High-Intensity Focused Electromagnetic (HIFEM) Energy With and Without Radiofrequency for Noninvasive Body Contouring: A Systematic Review.

BACKGROUND: Emsculpt Neo (EmSculpt NEO Device, BTL Industries, Inc.) is a FDA-cleared noninvasive body contouring treatment for increasing muscle tone and/or reducing fat. The device uses high-intensity electromagnetic energy to stimulate muscle contractions and to build muscle mass (Emsculpt) or a combination of electromagnetic energy with radiofrequency (Emsculpt NEO) to produce a synergistic effect of building muscle mass and reducing fat. In this study, we conduct a high-quality systematic review to evaluate outcomes for Emsculpt and Emsculpt NEO treatments for noninvasive body contouring. METHODS: An electronic search was performed of the PubMed, MEDLINE, Embase, and Web of Science databases using the key terms "High intensity focused electromagnetic therapy; HIFEM; Emsculpt; Emsculpt NEO; BTL Industries." The search included all articles published in English through January 2023. Inclusion criteria included articles noninvasive body contouring and reporting at least one outcome of interest (clinical or patient-reported outcomes). Methodological quality and risk of bias were assessed using the GRADE criteria. Articles involving applications other than for body contouring, animal studies, and review articles were excluded. RESULTS: Of the 159 articles identified in the initial search strategy, 51 met relevance based on abstract screening. Fifteen clinical studies were identified, including Emsculpt (n=11) and Emsculpt NEO (n=2). The typical protocol involved four treatments given over a 2-4-week period (range 3-8 treatments) with increase to 100% intensity setting and 1-6-month follow-ups. No complications were reported. Abdominal measurements were obtained using imaging were reported in eight studies. Treated areas included the buttocks (n=4), thighs (n=3), arms or calves (n=1), and abdomen (n=11). For abdominal contouring, mean reductions of fat thickness were 5.5 mm, muscle thickness of 2 mm, and rectus diastasis improvement of 3.0 mm. No studies reported weight change before and after treatment. All studies with patient-reported outcomes report high patient satisfaction. Two studies report marginal or no benefit of treatment. Certain studies failed to report comorbidities or demographic characteristics other than age and sex, which precludes analysis of specific subgroups that may benefit from treatment. Furthermore, certain studies failed to address how missing data or the final study population was analyzed. CONCLUSION: This systematic review reports on currently published evidence regarding the efficacy and safety of Emsculpt and Emsculpt NEO for body contouring. High-quality level data reporting with patient-reported outcomes will optimize shared decision-making and informed consent. LEVEL OF EVIDENCE II: Therapeutic study. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Subtle conformational changes between CX3CR1 genetic variants as revealed by resonance energy transfer assays.

The chemokine CX3CL1 is expressed as a membrane protein that forms a potent adhesive pair with its unique receptor CX3CR1. This receptor has 3 natural variants, V249-T280 (VT), I249-T280 (IT), and I249-M280 (IM), whose relative frequencies are significantly associated with the incidence of various inflammatory diseases. To assess the adhesive potency of CX3CR1 and the molecular diversity of its variants, we assayed their clustering status and their possible structural differences by fluorescence/bioluminescence resonance energy transfer (FRET or BRET) techniques. FRET assays by flow cytometry showed that the CX3CR1 variants cluster, in comparison with appropriate controls. BRET assays showed low nonspecific signals for VT and IT variants and high specific signals for IM, and thus pointed out a structural difference in this variant. We used molecular modeling to show how natural point mutations of CX3CR1 affect the packing of the 6th and 7th helices of this G-protein coupled receptor. Moreover, we found that the BRET technique is sensitive enough to detect these tiny changes. Consistently with our previous finding that CX3CL1 aggregates, our data here indicate that CX3CR1 clustering may contribute to the adhesiveness of the CX3CL1-CX3CR1 pair and may thus represent a new target for anti-inflammatory therapies.