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LORIENT PREFACE

The Science of Preservation

The design and research of Preface

Because it is a material added to the face,
we also consider cell response
and effects on the surrounding environment.

For Preface, the design of the material was examined,
and inflammation-related responses after exposure
to the material were studied in an in vitro cell study.

The center dot and the inner circle are the in vitro cell study of Preface (material extract → adipocytes → macrophages, expression of inflammation-related genes). The outer circle is the tissue environment examined through the literature. This is a conceptual diagram of the scope examined and does not represent results.

This page presents three kinds of material separately.
They are related literature, the product design of Preface
and the in vitro cell study of Preface.
For each, the subjects, conditions
and scope of interpretation are stated.

Literature 01 · Human Imaging Study

Change in facial volume
before and after weight loss

In 20 patients prescribed a weight-loss medication,
the average weight loss was about 11 kg.
When facial images from before and after the prescription
were compared, midface volume had decreased
by a median of about 9%.
The decrease was about 11% in the superficial fat compartments
and about 7% in the deep compartments,
and the decrease in the deep compartments was less consistent [1].

Change in facial volume before and after weight loss

Human observational study · 20 patients · mean weight loss of approx. 11 kg · comparison of CT and MR images before and after a prescribed weight-loss medication

These are the percentage decreases in each layer observed in a comparison of facial images before and after a prescribed weight-loss medication (all three values are medians). The three values are not additive [1].

Literature 02 · Facial Anatomy

Skin, fat and supporting structures
involved in the shape of the face

Beneath the skin, superficial fat, deep fat
and the structures that support them form layers.
The size and position of each layer, and the way the layers
fit together, are involved in the shape of the face.

The outermost layer of the face.
Its thickness and elasticity, and the condition of the layers
beneath it, are involved in the shape seen from the outside.

The fat layer directly beneath the skin.
The amount and distribution of superficial fat
are involved in the shape of the face.
The structure of the septa that divide the compartments
differs by region.
In one observational study, this was the layer
that had decreased more after weight loss [1].

The layer that creates depth and projection.
It differs from the superficial layer in both position and role.

Fascia, retaining ligaments and the skeleton form
the framework that sets the position of the layers.

Literature 03 · Adipose Tissue

Weight loss and cellular changes
in adipose tissue

One study looked directly at adipose tissue after weight loss in humans. In 25 people with obesity, abdominal subcutaneous fat was compared before bariatric surgery and after weight loss. Stress- and senescence-related signals in adipocytes, precursor cells and vascular cells had decreased. Macrophage infiltration had also decreased, but the activation state of the macrophages had not fully reverted. In this study, adipose tissue after weight loss had changed in the state of its cells as well as in its amount [2].

A mouse study observed adipose tissue during weight loss. When food intake was reduced in mice with induced obesity, the proportion of macrophages in subcutaneous adipose tissue rose from about 10% to 20% on the third day, and that time point coincided with the time when lipolysis was most active. The incoming macrophages took up the released lipids, and the authors interpreted this as a buffering role [3]. In another study in mice and cultured adipocytes, inducing lipolysis by receptor stimulation raised the expression of an inflammatory signal (IL-6) in adipocytes [4].

When a mouse adipocyte cell line and a macrophage cell line were cultured together, inflammatory signals (such as TNF-α) increased markedly, and the authors proposed a loop in which free fatty acids from adipocytes and inflammatory signals from macrophages amplify each other [5,6]. In cultured-cell studies, such inflammatory signals increased lipolysis and decreased fat storage and the differentiation of preadipocytes [7–10]. When human adipocytes were given macrophage-conditioned medium and only the IL-1β in it was neutralized, the increased lipolysis and the reduced insulin signaling were reversed to a considerable extent [11].

Even with the same signal, results differed with the state of the cells and the duration of exposure. IL-1β briefly supported the differentiation of early precursor cells, but as exposure continued, that effect disappeared and only the inflammatory response remained [12].

Signal feedback triggered by lipolysis

Observations in rodents and cultured cells [3–11]

In rodents, macrophages in adipose tissue increased temporarily early in weight loss, and that time point coincided with when lipolysis was most active [3]. Arrows show the direction of signals reported in each paper; they are not claims about the product [3–11].

Literature 04 · Hyaluronic Acid & ECM

Research on hyaluronic acid
and the extracellular matrix

Hyaluronic acid in the body has been studied
in the space between tissues, in the coat immediately
around cells, and at contact points on the cell surface.
The studies below address these three locations.

  1. 01
    Tissue SpaceThe space between tissues
    In a mouse digit-tip regeneration model,
    removing hyaluronic acid increased collagen,
    made the tissue stiffer and suppressed regeneration.
    Conversely, stabilizing the hyaluronic acid matrix
    reduced scarring and improved bone recovery [13].
  2. 02
    Pericellular CoatThe coat around cells
    Cells form a hyaluronic acid coat around themselves.
    Given the same growth factor, normal dermal fibroblasts
    formed a coat, while coat formation was reduced
    in cells derived from chronic wounds.
    The difference in the coat was also linked to where
    receptors are located on the cell membrane [14].
  3. 03
    Cell SurfaceContact points on the cell surface
    In a study in which cross-linked hyaluronic acid
    was injected into the buttock skin of people aged 70 or older,
    fibroblasts around the injected material were spread out
    4 weeks after injection, and type I procollagen gene
    expression in these cells was about 12 times higher
    than in fibroblasts from saline-injected skin [15].
    In a mouse macrophage study, inflammatory signals were lower
    in response to a stimulus given after prior exposure
    to hyaluronic acid, and the receptor CD44
    was involved in that pathway [16].

There are also studies on hyaluronic acid and matrix stiffness in adipose tissue. When hyaluronic acid was enzymatically removed from human adipose tissue samples, the expression of genes related to adipogenic differentiation decreased, and the differentiation of mouse-derived cultured adipocytes was also suppressed [17]. On an experimental gel substrate as soft as adipose tissue (a polyacrylamide gel coated with adipose tissue extracellular matrix; not hyaluronic acid), human adipose-derived stem cells kept a rounded shape and headed toward becoming adipocytes. When the substrate was stiffer, the cells spread widely and lost that direction [18]. Human preadipocytes cultured on an esterified hyaluronic acid scaffold differentiated into adipocytes [19], and when a hyaluronic acid gel was injected together with human adipose-derived stem cells under the skin of immunodeficient mice, new adipose tissue was observed after 8 weeks [20].

Product Design

Preface's cross-linked
hyaluronic acid design

The following are the design indicators measured for Preface
and the results of its in vitro cell study.
MoD and CrR are used to describe the chemical structure
of cross-linked hyaluronic acid.

Cross-linked hyaluronic acid is made by linking chains with a crosslinker. MoD is the amount of crosslinker bound to the chains. CrR is the share of bound crosslinker attached to the chains at both ends. Crosslinker attached at only one end does not form the network and remains as a pendant residue. The definitions of the two indicators and the NMR measurement method follow the literature [24,25].

The measured values for Preface are MoD about 1.4% (1H NMR) and CrR about 0.22 [28]. Among the 13 commercial cross-linked hyaluronic acid products analyzed in the literature, the product with the highest MoD had MoD about 17% and CrR about 0.09 [26]. The Preface values were not measured together in that publication, so the comparison is for reference only. There is no officially recognized reference value for CrR.

The two paragraphs below cover general literature that did not test Preface, and an internal exploratory analysis. There are cell studies on the purity and chemical modification of hyaluronic acid. In a test with mouse immune cells, purified pharmaceutical-grade hyaluronic acid did not raise inflammatory signals, and endotoxin contamination was confirmed in the reagents that caused a response (1 hyaluronic acid derived from human umbilical cord and 2 hyaluronidases) [21]. Hyaluronic acid whose modification level was raised from about 10% to 40% showed about 57% less binding to the receptor CD44 in a solution-state test (based on the modification type with the largest change) [22]. In a test in which human macrophages were cultured in collagen gels, hyaluronic acid that was not immobilized in the gel lowered inflammatory markers. When hyaluronic acid was chemically immobilized in the gel, this decrease was not seen [23]. All three studies dealt with experimental hyaluronic acid materials, not with Preface.

There is also an animal study on the degree of cross-linking and tissue response. When hyaluronic acid formulations with a lower and a higher degree of cross-linking were administered to immunologically pre-sensitized guinea pigs, inflammatory cell infiltration was lower with the lower one. The two formulations differed in physical properties as well as in degree of cross-linking [27]. This is not a study of Preface. An internal exploratory analysis [28] looked at the structural indicators of 12 products (including published values from the literature [26]) together with in vitro study values. Expression of inflammatory signals tended to be higher with a higher degree of modification (MoD) and lower with a higher effective crosslinker ratio (CrR) [28]. This is an exploratory analysis of trends, and structural indicators alone cannot predict the response of an individual product. The methods and results of the in vitro cell study of Preface follow.

Amount of crosslinker and share bound at both ends

Preface [28] (measurement method [24,25]) · compared with a commercial product in the literature [26]

The degree of modification is the amount of crosslinker attached to the chains, and the effective crosslinker ratio is the share of that crosslinker bound to the chains at both ends (the theoretical range of the ratio is 0–1; the axis is set to 0–0.25 to fit the data). The comparison value is that of the product with the highest MoD among the 13 commercial cross-linked HA products analyzed in the literature [26], and it was not measured together with the Preface value. The schematic above illustrates the concept and is not drawn to the proportions of the actual molecular structure. Inflammatory response or safety cannot be judged from these two values alone.

Rheological properties of Preface

Frequency sweep · 1 Hz · In-house test

Rheological properties of Preface — Frequency sweep · 1 Hz · In-house test
Storage modulus G′260.6 Pa
Loss modulus G″107.5 Pa
tan δ (G″ ÷ G′)0.41
Complex viscosity η*44,870 cP
These are in-house test values measured at a frequency of 1 Hz. When tan δ is less than 1, the elastic component (G′) is larger than the viscous component (G″). Values may vary with measurement conditions, and these values alone cannot be used to judge treatment outcomes or duration.
Scanning electron micrograph of Preface showing an interconnected porous network structure.
Electron microscope image of Preface (350×, scale bar 100 μm).
A porous, reticular structure made with Lorient's STORM™ Tech.
View the product information table

Product · In Vitro Study

Methods and results of the in vitro cell study

In an in vitro cell study using adipocytes and macrophages,
expression of inflammation-related genes was evaluated according to
the order of the lipolytic stimulus and product exposure.

01

Model

Differentiated 3T3-L1 adipocytes → conditioned medium → RAW264.7 macrophages

02

Outcome measures

IL-1α · IL-1β · IL-6 · TNF-α mRNA

03

Conditions

2 orders (treatment after stimulus · treatment before stimulus) × 3 combinations of cell and time point × 4 mRNAs = 24 endpoints.
In the after-stimulus order, adipocytes receive the stimulus for 4 hours and then the extract for 24 hours.
In the before-stimulus order, the extract is applied first for 24 hours and removed, then the stimulus is given and the cells are cultured for 24 more hours.
In both orders, the adipocyte culture medium is transferred to macrophages and read after 2 hours and 24 hours.

Inflammatory-signal mRNA expression in six other material families was 7.0–23.0 times that of Preface, as a median fold.

All 24 observed values for Preface were lower
than the stimulus-only control (=1) (0.01–0.93).
The values for the six other material families were numerically
higher than those of Preface at all 24 endpoints [28].
Of the six families, Cross-linked HA was tested
in a separate run of the same method.
The median fold is the median of the fold values relative
to Preface calculated for each of the 24 endpoints.

Other material families — relative to Preface

In vitro study · median fold across 24 endpoints

In the in vitro study, mRNA expression of inflammatory signals for each material family is shown as a fold relative to Preface. Bars are the median fold across 24 endpoints, and '24 / 24' means the values were numerically higher than Preface in all 24 endpoints [28].

The Cross-linked HA values (a cross-linked HA product with a high degree of modification) come from a separate run of the same method and were numerically higher than Preface at all 24 corresponding endpoints. Because the run was different, these values were not obtained side by side with the other five families, and no statistical tests are included in this material.

Material familyMedian foldEndpoints higher than Preface
PN + HA7.0×24 / 24
PLLA7.4×24 / 24
Human-derived extracellular matrix8.6×24 / 24
PCL11.1×24 / 24
PDLLA + HA11.1×24 / 24
Cross-linked HA (separate run)23.0×24 / 24

Expression of inflammation-related genes by test condition — Preface observed values (stimulus only = 1)

4 inflammatory signals (mRNA) × 6 conditions = 24 observed values

Differentiated 3T3-L1 adipocytes were exposed to the product extract, and the collected culture medium was transferred to RAW264.7 macrophages to evaluate the response. The measured items are the relative mRNA expression of IL-1α, IL-1β, IL-6 and TNF-α. In vitro results are observations under the conditions of that test. The exact values are in the table below [28].
Table 1. 24 Preface observed values — relative mRNA expression with the stimulus-only control set to 1
After stimulusmacrophages 2hAfter stimulusmacrophages 24hAfter stimulusadipocytes 24hBefore stimulusmacrophages 2hBefore stimulusmacrophages 24hBefore stimulusadipocytes 24h
IL-1α0.930.390.370.220.080.87
IL-1β0.040.300.140.250.120.11
IL-60.090.280.070.240.080.09
TNF-α0.010.340.080.250.070.18
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References

‘View source’ for each reference links to the original publication (DOI). No. 28 is an internal study report that directly evaluated Preface, and it has no public link.

  1. 1Sharma RK, et al. Otolaryngol Head Neck Surg. 2025;173(2):360-366. · Human observational study View source (reference 1, opens in a new window)
  2. 2Miranda AMA, et al. Nature. 2025;644(8077):769-779. · Human tissue study View source (reference 2, opens in a new window)
  3. 3Kosteli A, et al. J Clin Invest. 2010;120(10):3466-3479. · Animal study View source (reference 3, opens in a new window)
  4. 4Zhang W, et al. J Biol Chem. 2014;289(46):32178-32185. · Animal study · In vitro study View source (reference 4, opens in a new window)
  5. 5Suganami T, et al. Arterioscler Thromb Vasc Biol. 2005;25(10):2062-2068. · In vitro study View source (reference 5, opens in a new window)
  6. 6Suganami T, et al. Arterioscler Thromb Vasc Biol. 2007;27(1):84-91. · In vitro study View source (reference 6, opens in a new window)
  7. 7Zhang HH, et al. Diabetes. 2002;51(10):2929-2935. · In vitro study View source (reference 7, opens in a new window)
  8. 8Lagathu C, et al. Diabetologia. 2006;49(9):2162-2173. · In vitro study · Animal study View source (reference 8, opens in a new window)
  9. 9Constant VA, et al. Diabetologia. 2006;49(6):1402-1411. · In vitro study View source (reference 9, opens in a new window)
  10. 10Lacasa D, et al. Endocrinology. 2007;148(2):868-877. · In vitro study View source (reference 10, opens in a new window)
  11. 11Gao D, et al. Am J Physiol Endocrinol Metab. 2014;307(3):E289-E304. · In vitro study View source (reference 11, opens in a new window)
  12. 12Hofwimmer K, et al. Nat Commun. 2024;15(1):7957. · Animal study · In vitro study View source (reference 12, opens in a new window)
  13. 13Mui BWH, et al. Science. 2026;392(6794):eady3136. · Animal study View source (reference 13, opens in a new window)
  14. 14Morris NG, et al. Exp Cell Res. 2025;450(2):114646. · In vitro study View source (reference 14, opens in a new window)
  15. 15Quan T, et al. J Invest Dermatol. 2013;133(3):658-667. · Human interventional study View source (reference 15, opens in a new window)
  16. 16Muto J, et al. Mol Immunol. 2009;47(2-3):449-456. · Animal study · In vitro study View source (reference 16, opens in a new window)
  17. 17Drygalski K, et al. Biochim Biophys Acta Mol Cell Biol Lipids. 2024;1869(4):159470. · Human tissue study · In vitro study View source (reference 17, opens in a new window)
  18. 18Young DA, et al. Biomaterials. 2013;34(34):8581-8588. · In vitro study View source (reference 18, opens in a new window)
  19. 19Halbleib M, et al. Biomaterials. 2003;24(18):3125-3132. · In vitro study View source (reference 19, opens in a new window)
  20. 20Huang SH, et al. Int J Med Sci. 2015;12(2):154-162. · Animal study View source (reference 20, opens in a new window)
  21. 21Dong Y, et al. Sci Rep. 2016;6:36928. · In vitro study · Animal study View source (reference 21, opens in a new window)
  22. 22Kwon MY, et al. Biomaterials. 2019;222:119451. · In vitro study · Material characterization View source (reference 22, opens in a new window)
  23. 23Oates TCL, et al. Adv Biol (Weinh). 2025;9(12):e00682. · In vitro study View source (reference 23, opens in a new window)
  24. 24Kenne L, et al. Carbohydr Polym. 2013;91(1):410-418. · Material characterization (analytical method) View source (reference 24, opens in a new window)
  25. 25Wende FJ, et al. Carbohydr Polym. 2017;157:1525-1530. · Material characterization (analytical method) View source (reference 25, opens in a new window)
  26. 26Lee W, Yang EJ. Polymers. 2024;16(20):2878. · Material characterization View source (reference 26, opens in a new window)
  27. 27Chen Y, et al. Aesthetic Plast Surg. 2026;50(15):6383-6392. · Animal study View source (reference 27, opens in a new window)
  28. 28Joonghun Pharmaceutical, New Drug Research Team. Internal study report on Preface structural indicators (MoD·CrR) and in vitro cell study. 2026.

See the design and test results
of Preface in more detail.

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