Topical valrubicin application reduces skin inflammation in murine models.

BACKGROUND: Valrubicin is a cytostatic anthracycline analogue, lacking toxicity by skin and tissue contact, and represents a new drug with potential for topical treatment of psoriasis and nonmelanoma skin cancer (NMSC); the beneficial effects have been partly explained by its antiproliferative and proapoptotic characteristics. OBJECTIVES: To assess the effect of valrubicin on skin inflammation as inflammation also plays a key role in psoriasis and NMSC. METHODS: The effect of topical valrubicin treatment on skin inflammation in vivo was addressed in skin inflammation mouse models, where 12-O-tetradecanoylphorbol 13-acetate was used to induce irritant contact dermatitis. An acute and a chronic model were included, to investigate the effect of valrubicin in short-term inflammation and in more persistent inflammation. Inflammation-associated ear oedema was evaluated by measuring ear thickness, infiltration of neutrophil cells, and expression of inflammatory cytokines, interleukin (IL)-1ß and IL-6. RESULTS: Topical valrubicin treatment effectively reduced the inflammatory response in the acute and the chronic models. CONCLUSIONS: The present data document an anti-inflammatory effect of valrubicin, and may suggest an interesting new role for valrubicin in other debilitating skin diseases in which inflammation is a significant factor.

Stereological estimation of epidermal volumes and dermo-epidermal surface area in normal skin.

Quantitative morphological studies of the healthy epidermis are essential in providing a range of parameter estimates that can be considered within the range of normality. Stereology is a set of statistical tools that provides potentially unbiased and precise estimates of 3-dimensional tissue characteristics from 2-dimensional sections. We set out to establish reference values for the volume of the viable epidermis contained within a four-millimetre punch biopsy (V(epi)), the volume of the stratum corneum (V(SC)) and the surface area of the dermo-epidermal junction(A(DEJ)) in 4 predetermined body regions by use of stereology. Four-millimetre punch biopsies were taken from 20 freshly diseased corpses, fixed in formalin and embedded in paraffin. V(epi), V(SC) and A(DEJ) were established stereologically for all 4 body locations followed by pairwise comparison of means after Bonferroni correction. V(epi) was significantly larger in the sole compared to all other body locations (p < 0.01). Furthermore, linear regression analysis showed a strong linear relationship between V(epi) and V(SC) in the sole (r = 0.70). Our results suggest that the viable layers of the epidermis might also serve a mechanical function, either directly or by providing the stratum corneum with keratinocytes to support the hyperkeratosis in the weight-bearing parts of the skin.

Hidradenitis suppurativa: a disease of the absent sebaceous gland? Sebaceous gland number and volume are significantly reduced in uninvolved hair follicles from patients with hidradenitis suppurativa.

BACKGROUND: The pathogenesis of hidradenitis suppurativa (HS) is not clearly understood. The nomenclature suggests an important role for the apocrine glands but recent evidence implicates the pilosebaceous unit as a more likely candidate to play a central role in the pathogenesis. OBJECTIVES: Our aim was to estimate the volume of the follicular epithelium, the follicular lumen and the sebaceous glands of patients with HS and healthy controls by means of stereology. METHODS: Four-millimetre punch biopsies were taken from 21 patients with HS and nine healthy controls, fixed in formalin, embedded in paraffin and stained with haematoxylin and eosin prior to volume estimation using the Cavalieri principle. RESULTS: Sebaceous gland tissue could be visualized in only 10 of 15 suitable hair follicle biopsies from patients with HS but was present in all biopsies from healthy controls (P = 0·05) and the mean sebaceous gland volume per follicle was one-seventh of that of healthy controls (P = 0·03). There was no significant difference between patients with HS and healthy controls with regard to follicular epithelium and follicle lumen volume. CONCLUSIONS: Our results suggest that the absence or reduced volume of the sebaceous gland may play a role in the pathogenesis of HS. The presence of fibrosis suggests that sebaceous glands are obliterated early in the pathogenesis of HS.

Interleukin-20 plays a critical role in maintenance and development of psoriasis in the human xenograft transplantation model.

BACKGROUND: Interleukin (IL)-20 is a recently discovered cytokine displaying increased levels in psoriatic lesions. Interestingly, IL-20 levels decrease with antipsoriatic treatment, correlating with clinical improvement. However, the role of IL-20 in the aetiology of psoriasis is unknown. OBJECTIVES: In this study, we investigate the effects both of blocking IL-20 signalling in psoriatic plaques and of adding IL-20 to nonlesional psoriasis skin. METHODS: We employed the human skin xenograft transplantation model in which psoriatic plaques and nonlesional keratome skin biopsies obtained from donors with moderate to severe plaque psoriasis were transplanted on to immuno-deficient mice. The transplanted mice were treated with anti-IL-20 antibodies or recombinant human IL-20. RESULTS: We demonstrate that blocking IL-20 signalling with anti-IL-20 antibodies induces psoriasis resolution and inhibits psoriasis induction. We also demonstrate that continuous IL-20 infusion, together with injection of additional nonactivated leucocytes, promotes induction of psoriasis in nonlesional skin from patients with psoriasis. CONCLUSIONS: The results suggest that IL-20 plays a critical role in the induction and maintenance of psoriasis, and IL-20 is suggested as a new possible specific target in psoriasis treatment.

Tissue distribution and engraftment of human mesenchymal stem cells immortalized by human telomerase reverse transcriptase gene.

Engraftment of mesenchymal stem cells (MSC) in peripheral tissues for replenishing of local stem cell function has been proposed as a therapeutic approach to degenerative diseases. We have previously reported the development of an immortalized human telomerase reverse transcriptase transduced MSC line (hMSC-TERT). In the present study, we co-transduced hMSC-TERT with enhanced green fluorescent protein gene, and studied tissue distribution, engraftment, and cell survival after intracardiac and intravenous injections in immunodeficient mice. The pattern of organ distribution suggested that infused cells were efficiently arrested in microvasculature during first-pass, but only for a fraction of the infused cells was arrest followed by vascular emigration and tissue engraftment. Few engrafted cells in lungs, heart, and kidney glomeruli remained after 4 weeks. These observations are consistent with several reports on limited systemic transplantability of primary MSC. HMSC-TERT may constitute a valuable tool for mechanistic studies on how to control MSC homing and engraftment.

Aged human bone marrow stromal cells maintaining bone forming capacity in vivo evaluated using an improved method of visualization.

Age-related decreased osteoblast function is a well-known but poorly understood phenomenon. Previous studies that examined the effects of donor age on osteoblast functions employed in vitro assays that may not reflect the true osteoblast capacity for bone formation. Thus, we have developed an in vivo assay for quantifying the bone forming capacity (BFC) and we compared the BFC of osteoblastic cells obtained from young and old donors. Osteoblasts were obtained from human bone marrow stromal cell cultures and implanted subcutaneously in immuno-deficient mice (NOD/LtSz- Prkdc(scid)). After 8 weeks, the implants were removed and embedded un-decalcified in methyl methacrylate (MMA). Sections were stained histochemically with Goldner's Trichrome stain and immuno-histochemically using human-specific antibodies against known osteogenic markers. Implanted human marrow stromal cells (hMSC) were able to form bone in vivo. The donor origin of bone was verified using several human-specific antibodies. Dose-response experiments demonstrated that 5 x 10(5) hMSC per implant gave the maximal bone formation after 8 weeks. No difference in BFC was observed between cells obtained from young (24-30 years old; mean age 27 +/- 2 years, n = 5) and old (71-81 years old; mean age 75 +/- 4 years, n = 5) donors. Our study demonstrates that the capacity of hMSC to form bone in vivo is maintained with age and suggests that the observed senescence-associated decrease in bone formation is due to a defect in the bone microenvironment, the nature of which remains to be determined.

Maintenance of osteoblastic and adipocytic differentiation potential with age and osteoporosis in human marrow stromal cell cultures.

Osteoblasts and adipocytes share a common precursor cell in the bone marrow stroma, termed marrow stromal cell (MSC). As the volume of bone adipose tissue increases in vivo with age, we hypothesized that decreased bone formation observed during aging and in patients with osteoporosis (OP) is the result of enhanced adipogenesis and decreased osteoblastogenesis from the MSCs. Thus, cultures of MSCs were established from young donors (age 18-42, n = 34), elderly healthy donors (age 66-78, n = 20), and patients with OP (age 58-76, n = 15). Cells were cultured for 2 weeks in an adipogenic medium (containing 15% horse serum and 100 nM dexamethasone), osteogenic medium (containing 10% fetal calf serum [FCS] and 10 nM calcitriol), or control medium (10% FCS). The MSCs were identified by their abilities to form colonies. Total number of colonies, osteoblastic colonies stained positive for alkaline phosphatase (AP+), and adipocytic colonies containing adipocytes (Ad+) were quantitated. In addition, steady state mRNA levels of gene markers of adipocytic and osteoblastic phenotypes were determined using reverse-transcriptase polymerase chain reaction (RT-PCR). The adipogenic and osteogenic media induced cell differentiation and the expression of adipocytic and osteoblastic lineage-specific markers, respectively. We found no age-related changes in the osteoblastic or adipocytic colony formation or the steady state levels of mRNA of the adipogenic or osteogenic gene markers. Cells obtained from patients with OP showed a pattern of differentiation similar to those of age-matched controls. In conclusion, MSCs maintain their differentiation potential during aging and in patients with OP. Other mechanisms responsible for age-related decrease in bone formation need to be determined.

Adipocyte tissue volume in bone marrow is increased with aging and in patients with osteoporosis.

Aging of the human skeleton is characterized by decreased bone formation and bone mass and these changes are more pronounced in patients with osteoporosis. As osteoblasts and adipocytes share a common precursor cell in the bone marrow, we hypothesized that decreased bone formation observed during aging and in patients with osteoporosis is the result of enhanced adipognesis versus osteoblastogenesis from precursor cells in the bone marrow. Thus, we examined iliac crest bone biopsies obtained from 53 healthy normal individuals (age 30-100) and 26 patients with osteoporosis (age 52-92). Adipose tissue volume fraction (AV), hematopoietic tissue volume fraction (HV) and trabecular bone volume fraction (BV) were quantitated as a percentage of total tissue volume fraction (TV) (calculated as BV + AV + HV) using the point-counting method. We found an age-related increase in AV/TV (r = 0.53, P < 0.001, n = 53) and an age-related decline in BV/TV (r = -0.46, P < 0.001, n = 53) as well as in the HV/TV (r -0.318, P < 0.05, n = 53). There was an age-related inverse correlation between BV/TV and AV/TV (r = -0.58, P < 0.001). No significant correlation between the AV/TV and the body mass index (r = 0.06, n.s., n = 52) was detectable. Compared with age-matched controls, patients with osteoporosis exhibited an increased AV/TV (P < 0.05) and decreased BV/TV (P < 0.05) but no statistically significant difference in HV/TV. Our data support the hypothesis that with aging and in osteoporosis an enhanced adipogenesis is observed in the bone marrow and that these changes are inversely correlated to decreased trabecular bone volume. The cellular and molecular mechanisms mediating these changes remain to be determined.

[Mesenchymal stem cells. Potential use in cell and gene therapy of bone loss caused by aging and osteoporosis]. / Mesenkymale stamceller. Potentielle anvendelser i celle- og genterapi ved knogletab forårsaget af aldring og osteoporose.

Mesenchymal stem cells (MSC) originate from bone marrow and give rise to various cell types, including osteoblasts, chondrocytes, adipocytes, and myocytes. Lineage-specific differentiation is dependent on activation of specific transcription factors. MSCs play an important role in bone modelling and remodelling where they give rise to the osteoblasts necessary for bone formation. Human studies have shown that the number and differentiation potential of MSC are unchanged with age and osteoporosis. In recent years, there has been an increasing interest in the clinical use of MSCs. These have been used to augment healing of bone fractures. Some animal studies have shown that MSCs infused intravenously target bone and possibly participate in bone formation. These studies represent the beginning of a new era, where transplantation with autologous MSCs or genetically-modified MSCs expanded in vitro is a potential treatment strategy to augment bone formation in patients with diverse metabolic and genetic bone diseases, including osteoporosis.

Number and proliferative capacity of osteogenic stem cells are maintained during aging and in patients with osteoporosis.

Decreased bone formation is an important pathophysiological mechanism responsible for bone loss associated with aging and osteoporosis. Osteoblasts (OBs), originate from mesenchymal stem cells (MSCs) that are present in the bone marrow and form colonies (termed colony-forming units-fibroblastic [CFU-Fs]) when cultured in vitro. To examine the effect of aging and osteoporosis on the MSC population, we quantified the number of MSCs and their proliferative capacity in vitro. Fifty-one individuals were studied: 38 normal volunteers (23 young individuals [age, 22-44 years] and 15 old individuals [age, 66-74 years]) and 13 patients with osteoporosis (age, 58-83 years). Bone marrow was aspirated from iliac crest; mononuclear cells were enriched in MSCs by magnetic activated cell sorting (MACS) using STRO-1 antibody. Total CFU-F number, size distribution, cell density per CFU-F, number of alkaline phosphatase positive (ALP+) CFU-Fs, and the total ALP+ cells were determined. In addition, matrix mineralization as estimated by alizarin red S (AR-S) staining was quantified. No significant difference in colony-forming efficiency between young individuals (mean +/- SEM; 87 +/- 12 CFU-Fs/culture), old individuals (99 +/- 19 CFU-Fs/culture), and patients with osteoporosis (129 +/- 13 CFU-Fs/culture; p = 0.20) was found. Average CFU-F size and cell density per colony were similar in the three groups. Neither the percentage of ALP+ CFU-Fs (66 +/- 6%, 65 +/- 7%, and 72 +/- 4% for young individuals, old individuals, and patients with osteoporosis, respectively) nor the percentage of ALP+ cells per culture (34 +/- 5%, 40 +/- 6%, and 41 +/- 4%) differed between groups. Finally, mineralized matrix formation was similar in young individuals, old individuals, and patients with osteoporosis. Our study shows that the number and proliferative capacity of osteoprogenitor cells are maintained during aging and in patients with osteoporosis and that other mechanisms must be responsible for the defective osteoblast (OB) functions observed in these conditions.