Laser-assisted lipolysis for knee remodelling: A prospective study in 30 patients

Unsightly fat knees are a frustrating aesthetic deformity exacerbated by genetic predisposition and resistance to diet. This article reports our experience with laser-assisted lipolysis (LAL) in knee remodelling.

Laser-assisted lipolysis in the treatment of gynecomastia: a prospective study in 28 patients

Gynecomastia is the most common breast pathology. Numerous excisions and liposuction techniques have been described to correct bilateral male breast enlargement. Recently, there has been a shift from the open approach to minimally invasive techniques. This article reports a 5-year experience using laser-assisted lipolysis (LAL) to treat gynecomastia, and describes the surgical technique. Between January 2006 and December 2010, a total of 28 patients with bilateral gynecomastia were treated with LAL. Patients had a mean age of 36.5 years (range 24 to 56 years). LAL was performed with a 980-nm diode laser (continuous emission, 15 W power, 8-12 kJ total energy per breast) after tumescent anesthetic infiltration. The breast was evaluated objectively by two physicians who compared chest circumference and photographs. Patients were also asked to score the results using a visual analogue scale: 75 to 100 (very good), 50-74 (good), 25 to 49 (fair) and 0 to 24 (poor). The postoperative period for all patients was incident-free. After 6 months, 18 patients (64.3%) scored the results as "very good", 6 as "good" (21.4%), 3 as "fair" (10.7%) and 1 "poor" (3.6%). Mean chest circumferences pre- and postoperatively were, respectively, 117.4 ± 11.1 cm and 103.3 ± 7.5 cm (p < 0.001), corresponding to a mean difference of 14.1 cm. Physicians scored the photographs as "very good" in 22 patients (78.6%), as "good" in five patients (17.9%), and as "fair" in one patient (3.6%). LAL in gynecomastia is safe and produces significant effects on fatty tissue, with a reduction in breast volume, together with significant skin tightening. Provided an appropriate amount of energy is delivered by an experienced operator, the results are both significant and consistent.

Plasma leptin and mRNA expression of lipogenesis and lipolysis-related factors in bovine adipose tissue around parturition

The objective was to study changes in plasma leptin concentration parallel to changes in the gene expression of lipogenic- and lipolytic-related genes in adipose tissue of dairy cows around parturition. Subcutaneous fat biopsies were taken from 27 dairy cows in week 8 antepartum (a.p.), on day 1 postpartum (p.p.) and in week 5 p.p. Blood samples were assayed for concentrations of leptin and non-esterified fatty acids (NEFA). Subcutaneous adipose tissue was analysed for mRNA abundance by real-time qRT-PCR encoding for leptin, adiponectin receptor 1 (AdipoR1), adiponectin receptor 2 (AdipoR2), hormones-sensitive lipase (HSL), perilipin (PLIN), lipoprotein lipase (LPL), acyl-CoA synthase long-chain family member 1 (ACSL1), acetyl-CoA carboxylase (ACC), fatty acid synthase (FASN) and glycerol-3-phosphate dehydrogenase 2 (GPD2). Body weight and body condition score of the cows were lower after parturition than before parturition. The calculated energy balance was negative in week 1 and 5 p.p., with higher negative energy balance in week 1 p.p. compared with that in week 5 p.p. On day 1 p.p., highest concentrations of NEFA (353.3 mumol/l) were detected compared with the other biopsy time-points (210.6 and 107.7 mumol/l, in week 8 a.p., and week 5 p.p. respectively). Reduced plasma concentrations of leptin during p.p. when compared with a.p. would favour increasing metabolic efficiency and energy conservation for mammary function and reconstitution of body reserves. Lower mRNA abundance of ACC and FASN expression on day 1 p.p. compared with other biopsy time-points suggests an attenuation of fatty acid synthesis in subcutaneous adipose tissue shortly after parturition. Gene expression of AdipoR1, AdipoR2, HSL, PLIN, LPL, ACSL1 and GPD2 was unchanged over time.

Enamel matrix derivative inhibits adipocyte differentiation of 3T3-L1 cells via activation of TGF-βRI kinase activity

Enamel matrix derivative (EMD), an extract of fetal porcine enamel, and TGF-β can both suppress adipogenic differentiation. However, there have been no studies that functionally link the role of EMD and TGF-β in vitro. Herein, we examined whether TGF-β signaling contributes to EMD-induced suppression of adipogenic differentiation. Adipogenesis was studied with 3T3-L1 preadipocytes in the presence of SB431542, an inhibitor of TGF-βRI kinase activity. SB431542 reversed the inhibitory effect of EMD on adipogenic differentiation, based on Oil Red O staining and mRNA expression of lipid regulated genes. SB431542 also reduced EMD-stimulated expression of connective tissue growth factor (CTGF), an autocrine inhibitor of adipogenic differentiation. Moreover, short interfering (si)RNAs for CTGF partially reversed the EMD-induced suppression of lipid regulated genes. We conclude that the TGF-βRI - CTGF axis is involved in the anti-adipogenic effects of EMD in vitro.

The Formation of an Insulin-responsive Vesicular Cargo Compartment Is an Early Event in 3T3-L1 Adipocyte Differentiation

Differentiating 3T3-L1 cells exhibit a dramatic increase in the rate of insulin-stimulated glucose transport during their conversion from proliferating fibroblasts to nonproliferating adipocytes. On day 3 of 3T3-L1 cell differentiation, basal glucose transport and cell surface transferrin binding are markedly diminished. This occurs concomitant with the formation of a distinct insulin-responsive vesicular pool of intracellular glucose transporter 1 (GLUT1) and transferrin receptors as assessed by sucrose velocity gradients. The intracellular distribution of the insulin-responsive aminopeptidase is first readily detectable on day 3, and its gradient profile and response to insulin at this time are identical to that of GLUT1. With further time of differentiation, GLUT4 is expressed and targeted to the same insulin-responsive vesicles as the other three proteins. Our data are consistent with the notion that a distinct insulin-sensitive vesicular cargo compartment forms early during fat call differentiation and its formation precedes GLUT4 expression. The development of this compartment may result from the differentiation-dependent inhibition of constitutive GLUT1 and transferrin receptor trafficking such that there is a large increase in, or the new formation of, a population of postendosomal, insulin-responsive vesicles.

Reversing adipocyte differentiation: Implications for treatment of obesity

Conventional treatment of obesity reduces fat in mature adipocytes but leaves them with lipogenic enzymes capable of rapid resynthesis of fat, a likely factor in treatment failure. Adenovirus-induced hyperleptinemia in normal rats results in rapid nonketotic fat loss that persists after hyperleptinemia disappears, whereas pair-fed controls regain their weight in 2 weeks. We report here that the hyperleptinemia depletes adipocyte fat while profoundly down-regulating lipogenic enzymes and their transcription factor, peroxisome proliferator-activated receptor (PPAR)γ in epididymal fat; enzymes of fatty acid oxidation and their transcription factor, PPARα, normally low in adipocytes, are up-regulated, as are uncoupling proteins 1 and 2. This transformation of adipocytes from cells that store triglycerides to fatty acid-oxidizing cells is accompanied by loss of the adipocyte markers, adipocyte fatty acid-binding protein 2, tumor necrosis factor α, and leptin, and by the appearance of the preadipocyte marker Pref-1. These findings suggest a strategy for the treatment of obesity by alteration of the adipocyte phenotype.

A peroxisome proliferator-activated receptor γ ligand inhibits adipocyte differentiation

The peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors that regulate glucose and lipid homeostasis. The PPARγ subtype plays a central role in the regulation of adipogenesis and is the molecular target for the 2,4-thiazolidinedione class of antidiabetic drugs. Structural studies have revealed that agonist ligands activate the PPARs through direct interactions with the C-terminal region of the ligand-binding domain, which includes the activation function 2 helix. GW0072 was identified as a high-affinity PPARγ ligand that was a weak partial agonist of PPARγ transactivation. X-ray crystallography revealed that GW0072 occupied the ligand-binding pocket by using different epitopes than the known PPAR agonists and did not interact with the activation function 2 helix. In cell culture, GW0072 was a potent antagonist of adipocyte differentiation. These results establish an approach to the design of PPAR ligands with modified biological activities.

Opposing roles of pRB and p107 in adipocyte differentiation

The retinoblastoma (RB) family of proteins, pRB, p107, and p130, have been postulated to be partially redundant in their ability to regulate progression through the G1 phase of the cell cycle. However, pRB appears to be unique in its capacity as a classical tumor suppressor, possibly because of a specialized role in maintaining the balance between proliferation and differentiation. A variety of studies have in fact revealed an apparent role for pRB in cellular differentiation and development. However, roles for p107 and p130 in differentiation have not yet been established, and knockout mouse studies have indicated that they may be functionally redundant during development, and possibly perform a role in differentiation distinct from that of pRB. Using adipogenesis as a model, we have indeed found distinct roles for the pRB family proteins in regulating differentiation. 3T3 fibroblasts deficient in p107 and p130 differentiate with high efficiency, whereas pRB−/− 3T3 cells exhibit defects in their differentiation potential. Moreover, over-expression of pRB in wild-type cells promotes differentiation, whereas over-expression of p107 antagonizes differentiation. The seemingly opposing roles of pRB family members in adipocyte differentiation can be explained, at least in part, by a requirement for pRB in maintaining cell cycle exit as well as potentiating the activity of the differentiation-associated transcription factor, C/EBPα. p107 does not affect C/EBPα-driven transcription and is not required for cell cycle exit, but instead, loss of p107 lowers the requirement for the differentiation factor PPARγ. These findings suggest contrasting biological roles for individual members of the pRB family of proteins that may explain why pRB, but not p107, is commonly mutated during human tumor development.

Proteolytic cleavage product of 30-kDa adipocyte complement-related protein increases fatty acid oxidation in muscle and causes weight loss in mice

Adipocyte complement-related protein (30 kDa) (Acrp30), a secreted protein of unknown function, is exclusively expressed in differentiated adipocytes; its mRNA is decreased in obese humans and mice. Here we describe novel pharmacological properties of the protease-generated globular head domain of Acrp30 (gAcrp30). Acute treatment of mice with gAcrp30 significantly decreased the elevated levels of plasma free fatty acids caused either by administration of a high fat test meal or by i.v. injection of Intralipid. This effect of gAcrp30 was caused, at least in part, by an acute increase in fatty acid oxidation by muscle. As a result, daily administration of a very low dose of gAcrp30 to mice consuming a high-fat/sucrose diet caused profound and sustainable weight reduction without affecting food intake. Thus, gAcrp30 is a novel pharmacological compound that controls energy homeostasis and exerts its effect primarily at the peripheral level.

The adipocyte specific transcription factor C/EBPalpha modulates human ob gene expression.

The ob gene product, leptin, apparently exclusively expressed in adipose tissue, is a signaling factor regulating body weight homeostasis and energy balance. ob gene expression is increased in obese rodents and regulated by feeding, insulin, and glucocorticoids, which supports the concept that ob gene expression is under hormonal control, which is expected for a key factor controlling body weight homeostasis and energy balance. In humans, ob mRNA expression is increased in gross obesity; however, the effects of the above factors on human ob expression are unknown. We describe the structure of the human ob gene and initial functional analysis of its promoter. The human ob gene's three exons cover approximately 15 kb of genomic DNA. The entire coding region is contained in exons 2 and 3, which are separated by a 2-kb intron. The first small 30-bp untranslated exon is located >10.5 kb upstream of the initiator ATG codon. Three kilobases of DNA upstream of the transcription start site has been cloned and characterized. Only 217 bp of 5' sequence are required for basal adipose tissue-specific expression of the ob gene as well as enhanced expression by C/EBPalpha. Mutation of the single C/EBPalpha site in this region abolished inducibility of the promoter by C/EBPalpha in cotransfection assays. The gene structure will facilitate our analysis of ob mutations in human obesity, whereas knowledge of sequence elements and factors regulating ob gene expression should be of major importance in the prevention and treatment of obesity.

Identification and characterization of an immunophilin expressed during the clonal expansion phase of adipocyte differentiation.

Mouse 3T3-L1 cells differentiate into fat-laden adipocytes in response to a cocktail of adipogenic hormones. This conversion process occurs in two discrete steps. During an early clonal expansion phase, confluent 3T3-L1 cells proliferate and express the products of the beta and delta members of the CCAAT/enhancer binding protein (C/EBP) family of transcription factors. The cells subsequently arrest mitotic growth, induce the expression of the alpha form of C/EBP, and acquire the morphology of fully differentiated adipocytes. Many of the genes induced during the terminal phase of adipocyte conversion are directly activated by C/EBP alpha, and gratuitous expression of this transcription factor is capable of catalyzing adipose conversion in a number of different cultured cell lines. The genetic program undertaken during the clonal expansion phase of 3T3-L1 differentiation, controlled in part by C/EBP beta and C/EBP delta, is less clearly understood. To study the molecular events occurring during clonal expansion, we have identified mRNAs that selectively accumulate during this phase of adipocyte conversion. One such mRNA encodes an immunophilin hereby designated FKBP51. In this report we provide the initial molecular characterization of FKBP51.

Nur77 regulates lipolysis in skeletal muscle cells - Evidence for cross-talk between the beta-adrenergic and an orphan nuclear hormone receptor pathway

Skeletal muscle is a major mass peripheral tissue that accounts for similar to 40% of total body weight and 50% of energy expenditure and is a primary site of glucose disposal and fatty acid oxidation. Consequently, muscle has a significant role in insulin sensitivity, obesity, and the blood-lipid profile. Excessive caloric intake is sensed by the brain and induces beta-adrenergic receptor (beta-AR)- mediated adaptive thermogenesis. beta-AR null mice develop severe obesity on a high fat diet. However, the target gene(s), target tissues(s), and molecular mechanism involved remain obscure. We observed that 30 - 60 min of beta-AR agonist ( isoprenaline) treatment of C2C12 skeletal muscle cells strikingly activated (> 100-fold) the expression of the mRNA encoding the nuclear hormone receptor, Nur77. In contrast, the expression of other nuclear receptors that regulate lipid and carbohydrate metabolism was not induced. Stable transfection of Nur77-specific small interfering RNAs (siNur77) into skeletal muscle cells repressed endogenous Nur77 mRNA expression. Moreover, we observed attenuation of gene and protein expression associated with the regulation of energy expenditure and lipid homeostasis, for example AMP-activated protein kinase gamma 3, UCP3, CD36,adiponectin receptor 2, GLUT4, and caveolin-3. Attenuation of Nur77 expression resulted in decreased lipolysis. Finally, in concordance with the cell culture model, injection and electrotransfer of siNur77 into mouse tibialis cranialis muscle resulted in the repression of UCP3 mRNA expression. This study demonstrates regulatory cross-talk between the nuclear hormone receptor and beta-AR signaling pathways. Moreover, it suggests Nur77 modulates the expression of genes that are key regulators of skeletal muscle lipid and energy homeostasis. In conclusion, we speculate that Nur77 agonists would stimulate lipolysis and increase energy expenditure in skeletal muscle and suggest selective activators of Nur77 may have therapeutic utility in the treatment of obesity.

Regulated localization of rab18 to lipid droplets - Effects of lipolytic stimulation and inhibition of lipid droplet catabolism

Rab GTPases are crucial regulators of membrane traffic. Here we have examined a possible association of Rab proteins with lipid droplets (LDs), neutral lipid-containing organelles surrounded by a phospholipid monolayer, also known as lipid bodies, which have been traditionally considered relatively inert storage organelles. Although we found close apposition between LDs and endosomal compartments labeled by expressed Rab5, Rab7, or Rab11 constructs, there was no detectable labeling of the LD surface itself by these Rab proteins. In contrast, GFP-Rab18 localized to LDs and immunoelectron microscopy showed direct association with the monolayer surface. Green fluorescent protein (GFP)-Rab18-labeled LDs underwent oscillatory movements in a localized area as well as sporadic, rapid, saltatory movements both in the periphery of the cell and toward the perinuclear region. In both adipocytes and non-adipocyte cell lines Rab18 localized to a subset of LDs. To gain insights into this specific localization, Rab18 was co-expressed with Cav3(DGV), a truncation mutant of caveolin-3 shown to inhibit the catabolism and motility of lipid droplets. GFP-Rab18 and mRFP-Cav3(DGV) labeled mutually exclusive subpopulations of LDs. Moreover, in 3T3-L1 adipocytes, stimulation of lipolysis increased the localization of Rab18 to LDs, an effect reversed by beta-adrenergic antagonists. These results show that a Rab protein localizes directly to the monolayer surface of LDs. In addition, association with the LD surface was increased following stimulation of lipolysis and inhibited by a caveolin mutant suggesting that recruitment of Rab18 is regulated by the metabolic state of individual LDs.