Safety of Mesenchymal Stem Cells Therapy in Patients with Inflammatory Bowel Diseases - 5 Year Follow-up

Aim: To compare safety profile of therapy in patients with ulcerative colitis (UC) and Crohn’s disease . Materials Adverse events were analyzed in 103 patients with inflammatory bowel disease after administration MSCs (56 patients UC and 47 patients CD). The findings were compared with data obtained in 208 patients with UC and CD, receiving standard antiinflammatory therapy. All analyzed patients were similar in demographic characteristics, the duration of disease, the extent of disease, course of disease, phenotype and degree of disease. The analysed groups did not include patients, treated with anti-TNF therapy. The safety of therapy was evaluated by presense of complications, developed during follow-up period. Results: We conducted analysis of side effects in 103 IBD patients, treated with mesenchymal stem cells, comparing with 208 UC and CD patients, treated with standard anti-inflammatory therapy and finally we did not reveal any differences in developing acute posttransfusional toxicity, infectious complications, exacerbation of chronic inflammatory diseases, serious infectious complications, malignancy and death in UC and CD patients, besides transitive febrile. Conclusion: Results of our study show that innovative method of cell therapy is safe in clinical practice. course of diseases, variability and difficult-to-control response to treatment. Crohn disease is devious, because there is a well-known disconnect between its clinical manifestations (general state, stool frequency, body weight, abdominal pain) and degree of mucosal lesions, course and prognosis of disease. Accumulating evidence indicates that we need to look beyond clinical symptoms of CD while determination degree and extent of remission. occurrence of longer term adverse effects (death, malignancy). toxicity, infectious complications, exacerbation of chronic inflammatory diseases, serious infectious complications, malignancy and lethal cases in UC and CD patients, treated with standard anti-inflammatory therapy.


INTRODUCTION
Inflammatory bowel diseases-is the umbrella term for group of chronic diseases of gastrointestinal tract with unknown etiology, that is characterized by nonspecific destructive immune inflammation of intestine, resulted in local and systemic complications [1].
Inflammatory bowel diseases include ulcerative colitis, Crohn's disease and undifferentiated colitis. Ulcerative colitis and Crohn's diseases share many similarities, such as histological pattern of inflammation, pathogenesis and clinical manifestations. But there are some differences in ulcerative colitis, the large intestine (colon) is typically the only site that is affected, whereas in Crohn's disease, the location of the inflammation may occur anywhere along the digestive tract from the mouth to the anus. The clinical manifestations of Crohn's disease are much more variable than those of ulcerative colitis. These two types of inflammatory bowel diseases differ also in its various complications, prognosis and response to treatment (Table 1). Crohn's disease is characterized by unpredictable course of diseases, variability and difficult-to-control response to treatment. Crohn disease is devious, because there is a well-known disconnect between its clinical manifestations (general state, stool frequency, body weight, abdominal pain) and degree of mucosal lesions, course and prognosis of disease. Accumulating evidence indicates that we need to look beyond clinical symptoms of CD while determination degree and extent of remission. Deep remission in CD is defined as absence of clinical, immunobiological and histologic signs of inflammation -remission beyond symptoms [5]. It means also normalization of serum and fecal biomarkers of active inflammation.
Randomized clinical trials suggest that mucosal healing in CD can be achieved by anticytokine treatment. Anti-TNF therapy has been shown to change options in CD treatment. The strategy in CD treatment in the pre-cytokine era was only achievement of clinical remission and reduction in the use of glucocorticosteroids. Current goals of CD treatment include induction and maintenance nonsteroidal remission, achievement and maintenance of mucosal healing, prevention of complications, reduction of hospitalization and surgery rate, improvement quality of life in CD patients.
Bone-marrow derived mesenchymal stem cells therapy is one of the innovative methods of CD treatment [6]. Mesenchymal stromal cells (mesenchymal stem cells; MSC) area heterogeneous group of cells, that can be isolated from many tissues (bone marrow, adipose tissue, dental pulpe). First described in 1960-years of XX century [7], MSC have recently received attention in a number of different clinical fields for their potential therapeutic effects. Although often described as «adult stem cells», MSC's have limited cellular differentiation ability. Instead, pre-clinical evidence suggests that MSCs exert their beneficial effects largely through immunomodulatory and paracrine mechanisms. MSCs home to sites of inflammation and secrete bioactive molecules, and thus may be especially effective in different proinflammatory diseases [8].
There is a growing body of literature demonstrating the efficacy of MSC therapy in a variety of pre-clinical models, including acute lung injury [9,10], septic shock [11], acute myocardial infarction [12]. Several small clinical trials have investigated efficacy and safety of MSCs in diseases including chronic heart failure, acute myocardial infarction, hematological malignancies, Crohn's disease [13] and graft-versus-host disease.
However, safety concerns represent a significant barrier to the successful translation of MSCs into an acceptable clinical therapeutic. Potential risk is associated with its proliferative capacity, susceptibility to infectious complications given their immunosupressive effects, embolism of the cells, zoonoses associated with cell culture reagents, and acute or chronic immunogenicity of the cells themselves [14].
Therefore, we conducted a systematic review of randomized and non-randomized controlled trials as well as uncontrolled clinical trials in foreign literature, that examined the safety and efficacy of intravascularly delivered MSCs, and revealed their most frequent adverse events [15].
Adverse events were grouped according to the immediacy of the event-acute infusional toxicity, fever, the occurrence of organ system complications (neurological, pulmonary, cardiovascular, gastrointestinal and renal, and hematologic systems), infection, and the occurrence of longer term adverse effects (death, malignancy).
In the third group of CD patients acute infusional toxicity like hives and Quincke's edema were detected in 2/47 patients (4.25%) immediately after MSC injection, in the fourth group there were no complications during antiinflammatory therapy, but these manifestations have no statistically significance between groups (x2-2.3, p=0.07) ( Table 4). Increase in body temperature up to 37.2-37.40 С during 12 hours after MSC injection or fever up to 38.00 С was noticed in 22 patients of third group (46.8%), in the fourth group of patients there was no fever, associated with intravenous interventions (medication injection) or per se administration was found in 0/124 (0%). Fever and mild increase of temperature after MSC injection were statistically significant compare to control group -RR -58.5 (95% CI 8.1 -422.0), x2-58.5, p<0.001. Non-serious infectious complications and exacerbation of chronic inflammatory diseases during therapy observed in 12 patients of 47 in the third group, that accounts 25.5%, in the fourth group-in 48 (38.7%) patients of 124, that had no significant difference: RR -0.67 (95% CI 0.39 -1.15), x2-1.86, p=0.17.
There were no differences between third and fourth groups in risk of serious infectious complications (pneumonia, pleurisy, activation of latent tuberculosis) during standard antiinflammatory CD therapy and therapy with MSC. In the third group one patient developed pneumonia 1/47 (2.1%), in the fourth group two cases of pneumonia and one case of latent tuberculosis activation were detected -3/124 (2.4%) (RR-0.88, 95% CI 0.09-1.85; x2-0.21; р=0.7).
In the third group of CD patients no cases of colorectal cancer were found. In the third group during five-year follow-up period no lethal outcomes were documented, in the fourth group one lethal case (0.8%), unlinked to underlying disease was found (x2-0.26; р=0.61). In the fourth group malignant transformation was noted in 2 patients (1.6%) from 124 (x2-0.01; р=0.93).
In patients with UC and CD, receiving MSC treatment, no cardiovascular, pulmonary, neurological, renal, and hematologic systems complications were detected. We have detected significant association between MSC injection and fever. However, fever was transient and not associated with long term sequelae. The mechanisms for fever are not clear but could be related to acute inflammatory reactions by a subset of patients to particular preparations of MSCs, not unlike similar reactions occasionally observed with red blood cell and fresh frozen plasma administration [47].
Although malignant transformation is a theoretical risk, our own experience and literature analysis, presented in this chapter found no association between MSCs and tumour formation.
Concerns related to tumourgenicity of MSCs were raised by preclinical studies demonstrating increased tumour burden in vivo [48]. Although recent position papers have suggested low probability of malignant transformation and tumour formation with MSCs [8]. Malignancy occurred only in studies involving participants with ongoing or previous malignancies; no de novo malignancies were observed.
Although MSC immunomodulatory effects may be beneficial in pro-inflammatory diseases, these same effects may leave a patient susceptible to infection. [49]. The question arised-whether immunosuppressive therapy could increase risk of infections? This review did not demonstrate any evidence of increased susceptibility to infections with MSC administration.
In our chapter, infections were common in already immunosuppressed patients (e.g. following hematopoietic stem cell transplant), however the infection rates were similar to those in control group of patients [47,48].
Absence of posttransfusional reaction may be explained by low MSC immunogenicity, due to absence HLA class II and low level of expression HLA I class at their surface [56]. The use of fetal bovine serum for culturing MSCs could be one of the reasons for above mentioned posttransfusional toxicity, and another potential concern with MSC therapy application is the use of dimethylsulfoxide as cryopreservative, which has toxic side effects and could cause hypersensitivity reactions [57]. Thus, greater vigilance may be needed in future studies for reporting cellular viability and monitoring for potential dimethylsulfoxide related adverse events. Results from our study should provide some assurance to investigators and health regulators that, with the present evidence, this innovative therapy appears safe.