Mesenchymal stromal cells for articular cartilage repair: preclinical studies

Rheumatic diseases such as osteoarthritis (OA) are a major social and economic burden because of the population aging and the lack of curative solutions. An effective cell therapy may be the best treatment option for OA and other cartilage diseases. However, the main cellular strategy used to repair articular cartilage, the transplantation of autologous chondrocytes, is limited to a small number of patients with traumatic lesions. The use of joint replacement after years of disease progression proves the great medical need in current practice. Mesenchymal stromal/stem cells (MSCs) provide an alternative cell source for cartilage regeneration due to numerous advantages, comprising relative ease to isolate and culture, chondrogenic capacity, and anti-inflammatory effects. Initial clinical trials with MSCs have led to encouraging results, but many variables have to be considered to attain true amelioration of disease or repair (type and status of cartilage disease, source and conditions of cells, administration regime, combinatorial approaches). Particularly, allogeneic MSCs are an advantageous cellular product. The animal models chosen for preclinical evaluation are also relevant for successful translation into clinical practice. Considering the limitations in the field, rigorous comparative and validating studies in well-established animal models (including large animals) are still needed to set up the bases for additional clinical trials. The present review of studies performed in small and large animal models should help clarify the applicability of MSC-based therapies for articular cartilage repair.

Xenotransplantation of pig chondrocytes: therapeutic potential and barriers for cartilage repair

Transplantation may be the best option for the repair of many cartilage lesions including early osteoarthritis. Currently, autologous and allogeneic chondrocytes are grafted into cartilage defects to treat selected patients with moderate clinical success. However, their limited use justifies exploring novel therapies for cartilage repair. Xenotransplantation could become a solution by offering high cell availability, quality and genetic engineering capabilities. The rejection process of xenogeneic cartilage is thus being elucidated in order to develop counteractive strategies. Initial studies determined that pig cartilage xenografts are rejected by a slow process comprising humoral and cellular responses in which the galactose α1,3-galactose antigen participates. Since then, our group has identified key mechanisms of the human response to pig chondrocytes (PCs). In particular, human antibody and complement contribute to PC rejection by inducing a pro-inflammatory milieu. Furthermore, PCs express and up-regulate molecules which are functionally relevant for a variety of cellular immune responses (SLA-I, the potent co-stimulatory molecule CD86, and adhesion molecules VCAM-1 and ICAM-1). These participate by triggering a T cell response, as well as supporting a prominent role of the innate immune responses led by natural killer (NK) cells and monocytes/macrophages. Human NK cells lyse PCs by using selected NK activating receptors, whereas human monocytes are activated by PCs to secrete cytokines and chemokines. All this knowledge sets the bases for the development of genetic engineering approaches designed to avert rejection of xenogeneic chondrocytes and leads the way to developing new clinical applications for cartilage repair.

Angiogenic and prothrombotic markers in extensive slow-flow vascular malformations: implications for antiangiogenic/antithrombotic strategies

BACKGROUND

Venous and combined malformations are slow-flow haemodynamically inactive lesions that are present at birth and worsen slowly with advancing age, showing no tendency towards involution. The pathogenesis of vascular anomalies has not been fully elucidated, but their formation and progression are closely related to angiogenesis. Localized intravascular coagulation associated with venous or combined malformations is characterized by low fibrinogen, high D-dimers, and normal platelet count.

OBJECTIVES

To assess the relationship of angiogenic factors with prothrombotic and endothelial damage/dysfunction markers in patients with extensive slow-flow vascular malformations.

METHODS

A 2-year study (2005-2007) included 31 consecutive patients with extensive slow-flow vascular malformations from one centre.

RESULTS

Serum levels of the endothelial receptor tyrosine kinase TIE-2, matrix metalloproteinase (MMP)-9 and angiopoietin (Ang)-2 and plasma levels of D-dimer, plasminogen activator inhibitor type 1 (PAI-1), tissue-type plasminogen activator and von Willebrand factor (vWf) were significantly increased in patients compared with healthy controls, whereas serum levels of vascular endothelial growth factor (VEGF)-C, VEGF-D, MMP-2, Ang-1, platelet-derived growth factor (PDGF)-AB and PDGF-BB were significantly decreased in patients compared with controls. A strong positive correlation was present between Ang-1 and PDGF-AB levels (r = 0.63, P < 0.001), between PDGF-AB and PDGF-BB levels (r = 0.67, P < 0.001), and between fibrinogen and PAI-1 levels (r = 0.41, P = 0.031). A strong negative correlation was present between Ang-1 and vWf levels (r = -0.48, P = 0.006), between D-dimer and fibrinogen levels (r = -0.71, P < 0.001), and between PDGF-AB and vWf levels (r = -0.42, P = 0.017).

CONCLUSIONS

These findings suggest that angiogenic, coagulation and endothelial damage/dysfunction markers are possibly linked in pathogenesis of extensive slow-flow vascular malformations, and might have therapeutic implications.

[Prolonged complete clinical remission in patients with severe pemphigus vulgaris after cycles of intravenous cyclophosphamide]

BACKGROUND

Corticosteroids are the systemic treatment of choice in patients with pemphigus vulgaris, but chronic administration is associated with side effects. Intravenous treatment with cyclophosphamide can improve the clinical signs of pemphigus vulgaris.

MATERIAL AND METHODS

We prospectively studied 8 patients diagnosed with pemphigus vulgaris. Six of these had mucocutaneous pemphigus vulgaris and 2 had mucosal pemphigus vulgaris. Treatment consisted of 10 cycles of cyclophosphamide at a dose of 10-15 mg/kg separated by 15 days, while maintaining the initial corticosteroid and immunosuppressant dose. Clinical efficacy was assessed and the anti-epidermal intercellular substance (EIS) and anti-desmoglein (DSG) 3 and 1 antibody titers were monitored (by indirect immunofluorescence and enzyme-linked immunosorbent assay, respectively).

RESULTS

All patients with pemphigus vulgaris responded excellently to treatment. Five of the 8 patients achieved complete remission of pemphigus lesions after 10 cycles of cyclophosphamide. In the other 3 patients, the skin lesions disappeared a few weeks after the last cycle of cyclophosphamide. A substantial reduction in immuno suppressant dose was possible in all patients. Furthermore, an improved immunologic response was observed in all cases after cyclophosphamide treatment, with decreased anti-DSG1 and anti-DSG3 antibody titers and well as decreased circulating anti-EIS antibody titers. During the mean 15.1 month follow-up (range, 1-25 months), no new lesions appeared and no side effects of cyclophosphamide therapy were reported.

CONCLUSIONS

Fortnightly cycles of intravenous cyclophosphamide may be a useful therapeutic option in patients with severe pemphigus vulgaris. A reduction of corticosteroid dose was possible with this therapeutic approach and the cumulative cyclophosphamide dose was lower than with daily oral administration. Our findings also show that the therapeutic approach induces clinical and immunologic remission in most patients.

[Repigmentation of gray hair after thyroid hormone treatment]

BACKGROUND AND OBJECTIVES

Darkening of gray and white hairs occurred in 2 patients with increased exogenous triiodothyronine (T3) due to treatment of myxedema coma in one case and iatrogenic hyperthyroidism in the other. We hypothesized that thyroid hormone may affect the homeostasis of hair follicles. To test our hypothesis and investigate the influence of thyroid hormone on the hair cycle, we used an in vivo murine model and an in vitro model based on culture of follicular units.

METHODS

We used the standard C57BL/6 murine model of the hair cycle. T3 (0.5 microg) dissolved in ethanol was applied topically once daily for 10 days to a depilated area in the telogen phase on the backs of the mice. Follicular units, obtained from hair transplant interventions, were cultured in vitro with different concentrations of T3.

RESULTS

On day 5, all T3-treated mice entered the anagen phase, whereas the anagen phase started spontaneously in control mice on day 9, and not until day 15 had all controls entered this phase. In the in vitro experiment, follicular units treated with 100 nmol/L T3 grew significantly larger compared to the control group.

CONCLUSIONS

These data suggest that follicles in the telogen phase can be induced to enter the anagen phase by the topical application of T3. This thyroid hormone may reverse graying of the terminal hair. In the in vitro experiments, T3 stimulated hair shaft growth. Follicular melanocytes may be the target cell for these actions.

Ear, nose and throat manifestations in pemphigus vulgaris

BACKGROUND

Pemphigus vulgaris (PV) is an autoimmune disease characterized by mucocutaneous intraepithelial blisters and pathogenic autoantibodies against desmoglein 3. There are two clinical forms: mucosal (MPV) and mucocutaneous (MCPV). The frequency of ear, nose and throat (ENT) involvement in PV is not clearly defined. Only a few isolated individual cases have been reported.

OBJECTIVES

The objective of our study was to determine the incidence of ENT involvement in patients with PV.

PATIENTS

We studied prospectively all 16 patients diagnosed with PV and treated in the Department of Dermatology of the University Clinic of Navarra between 2001 and 2005. They were 10 cases of MPV and six cases of MCPV. All patients were evaluated for ENT manifestations by endoscopic examination.

RESULTS

Of the 16 patients, 13 presented with throat symptoms (81%), 12 pharyngeal (75%) and seven laryngeal symptoms (44%). Fourteen patients (88%) had active PV lesions on endoscopic evaluation (eight patients had active lesions on both pharyngeal and laryngeal mucosa, four had PV lesions only on laryngeal mucosa and two had PV lesions on pharyngeal mucosa). Laryngeal lesions were most commonly present in MPV patients. The frequency of nasal symptoms (38%) was lower than active PV lesions (62%) found on ENT examination. Oral symptoms and oral active PV lesions were the most frequent findings (94%). Only three patients with MCPV showed erosions on the external auditory canal.

CONCLUSIONS

As ENT endoscopy allows more extensive areas of mucosa to be examined than simple visual inspection, we recommend that it be included in the examination of all patients with PV. By obtaining more complete information concerning the extent of the disease, a more accurate diagnosis can be made, better choice of drug and dose may be decided and, ultimately, response to treatment may be improved.

Combined inguinal herniorrhaphy and transurethral prostatectomy

Between January 1979 and June 1988, 41 men underwent combined inguinal herniorrhaphy and transurethral prostatectomy at the Instituto Nacional de la Nutrición in México. These cases (group 1) were compared retrospectively with 100 consecutive cases of inguinal herniorrhaphy alone (group 2) and 100 consecutive cases of transurethral prostatectomy alone (group 3) during the same period. Group 1 had the highest incidence of preoperative risk factors because of age and associated medical problems. However, there were no significant differences in the rate of operative or postoperative complications between groups. No recurrences of inguinal hernia were recorded in group 1 after a follow-up period of 47.1 months. The length of hospitalization was similar between groups, and no patient died. Our observations suggest that when an inguinal hernia and symptomatic prostatism occur together, combined inguinal herniorrhaphy and transurethral prostatectomy is a practical, safe and effective operative procedure. The advantages of this combined procedure include one anaesthetic period, one operative procedure, one hospital stay and one convalescence with morbidity and mortality rates that are comparable to those of inguinal herniorrhaphy or transurethral prostatectomy alone.