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Papers by M. Ainola

Abstracts Accepted for Publication, 2017

Frontiers in Medicine, 2017

Ankylosing spondylitis (AS) is typically characterized by focal bone overgrowth and also by syste... more Ankylosing spondylitis (AS) is typically characterized by focal bone overgrowth and also by systemic bone loss. We hypothesize that the increased osteoproliferation found in AS might be partially due to reduced ability of osteoclast precursors (OCPs) to differentiate into osteoclasts (OCs). Therefore, our aim was to characterize bone remodeling and pro-osteoclastogenesis inflammatory environment, monocytes' phenotype, and in vitro osteoclast differentiation in AS patients. Methods: Patients with active AS without any ongoing therapy and age-and gendermatched healthy donors were recruited. Receptor activator of nuclear factor-κβ (RANKL) surface expression on circulating leukocytes and frequency and phenotype of monocyte subpopulations were assessed. Quantification of serum levels of bone turnover markers and cytokines, in vitro OC differentiation assay and quantitative reverse transcription real-time PCR for OC-specific genes were performed. results: Pro-and anti-inflammatory cytokine serum levels were higher in AS patients than in controls. RANKL neutrophil expression was higher in AS patients when compared to healthy donors, but CD51/CD61 expression was lower in the classical monocyte subpopulation. Concerning osteoclastogenesis, we found no differences in the in vitro osteoclast differentiating potential of these cells when compared to healthy donors. However, we observed low expression of CSF1R, RANK, and NFATc1 in AS OCPs. conclusion: Despite the high levels of pro-inflammatory cytokines present in AS patients, no differences in the number of OC or resorbed area were found between AS patients and healthy donors. Moreover, we observed that OCPs have low OC-specific gene expression. These findings support our hypothesis of an impaired response of OCPs to pro-osteoclastogenic stimuli in vivo in AS patients.

Annals of the Rheumatic Diseases, 2016

Background Sjögren's syndrome (SS) is a common autoimmune disease targeting salivary and lacr... more Background Sjögren's syndrome (SS) is a common autoimmune disease targeting salivary and lacrimal glands. It is strongly female-dominant characterized by low estrogen (E) levels combined with a local intracrine dihydrotestosterone defect (DHT) [1, 2]. It is assumed that the primary effect in SS is the abnormal apoptosis of salivary gland cells, combined with increased production and abnormal handling of the apoptotic particles [3]. Objectives The working hypothesis was that these hormonal defects lead to increased apoptosis of the epithelial cells and pro-inflammatory plasmacytoid dendritic cell (pDC) mediated host responses. Apoptosis induced particles contain SS autoantigens, which may affect immune cells. Methods Apoptotic particles were collected by different centrifugation steps. The expression and localization of SS autoantigens (α-fodrin and SS-A) was analysed with flow cytometry. Isolated apoptotic particles were used to stimulate pDCs. The effect of the particles on TLR7/9 expression in pDCs was studied with qPCR and the elicited cytokine/interferon (IFN) profile with xMAP and ELISA measurements. To study the effects of sex steroids, pDCs were cultured without and with various concentrations of dehydroepiandrosterone (DHEA), DHT and 17-β-estradiol (E2). Results Apoptosis-induced apoptotic particles contained SS-autoantigens and hy1-RNA. These particles were internalized by pDCs, which stimulated the TLR expression and the production of proinflammatory cytokines TNF-α, interleukin-6 (IL-6) and IL-8. On the contrary, type I IFN production was not induced. Androgens inhibited the particle-induced increase of TLR9 expression in pDCs. Conclusions Apoptosis of epithelial cells leads to translocation of SS-autoantigens and single-stranded hy1-RNA to apoptotic blebs and membrane particles. The apoptotic particles are internalized by pDCs, which in response mature and produce proinflammatory cytokines. Androgens affect to redistribution of autoantigens and diminish the particle-elicited increase of TLR expression in pDCs. Apoptosis of salivary gland cells lead to formation of apoptotic particles, which might affect immunotolerance, production of autoantibodies and onset of autoinflammation. This event might describe how the immunologic tolerance is broken in the early stages of SS. References Porola P, Virkki L, Przybyla BD, Laine M, Patterson TA, Pihakari A, Konttinen YT. Androgen deficiency and defective intracrine processing of dehydroepiandrosterone in salivary glands in SS. J Rheumatol 35(11):2229–35, 2008 Konttinen YT, Stegajev V, Al-Samadi A, Porola P, Hietanen J, Ainola M. SS and extragonadal sex steroid formation: A clue to a better disease control? J Steroid Biochem Mol Biol 145C:237–244, 2015 Konttinen YT, Fuellen G, Bing Y, Porola P, Stegaev V, Trokovic N, Falk SS, Liu Y, Szodoray P, Takakubo Y. Sex steroids in SS. J Autoimmun 39(1–2):49–56, 2012 Disclosure of Interest None declared

PloS one, 2015

Ankylosing Spondylitis (AS) is characterized by excessive local bone formation and concomitant sy... more Ankylosing Spondylitis (AS) is characterized by excessive local bone formation and concomitant systemic bone loss. Tumor necrosis factor (TNF) plays a central role in the inflammation of axial skeleton and enthesis of AS patients. Despite reduction of inflammation and systemic bone loss, AS patients treated with TNF inhibitors (TNFi) have ongoing local bone formation. The aim of this study was to assess the effect of TNFi in the differentiation and activity of osteoclasts (OC) in AS patients. 13 AS patients treated with TNFi were analyzed at baseline and after a minimum follow-up period of 6 months. 25 healthy donors were recruited as controls. Blood samples were collected to assess receptor activator of nuclear factor kappa-B ligand (RANKL) surface expression on circulating leukocytes and frequency and phenotype of monocyte subpopulations. Quantification of serum levels of bone turnover markers and cytokines, in vitro OC differentiation assay and qRT-PCR for OC specific genes were ...

Journal of Biomaterials Applications, 2015

The aim was to develop a hybrid three-dimensional-tissue engineering construct for chondrogenesis... more The aim was to develop a hybrid three-dimensional-tissue engineering construct for chondrogenesis. The hypothesis was that they support chondrogenesis. A biodegradable, highly porous polycaprolactone-grate was produced by solid freeform fabrication. The polycaprolactone support was coated with a chitosan/polyethylene oxide nanofibre sheet produced by electrospinning. Transforming growth factor-β3-induced chondrogenesis was followed using the following markers: sex determining region Y/-box 9, runt-related transcription factor 2 and collagen II and X in quantitative real-time polymerase chain reaction, histology and immunostaining. A polycaprolactone-grate and an optimized chitosan/polyethylene oxide nanofibre sheet supported cellular aggregation, chondrogenesis and matrix formation. In tissue engineering constructs, the sheets were seeded first with mesenchymal stem cells and then piled up according to the lasagne principle. The advantages of such a construct are (1) the cells do no...

The Journal of steroid biochemistry and molecular biology, 2015

Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphoplasmacytoid focal ad... more Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphoplasmacytoid focal adenitis leading to mucosal dryness, with 9:1 female dominance and peak incidence at menopause. Due to autoimmune adenitis it can be speculated that the normal epithelial cell renewal has failed, possibly as a result of local intracrine failure to process dehydroepiandrosterone (DHEA) to dihydrotestosterone (DHT). Local intracrine/-cellular DHT deficiency seems to predispose to SS if estrogens are low, in menopausal women and in men. This intracrine failure could be the initial noxious stimulus, factor X, initiating the development of SS. Abnormal release and presentation of exocrine gland-derived antigens (Ag-epitopes), in a complex with major histocompatibility complex class II (MHC II), by migratory dendritic cells (DC) activates T-cells in the regional lymph nodes. B-cells with the same specificity capture and present self-Ag to Th-cells which provide T-cell help. B-cells transform to ...

The Journal of Pathology, 2001

Aseptic loosening of prosthetic components, the most common long-term complication after total hi... more Aseptic loosening of prosthetic components, the most common long-term complication after total hip replacement (THR), is characterized by the formation of a synovial membrane-like interface tissue (SMLIT). It was hypothesized that the hyaluronan synthase (HAS)/hyaluronan (HA)/HA receptor CD44 signalling system is responsible for the synovial-like differentiation of the interface membrane. SMLIT was therefore compared with osteoarthritis (OA) synovial membrane by using reverse transcriptase polymerase chain reaction (RT-PCR) of HAS 1, 2 and 3, histochemical HA assay, and immunohistochemistry of CD44 and its non-HA ligands. All three isoforms of HAS were found in these samples. HA and CD44 were most abundant in the lining, but the signal was actually stronger in aseptic loosening than in OA (p<0.01). The non-HA CD44 ligands, collagen type VI, fibronectin, osteopontin, and MCP-1, had a similar distribution pattern in both tissues. These results confirm the synovial-like structure of the interface tissue lining. The pressure waves and movement of the HA-rich pseudosynovial fluid seem to drive HA into the implant-to-host interface, which itself also produces HA. HA may be responsible for the induction of a synoviallike lining at the interface through HA-CD44 signalling.

Arthritis & Rheumatism, 2012

Osteoarthritis (OA) is considered to be primarily a disease of the hyaline articular cartilage, w... more Osteoarthritis (OA) is considered to be primarily a disease of the hyaline articular cartilage, which secondarily affects subchondral bone and synovial membrane. The exact nature and mechanisms of OA, particularly during the early phases of the disease, are unknown. OA per se might in part relate to the poor inherent repair capacity of the articular cartilage, which during the lifetime of modern (long-lived) human beings, is gradually subjected to progressive and accumulative wear and tear. However, the idea of OA as a simple wear-and-tear disease has been widely rejected because various biologic processes, such as inflammation and enzymatic cartilage degradation, are apparently involved in its pathogenesis. Recent findings provide possible new explanatory pathogenic models that intimately link the two phenomena—biomechanical wear and tear of the cartilage (osteoarthrosis) and inflammation (osteoarthritis)—to each other. Although mesenchymal progenitor cells have been found in the cartilage matrix (1), cartilage cannot recruit circulating mesenchymal stem cells and is unable to organize the repair according to the developmental programs that, during the embryonic and fetal stages, created the delicate molecular collagen and architectural tissue structure of true synovial diarthrodial joints. Structural degeneration, cartilage thinning, and sclerosis of the subchondral bone plate are indeed common in the elderly population, but clinically manifest OA with pain is, fortunately, much rarer. This depends in part on the avascular nature of the cartilage; cartilage contains neither blood nor lymphatic vessels. This makes it impossible for the cartilage to recruit leukocytes and, according to the conventional view, makes it unable to mount an inflammatory response that is recognizable by the classic signs of redness, local inflammatory swelling, pain, increased local temperature, and impaired function. The question is whether cartilage can mount an inflammatory cellular (chondrocyte) response, which then via transfer of the locally produced messenger molecules to synovium causes synovitis, with classical signs of inflammation. Cartilage is also aneural, which might be useful from the functional point of view, considering the high peak loads and trauma that the cartilage covering the ends of the bone is naturally subjected to during cyclic activities and traumatic “high-energy” activities in particular. Due to the lack of primary afferent nociceptive nerves, cartilage also cannot be a source of nociceptive or inflammatory pain. Pain in OA is therefore considered to be caused by secondary involvement of the synovium, that is, osteoarthritic synovitis, which has an unclear pathogenesis. In any case, it has been emphasized that the lymphocyte-rich mononuclear cell infiltrates seen in OA are relatively similar to those seen in rheumatoid arthritis (RA) and that, at the superficial level at least, the differences between secondary OA synovitis and primary RA synovitis are quantitative rather than qualitative. The results reported by Opolka and coworkers (2) elsewhere in this issue of Arthritis & Rheumatism can be used to question this line of speculation. The investigators show that both in micromass and monolayer culture, primary costal chondrocytes from newborn mice produce neuronal transmitters, substance P (SP), and some of them probably also norepinephrine (NE) (because they contained tyrosine hydroxylase, the ratelimiting enzyme of its biosynthesis). Furthermore, chondrocytes contain neurokinin type 1 (NK-1) receptor and -adrenergic (possibly all subtypes, although monolayer cultures did not contain 1a or 2c) and Y. T. Konttinen, MD, PhD, D. C. E. Nordström, MD, PhD: Helsinki University Central Hospital, Helsinki, Finland; T. Sillat, MD: Coxa Hospital for Joint Replacement, Tampere, Finland; G. Barreto, BSc: Orton Orthopaedic Hospital of the Orton Foundation, Helsinki, Finland; M. Ainola, PhD: University of Helsinki, Helsinki, Finland. Address correspondence to Y. T. Konttinen, MD, PhD, Institute of Clinical Medicine, Department of Medicine, Biomedicum 1, PO Box 700, Helsinki University Central Hospital, Helsinki FIN00029, Finland. E-mail: yrjo.konttinen@helsinki.fi. Submitted for publication October 3, 2011; accepted in revised form October 25, 2011.

Journal of Materials Science, 2017

The two-stage induced-membrane technique for treatment of large bone defects has become popular a... more The two-stage induced-membrane technique for treatment of large bone defects has become popular among orthopedic surgeons. In the first operation, the bone defect is filled with poly(methyl methacrylate) (PMMA), which is intended to produce a membrane around the implant. In the second operation, PMMA is replaced with autograft or allograft bone. Bioactive glasses (BAGs) are bone substitutes with bonestimulating and angiogenetic properties. The aim of our study was to evaluate the inductive vascular capacity of BAG-S53P4 and poly(lactide-co-glycolide) (PLGA)coated BAG-S53P4 for potential use as bone substitutes in a single-stage inducedmembrane technique. Sintered porous rods of BAG-S53P4, PLGA-coated BAG-S53P4 and PMMA were implanted in the femur of 36 rabbits for 2, 4 and 8 weeks. The expression of vascular endothelial growth factor (VEGF) and tumor necrosis factor alpha (TNF) in the induced membranes of implanted materials was analyzed with real-time quantitative polymerase chain reaction and compared with histology. Both uncoated BAG-S53P4 and PLGA-coated BAG-S53P4 increase expression of VEGF and TNF, resulting in higher amounts of capillary beds, compared with the lower expression of VEGF and less capillary beads observed for negative control and R. Bjö rkenheim and G. Strö mberg have contributed equally to this work.

Introduction: Ankylosing spondylitis (AS) is typically characterized by focal bone over-growth an... more Introduction: Ankylosing spondylitis (AS) is typically characterized by focal bone over-growth and also by systemic bone loss. We hypothesize that the increased osteopro-liferation found in AS might be partially due to reduced ability of osteoclast precursors (OCPs) to differentiate into osteoclasts (OCs). Therefore, our aim was to characterize bone remodeling and pro-osteoclastogenesis inflammatory environment, monocytes' phenotype, and in vitro osteoclast differentiation in AS patients.

Objective. Tumor necrosis factor (TNF) increases circulating osteoclast (OC) precursors numbers b... more Objective. Tumor necrosis factor (TNF) increases circulating osteoclast (OC) precursors numbers by promoting their proliferation and differentiation. The aim of this study was to assess the effect of TNF inhibitors (TNFi) on the differentiation and activity of OC in rheumatoid arthritis (RA) patients. Methods. Seventeen RA patients treated with TNFi were analyzed at baseline and after a minimum follow-up period of 6 months. Blood samples were collected to assess receptor activator of nuclear factor kappa-B ligand (RANKL) surface expression on circulating leukocytes and frequency and phenotype of monocyte subpopulations. Quantification of serum levels of bone turnover markers, in vitro OC differentiation assays, and qRT-PCR for OC specific genes was performed. Results. After TNFi therapy, patients had reduced RANKL surface expression in B-lymphocytes and the frequency of circulating classical CD14 bright CD16 − monocytes was decreased. Serum levels of sRANKL, sRANKL/OPG ratio, and CTX-I were reduced in RA patients after TNFi treatment. Moreover, after exposure to TNFi, osteoclast differentiation and activity were decreased, as well as the expression of TRAF6 and cathepsin K. Conclusion. We propose that TNFi arrests bone loss and erosion, through two pathways: direct reduction of osteoclast precursor numbers and inhibition of intracellular signaling pathways acting through TRAF6.

Oral diseases, 2015

Oral lichen planus (OLP) is an autoimmune disease characterized by a band-like T-cell infiltrate ... more Oral lichen planus (OLP) is an autoimmune disease characterized by a band-like T-cell infiltrate below the apoptotic epithelial cells and degenerated basement membrane. We tested the hypothesis that the high-affinity histamine H4 receptors (H4 Rs) are downregulated in OLP by high histamine concentrations and proinflammatory T-cell cytokines. Immunohistochemistry and immunofluorescence staining, image analysis and quantitative real-time polymerase chain reaction of tissue samples and cytokine-stimulated cultured SCC-25 and primary human oral keratinocytes. H4 R immunoreactivity was weak in OLP and characterized by mast cell (MC) hyperplasia and degranulation. In contrast to controls, H4 R immunostaining and MC counts were negatively correlated in OLP (P = 0.003). H4 R agonist at nanomolar levels led to a rapid internalization of H4 Rs, whereas high histamine concentration and interferon-γ decreased HRH4 -gene transcripts. Healthy oral epithelial cells are equipped with H4 R, which di...

Oral diseases, 2015

It was hypothesized that beta 2 defensin (BD-2) is increased in RAU lesions compared with healthy... more It was hypothesized that beta 2 defensin (BD-2) is increased in RAU lesions compared with healthy controls to promote anti-microbial host defence. RAU and control mucosa samples were subjected to quantitative real-time PCR and immunostained for BD-2, CD68, mast cell tryptase and 4-hydroxynonenal (4HNE). The effect of tumour necrosis factor-α (TNF-α) ± interleukin-17C (IL-17C), without and with vitamin K3, was studied on BD-2 expression in epithelial SCC-25 cells. Although BD-2 mRNA did not differ between healthy and RAU mucosa, BD-2 stained strongly in acute-phase RAU epithelium (P = 0.001). In controls, subepithelial BD-2(+) cells were mast cells and macrophages, whereas in RAU, most infiltrating leucocytes were BD-2(+) (P = 0.004). In cell culture, BD-2 was increased 124-fold by TNF-α (P < 0.0001) and 208-fold synergistically together with IL-17C (P < 0.0001). 4HNE staining of RAU epithelium was not significantly increased, and vitamin K3-induced reactive oxygen species (ROS...

introduction: Ankylosing spondylitis (AS) is typically characterized by focal bone over-growth an... more introduction: Ankylosing spondylitis (AS) is typically characterized by focal bone over-growth and also by systemic bone loss. We hypothesize that the increased osteopro-liferation found in AS might be partially due to reduced ability of osteoclast precursors (OCPs) to differentiate into osteoclasts (OCs). Therefore, our aim was to characterize bone remodeling and pro-osteoclastogenesis inflammatory environment, monocytes' phenotype, and in vitro osteoclast differentiation in AS patients.

Journal of Oral Pathology & Medicine, 2014

Recurrent aphthous ulcer (RAU) is an ulcerative disease of non-keratinized oral mucosa. Colon and... more Recurrent aphthous ulcer (RAU) is an ulcerative disease of non-keratinized oral mucosa. Colon and bronchial epithelial cells produce interleukin-17C (IL-17C) upon stimulation of Toll-like receptor 2 (TLR2), TLR3 and TLR5, which are highly expressed in epithelial cells in RAU lesions. We therefore investigated the eventual presence and function of IL-17C in cultured human oral keratinocytes (HOK) and control biopsies compared to RAU lesions. Expression of IL-17A, IL-17C, IL-17RA and IL-17RE was analysed in cultured HOK cells using quantitative real-time polymerase chain reaction (qRT-PCR). HOK cells were stimulated with IL-17C and analysed for IL-8 and tumour necrosis factor-α (TNF-α) using qRT-PCR. Control mucosa (n = 5) was immunostained for IL-17A, IL-17C, IL-8, TNF-α and mast cell tryptase and compared with RAU lesions (n = 5) using the mean grey scale value. IL-17C, but no IL-17A, mRNA was found in cultured HOK cells. Components of the heterodimeric IL-17RA/IL-17RE receptor for IL-17C were also highly expressed. Stimulation of HOK with IL-17C increased TNF-α mRNA (P = 0.03; IL-8 increase was not statistically significant). HOK in RAU lesions stained intensively for IL-17C compared to controls (P = 0.006). This was associated with increased epithelial immunostaining of TNF-α (P = 0.04) and IL-8 (P = 0.02). Most of the inflammatory cells which stained for IL-17A in control mucosa and RAU lesions were also mast cell tryptase positive. IL-17C is highly expressed in epithelial cells in RAU lesions, where it seems to stimulate oral keratinocytes via IL-17RA/IL-17RE to produce pro-inflammatory cytokines. Human oral epithelial cells are probably important inflammatory cells in RAU.

Scandinavian Journal of Rheumatology, 2015

Clinical and experimental rheumatology

Synovial inflammation in rheumatoid arthritis (RA) leads to pannus tissue invasion and destructio... more Synovial inflammation in rheumatoid arthritis (RA) leads to pannus tissue invasion and destruction of cartilage/bone matrix by proteinases. Our intention was to analyze some of the key matrix metalloproteinases (MMPs) in pannus tissue overlying evolving cartilage erosions in RA.

Clinical and experimental rheumatology

To test if the pannus tissue is characterized by a high receptor activator of nuclear factor kapp... more To test if the pannus tissue is characterized by a high receptor activator of nuclear factor kappaB ligand to osteoprotegerin (RANKL:OPG) ratio, which could explain local osteoclastogenesis and formation of bony erosions. Messenger RNA and protein expressions of RANKL and OPG in rheumatoid and osteoarthritic tissue samples were measured using quantitative real-time RT-PCR and Western blot/densitometry. Pannus and synovitis fibroblasts explanted from tissue samples were cultured in vitro without and with TNF-alpha, IL-1Beta or IL-17 and analyzed quantitatively for RANKL expression. The ability of pannus fibroblasts to induce formation of multinuclear osteoclast-like cells from human monocytes, with macrophage-colony stimulating factor (M-CSF) but without RANKL added, was tested. Histochemical staining was used to assess the eventual presence of RANKL and tartrate resistant acid phosphatase positive osteoclast-like cells at the pannus-bone interface. RANKL:OPG ratios of messenger RNA ...

Oral diseases, 2015

Abstracts Accepted for Publication, 2017

Frontiers in Medicine, 2017

Annals of the Rheumatic Diseases, 2016

PloS one, 2015

Journal of Biomaterials Applications, 2015

The Journal of steroid biochemistry and molecular biology, 2015

The Journal of Pathology, 2001

Arthritis & Rheumatism, 2012

Journal of Materials Science, 2017

Oral diseases, 2015

Journal of Oral Pathology & Medicine, 2014

Scandinavian Journal of Rheumatology, 2015

Clinical and experimental rheumatology

Oral diseases, 2015