Maintenance of an Acidic Skin Surface with a Novel Zinc Lactobionate Emollient Preparation Improves Skin Barrier Function in Patients with Atopic Dermatitis.

INTRODUCTION: The skin of patients with atopic dermatitis (AD) is characterised by elevated pH. As a central homeostatic regulator, an increased pH accelerates desquamation and suppresses lipid processing, resulting in diminished skin barrier function. The aim of this study was to determine whether a novel zinc lactobionate emollient cream can strengthen the skin barrier by lowering skin surface pH. METHODS: A double-blind, forearm-controlled cohort study was undertaken in patients with AD. Participants applied the test cream to one forearm and a vehicle cream to the other (randomised allocation) twice daily for 56 days. Skin surface pH and barrier function (primary outcomes) were assessed at baseline and after 28 days and 56 days of treatment, amongst other tests. RESULTS: A total of 23 adults with AD completed the study. During and after treatment, a sustained difference in skin surface pH was observed between areas treated with the test cream and vehicle (4.50 ± 0.38 versus 5.25 ± 0.54, respectively, p < 0.0001). This was associated with significantly reduced transepidermal water loss (TEWL) on the test cream treated areas compared with control (9.71 ± 2.47 versus 11.20 ± 3.62 g/m2/h, p = 0.0005). Improvements in skin barrier integrity, skin sensitivity to sodium lauryl sulphate, skin hydration, and chymotrypsin-like protease activity were all observed at sites treated with the test cream compared with the control. CONCLUSION: Maintenance of an acidic skin surface pH and delivery of physiologic lipids are beneficial for skin health and may help improve AD control by reducing sensitivity to irritants and allergens.

Different types of emollient cream exhibit diverse physiological effects on the skin barrier in adults with atopic dermatitis.

BACKGROUND: Eczema (atopic dermatitis; AD) is a very common itchy skin condition affecting 1 in 5 children and up to 1 in 10 adults worldwide. The skin of eczema sufferers is prone to redness, irritation and dryness because it does not form an effective barrier, i.e. the ability of the skin to stop irritants, allergens and microorganisms getting into the body. Skin barrier dysfunction is a hallmark of AD. The regular and liberal (600 g/week for an adult) use of emollients is recommended for all patients with eczema), even between episodes of itching and redness, to soften and soothe the skin. In England alone, almost 9 million prescriptions for emollient creams were issued in 2018, at a cost of over £50 million. Despite this widespread use, relatively little is known about how commonly prescribed emollient creams affect the skin's barrier, and thus the role of moisturizers in AD development and progression remains unclear. We set out to compare three different types of emollient cream and a no-treatment control. AIM: To compare the barrier-strengthening properties of a new moisturizer containing urea and glycerol (urea-glycerol cream; UGC), with those of a glycerol-containing moisturizer (glycerol cream; GC), a simple paraffin cream (PC) with no humectant, and a no-treatment control (NTC). METHODS: This was an observer-blinded prospective Phase 2 within-subject multilateral single-centre randomized controlled trial in adults with AD (Clinical Trials #NCT03901144). The intervention involved 4 weeks of treatment, twice daily, with the three products applied to one of four areas on the forearms the (the fourth area was the untreated control, randomized allocation). Skin properties [dryness, transepidermal water loss (TEWL), hydration and natural moisturizing factor (NMF) levels] were assessed before, during and after treatment to see what happened to the skin's barrier. The primary outcome was skin sensitivity to the irritant sodium lauryl sulfate (SLS) after treatment. We performed tests on the skin before and after treatment to see what happened to the skin's barrier. RESULTS: In total, 49 patients were randomized, completed treatment and included in the analysis. UGC significantly reduced the response to SLS as indicated by a reduction in TEWL compared with NTC (-9.0 g/m2 /h; 95% CI -12.56 to -5.49), with PC (-9.0 g/m2 /h; 95% CI -12.60 to -5.44) and with GC -4.2 g/m2 /h; 95% CI 7.76 to -0.63). Skin moisturization improved at sites treated with UGC compared with NTC and PC, and this was accompanied by concordant changes in dryness and NMF levels. Subgroup analysis suggested FLG-dependent enhancement of treatment effects. CONCLUSION: The study showed that not all emollient creams for eczema are equal. The simple paraffin-based emollient, which represents the most widely prescribed type of emollient cream in England, had no effect on the skin's barrier and reduced the skin's NMF. UGC markedly improved the skin's barrier and protected against irritation. GC performed better than PC, but not as well as UGC. UGC strengthened the skin barrier through a mechanism involving increased NMF levels in the skin, and imparted protection from SLS-induced irritation. By helping correct a major pathophysiological process, UGC has the potential to improve the long-term control of AD. The results show that different emollient creams have different effects on our skin, and only certain types have the ability to improve the skin's barrier and protect against irritants that trigger eczema.

Enhancement of stratum corneum lipid structure improves skin barrier function and protects against irritation in adults with dry, eczema-prone skin.

BACKGROUND: The skin of patients with atopic dermatitis is characterized by abnormal stratum corneum lipid levels. Consequently, the lamellar matrices are disrupted and skin barrier function is diminished, increasing skin sensitivity to irritants and allergens. OBJECTIVES: To determine whether a cream containing ceramides, triglycerides and cholesterol in a multivesicular emulsion can reinforce the skin barrier and protect against skin irritation. METHODS: A randomized observer-blind intrapatient-controlled study in 34 adults with dry, eczema-prone skin was conducted. Each participant underwent 4 weeks of treatment with the test cream on one forearm and lower leg and a reference emollient cream on the other. Skin properties were determined before and after treatment. Lipid structure was assessed by Fourier-transform infrared spectroscopy using a novel interface. RESULTS: Skin barrier integrity was greater at sites treated with the test cream [effect size for area under the transepidermal water loss curve -162, 95% confidence interval (CI) -206 to -118]. Skin sensitivity to sodium lauryl sulfate was reduced (-0·5 points visual redness, 97·57% CI -1·00 to -0·25), as was transepidermal water loss (-15·3 g m-2 h-1 , 95% CI -20·3 to -10·4) compared with the reference. Sites treated with the test cream displayed enhanced lipid chain ordering, which was significantly associated with skin barrier integrity (r = 0·61). Compared with the reference, treatment with the test cream increased hydration (8·61 capacitance units, 95% CI 6·61-10·6) and decreased signs of dryness. CONCLUSIONS: The test cream facilitates skin barrier restoration and protects the skin from dryness and irritation. Compared with a commonly prescribed emollient in the UK, the test cream is highly suited to the management of dry, sensitive skin.

An Investigation of the Skin Barrier Restoring Effects of a Cream and Lotion Containing Ceramides in a Multi-vesicular Emulsion in People with Dry, Eczema-Prone, Skin: The RESTORE Study Phase 1.

INTRODUCTION: The replenishment of skin lipids depleted in the dry skin state is a desirable therapeutic target to restore skin moisturization; however, there is limited evidence demonstrating the success of this approach through the use of topical emollients. The purpose of this study was to provide evidence of the benefits of a cream and equivalent lotion containing skin lipids in a multi-vesicular emulsion for the management of dry skin. The hypothesis was that the test cream and test lotion could sustain skin moisturization for longer than traditional emollients by sustainably delivering skin lipids. METHODS: A double-blind intra-subject vehicle-controlled single open-application test on the lower legs in people with dry, atopic dermatitis (atopic eczema)-prone, skin was conducted. There were six treatment sites, three per lower leg in each participant, which were treated with the test cream, the test lotion, three reference creams commonly prescribed in the UK and no treatment as a control. After baseline measurements of skin hydration, 100 µl of the test/reference creams was applied to each of the relevant treatment sites (random site allocation). Following treatment, measurements of skin hydration and scoring of visual dryness was conducted at timed intervals (3, 6, 12 and 24 h post-product application). RESULTS: The test cream and lotion both significantly increased skin hydration and reduced skin dryness for at least 24 h following a single application compared to a no treatment control site. Compared to three reference emollient creams the test cream and test lotion were the only products capable of sustaining clinically meaningful improvements in skin moisturization for 24 h. CONCLUSION: The sustained moisturization imparted by the test products reduces the need for frequent emollient application, often requiring 3-4 applications per day for traditional emollients, and should reduce the high burden of managing dry skin conditions like atopic dermatitis.

Effect of Hypoglycemia on Inflammatory Responses and the Response to Low-Dose Endotoxemia in Humans.

CONTEXT: Hypoglycemia is emerging as a risk for cardiovascular events in diabetes. We hypothesized that hypoglycemia activates the innate immune system, which is known to increase cardiovascular risk. OBJECTIVE: To determine whether hypoglycemia modifies subsequent innate immune system responses. DESIGN AND SETTING: Single-blinded, prospective study of three independent parallel groups. PARTICIPANTS AND INTERVENTIONS: Twenty-four healthy participants underwent either a hyperinsulinemic-hypoglycemic (2.5 mmol/L), euglycemic (6.0 mmol/L), or sham-saline clamp (n = 8 for each group). After 48 hours, all participants received low-dose (0.3 ng/kg) intravenous endotoxin. MAIN OUTCOME MEASURES: We studied in-vivo monocyte mobilization and monocyte-platelet interactions. RESULTS: Hypoglycemia increased total leukocytes (9.98 ± 1.14 × 109/L vs euglycemia 4.38 ± 0.53 × 109/L, P < 0.001; vs sham-saline 4.76 ± 0.36 × 109/L, P < 0.001) (mean ± SEM), mobilized proinflammatory intermediate monocytes (42.20 ± 7.52/µL vs euglycemia 20.66 ± 3.43/µL, P < 0.01; vs sham-saline 26.20 ± 3.86/µL, P < 0.05), and nonclassic monocytes (36.16 ± 4.66/µL vs euglycemia 12.72 ± 2.42/µL, P < 0.001; vs sham-saline 19.05 ± 3.81/µL, P < 0.001). Following hypoglycemia vs euglycemia, platelet aggregation to agonist (area under the curve) increased (73.87 ± 7.30 vs 52.50 ± 4.04, P < 0.05) and formation of monocyte-platelet aggregates increased (96.05 ± 14.51/µL vs 49.32 ± 6.41/µL, P < 0.05). Within monocyte subsets, hypoglycemia increased aggregation of intermediate monocytes (10.51 ± 1.42/µL vs euglycemia 4.19 ± 1.08/µL, P < 0.05; vs sham-saline 3.81± 1.42/µL, P < 0.05) and nonclassic monocytes (9.53 ± 1.08/µL vs euglycemia 2.86 ± 0.72/µL, P < 0.01; vs sham-saline 3.08 ± 1.01/µL, P < 0.05), with platelets compared with controls. Hypoglycemia led to greater leukocyte mobilization in response to subsequent low-dose endotoxin challenge (10.96 ± 0.97 vs euglycemia 8.21 ± 0.85 × 109/L, P < 0.05). CONCLUSIONS: Hypoglycemia mobilizes monocytes, increases platelet reactivity, promotes interaction between platelets and proinflammatory monocytes, and potentiates the subsequent immune response to endotoxin. These changes may contribute to increased cardiovascular risk observed in people with diabetes.

Histamine H4 receptor mediates chemotaxis of human lung mast cells.

The diverse effects of histamine are mediated by discrete histamine receptors. The principal repository of histamine in the body is the mast cell. However, the effects of histamine on mast cells, especially those of human origin, have not been fully elucidated. In this study, the expression of histamine receptors in human lung mast cells was evaluated. Moreover, the effects of histamine receptor engagement on both mediator release and chemotaxis were investigated. Mast cells were isolated and purified from human lung tissue. Histamine receptor expression was determined by RT-PCR and q-PCR. Both methods for the detection of histamine receptors were in accordance and human lung mast cells expressed mRNA for histamine H4 and histamine H1 receptors, variably expressed histamine H2 receptor but did not express histamine H3 receptor. The effects of selective histamine receptor agonists on the release of both pre-formed (histamine) and newly-synthesised (cysteinyl-leukotriene, prostaglandin D2) mediators were investigated. None of the agonists tested had any direct effects on mediator release. None of the agonists modulated release stimulated by anti-IgE. Further studies showed that histamine induced migration of mast cells. Chemotaxis appeared to be mediated by the histamine H4 receptor since JNJ28610244 (H4 agonist) was chemotactic for mast cells whereas 2-(2-pyridyl) ethylamine (H1 agonist) was not. Furthermore, the selective histamine H4 receptor antagonist, JNJ7777120, effectively reversed the chemotaxis of mast cells induced by JNJ28610244. Overall, these experiments identify the histamine H4 receptor as chemotactic for human lung mast cells. This mechanism might influence mast cell accumulation in the lung.

Prostaglandin D2 generation from human lung mast cells is catalysed exclusively by cyclooxygenase-1.

Mast cells are an exceptionally rich source of prostaglandin D2 (PGD2). PGD2 is pro-inflammatory and can cause bronchoconstriction. The enzyme cyclooxygenase (COX) is central to the generation of prostanoids such as PGD2. Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit COX. COX exists as two isoforms, COX-1 and COX-2. The principal aim of this study was to establish whether COX-1 and/or COX-2 mediates PGD2 generation from human lung mast cells. Mast cells were isolated from human lung tissue and purified by flotation over Percoll and immunomagnetic bead separations. The cells were activated with anti-IgE or Stem Cell Factor (SCF). The generation of PGD2 was determined by ELISA. The effects of NSAIDs (aspirin, ibuprofen, diclofenac, naproxen, indomethacin), COX-1 selective (FR122047), and COX-2 selective (celecoxib) inhibitors on PGD2 generation were determined. The expression of COX-1 and COX-2 in mast cells was determined by Western blotting. All the NSAIDs tested abrogated stimulated PGD2 generation from mast cells except aspirin which was only weakly effective. FR122047 was an effective inhibitor of PGD2 generation (EC50 ~25nM) from mast cells whereas celecoxib was ineffective. Immunoblotting indicated that COX-1 was strongly expressed in all mast cell preparations while COX-2 expression was weak. No induction of COX-2 was observed following activation of mast cells. These findings indicate that COX-1 is the principal isoform involved in generating PGD2 from human lung mast cells. These studies provide insight into the potential behaviour of NSAIDs in the context of respiratory diseases.

The anti-inflammatory effects of PGE2 on human lung macrophages are mediated by the EP4 receptor.

BACKGROUND AND PURPOSE: PGE2 inhibits cytokine generation from human lung macrophages. However, the EP receptor that mediates this beneficial anti-inflammatory effect of PGE2 has not been defined. The aim of this study was to identify the EP receptor by which PGE2 inhibits cytokine generation from human lung macrophages. This was determined by using recently developed EP receptor ligands. EXPERIMENTAL APPROACH: The effects of PGE2 and EP-selective agonists on LPS-induced generation of TNF-α and IL-6 from macrophages were evaluated. The effects of EP2 -selective (PF-04852946, PF-04418948) and EP4 -selective (L-161,982, CJ-042794) receptor antagonists on PGE2 responses were studied. The expression of EP receptor subtypes by human lung macrophages was determined by RT-PCR. KEY RESULTS: PGE2 inhibited LPS-induced and Streptococcus pneumoniae-induced cytokine generation from human lung macrophages. Analysis of mRNA levels indicated that macrophages expressed EP2 and EP4 receptors. L-902,688 (EP4 receptor-selective agonist) was considerably more potent than butaprost (EP2 receptor-selective agonist) as an inhibitor of TNF-α generation from macrophages. EP2 receptor-selective antagonists had marginal effects on the PGE2 inhibition of TNF-α generation, whereas EP4 receptor-selective antagonists caused rightward shifts in the PGE2 concentration-response curves. CONCLUSIONS AND IMPLICATIONS: These studies demonstrate that the EP4 receptor is the principal receptor that mediates the anti-inflammatory effects of PGE2 on human lung macrophages. This suggests that EP4 receptor agonists could be effective anti-inflammatory agents in human lung disease.

Influence of beta2-adrenoceptor gene polymorphisms on beta2-adrenoceptor expression in human lung.

BACKGROUND: The aim of the present study was to establish whether polymorphisms, especially those within the promoter region, of the beta(2)-adrenoceptor gene (ADRB2) influence beta(2)-adrenoceptor expression in human lung. METHODS: The density of beta-adrenoceptors in human lung tissue (n=88) was determined by saturation binding using the radioligand, iodinated cyanopindolol. Discrimination of beta(1)- and beta(2)-adrenoceptors was determined using the highly selective beta(1)-adrenoceptor antagonist, CGP20712A. Genotype was determined at 5 positions of ADRB2 previously reported as polymorphic. Potential influences of single nucleotide polymorphisms (SNPs) within the promoter region (-367, -47) and coding block (46, 79, 491) of ADRB2 on beta(2)-adrenoceptor expression were investigated. RESULTS: The density of beta(2)-adrenoceptors was variable among the 88 lung preparations studied ranging from 17 to 177fmol/mg protein (mean+/-S.E.M., 72+/-4fmol/mg protein). There was no influence of genotype on beta(2)-adrenoceptor expression for any of the polymorphisms studied except at position 491. The polymorphism at position 491C>T, leading to a change from thr to ile at amino acid 164, is uncommon. Preparations genotyped as heterozygous (126+/-15fmol/mg protein; n=5) expressed significantly (P=0.0005) higher levels of beta(2)-adrenoceptor than those that were homozygous (69+/-4fmol/mg protein; n=83). CONCLUSION: With the exception of position 491, these data indicate that polymorphisms of ADRB2 do not influence beta(2)-adrenoceptor expression in human lung.

Prostaglandin E2 activates EP2 receptors to inhibit human lung mast cell degranulation.

The prostanoid, PGE2, is known to inhibit human lung mast cell activity. The aim of the present study was to characterize the EP receptor that mediates this effect. PGE2 (pEC(50), 5.8+/-0.1) inhibited the IgE-mediated release of histamine from mast cells in a concentration-dependent manner. Alternative EP receptor agonists were studied. The EP2-selective agonist, butaprost (pEC50, 5.2+/-0.2), was an effective inhibitor of mediator release whereas the EP1/EP3 receptor agonist, sulprostone, and the EP1-selective agonist, 17-phenyl-trinor-PGE2, were ineffective. The DP agonist PGD2, the FP agonist PGF(2alpha), the IP agonist iloprost and the TP agonist U-46619 were ineffective inhibitors of IgE-mediated histamine release from mast cells. PGE2 induced a concentration-dependent increase in intracellular cAMP levels in mast cells. The effects of the EP1/EP2 receptor antagonist, AH6809, and the EP4 receptor antagonist, AH23848, on the PGE2-mediated inhibition of histamine release were determined. AH6809 (pK(B), 5.6+/-0.1) caused a modest rightward shift in the PGE2 concentration-response curve, whereas AH23848 was ineffective. Long-term (24 h) incubation of mast cells with either PGE2 or butaprost (EP2 agonist), but not sulprostone (EP1/EP3 agonist), caused a significant reduction in the subsequent ability of PGE2 to inhibit histamine release. Collectively, these data suggest that PGE2 mediates effects on human lung mast cells by interacting with EP2 receptors.

Mast cell beta2-adrenoceptors.

The human lung mast cell is a crucial effector cell in the mediation of asthma. Activation of mast cells by allergens, and other insults, leads to the elaboration of a wide variety of autacoids that cause bronchoconstriction and promote inflammation. Of the drugs that are used to treat asthma, only bronchodilator beta2-adrenoceptor agonists are effective at inhibiting the elaboration of mediators from mast cells. Both short- and long-acting beta2-adrenoceptor agonists are effective inhibitors of mast cells although there are differences in the degree of inhibitory activity attained with a given agonist. Human lung mast cells express a homogeneous population of beta2-adrenoceptors. However, the density of beta2-adrenoceptors differs from preparation to preparation and this may influence the extent to which agonists stabilise mast cell activity. Tolerance to the mast cell-stabilising activity of beta2-adrenoceptor agonists can be readily demonstrated. As a generalisation, agonists that are more effective inhibitors of mediator release also induce greater levels of tolerance although weaker agonists induce greater levels of tolerance than might be expected. However, the extent of tolerance does not correlate with the degree of beta2-adrenoceptor loss. The inhibitory activity of agonists and the extent of tolerance observed may be influenced by genetic polymorphisms in the gene for the beta2-adrenoceptor.

Influence of the thr164ile polymorphism in the beta2-adrenoceptor on the effects of beta-adrenoceptor agonists on human lung mast cells.

We have examined the influence of the thr164ile polymorphism in the beta(2)-adrenoceptor on the ability of the beta-adrenoceptor agonists, isoprenaline and salbutamol, to stabilise human lung mast cells. A total of 124 mast cell preparations were genotyped and, of these, 120 were found to be homozygous (thr164thr) at position 164 of the beta(2)-adrenoceptor and 4 were heterozygous (thr164ile). None of the preparations was homozygous for ile at position 164. In these preparations, the effects of isoprenaline and salbutamol on the IgE-mediated release of histamine from mast cells were studied. Both isoprenaline and salbutamol inhibited histamine release in a concentration-dependent manner. Average inhibitory potencies for both agonists, as assessed by pD(2) values, were higher in homozygous than in heterozygous preparations. For isoprenaline, this difference was statistically significant (P < 0.005), whereas for salbutamol, it was not (P = 0.21). These data suggest that the thr164ile polymorphism in the beta(2)-adrenoceptor may influence the extent to which certain beta-adrenoceptor agonists inhibit the responses of mast cells.