[Oncological and functional results of focal treatment of localized prostate cancer with HIFU]

INTRODUCTION

In recent years, improved diagnosis of prostate cancer has allowed the development of focal therapy, in order to reduce the morbidity of treatments. Our study assesses the medium-term oncological and functional results of FocalOne® HIFU treatment in localized prostate cancer.

METHODS

This is a retrospective, multicentre study including patients with low- or intermediate-risk localized prostate cancer treated with Focal one HIFU between November 2014 and December 2019. The primary endpoint was the retreatment rate and subgroup analyses were performed to identify predictive factors of retreatment.

RESULTS

One hundred and thirty-seven patients were included with a median follow-up of 25.5 months. Seventy percent of patients had clinical stage T2, 64% had an ISUP score of 2 or 3 on initial biopsies and 38% were treated with hemi-ablation. Follow-up biopsies were performed in 76.6% of patients during follow-up with 21.8% having clinically significant cancers. The retreatment rate at 24 months was 37.2%, with positive biopsies being the primary criterion for retreatment. Patients with a PSA>8ng/mL had a significantly higher retreatment rate. Finally, morbidity remained acceptable with 5.8% of patients requiring reoperation for complications and 21% for de novo erectile dysfunction.

CONCLUSION

Our results are in agreement with those of the literature, seeming to indicate a lower morbidity of the focal treatment by HIFU compared to the radical treatments while offering an acceptable oncological control. Prospective randomized trials are ongoing.

LEVEL OF EVIDENCE: 4

Nicotinic acid effects on insulin sensitivity and hepatic lipid metabolism: an in vivo to in vitro study

Our aim was to characterize the effects and the underlying mechanisms of the lipid-regulating agent Niaspan(®) on both insulin action and triglyceride decrease in 20 nondiabetic, dyslipidemic men with metabolic syndrome receiving Niaspan(®) (2 g/day) or placebo for 8 weeks in a randomized, cross-over study. The effects on plasma lipid profile were characterized at the beginning and the end of each treatment period; insulin sensitivity was assessed using the 2-step euglycemic hyperinsulinemic clamp and VLDL-triglyceride turnover by measuring plasma glycerol enrichment, both at the end of each treatment period. The mechanism of action of nicotinic acid was studied in HuH7 and mouse primary hepatocytes. Lipid profile was improved after Niaspan(®) treatment with a significant-28% decrease in triglyceride levels, a+17% increase in HDL-C concentration and unchanged levels of fasting nonesterified fatty acid. VLDL-tri-glyceride production rate was markedly reduced after Niaspan(®) (-68%). However, the treatment induced hepatic insulin resistance, as assessed by reduced inhibition of endogenous glucose production by insulin (0.7±0.4 vs. 1.0±0.5 mg/kg · min, p<0.05) and decrease in fasting hepatic insulin sensitivity index (4.8±1.8 vs. 3.2±1.6, p<0.05) in the Niaspan(®) condition. Nicotinic acid also reduced insulin action in HuH7 and primary hepatocytes, independently of the activation of hepatic PKCε. This effect was associated with an increase in diacylglycerol and a decrease in tri-glyceride contents that occurred in the absence of modification of DGAT2 expression and activity. Eight weeks of Niaspan(®) treatment in dyslipidemic patients with metabolic syndrome induce hepatic insulin resistance. The mechanism could involve an accumulation of diacylglycerol and an alteration of insulin signaling in hepatocytes.

Subcutaneous adipose tissue remodeling during the initial phase of weight gain induced by overfeeding in humans

CONTEXT

Deciphering the early processes occurring in adipose tissue during weight gain is a major issue for understanding the development of fat mass and obesity. Experimental overfeeding in humans is a unique situation to tackle these events.

OBJECTIVE

Our aim was to identify the pathways involved in sc adipose tissue remodeling during the initial phase of weight gain.

RESEARCH DESIGN AND METHODS

Forty-four healthy men were involved in an overfeeding protocol with a lipid-enriched diet (+760 kcal/d) for 2 months. Subcutaneous abdominal adipose tissue biopsies were taken for histology, transcriptomics, and Western blotting in the basal state, after 14 d, and at the end of the protocol.

RESULTS

Overfeeding significantly increased body weight (+2.5 kg) and fat mass. Reorganization of gene expression patterns occurred in adipose tissue with an up-regulation of numerous genes involved in lipid metabolism and storage, followed by clusters of genes related to angiogenesis and extracellular matrix remodeling. Histological examination showed increased microvascular density and connective tissue deposition after 56 d of overfeeding, with no changes in the number of macrophages or inflammatory cells. Inhibition of the canonical Wnt/β-catenin signaling pathway and induction of the renin-angiotensin system might be implicated in the remodeling of sc adipose tissue.

CONCLUSIONS

We characterize the coordinated and time-dependent processes that occur in human adipose tissue during the early phase of weight gain in healthy subjects and identify pathways representing potential targets in pathologies of adipose development, including obesity.

Isoform-specific defects of insulin stimulation of Akt/protein kinase B (PKB) in skeletal muscle cells from type 2 diabetic patients

AIMS/HYPOTHESIS

The serine/threonine kinase Akt/protein kinase B (PKB) is required for the metabolic actions of insulin. Controversial data have been reported regarding Akt defective activation in the muscle of type 2 diabetic patients. Because three Akt isoforms exist, each having a distinct physiological role, we investigated the contribution of isoform-specific defects to insulin signalling in human muscle.

METHODS

The phosphorylation pattern and kinase activity of each Akt isoform were compared in primary myotubes from healthy control participants and type 2 diabetic patients. Phosphorylation of Ser(473) and of Thr(308) in each isoform was determined after immunoprecipitation in myotubes treated or not with insulin.

RESULTS

Muscle cells from diabetic patients displayed defective insulin action and a drastic reduction of insulin-stimulated activity of all Akt isoforms. This was associated with specific defects of their phosphorylation pattern in response to insulin, with impaired Akt2- (and to a lower extent Akt3-) Ser(473) phosphorylation, and with altered Akt1-Thr(308) phosphorylation. These defects were not due to faulty phosphoinositide-dependent protein kinase 1 (PDK1) production or activation. Rather, we found higher levels of the Akt2-Ser(473)-specific protein phosphatase PH domain leucine-rich repeat protein phosphatase 1 (PHLPP1) in muscle from diabetic patients, which may contribute to the alteration of Akt2-Ser(473) phosphorylation.

CONCLUSIONS/INTERPRETATION

These results suggest that several mechanisms affecting Akt isoforms, including deregulated production of PHLPP1, could underlie the alterations of skeletal muscle insulin signalling in type 2 diabetes. Taking into account the recently described isoform-specific metabolic functions of Akt, our results provide mechanistic insight that may contribute to the defective regulation of glucose and lipid metabolisms in the muscle of diabetic patients.

Increased adiponectin receptor-1 expression in adipose tissue of impaired glucose-tolerant obese subjects during weight loss

OBJECTIVE

To investigate the mRNA expression of adiponectin, AdipoR1 and AdipoR2, the two recently cloned adiponectin receptors and peroxisome proliferator activated receptor (PPAR)gamma2 in adipose tissue of obese individuals before and during a very low calorie diet (VLCD) inducing weight loss.

METHODS

Twenty-three non-diabetic obese subjects with normal (NGT, n = 11) or impaired glucose tolerance (IGT, n = 12) (age, 47 +/- 3 years; body mass index, 39.3 +/- 1.3 kg/m2) were studied before and after a 3-week 3.9 MJ diet daily without exercise. mRNA levels of nine IGT and six NGT subjects were measured by real-time PCR in s.c. abdominal adipose tissue.

RESULTS

Metabolic parameters and insulin sensitivity were improved by VLCD in the IGT group, but minimally affected in the NGT group. VLCD increased expression of AdipoR1 in the IGT (P = 0.02), but not in the NGT group. Adiponectin, AdipoR2 and PPARgamma2 mRNA levels did not change during VLCD in any group. In the IGT, but not in the NGT group, AdipoR1 and AdipoR2 expressions were positively related to that of PPARgamma2 and, after VLCD, AdipoR1 and AdipoR2 expressions were positively related to each other and to that of adiponectin.

CONCLUSION

In the NGT group, the 3-week VLCD inducing weight loss did not modify metabolic parameters, insulin sensitivity and the expression of the adiponectin system in adipose tissue. By contrast, in the IGT group, AdipoR1 expression increased and we found a coordinate regulation of the expression of adiponectin and its receptors. These modifications could participate, through adiponectin action on adipocytes, to the improved metabolic parameters observed in IGT subjects.

Activation of liver X receptors promotes lipid accumulation but does not alter insulin action in human skeletal muscle cells

AIMS/HYPOTHESIS

The aim of this study was to investigate the effects of liver X receptor (LXR) activation on lipid metabolism and insulin action in human skeletal muscle cells prepared from control subjects and from patients with type 2 diabetes.

SUBJECTS AND METHODS

Cultured myotubes were obtained from muscle biopsies of 11 lean, healthy control subjects and ten patients with type 2 diabetes. The mRNA levels of LXR isoforms and lipogenic genes were estimated by RT-quantitative PCR, and the effects of LXR agonists on insulin action were evaluated by assays of protein kinase B serine 473 phosphorylation and glycogen synthesis.

RESULTS

Both LXRalpha and LXRbeta were expressed in human skeletal muscle and adipose tissue and there was no difference in their mRNA abundance in tissues from patients with type 2 diabetes compared with control subjects. In cultured muscle cells, LXR activation by T0901317 strongly increased expression of the genes encoding lipogenic enzymes, including sterol regulatory element binding protein 1c, fatty acid synthase and stearoyl-CoA desaturase 1, and also promoted triglyceride accumulation in the presence of a high glucose concentration. Importantly, these effects on lipid metabolism did not affect protein kinase B activation by insulin. Furthermore, LXR agonists did not modify insulin action in muscle cells from patients with type 2 diabetes.

CONCLUSIONS/INTERPRETATION

These data suggest that LXR agonists may lead to increased utilisation of lipids and glucose in muscle cells without affecting the mechanism of action of insulin. However, the long-term consequences of triglyceride accumulation in muscle should be evaluated before the development of effective LXR-based therapeutic agents.

Changes in adiponectin receptor expression in muscle and adipose tissue of type 2 diabetic patients during rosiglitazone therapy

AIMS/HYPOTHESIS

Adiponectin is important in the regulation of insulin sensitivity in man. Its receptors, adipoR1 and R2, have recently been identified, but their expression in adipose tissue and their regulation in response to insulin sensitisation of diabetic patients have never been assessed. We therefore explored the regulation of adipoR1/R2 and adiponectin expression in adipose tissue and skeletal muscle, and of adiponectin plasma concentrations in response to insulin sensitisation by rosiglitazone.

METHODS

Patients with type 2 diabetes were studied in a double-blind, placebo-controlled crossover study, using in vivo arteriovenous techniques of measuring adipose tissue and muscle blood flow, combined with measurement of adipose tissue and skeletal muscle gene expression.

RESULTS

Rosiglitazone treatment increased adiponectin concentrations by 69%. Skeletal muscle adipoR1 expression was down-regulated from 109.0 (70.1-165.7) (median [interquartile range]) to 82.8 (63.6-89.3) relative units (p=0.04), but adipose tissue adipoR1 expression was up-regulated from 5.3 (4.4-9.4) to 11.2 (4.8-15.3) relative units (p=0.02) by rosiglitazone. In contrast to adipoR1 expression, adipoR2 expression was not altered by rosiglitazone in either of the tissues. The increase in adipose tissue adipoR1 expression with rosiglitazone was associated with increased postprandial triglyceride clearance (r=0.67, p=0.05), and increased fasting fatty acid output (r=0.78, p=0.01) measured in subcutaneous adipose tissue.

CONCLUSIONS/INTERPRETATION

AdipoR1 expression is up-regulated in adipose tissue but down-regulated in skeletal muscle by rosiglitazone. These data suggest that adipoR1 plays a role in mediating the effects of adiponectin in specific tissues in relation to insulin sensitisation.

WY-14643 and 9-cis-retinoic acid induce IRS-2/PI 3-kinase signalling pathway and increase glucose transport in human skeletal muscle cells: differential effect in myotubes from healthy subjects and Type 2 diabetic patients

AIMS/HYPOTHESIS

To determine the effects of peroxisome proliferator-activated receptor α (PPARα) and retinoid X receptor (RXR) agonists on insulin action, we investigated the effects of Wy-14643 and 9-cis-retinoic acid (9-cis-RA) on insulin signalling and glucose uptake in human myotubes.

METHODS

Primary cultures of differentiated human skeletal muscle cells, established from healthy subjects and Type 2 diabetic patients, were used to study the effects of Wy-14643 and 9-cis-RA on the expression and activity of proteins involved in the insulin signalling cascade. Glucose transport was assessed by measuring the rate of [³H]2-deoxyglucose uptake.

RESULTS

Wy-14643 and 9-cis-RA increased IRS-2 and p85α phosphatidylinositol 3-kinase (PI 3-kinase) mRNA and protein expression in myotubes from non-diabetic and Type 2 diabetic subjects. This resulted in increased insulin stimulation of protein kinase B phosphorylation and increased glucose uptake in cells from control subjects. Myotubes from diabetic patients displayed marked alterations in the stimulation by insulin of the IRS-1/PI 3-kinase pathway. These alterations were associated with blunted stimulation of glucose transport. Treatment with Wy-14643 and 9-cis-RA did not restore these defects but increased the basal rate of glucose uptake.

CONCLUSIONS/INTERPRETATION

These results demonstrate that PPARα and RXR agonists can directly affect insulin signalling in human muscle cells. They also indicate that an increase in the IRS-2/PI 3-kinase pathway does not overcome the impaired stimulation of the IRS-1-dependent pathway and does not restore insulin-stimulated glucose uptake in myotubes from Type 2 diabetic patients.

Expression of key genes of fatty acid oxidation, including adiponectin receptors, in skeletal muscle of Type 2 diabetic patients

AIMS/HYPOTHESIS

Defective oxidation of long-chain fatty acids is a feature of insulin resistance and Type 2 diabetes. Our aim was to compare the expression levels of the genes encoding the major proteins and enzymes of this pathway in skeletal muscle of healthy subjects and Type 2 diabetic patients.

METHODS

The basal and insulin-regulated mRNA concentration of 16 genes was quantified using real-time PCR in skeletal muscle biopsies taken before and at the end of a 3-hour hyperinsulinaemic-euglycaemic clamp in healthy lean subjects and in insulin-resistant obese patients with manifest Type 2 diabetes.

RESULTS

Acetyl CoA carboxylase-2 mRNA expression was increased 2.5-fold in the muscle of the diabetic patients. The expression of carnitine palmitoyl transferase-1, of the two adiponectin receptors and of genes involved in fatty acid transport and activation was not altered in diabetic patients. Hyperinsulinaemia for 3 hours increased the expression of several genes of fatty acid oxidation, including adiponectin receptor-1 and peroxisome proliferator-activated receptor gamma coactivator-1 alpha. It also reduced pyruvate dehydrogenase 4 mRNA levels. The effects of insulin on gene expression were markedly altered in the muscle of Type 2 diabetic patients except for adiponectin receptor-1 and pyruvate dehydrogenase 4 mRNAs.

CONCLUSIONS/INTERPRETATION

The expression of adiponectin receptors was not altered in the muscle of Type 2 diabetic patients. The observed overexpression of acetyl CoA carboxylase-2 is consistent with the hypothesis that increased skeletal muscle malonyl CoA concentrations in Type 2 diabetes may contribute to the inhibition of long-chain fatty acid oxidation.

Human chemokine receptors CCR5, CCR3 and CCR2B share common polarity motif in the first extracellular loop with other human G-protein coupled receptors implications for HIV-1 coreceptor function

Chemokine receptors (CRs) are 7-helix membrane proteins from the family of G-protein coupled receptors (GPCRs). A few human CRs act as cofactors for macrophage-tropic (M-tropic) human immunodeficiency virus type-1 (HIV-1) entry into cells, while others do not. In this study, we describe an application of molecular modeling techniques to delineate common molecular determinants that might be related to coreceptor activity, and the use of the data to identify other GPCRs as putative cofactors for M-tropic HIV-1 entry. Subsequently, the results were confirmed by an experimental approach. The sequences of extracellular domains (ECDs) of CRs were employed in a compatibility search against a database of environmental profiles derived for proteins with known spatial structure. The best-scoring sequence-profile alignments obtained for each ECD were compared in pairs to check for common patterns in residue environments, and consensus sequence-profile fits for ECDs were also derived. Similar hydrophobicity motifs were found in the first extracellular loops of the CRs CCR5, CCR3, and CCR2B, and are all used by M-tropic HIV-1 for cell entry. In contrast, other CRs did not reveal common motifs. However, the same environmental pattern was also delineated in the first extracellular loop of some human GPCRs showing either high (group 1) or low (group 2) degree of similarity of their polarity patterns with those in HIV-1 coreceptors. To address the question of whether the delineated molecular determinant plays a critical role in the receptor-virus binding, three of the identified GPCRs, bradykinin receptor (BRB2) and G-protein receptor (GPR)-CY6 from group 1, and GPR8 from group 2, were cloned and transfected into HeLa-CD4 cells, which are nonpermissive to M-tropic HIV-1 infection. We demonstrate that, similar to CCR5, the two selected GPCRs from group 1 were capable of mediating M-tropic HIV-1 entry, whereas GPR8 from group 2 did not serve as HIV-1 coreceptor. The potential biological significance of the identified structural motif shared by the human CCR5, CCR3, CCR2B and other GPCRs is discussed.