Cooling for fat

Mechanism Underlying Tissue Cryotherapy to Combat Obesity/Overweight: Triggering Thermogenesis

“…We report that serial daily abdominal tissue cooling (tissue cryotherapy) produces progressive loss of AT, confirmed by dual-energy X-ray absorptiometry. No adverse events were reported for the participants in this study, in accordance with previous studies and meta-analysis that the tissue cryotherapy procedure is safe and well tolerated [ 14 , 17 , 40 , 41 ]. Following six procedures, there was a parallel decline in BMI (∼2%; 0.5 units) and fat mass content determined by whole-body scanning (∼3.8%).…”

“…It has been suggested that the presence of fatty deposits renders adipose cells highly susceptible to cell killing produced by cooling, mediated by aggregation/crystallization mechanisms leading to cell disruption and/or apoptotic/necrotic cell death, followed by local inflammation and a protracted period (weeks) of immune cell infiltration and clearance of cell debris [ 12 , 14 , 16 , 17 , 39 ]. However, in contrast to earlier reports that there is no evident change in body fat shortly after the procedure [ 14 , 16 , 17 , 39 ], we report significant beneficial effects within a short time frame after the procedure, an effect too rapid to be explained by cell death and clearance. In addition, serial daily applications of tissue cooling produced further progressive losses of waist circumference, body weight, BMI, and body fat mass that could be incompatible with the cell disruption hypothesis.…”

“…All had a BMI in either the normal range (67–71%) or overweight/obese (29–33%), and no subject undertaking the procedure was classified as underweight. Tissue cryotherapy, a noninvasive procedure [ 14 , 17 , 40 , 41 ], does not require formal institutional ethical approval. All participants gave written informed consent for their involvement in the study, data analysis, and preparation for publication.…”

“…An alternative approach, body cooling, involves either environmental cold exposure (e.g., [ 6 – 9 ]) or devices to reduce the skin temperature (e.g., [ 10 , 11 ]), leading to systemic or local exposure of fatty tissues to active cooling [ 12 – 15 ]. With respect to tissue cooling, it has been hypothesized that adipocytes are more sensitive to cooling than other tissue types and that cooling leads to crystallization of cytoplasmic lipids, disruption of cellular integrity, cell death via apoptosis/necrosis, and inflammation, leading to selective loss of AT over a period of weeks to months by a process dubbed “selective cryolysis” or “cryolipolysis” ([ 12 , 16 ], reviewed in [ 14 , 17 ]). Selective sensitivity of fatty tissue to cold has a long history, and for over a century there have been observations of local adipose tissue lesions in regions exposed to local cooling [ 15 ].…”

“…The mechanistic basis is of direct clinical relevance because if tissue cryotherapy operates by inducing adipocyte cell death, then repeat procedures must be widely spaced (e.g., 8 weeks apart) to allow removal of cell debris and resolution of inflammation [ 12 , 39 ]. Indeed, it has been reported that beneficial results are only observed after weeks or months, the recommended area for application is limited to local prominences of fatty tissue (“saddlebags”), and it is necessary to wait for a long period (1–3 months) before proceeding to a new zone [ 12 , 14 , 16 , 17 ]. By contrast, others have suggested the possibility that the beneficial effects of body cooling might take place by increasing nonshivering thermogenesis (e.g., [ 18 , 19 ]); if confirmed, this would allow simultaneous application to different body regions, and moreover, repeated cryoexposure might be effective in driving the loss of adipose tissue [ 18 ].…”