, or subjects with familiar history of early cardiovascular disease, or cardiovascular patients should discuss with their physician their drinking habits. No abstainer should be advised to drink for health reasons. Alcohol use must be discouraged in specific physiological or personal situations or in selected age classes (children and adolescents, pregnant and lactating women and recovering alcoholics). Moreover, the possible interactions between alcohol and acute or chronic drug use must be discussed with the primary care physician.

CONCLUSIONS

The choice to consume alcohol should be based on individual considerations, taking into account the influence on health and diet, the risk of alcoholism and abuse, the effect on behaviour and other factors that may vary with age and lifestyle. Moderation in drinking and development of an associated lifestyle culture should be fostered.

Analysis of intracellular human immunodeficiency virus (HIV)-1 drug resistance mutations in multi-failed HIV-1-infected patients treated with a salvage regimen: 72-week follow-up

The human immunodeficiency virus (HIV) mutational archive of proviral DNA was monitored during a 72-week follow-up in 20 multidrug-experienced HIV-1-infected patients treated with a darunavir/ritonavir-based salvage therapy. At the beginning of the study, all patients harboured a number of intracellular drug resistance-associated mutations (RAMs) in peripheral blood mononuclear cells. In some patients, a significant fluctuation in the number of RAMs was observed during the observation period. However, all patients, notwithstanding the presence or the fluctuation of intracellular RAMs, showed a persistently undetectable viraemia. The data suggest that the archived resistant viral variants change during suppressive therapy, but that the variants are unable to re-emerge and to affect virological response.