Micro fractured Adipose Tissue Graft (Lipogems), Regenerative Surgery and Potential Outcomes for Infectious and Cancer Diseases
Carlo Tremolada1, Pierre Rocheteau2, Carmelo Bisognano2 *, Offer Zeira3, and Giulio Alessandri4
1Image Regenerative Clinic, Milano, Italy
2Exogems SA, c/o Biopole, Epallinges, Switzerland
3Department of Neurology, Neurosurgery and Imaging diagnostics, Stem Cells and Regenerative Medicine
San Michele Veterinary Hospital, Tavazzano con Villavesco, Italy
4StaMeTec coordinated Research Centre, Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan
*Corresponding author: Carmelo Bisognano, Exogems SA, c/o Biopole, Epallinges, Switzerland
Citation: Tremolada C, Rocheteau P, Bisognano C, Zeira O, Alessandri G. (2023) Micro fractured Adipose Tissue Graft (Lipogems), Regenerative Surgery and Potential Outcomes for Infectious and Cancer Diseases. J Stem Cell Res. 4(2):1-15.
Received: September 6, 2023 | Published: September 27, 2023.
Copyright© 2023 by Tremolada C. All rights reserved. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
In the past few years, interest in adipose tissue as an ideal source of mesenchymal stem cells (MSCs) has increased since they are able to secrete many bioactive molecules and exosomes. MSCs are being used increasingly for many clinical applications, such as orthopedic, plastic, and reconstructive surgery. An innovative technique (Lipogems®) has been developed to obtain micro fragmented adipose tissue (MFAT) with an intact stromal vascular niche and MSCs with a high regenerative capacity. The Lipogems technology, is an easy-to-use system designed to harvest, process, and inject refined fat tissue and is characterized by optimal handling ability and a great regenerative potential based on adipose-derived MSCs. As a further step, bioactive molecules and exosomes produced either by the MSCs extracted and from Lipogems/MFAT itself will be studied by Exogems Inc., a new venture that will leverage the potential of this secretome to treat infections and cancer.
Adipose tissue; Exosomes; Mesenchymal cells; Cancer; Infections
The adipose tissue (AT), encompassing subcutaneous and visceral fat, constitutes the largest organ within our body and serves a range of functions, both in terms of structure and endocrine activity . This tissue comprises various cellular elements (depicted in Figure 1 and possesses an intricate network of small capillaries that actively engage in the body's self-repair mechanisms. Notably abundant in pericytes (illustrated in Figure 2), which serve as precursors to mesenchymal stem cells (MSCs), crucial components in the healing process . Throughout history, fat has been harnessed for medicinal purposes, with applications dating back to military physicians in the Napoleonic era. However, it was not until the 1980s that the liposuction technique emerged, revolutionizing access to sizable fat deposits using progressively less invasive methods. This paved the way for the popularity of lipofilling, an approach involving the autologous transplantation of adipose tissue. Initially used to restore lost volume, such as in breast reconstruction or facial deformities, its application expanded to regenerative purposes, particularly in addressing scars and radio dermatitis . Despite delivering promising clinical outcomes, traditional lipofilling techniques encountered significant challenges, notably variations in results (volume absorption, residual irregularities, and fibrosis), as well as unpredictability in regenerative outcomes .
Figure 1: Adipose tissue is composed of many cellular components which can be separated by enzymatic treatment. These are found in the Stromal Vascular Fraction (SVF) .
Figure 2: (a) Pericytes (red cells) sit around the microvessels of all tissues and are the precursor of MSCs. Electronic microscopy showing pericytes in a 5-micron capillary. (b) Lipogems cluster (adipocytes are in orange and Pericytes are in green) showing the pericytes and the intact microvessels on the surface of the cluster .
Comparative analysis of adipose tissue and bone marrow aspirate as sources of biologically and clinically active Mscs for regenerative applications
Both AT and bone marrow (BM) have emerged as primary contenders for regenerative therapies in the musculoskeletal system, owing to their minimally invasive harvesting methods and the presence of MSCs in their aspirates. The scrutiny of MSCs originating from BM began with Arnold Caplan's pioneering investigations, building upon the established knowledge of BM as the precursor site for hematopoietic stem cells. Although BM derived MSCs took the lead in terms of study, isolation, and characterization, AT has shown to possess comparable regenerative attributes, boasting distinct advantages like abundance, even simpler harvesting procedures, and a substantially larger yield of MSCs [4-5]. The functional and clinical impact of MSCs predominantly hinges on their secretome, encompassing exosomes, proteins, and RNAs. This secretome is so influential that Caplan himself coined the term "Medicinal Signaling Cell" to underscore their pivotal biological role in maintaining tissues and responding to injuries, particularly by modulating inflammation and macrophage activity. Following a traumatic event to a tissue's capillary wall, pericytes detach and transform into MSCs within minutes to hours, releasing a plethora of cytokines that impede inflammation, especially induced by macrophages . In the subsequent weeks, more specialized cytokines are secreted, fostering antibiotic, antifibrotic, angiogenetic, and analgesic effects . This field of medical research is experiencing a surge, evident from over 8500 literature entries in the past year alone.
The specific density of MSCs required to induce certain biological responses remains unclear. Nevertheless, the efficacious clinical outcomes observed in symptomatic osteoarthritis treatment using concentrated bone marrow aspirate (BMAC), containing approximately 20,000 MSCs per cubic centimeter, closely rival the results from lipogems at one year. Notably, lipogems boasts a significantly higher average content of about 1,000,000 MSCs per cubic centimeter. While counting MSCs directly in bone marrow is comparatively straightforward, doing so in AT poses challenges due to the majority of MSCs being sensnared within micro vessels present in tissue clusters. Counting MSCs in AT necessitates enzymatic or mechanical separation processes, which entail either complete (enzymatic) or partial (mechanical) disruption of adipose tissue and its inherent structure. This yields a cellular amalgam known as the stromal vascular fraction (SVF), extensively employed in clinical and laboratory research, yet subject to notable regulatory issues in standard clinical practice. Interestingly, SVF from 1 cubic centimeter of adipose tissue contains around 500 times more MSCs compared to 1 cubic centimeter of unconcentrated bone marrow aspirate . None the less, as observed in clinical trials, there exists a modest correlation between the quantity of MSCs and the ensuing biological and clinical effects .
The preceding discussion underscores a critical point: Lipogems is unequivocally not a device designed for the mechanical isolation of MSCs, a common misconception held by many [8-10]. Contrary to this misunderstanding, MFAT, the outcome of Lipogems, stands in stark contrast to the stromal vascular fraction (SVF) generated through enzymatic or mechanical breakdown of the lipoaspirate, which necessitates complete dismantling of the original tissue structure to facilitate potential MSC isolation and cultivation. The Lipogems extract represents AT that has been substantially reduced in size and thoroughly cleansed from a lipoaspirate, maintaining clusters of approximately 3mm. It is crucial to grasp that this extract remains authentic AT, still containing fully intact clusters measuring around 0.3/0.5 mm. Of notable significance is the fact that the surface of these clusters is rich in microvessels, presenting an exposure that is considerably amplified (roughly 6000 times greater) when compared to the initial lipoaspirate . Recognizing the distinctions between various regenerative preparations holds immense importance in comprehending their divergent biological and clinical impacts. Notably, it remains far from certain, as previously mentioned, that a higher quantity of MSCs invariably leads to more pronounced biological effects. This applies to both the secrete and exosomes obtained in vitro, as well as the evaluation of final biological effects in animal studies conducted in vivo [12-13].
The Lipogems Device and the Resemblance of MFAT (Lipogems) to Lipoaspirate, with Enhanced Biological Attributes, Rendering it a Natural Implantable Bioreactor
Originally conceived and patented with the aim of optimizing clinical outcomes in lipofilling, the Lipogems system (depicted in Figure 3) operates by aspirating adipose tissue using small, disposable cannulas (14G) featuring multiple oval apertures sized at 2x1 mm. This choice of aperture dimensions, while smaller, avoids procedural delays and excessive damage to the aspirated fat. Subsequently, the aspirated adipose tissue, characterized by clusters around 3 mm in size, undergoes processing within a completely sealed device. Within this device, the fat is meticulously washed to remove blood, oily residues, and inflammatory components. Concurrently, the adipose clusters are gradually diminished in size to approximately 0.3 mm using precise mechanical forces applied through sharp filters. The correct execution of this process is pivotal, as emphasized in the Lipogems tutorial an especially critical factor is the exclusion of air during the procedure. This ensures that volumetric reduction occurs while harnessing the protective influence of physiological pressure, preventing the adipocytes from rupturing and preserving the structural integrity of the adipose tissue. The marbles contained within the device serve not to fragment the adipose tissue, but to facilitate effective cleansing against the gravitational forces of the oily and blood emulsion. They also contribute to dispersing the tissue, enabling it to pass smoothly through the subsequent cutting filter. During this process, shaking should be carried out for a duration lasting no less than 20 seconds and no more than 90 seconds, all the while assuring the absence of air within the device. This meticulous procedure contributes to the successful transformation of the AT into MFAT, commonly referred to as Lipogems. It is important to recognize that this MFAT, despite its resemblance to lipoaspirate, showcases enhanced biological properties, to the extent that it can be deemed a natural implantable bioreactor.
Figure 3: The Lipogems system .
The Lipogems product (depicted in Figure 4) embodies a tissue fragment that has been meticulously cleansed of oily residues and deceased cells, preserving its structural integrity at a diameter of around 300 microns (0.3 mm). This product essentially serves as a natural implantable bioreactor, encompassing the essential components for an optimal natural regenerative response: the scaffold (notably integrating seamlessly even at the microvascular level of adipose tissue), the cells (particularly pericytes/MSCs), and the growth factors (cytokines secreted in response to mechanical trauma and subsequently tailored to the implantation environment of Lipogems clusters). When this tissue is locally injected, it functions as a living graft that seamlessly integrates with the recipient tissue. Its modest size and structural integrity render it an ideal graft, facilitating both swift passive and active revascularization processes. This, in turn, enable it to effectively serve over an extended period, considerably enhancing the inherent potential for local healing. Pertinently, it is intriguing to observe how individual recovery following trauma or illness differs significantly due to the vascular micro-density of tissues [14-15]. This micro-density varies inversely with age and overall health conditions, evidenced by decreased vascular micro-density in conditions such as diabetes and in elderly tissue, as opposed to pediatric tissue.
Figure 4: The MFAT derived from Lipogems .
The process of downsizing the lipoaspirate from a diameter of 3mm to 0.3mm engenders a substantial escalation in the quantity of grafted fragments: each initial fragment gives rise to approximately 1000 fully intact pieces, each adorned with a surface layer of capillaries. Notably, this augmented surface area experiences an even more substantial enlargement, reaching up to around 6000 times its initial size. Consequently, an extensive network of capillaries, accompanied by a substantial presence of pericytes poised to naturally func- 174 tion, becomes exposed. Furthermore, investigations have demonstrated that Micro-Fragmented Adipose Tissue (MFAT) actively generates microcapillaries in vitro, akin to the process observed in an aorta ring . Intriguingly, MFAT also stimulates neovasculogenesis within the recipient tissue (as depicted in Figure 5) .