Functional Differences in Visceral and Subcutaneous Fat Pads Originate from Differences in the Adipose Stem Cell

Metabolic pathologies mainly originate from adipose tissue (AT) dysfunctions. AT differences are associated with fat-depot anatomic distribution in subcutaneous (SAT) and visceral omental (VAT) pads. We address the question whether the functional differences between the two compartments may be present early in the adipose stem cell (ASC) instead of being restricted to the mature adipocytes. Using a specific human ASC model, we evaluated proliferation/differentiation of ASC from abdominal SAT-(S-ASC) and VAT-(V-ASC) paired biopsies in parallel as well as the electrophysiological properties and functional activity of ASC and their in vitro-derived adipocytes. A dramatic difference in proliferation and adipogenic potential was observed between the two ASC populations, S-ASC having a growth rate and adipogenic potential significantly higher than V-ASC and giving rise to more functional and better organized adipocytes. To our knowledge, this is the first comprehensive electrophysiological analysis of ASC and derived-adipocytes, showing electrophysiological properties, such as membrane potential, capacitance and K+-current parameters which confirm the better functionality of S-ASC and their derived adipocytes. We document the greater ability of S-ASC-derived adipocytes to secrete adiponectin and their reduced susceptibility to lipolysis. These features may account for the metabolic differences observed between the SAT and VAT. Our findings suggest that VAT and SAT functional differences originate at the level of the adult ASC which maintains a memory of its fat pad of origin. Such stem cell differences may account for differential adipose depot susceptibility to the development of metabolic dysfunction and may represent a suitable target for specific therapeutic approaches

Lateral collateral ulnar ligament reconstruction techniques in posterolateral rotatory instability of the elbow: A systematic review

Background: Elbow chronic instability is a disable complication, presenting as recurrent joint subluxations or dislocations. This systematic review aims to assess (1) the clinical outcome and (2) the complication rates of the surgical techniques currently used in the management of posterolateral rotatory elbow insta- bility. Methods: OVID-MEDLINE®, SCOPUS, and PubMed were searched from January 2009 to February 2019 to identify relevant studies. The search terms used were "LUCL", "Posterolateral dislocation", "Elbow Docking technique", "Elbow Jobe technique" and "Elbow single strand technique". The methodological qualities of the studies were evaluated, relevant data were extracted. Results: Three studies, published between 2012 and 2015, were included in this review. No studies con- cerning the single strand technique met the inclusion criteria. The included studies had a level of evi- dence IV and recruited 33 patients undergoing a Jobe technique reconstruction and 8 patients undergoing a Docking technique. Jobe procedure registered better clinical and functional outcome, assessed using the Mayo Clinic Elbow Performance Scale (MEPS), compared with patients managed with Docking technique. Nonetheless, this difference is not significant. There was not a significantly different complication rate ( p = 0.57) between patients treated with these two different techniques. Conclusion: This systematic review showed that both Jobe and Docking techniques are safe and effective in the treatment of posterolateral elbow instability. However, future studies with larger sample size and a longer follow-up interval are needed to draw stronger conclusions on the efficacy of the different LUCL surgical reconstruction techniques.Background: Elbow chronic instability is a disable complication, presenting as recurrent joint subluxations or dislocations. This systematic review aims to assess (1) the clinical outcome and (2) the complication rates of the surgical techniques currently used in the management of posterolateral rotatory elbow instability.Methods: OVID-MEDLINE (R), SCOPUS, and PubMed were searched from January 2009 to February 2019 to identify relevant studies. The search terms used were "LUCL", "Posterolateral dislocation", "Elbow Docking technique", "Elbow Jobe technique" and "Elbow single strand technique". The methodological qualities of the studies were evaluated, relevant data were extracted.Results: Three studies, published between 2012 and 2015, were included in this review. No studies concerning the single strand technique met the inclusion criteria. The included studies had a level of evidence IV and recruited 33 patients undergoing a Jobe technique reconstruction and 8 patients undergoing a Docking technique. Jobe procedure registered better clinical and functional outcome, assessed using the Mayo Clinic Elbow Performance Scale (MEPS), compared with patients managed with Docking technique. Nonetheless, this difference is not significant. There was not a significantly different complication rate (p = 0.57) between patients treated with these two different techniques.Conclusion: This systematic review showed that both Jobe and Docking techniques are safe and effective in the treatment of posterolateral elbow instability. However, future studies with larger sample size and a longer follow-up interval are needed to draw stronger conclusions on the efficacy of the different LUCL surgical reconstruction techniques. (C) 2020 Published by Elsevier Ltd

Electrophysiological properties of ASC and of the derived <i>in vitro</i>-differentiated adipocytes.

<p>Electrophysiological analysis was performed on ASC and their corresponding <i>in vitro</i>-differentiated adipocytes in patch clamp condition. RMP: resting membrane potential. C_m: membrane capacitance. G_m and G_m/C_m: total and specific membrane conductance, respectively. V_th: voltage threshold of activation of the three types of K⁺ currents investigated (I_BK, I_Ks and I_Kir). K⁺ current activation time constant (τ) for I_BK and I_Ks and current density I_BK/C_m and I_Ks/C_m values have been obtained at 50 mV and I_Kir/C_m at −110 mV. Mean ±SE values are reported. Student's <i>t</i> test was applied to compare paired samples: **,***P<0.01 and 0.001 V- versus S-ASC and V- versus S-ADIPO; §, §§, §§§ P<0.05, 0.01, 0.001 S- or V-ADIPO versus the corresponding ASC. Total number of analyzed cells (n) in populations obtained from 5 different subjects were: S-ASC (n = 84), V-ASC (n = 82), S-ADIPO (n = 54), V-ADIPO (n = 52); for I_Kir: S-ASC (n = 17), V-ASC (n = 18), S-ADIPO (n = 28), V-ADIPO (n = 24). mV: milli Volt; pF: pico Faraday; nS: nano Siemens; ms: milli seconds; pA: pico Ampere.</p

Differences in adipogenic potential and functional capabilities in ASC and in their <i>in vitro</i>-derived adipocytes.

<p>Expression of the adipogenic genes PPARgamma (A), FABP4 (B) and adiponectin (C) evaluated by quantitative real time RT-PCR is higher in S- compared to derived V-ADIPO. Data are expressed by box charts of gene expression ratio versus GAPDH (C) or fold increase between adipocytes and ASC (A, B). Boxes indicate the 25^th (lower) and 75^th (upper) percentiles. Horizontal lines and dots in the boxes indicate the 50^th percentile value (median) and mean value, respectively. Vertical lines give the 10^th and 90^th percentile limits of the data. Statistical analysis for non-parametric distribution was performed with Wilcoxon text: *P<0.05, ***P<0.001 S- versus V-ADIPO, n = 30 experiments with cells obtained from 14 independent subjects. D: Western Blot analysis of Adiponectin (upper panel) and FABP4 (lower panel) protein expression in ASC compared to the derived adipocytes. Molecular weight (MW) in kDa has been indicated for both standards and proteins of interest. Equal protein loading was verified by probing for the housekeeping protein actin. SAT and VAT samples from the same subject were run as positive controls. Representative of 5 independent experiments performed on cells obtained from 5 subjects. E: Immunofluorescence analysis of FABP4 (left panel) in <i>in vitro</i>-differentiated S-ADIPO (upper panel) and V-ADIPO (lower panel) revealed positivity for the enzyme around the intracellular lipid droplets. Right panels: corresponding bright field microscopy. F: Adipogenic potential of S- and V-ASC has been evaluated as AdipoRed staining of intracellular lipid droplets in the derived adipocytes. Results are expressed as mean ± SE fold increase of AdipoRed absorbance (left axis) in adipocytes versus the corresponding ASC. Lipolytic activity (right axis) of the same adipocytes evaluated as AdipoRed absorbance fold decrease following 12 h treatment with 1 µM isoproterenol. *P<0.001 S- versus V-ADIPO. G: Adiponectin secretion evaluated during <i>in vitro</i>-induced adipogenesis in S- and V-ASC at two different time points (T1 and T2, 14 and 21 days of differentiation respectively) by ELISA adiponectin kit. °P<0.001 T2 versus T1; *P<0.001 S- versus V-ADIPO.</p

Voltage dependence of the two kind of I_K,DR (I_BK and I_Ks) and of I_Kir.

<p>(A) Plots represent the maximum mean value of I_K,DR (a), I_BK and I_Ks (b,c) as a function of the applied voltage step recorded in the presence of Ba²⁺ from all experiments as in Fig. 6 G–J. Note the different ordinate scale for ASC and ADIPO. Panels put in evidence that I_K,DR, I_BK and I_Ks are reduced in size in the ADIPO versus the corresponding ASC. (B) K⁺ currents in representative cells elicited by voltage ramp stimulation in Control external solution without Ba²⁺ recording the total K⁺ currents (I_K,tot) (a, – Ba²⁺) and after adding 0.1 mM Ba²⁺ to block I_Kir and record I_K,DR (b, +Ba²⁺ 0.1 mM). I_Kir have been obtained by detracting current traces recorded in the presence of Ba²⁺ from those in the absence (c). I_K/C_m and V_th mean ± SE values and number of experiments are indicated in Tab 2.</p