Muhammad Nadeem Aslam

IL-1RL2 and Its Ligands Contribute to the Cytokine Network in Psoriasis

Psoriasis is a common immune-mediated disease in European populations; it is characterized by inflammation and altered epidermal differentiation leading to redness and scaling. T cells are thought to be the main driver, but there is also evidence for an epidermal contribution. In this article, we show that treatment of mouse skin overexpressing the IL-1 family member, IL-1F6, with phorbol ester leads to an inflammatory condition with macroscopic and histological similarities to human psoriasis. Inflammatory cytokines thought to be important in psoriasis, such as TNF-α, IL-17A, and IL-23, are upregulated in the mouse skin. These cytokines are induced by and can induce IL-1F6 and related IL-1 family cytokines. Inhibition of TNF or IL-23 inhibits the increased epidermal thickness, inflammation, and cytokine production. Blockade of IL-1F6 receptor also resolves the inflammatory changes in human psoriatic lesional skin transplanted onto immunodeficient mice. These data suggest a role for IL-1F family members in psoriasis.

A combination of curcumin and ginger extract improves abrasion wound healing in corticosteroid‐impaired hairless rat skin

Hairless rats were topically treated with a combination of 10% curcumin and 3% ginger extract (or with each agent alone) for a 21‐day period. Following this, the rats were treated topically with Temovate (corticosteroid) for an additional 15 days. At the end of the treatment period, superficial abrasion wounds were induced in the treated skin. Abrasion wounds healed more slowly in the skin of Temovate‐treated rats than in skin of control animals. Healing was more rapid in skin of rats that had been pretreated with either curcumin or ginger extract alone or with the combination of curcumin–ginger extract (along with Temovate) than in the skin of rats treated with Temovate and vehicle alone. Skin samples were obtained at the time of wound closure. Collagen production was increased and matrix metalloproteinase‐9 production was decreased in the recently healed skin from rats treated with the botanical preparation relative to rats treated with Temovate plus vehicle. In none of the rats was there any indication of skin irritation during the treatment phase or during wounding and repair. Taken together, these data suggest that a combination of curcumin and ginger extract might provide a novel approach to improving structure and function in skin and, concomitantly, reducing formation of nonhealing wounds in “at‐risk” skin.

Fibroblast Response to Gadolinium: Role for Platelet-Derived Growth Factor Receptor

Objective:The purpose of this study was to assess the effects of gadolinium (Gd3+), provided as gadolinium chloride, on fibroblast function. Materials and Methods:Human dermal fibroblasts in monolayer culture and intact skin in organ culture were exposed to the lanthanide metal (1–20 &mgr;m). Results:Increased proliferation was observed, in association with upregulation of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinases-1, without an apparent increase in production of type I procollagen. A platelet-derived growth factor (PDGF) receptor-blocking antibody inhibited fibroblast proliferation in response to Gd3+ as did inhibitors of signaling pathways—that is, mitogen-activated protein kinase and phosphatidylinositol-3 kinase pathways—that are activated by PDGF. Conclusion:The responses to gadolinium chloride are similar to responses previously seen with chelated Gd3+ in clinically used magnetic resonance imaging contrast agents. Fibroblast responses appear to reflect Gd3+-induced PDGF receptor activation and downstream signaling. Increased dermal fibroblast proliferation in conjunction with effects on matrix metalloproteinase-1 and tissue inhibitor of metalloproteinases-1 could contribute to the fibroplastic/fibrotic changes seen in the lesional skin of individuals with nephrogenic systemic fibrosis.

A Mineral-Rich Red Algae Extract Inhibits Polyp Formation and Inflammation in the Gastrointestinal Tract of Mice on a High-Fat Diet

The purpose of this study was to determine whether a mineral-rich extract derived from the red marine algae Lithothamnion calcareum could be used as a dietary supplement for chemoprevention against colon polyp formation. A total of 60 C57bl/6 mice were divided into 3 groups based on diet. One group received a low-fat, rodent chow diet (AIN76A). The second group received a high-fat “Western-style” diet (HFWD). The third group was fed the same HFWD with the mineral-rich extract included as a dietary supplement. Mice were maintained on the respective diets for 15 months. Autopsies were performed at the time of death or at the completion of the study. To summarize, the cumulative mortality rate was higher in mice on the HFWD during the 15-month period (55%) than in mice from the low-fat diet or the extract-supplemented high-fat diet groups (20% and 30%, respectively; P < .05 with respect to both). Autopsies revealed colon polyps in 20% of the animals on the HFWD and none in animals of the other 2 groups (P < .05). In addition to the grossly visible polyps, areas of hyperplasia in the colonic mucosa and inflammatory foci throughout the gastrointestinal tract were observed histologically in animals on the high-fat diet. Both were significantly reduced in animals on the low-fat diet and animals on the extract-supplemented HFWD.These data suggest that the mineral-rich algae extract may provide a novel approach to chemoprevention in the colon.

Regulation of collagen turnover in human skin fibroblasts exposed to a gadolinium-based contrast agent.

Objective:Nephrogenic systemic fibrosis is a clinical syndrome linked with exposure in renal failure patients to gadolinium-based contrast agents (GBCAs) during magnetic resonance imaging. Recently, we demonstrated that GBCA exposure led to increased matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinases-1 (TIMP-1) levels in human skin fibroblasts. The goals of the present work were to assess the relationship between altered MMP-1/TIMP-1 expression and collagen production/deposition, and the intracellular signaling events that lead from GBCA stimulation to altered MMP-1 and TIMP-1 production. Materials and Methods:Human dermal fibroblasts were treated with one of the currently used GBCAs (Omniscan). Proliferation was quantified as were levels of MMP-1, TIMP-1, procollagen type I, and collagen type I. Signaling events were concomitantly assessed, and signaling inhibitors were used. Results:Fibroblasts exposed to Omniscan had increases in both MMP-1 and TIMP-1 levels. Omniscan treatment interfered with collagen turnover, leading to increased type I collagen deposition without an increase in type I procollagen production. U0126, an inhibitor of mitogen-activated protein kinase signaling, and LY294002, a phosphatidylinositol-3 kinase inhibitor, reduced MMP-1 levels. U0126 also reduced TIMP-1 levels, but LY294002 increased TIMP-1. Conclusion:These data provide evidence for complex regulation of collagen deposition in Omniscan-treated skin. They suggest that the major effect of Omniscan exposure is on an enzyme/inhibitor system that regulates collagen breakdown rather than on collagen production, per se.

Growth-inhibitory effects of a mineralized extract from the red marine algae, Lithothamnion calcareum, on Ca2+-sensitive and Ca2+-resistant human colon carcinoma cells

Proliferation and differentiation were assessed in a series of human colon carcinoma cell lines in response to a mineral-rich extract derived from the red marine algae, Lithothamnion calcareum. The extract contains 12% Ca2+, 1% Mg2+, and detectable amounts of 72 trace elements, but essentially no organic material. The red algae extract was as effective as inorganic Ca2+ alone in suppressing growth and inducing differentiation of colon carcinoma cells that are responsive to a physiological level of extracellular Ca2+ (1.4mM). However, with cells that are resistant to Ca2+ alone, the extract was still able to reduce proliferation and stimulate differentiation.

Separation of retinoid-induced epidermal and dermal thickening from skin irritation

The ability of the synthetic retinoid MDI-301, in which the carboxylic acid of 9-cis-retinoic acid (9-cis-RA) is replaced with an ester linkage, to induce epidermal and dermal thickening and skin irritation (erythema and flaking) in hairless (rhino) mice following its topical application was investigated in comparison with that of 14-all-trans-retinoic acid (14-all-trans-RA) and 9-cis-RA. MDI-301 induced epidermal proliferation leading to a thickened epidermis. Treated animals also demonstrated a prominent band of organized connective tissue immediately below the epidermis. In its ability to induce epidermal thickening, MDI-301 was quantitatively similar to 14-all-trans-RA and 9-cis-RA. However, unlike 14-all-trans-RA and 9-cis-RA, which produced skin irritation associated with a perivascular influx of mononuclear leukocytes into the dermis, there was no evidence of irritation with MDI-301 and little leukocyte infiltration. Intraperitoneal injection of either 14-all-trans-RA or MDI-301 also resulted in epidermal and dermal thickening. Irritation of skin was not observed in these animals but splenomegaly was prominent in animals treated with either agent.

7-Chloro-5-(4-hydroxyphenyl)-1-methyl-3-(naphthalen-2-ylmethyl)-4,5-dihydro-1H-benzo[b][1,4]diazepin-2(3H)-one (Bz-423), a Benzodiazepine, Suppresses Keratinocyte Proliferation and Has Antipsoriatic Activity in the Human Skin-Severe, Combined Immunodeficient Mouse Transplant Model

7-Chloro-5-(4-hydroxyphenyl)-1-methyl-3-(naphthalen-2-ylmethyl)-4,5-dihydro-1H-benzo[b][1,4]diazepin-2(3H)-one (Bz-423) is a benzodiazepine that has cytotoxic and cytostatic activity against a variety of cells in vivo and in vitro. In the present study, we demonstrate that Bz-423 (formulated for topical delivery) reduces epidermal hyperplasia in human psoriatic skin after transplantation to severe, combined immunodeficient (scid) mice. Bz-423 also suppresses the hyperplasia that develops in nonpsoriatic human skin as a consequence of transplantation to scid mice. Proliferation of human epidermal keratinocytes in monolayer culture was suppressed by Bz-423 at concentrations of 0.5 to 2.0 μM (noncytotoxic concentrations). Keratinocyte growth inhibition was accompanied by increased oxidant generation in Bz-423-treated cells, and treatment with vitamin E along with Bz-423 reversed the growth inhibition. Growth inhibition was accompanied by a redistribution of β-catenin from a cytoplasmic pool to the cell membrane and by reduced levels of c-myc and cyclin D1 (two molecules associated with Wnt pathway signaling). Several analogs of Bz-423 were examined for antiproliferative activity against human epidermal keratinocytes and human dermal fibroblasts in monolayer culture. Each of the analogs tested suppressed growth of both cell types, but in all cases, keratinocytes were more sensitive than fibroblasts. Two of the compounds were found to suppress epidermal hyperplasia induced with all-trans retinoic acid in organ cultures of human skin. Taken together, these data show that Bz-423 and certain analogs produce biological responses in skin cells in vitro and in vivo that are consistent with therapeutic goals for treating psoriasis or epidermal hyperplasia resulting from other causes.

Human colonic crypts in culture: segregation of immunochemical markers in normal versus adenoma-derived

In order to advance a culture model of human colonic neoplasia, we developed methods for the isolation and in vitro maintenance of intact colonic crypts from normal human colon tissue and adenomas. Crypts were maintained in three-dimensional Matrigel culture with a simple, serum-free, low Ca2+ (0.15 mM) medium. Intact colonic crypts from normal human mucosa were viably maintained for 3–5 days with preservation of the in situ crypt-like architecture, presenting a distinct base and apex. Abnormal structures from adenoma tissue could be maintained through multiple passages (up to months), with expanding buds/tubules. Immunohistochemical markers for intestinal stem cells (Lgr5), growth (Ki67), differentiation (E-cadherin, cytokeratin 20 (CK20) and mucin 2 (MUC2)) and epithelial turnover (Bax, cleaved Caspase-3), paralleled the changes in function. The epithelial cells in normal crypts followed the physiological sequence of progression from proliferation to differentiation to dissolution in a spatially and temporally appropriate manner. Lgr5 expression was seen in a few basal cells of freshly isolated crypts, but was not detected after 1–3 days in culture. After 24 h in culture, crypts from normal colonic tissue continued to show strong Ki67 and MUC2 expression at the crypt base, with a gradual decrease over time such that by days 3–4 Ki67 was not expressed. The differentiation marker CK20 increased over the same period, eventually becoming intense throughout the whole crypt. In adenoma-derived structures, expression of markers for all stages of progression persisted for the entire time in culture. Lgr5 showed expression in a few select cells after months in culture. Ki67 and MUC2 were largely associated with the proliferative budding regions while CK20 was localized to the parent structure. This ex vivo culture model of normal and adenomatous crypts provides a readily accessible tool to help understand the growth and differentiation process in human colonic epithelium.

Collagenolytic activity is suppressed in organ-cultured human skin exposed to a gadolinium-based MRI contrast agent.

Objective:Human skin produces increased amounts of matrix metalloproteinase-1 (MMP-1) when exposed in organ culture to Omniscan, one of the gadolinium-based MRI contrast agents (GBCA). MMP-1, by virtue of its ability to degrade structural collagen, contributes to collagen turnover in the skin. The objective of the present study was to determine whether collagenolytic activity was concomitantly up-regulated with increased enzyme. Materials and Methods:Skin biopsies from normal volunteers were exposed in organ culture to Omniscan. Organ culture fluids obtained from control and treated skin were examined for ability to degrade type I collagen. The same culture fluids were examined for levels of MMP-1, tissue inhibitor of metalloproteinases-1 (TIMP-1), and complexes of MMP-1 and TIMP-1. Results:Although MMP-1 was increased in culture fluid from Omniscan-treated skin, there was no increase in collagenolytic activity. In fact, collagenolytic activity declined. Increased production of TIMP-1 was also observed in Omniscan-treated skin, and the absolute amount of TIMP-1 was greater than the amount of MMP-1. Virtually all of the MMP-1 was present in MMP-1–TIMP-1 complexes, but the majority of TIMP-1 was not associated with MMP-1. When human dermal fibroblasts were exposed to TIMP-1 (up to 250 ng/mL), no increase in proliferation was observed, but an increase in collagen deposition into the cell layer was seen. Conclusion:Gadolinium-based MRI contrast agent exposure has recently been linked to a fibrotic skin condition in patients with impaired kidney function. The mechanism is unknown. The increase in TIMP-1 production and concomitant reduction in collagenolytic activity demonstrated here could result in decreased collagen turnover and increased deposition of collagen in lesional skin.