Mission impossible: Dermal delivery of growth factors via microneedling

The clinical application of transdermal delivery has been limited to lipophilic drugs with a molecular weight of less than 500 Da. The development of polymeric microneedles enabled the transdermal delivery of larger proteins and drugs. Extensive research has been conducted on the molecular size, solubility, pH, concentration, and polarity of transdermal delivery; however, the maximal molecular weight for transdermal microneedle delivery has not been established. Clinicians often use simple microneedles to deliver high molecular weight growth factors of platelet‐rich plasma across the skin; thus, we set out to explore the feasibility of delivering growth factors through microneedling. In this communication, we present histological evidence that microneedling do not enhance transdermal delivery of growth factors and thus provide no clinical benefit.     

Topical growth factor preparations for facial skin rejuvenation: A systematic review

Background

Cosmeceutical preparations containing growth factors (GFs) are widely used for facial rejuvenation.

Objective

We performed a systematic review to assess the evidence regarding their safety and effectiveness for facial rejuvenation.

Methods

Electronic databases (Cochrane Library, EMBASE, MEDLINE, and Scopus) were searched from 2000 to October 2022 for prospective trials and case series assessing topical GF preparations for facial rejuvenation in 10 or more participants.

Results

Thirty-three studies, including 9 randomized controlled trials (RCTs) and 24 uncontrolled case series, representing 1180 participants receiving 23 different topical preparations containing GFs met the inclusion criteria and were included. Of the 33 studies, nine used a placebo or active control. The GF preparations were applied twice daily in all except two studies, with a mean treatment duration of 3 months. Based on the investigator's assessment, preparations containing GFs induce a modest improvement in skin texture (median < 50%), fine lines/wrinkles (median < 35%), and overall facial appearance (median < 20%) versus baseline. Participant-assessed improvement was generally higher than investigator-assessed response. Three comparative RCTs showed no statistically significant differences between treatments. Studies were limited by heterogeneity with regard to the source and number of GFs used in the preparations, information about additional ingredients, and lack of standardization in the outcome measures. The preparations were associated with a low risk of adverse events. The persistence of the clinical improvements beyond 6 months is not known.

Conclusions

Administration of topical preparations containing GFs appears to be effective for facial skin rejuvenation, as demonstrated by the investigator- and participant-reported outcome measures.     

Endogenous growth factors as cosmeceuticals

ABSTRACT:  Growth factors play an important role in reversing the effects of skin aging mediated by chronological and environmental factors. Excessive oxidation of intra- and extracellular components result in breakdown of collagen and elastin network in the dermis and produce the effect of facial aging. Topical application of human growth factors in multiple clinical studies has been shown to reduce the signs and symptoms of skin aging, including statically significant reduction in fine lines and wrinkles and increase in dermal collagen synthesis. More double-blind and controlled studies are needed to confirm the preliminary clinical effects of growth factor products, and more controls on product quality and stability need to be established.     

Nerve growth factor increases the mitogenicity of certain growth factors for cultured human keratinocytes: A comparison with epidermal growth factor

Abstract Newborn foreskin and adult skin keratinocytes (KTs) were cultured in 24-well plates using keratinocyte basal medium (KBM) either alone or supplemented with epidermal growth factor (EGF) or nerve growth factor (NGF), plus one of the following: insulin (INS), insulin-like growth factors (IGF)-l or -2, transforming growth factor alpha (TGFα), basic fibroblast growth factor (bFGF). Culture was maintained until one group of cells reached about 30,000 cells/well, when cells were stained with crystal violet and the extracted dye used to quantify cell numbers. In some cases, cells were subjected to the hexosaminidase assay for enumeration. In KBM alone, EGF, IGF-1, IGF-2 and TGFα were milogenic to newborn KTs. In addition, NGF increased the growth of adult KTs, possibly by mechanisms involving synergy with autocrine growth factors. EGF augmented the growth of newborn cells in the presence of each of the growth factors except TGFα, but adult cells exhibited only additive effects. In the presence of IGF-1 or IGF-2, NGF stimulated the growth of both newborn and adult cells by as much as 150% above purely additive increases in cell numbers. NGF amplifies the effects of most neurotrophic factors that are also KT mitogens and may therefore be significant in psoriatic lesions, where many of these factors are overex-pressed, and in wound healing, in promoting KT growth.     

Stimulation of keratinocyte migration by growth factors.

Migration of keratinocytes from the wound edge is thought to be one of the critical features of reepithelialization. A quantitative migration assay was carried out using normal human keratinocytes. Keratinocytes, seeded on 12 well plates, were grown in serum free, keratinocyte growth medium (KGM, Curabo Co) with 0.08 mM Ca2+. The medium was switched from KGM to keratinocyte basal medium (KBM) 6 h prior to the wounding. Half of the plate's confluent monolayer of keratinocytes was removed with razor blade, and the remaining keratinocytes were incubated in KBM for 16 hrs in the presence of indicated growth factors. After incubation, the cells were fixed and counted at 100 magnification. Migration was quantitated by counting the number of cells in ten successive 125-microns zones. Transforming growth factor alpha (TGF-alpha), acidic and basic fibroblast growth factor (aFGF, bFGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), and insulin-like growth factor-I (IGF-I) stimulated the migration of keratinocytes, while TGF-beta suppressed it.     

Cosmeceuticals: undefined, unclassified, and unregulated

The cosmeceutical category is an undefined, unclassified, and unregulated area of dermatology that is yet in its infancy. Traditional cosmeceuticals involve the topical application of biologically active ingredients that affect the skin barrier and overall skin health. The ability of these ingredients to enhance skin functioning depends on how they are formulated into products that can maintain the integrity of the active ingredient, deliver it in a biologically active form to the skin, reach the target site in sufficient quantity to exert an effect, and properly release from the carrier vehicle. In the United States, cosmeceuticals are sold as cosmetics, making marketing, packaging, and aesthetic appeal important considerations. Ideally, the cosmeceutical should be clinically tested for efficacy to ensure a proven skin benefit and also to substantiate marketing claims. Governmental limitations of efficacy claims restrict cosmeceutical development because products can only be assessed in terms of their ability to improve skin appearance but not function. Improving function would remove the cosmeceutical from the cosmetic category and place it in the drug category. Herein lies the challenge of defining the cosmeceutical category.     

Growth factors,signal transduction,and cellular responses

The extraordinary advances in the field of growth factors and signal transduction have created new and promising therapeutic interventions. We intend to explain the difficult nomenclatures associated with growth factors and their mechanisms of action.     

激光照射对体外培养的婴儿血管瘤内皮细胞相关生长因子及细胞凋亡的影响

【摘要】 目的 研究激光照射对体外培养的婴儿血管瘤内皮细胞相关生长因子及细胞凋亡的影响。方法 活化培养的婴儿血管瘤内皮细胞分为3组,强脉冲光（IPL）组（23 J/cm2,照射1次）、激光组（1 064 nm Nd：YAG激光,90 J/cm2,照射1次）和对照组（不照射激光）。照射后第1、3、7天,RT-PCR检测血管内皮生长因子（VEGF）、VEGF受体2（VEGFR-2）及碱性成纤维细胞生长因子（bFGF）mRNA的表达,Western印迹检测VEGFR-2蛋白表达,ELISA检测细胞上清液中VEGF和bFGF的含量,流式细胞仪检测细胞凋亡。结果 与对照组相比,1 064 nm Nd：YAG激光照射后第7天,VEGF mRNA（0.363 ± 0.021比1.000 ± 0.023）、VEGFR-2 mRNA（0.483 ± 0.017比1.001 ± 0.031）、bFGF mRNA（0.402 ± 0.040比1.000 ± 0.004）表达均下降,VEGFR-2蛋白表达下降（0.332 ± 0.055比0.768 ± 0.096）,VEGF［（69.389 ± 24.179） ng/L比（334.506 ± 13.084） ng/L］和bFGF［（2.386 ± 0.151） ng/L比（9.165 ± 0.232） ng/L］分泌减少,细胞凋亡率（18.413% ± 2.654%比4.300% ± 0.036%）上升,差异均有统计学意义（P＜0.05）。与对照组相比,IPL组照射后第7天VEGF mRNA（0.436 ± 0.041比1.000 ± 0.023）、VEGFR-2 mRNA（0.493 ± 0.037比1.001 ± 0.031）、bFGF mRNA（0.490 ± 0.044比1.000 ± 0.004）表达下降,VEFGR-2蛋白表达下降（0.406 ± 0.037比0.768 ± 0.096）,VEGF［（128.858 ± 6.063） ng/L比（334.506 ± 13.084） ng/L］和bFGF［（2.723 ± 0.471） ng/L比（9.165 ± 0.232） ng/L］分泌减少,细胞凋亡率上升（16.597% ± 1.877%比4.300% ± 0.036%）,差异均有统计学意义（P＜0.05）。结论 1 064 nm Nd：YAG激光可能通过调节VEGF/VEGFR-2信号通路上的关键因子,以及细胞凋亡发挥对血管瘤内皮细胞的抑制作用,从而达到治疗血管瘤的作用。     

Cytokines and growth factors influence hair growth in vitro. Possible implications for the pathogenesis and treatment of alopecia areata

Factors that influence the growth of the anagen hair follicle or initiate the switch to a catagen growth pattern have so far not been definitely determined, but there is increasing evidence that cytokines and growth factors play an important role during these processes. Recently we detected an aberrant in situ expression pattern of cytokines of the Th1 type (IFNγ, IL-2) plus IL-1β expression in untreated alopecia areata (AA), and a switch to high levels of IL-10 TGF-β1 expression after successful treatment with the contact allergen diphenylcyclopropenone (DCP). Hence the question arose as to whether cytokines are able to arrest hair growth and whether IL-10 or TGFβ1 have the capacity to antagonize this process. Using whole-organ cultures of microdissected human hair follicles we studied the effect of a panel of cytokines and growth factors on hair growth and on the gross morphology of the hair follicles in vitro. IL-2, IL-10 and IFN-γ had no effect in this regard, whereas TGFβ1 partially inhibited hair growth and EGF, TNFα and IL-1β completely abrogated it. EGF and TNFα induced the formation of a club-like hair follicle, similar to catagen morphology of the hair bulb, whereas hair follicles grown in the presence of IL-1β or TGFβ1 showed no particular morphological changes. We conclude that cytokines and growth factors are pivotal regulators of hair growth at least in vitro. IL-1 is suggested as playing an important role during the pathogenesis of AA. Possible mediators of therapeutic contact dermatitis (IL-10, TGFβ1, TNFα, PGE₂) are, at least in vitro, not able to antagonize the IL-1β-triggered hair growth inhibition. Therefore, we infer that these mediators rather ‘modulate’ the immune response in AA.     

Role of fibroblast‐derived growth factors in regulating hyperpigmentation of solar lentigo

Background Cutaneous pigmentation is regulated by a complex melanogenic network in which both keratinocytes and fibroblasts synthesize growth factors and cytokines. Solar lentigo (SL) is characterized by hyperpigmented lesions occurring on photodamaged skin areas. Despite the association of SL to ultraviolet (UV) exposure, the mechanisms underlying the development of these spots are not completely defined. Objectives To analyse the involvement of the fibroblast‐derived growth factors, hepatocyte growth factor (HGF), keratinocyte growth factor (KGF) and stem cell factor (SCF) in SL hyperpigmentation; to evaluate whether the photoageing process occurring in fibroblasts could be responsible for the altered expression of these cytokines; and to investigate a new possible role of KGF in regulating pigmentation through the specific induction of melanogenic cytokines by keratinocytes. Methods We performed immunohistochemical analysis of HGF, KGF and SCF on SL biopsies. We analysed the mRNA expression of these cytokines using an in vitro model of photoageing induced on fibroblasts. Finally, we evaluated the effects of KGF on the expression of melanogenic cytokines at the mRNA and protein levels on keratinocytes. Results We found positive staining for HGF, KGF and SCF in the upper dermis of SL lesions and a significant induction of the three cytokines in photoaged fibroblasts. We also demonstrated the contribution of KGF to pigmentation, showing its ability specifically to modulate the expression of SCF in keratinocytes. Conclusions Fibroblasts may be persistently activated by UV exposure to release melanogenic growth factors; this inducible cytokine network acts both directly and indirectly through keratinocytes and may contribute to the hyperpigmentation of SL.     

Autocrine growth stimulation of human keratinocytes by epidermal cell-derived thymocyte-activating factor: implications for skin aging

Summary The monocyte-derived cytokine interleukin-1 (IL-1) has growth-promoting activity for a variety of cell types, including lymphocytes and fibroblasts. We have previously shown that the epidermal cell-derived thymocyte-activating factor (ETAF) strongly resembles IL-1 in terms of biological, biochemical, and molecular biological properties. Because some lymphokines are known ot alter epidermal cell growth and differentiation and because cultured epidermal keratinocytes are capable of autocrine growth stimulation in vitro through conditioning of their culture medium, we sought to evaluate the effect of ETAF on keratinocyte growth. While there was marked donor variability in the responsiveness of keratinocytes to ETAF, partially purified preparations of ETAF showed substantial ability to stimulate the growth of keratinocytes, particularly those of newborn donors. In addition, in conditioned media there appeared to be activities distinct from ETAF that also promoted keratinocyte growth. Keratinocytes in serum-free medium secreted large amounts of ETAF, as reported previously, and keratinocyte cultures derived from newborn donors secreted significantly more than did those derived from adult donors. These results are consistent with an autocrine growth regulatory role of ETAF in human epidermis and with an age-associated loss of this phenomenon.     

Effecting skin renewal: a multifaceted approach

The skin undergoes intrinsic aging as a normal course, but exposure to ultraviolet (UV) light results in major cumulative damage that manifests as the typical aged photodamaged skin. UV irradiation produces a sequence of changes within the skin layers starting with signaling processes following DNA damage and culminating in nonabsorbed fragmentation of collagen and other proteins within the extracellular matrix. These fragments promote the synthesis of matrix metalloproteinases (MMPs) that further aggravate the damage to the ground substance and add to fragment accumulation. This study describes a unique sequential approach to controlling this photodamage - inhibition of signaling, inhibition of MMPs, proteasome stimulation and mopping up of fragments, stimulation of procollagen and collagen production, and uniform packaging of new collagen fibers. Thus, a multifaceted approach is introduced with presentation of a unique product formulation based on these research principles.     

普萘洛尔及异丙肾上腺素对体外培养婴儿血管瘤内皮细胞增殖和血管内皮生长因子、碱性成纤维细胞生长因子表达的影响

目的：探讨普萘洛尔及异丙肾上腺素在体外对婴儿血管瘤内皮细胞增殖及血管内皮细胞生长因子（VEGF、VEGF-2）、人碱性成纤维细胞生长因子（bFGF）表达的影响。方法将体外培养的2~3代增殖期婴儿血管瘤内皮细胞分为普萘洛尔组和异丙肾上腺素组,其中普萘洛尔组分别换浓度为10、15、20 mg/L 普萘洛尔工作液（10、15、20 mg/L 普萘洛尔组）、空白 EGM-2培养基（空白组）和含0.16% DMSO EGM-2培养基（DMSO组）培养,而异丙肾上腺素组分别换5、10、20 mg/L 异丙肾上腺素工作液（5、10、20 mg/L 异丙肾上腺素组）和空白EGM-2培养基（空白组）培养。采用 MTT 法测定24、48、72、96 h 时各组血管瘤内皮细胞的增殖情况,ELISA 法测定培养24、48 h 时各组细胞培养上清液中 VEGF、VEGF-2、bFGF 的浓度。结果培养24、48 h 时,10、15、20 mg/L 普萘洛尔组血管瘤内皮细胞增殖差异无统计学意义（H 值分别为1.152、2.643,均 P >0.05）;72、96 h 时,20 mg/L 普萘洛尔组血管瘤内皮细胞的增殖明显低于空白组（P <0.05）,而空白组、DMSO 组及10、15 mg/L 普萘洛尔组间差异均无统计学意义。各浓度普萘洛尔、异丙肾上腺素作用24 h 时均对 VEGF、VEGF-2、bFGF 水平有一定影响。48 h 时,15、20 mg/L 普萘洛尔组 VEGF 水平均较空白组显著下降,同时10、15、20 mg/L 普萘洛尔组VEGF-2、bFGF 水平也均较空白组显著下降（P <0.05）;而5、10、20 mg/L 异丙肾上腺素组 VEGF 水平均较空白组显著升高（P <0.05）,20 mg/L 异丙肾上腺素组 VEGF-2、bFGF 水平均显著高于空白组及5、10 mg/L 异丙肾上腺素组（P <0.05）。结论一定浓度普萘洛尔作用于增殖期婴儿血管瘤内皮细胞一定时间后能够抑制细胞生长,而异丙肾上腺素反之,两者对细胞因子表达的影响作用也相反,因此推断普萘洛尔治疗婴儿血管瘤的机制可能与β肾上腺素能受体及其下游信号转导影响相关细胞因子表达相关。     

Cosmeceuticals: current trends and market analysis

The desire to maintain a youthful image combined with an emerging global market with disposable income has driven the development of many new industries. The cosmeceutical industry is based on the development and marketing of products that lie between cosmetics and pharmaceuticals. Today, there are over 400 suppliers and manufacturers of cosmeceutical products, and the industry is estimated to grow by 7.4% by 2012. Although a number of products advertise predictable outcomes, the industry is largely unregulated and any consumers of cosmeceutical products should consult a dermatologist prior to use. This review will provide a snapshot of the current trends of this industry and provide an analysis of this multi-billion dollar market.