Human skeletal muscle-derived stem/progenitor cells modified with connexin-43 prevent arrhythmia in rat post-infarction hearts and influence gene expression in the myocardium

Stem cell therapy in combination with genetic modification (e.g., transfection with the coding sequence for the connexion 43 gene, GJA1) may solve the problems associated with the occurrence of additional (secondary) stimulation in the post-infarcted heart (arrhythmia). Human skeletal muscle-derived stem/progenitor cells (SkMDS/PCs) were transfected with the pCiNeo-GJA1 plasmid at an efficiency of approximately 96%. Gene overexpression was assessed using qPCR, and subsequent analysis revealed that GJA1 expression increased more than 40-fold in SkMDS/PCs transfected with the appropriate coding sequence (SkMDS/PCsCX43) compared to that of the 'native' SkMDS/PCs control (SkMDS/PCsWT). Enhanced (4-fold) protein expression of connexin-43 was also confirmed by Western immunoblotting. Furthermore, using the arrhythmic score, we demonstrated the positive effects of SkMDS/PCsCX43 cell intervention in reducing additional secondary stimulations in rat post-infarcted hearts compared with that of wild-type cell delivery. Selected gene responses (Kcnq1, Cacna1c, Ncx1, Serca2a, and Tgfb1) showed significantly altered expression profiles in the rat myocardium upon intervention with SkMDS/PCsCX43. The genetic modification of human skeletal muscle-derived stem/progenitor cells with connexin-43 prevented the pro-arrhythmic effects of myogenic implanted stem cells on the host myocardium and positively influenced myocardial gene expression profiles in respect to myocardium conductivity.

Influence of hypoxia prevailing in post-infarction heart on proangiogenic gene expression and biological features of human myoblast cells applied as a pro-regenerative therapeutic tool

Cardiovascular diseases along with MI (myocardial infarction) lead to regional ischaemia and hypoxic conditions, which prevail after infarction. Diminished O₂ saturation which is related to elevated level of hypoxia inducible factor 1 (HIF-1) transcription factor, may switch the expression of many genes. To maximize effect of therapies proposed by regenerative medicine, it is essential to verify (within different time points after MI) the expression of proangiogenic genes and their receptors that are regulated, along with the expression of HIF-1α. We demonstrated a connection between the expression of Hif-1α (in murine post infarcted heart model) and the proangiogenic genes Vegf-a; and Plgf and their receptors during myocardial hypoxia. The innovative part of the study required establishment of the most accurate in vitro O₂ level corresponding to the hypoxia level prevailing in myocardium after MI. We determined the influence of hypoxia on the biology of human myoblasts in in vitro oxygen conditions (3%), corresponding to those prevailing in the heart after an infarction using a murine model. We also tested myoblasts that were genetically modified with VEGF-A/FGF-4 and PlGF under hypoxic conditions and compared their characteristics with cells cultured under normoxia and hyperoxia (standard in vitro conditions) with respect to myogenic gene expression, cell proliferation, fusion potential and proangiogenic function. The examination of genetically modified myoblasts under optimized in vitro hypoxia conditions led to the conclusion that hypoxia did not negatively influence the biological functions of the myoblasts, such as cell proliferation and/or proangiogenic characteristics. These results support the expected increased proregenerative effects of such genetically modified human myoblasts.

Implantation of autologous muscle-derived stem cells in treatment of fecal incontinence: results of an experimental pilot study

Background

The aim of this study is to present results of the implantation of autologous myoblasts into the external anal sphincter (EAS) in ten patients with fecal incontinence.

Methods

After anatomical and functional assessment of the patients’ EAS, a vastus lateralis muscle open biopsy was performed. Stem cells were extracted from the biopsy specimens and cultured in vitro. Cell suspensions were then administered to the EAS. Patients were scheduled for follow-up visits in 6-week intervals. Total follow-up was 12 months.

Results

All biopsy and cell implantation procedures were performed without complications. Nine of the patients completed a full 12-month follow-up. There was subjective improvement in six patients (66.7 %). In manometric examinations 18 weeks after implantation, squeeze anal pressures and high-pressure zone length increased in all patients, with particularly significant sphincter function recovery in five patients (55.6 %). Electromyographic (EMG) examination showed an increase in signal amplitude in all patients, detecting elevated numbers of propagating action potentials. Twelve months after implantation two patients experienced deterioration of continence, which was also reflected in the deterioration of manometric and EMG parameters. The remaining four patients (44.4 %) still described their continence as better than before implantation and retained satisfactory functional examination parameters.

Conclusions

Implantation of autologous myoblasts gives good short-term results not only in a subjective assessment, but also in objective functional tests. It seems that this promising technology can improve the quality of life of patients with fecal incontinence, but further study is required to achieve better and more persistent results.

Biological properties of human skeletal myoblasts genetically modified to simultaneously overexpress the pro-angiogenic factors vascular endothelial growth factor-A and fibroblast growth factor-4

Myocardial infarction results in cardiomyocyte loss and may eventually lead to cardiac failure. Skeletal myoblast transplantation into the scar area may compensate for this observed cell loss by strengthening the weakened myocardium and inducing myogenesis. Moreover, skeletal myoblasts may serve as potential transgene carriers for the myocardium (i.e., delivering pro-angiogenic factors, which may potentially improve blood perfusion in infarcted heart). We examined the influence of the simultaneous overexpression of two potent pro-angiogenic factors, fibroblast growth factor-4 (FGF-4) and vascular endothelial growth factor (VEGF), on human primary myoblast proliferation, cell cycle, resistance to hypoxic stress conditions and myogenic gene expression, as well as the induction of pro-angiogenic activities. We used a bicistronic plasmid vector encoding two factors introduced via an efficient myoblast electroporation method. The levels of overexpressed proteins were assessed, and their functionality at capillary formation was evaluated. This combined approach led to a high level of non-viral transient overexpression of both pro-angiogenic proteins, which proved to be potent regulators of blood vessel development assayed in capillary formation tests. We demonstrated in in vitro conditions that the transfection of human skeletal myoblasts with both FGF-4 and VEGF did not affect their basic biological properties such as the cell cycle, proliferation or expression of myogenic lineage-specific genes, and the modified cells adapted to oxidative stress conditions. Overall, the results obtained suggest that the applied combined approach with the use of two pro-angiogenic genes overexpressed in skeletal muscle stem cells may be an interesting alternative for the effective therapy of myocardial infarction in animal models and/or prospective clinical trials.

Transient and stable transfections of mouse myoblasts with genes coding for pro-angiogenic factors

Cardiomyocyte loss in the ischaemic heart can be the reason of many complications, eventually being even the cause of patient's death. Despite many promises, cell therapy with the use of skeletal muscle stem cells (SMSC) still remains to be modified and improved. Combined cell and gene therapy seems to be a promising strategy to heal damaged myocardium. In the present study we have investigated the influence of a simultaneous overexpression of two potent pro-angiogenic genes encoding the fibroblast growth factor-4 (FGF-4) and the vascular endothelial growth factor-A (VEGF-A) on a myogenic murine C2C12 cell line. We have demonstrated in in vitro conditions that myoblasts which overexpressed these factors exhibited significant changes in the cell cycle and pro-angiogenic potential with only slight differences in the expression of the myogenic genes. There was not observed the influence of transient or stable overexpression of FGF-4 and VEGF on cell apoptosis/necrosis in standard or oxidative stress conditions comparing to non transfected controls. Overall, our results suggest that the possible transplantation of myoblasts overexpressing pro-angiogenic factors may potentially improve the functionality of the injured myocardium although the definite proof must originate from in situ conducted pre-clinical studies.

Interleukin-1 superfamily genes expression in normal or impaired human spermatogenesis

Interleukin-1 (IL-1) is a pleiotropic cytokine that may play a role in contributing to the specific immune environment of mammalian testis and in regulating cell differentiation. We have determined the transcription activity of the IL-1 gene family (using real-time polymerase chain reaction (PCR)) in two main functional testicular compartments (interstitial and intratubular ones), and in tissue homogenates obtained from patients with fertility disorders (spermatogenic arrest and testicular tumors). We observed the prominent expression of gene coding for IL-1 receptor antagonist (IL-1RA) in a purified fraction of gametogenic cells (normal gonad). Caspase-1 (ICE - IL-1beta-converting enzyme) was highly expressed (on mRNA level) in interstitial compartments as well in testicular tumors (immune enhancement?). In addition we found, that the activity of IL-1RA gene decreased along spermatogenic alteration in an inversely related manner with IL-1alpha (from normal gonad through spermatogenic arrest to Sertoli cell only syndrome). Therefore, the quotient value of IL-1alpha/IL-1RA could potentially serve as the diagnostic molecular probe for spermatogenesis assessment. The precise level of mRNA for IL-1-IL-18 cytokines and their receptors, and specifically of the receptor antagonist in immune privileged gonad, could be one of the main factors responsible for maintaining testicular homeostasis, thus enabling generation of the mature spermatozoa.

Quantitative mRNA Analysis of IL-1 Gene System in Human Testis

PROBLEM

There is a growing body of evidence that interleukins exhibit modulatory activity on development of reproductive cells. In this context, there appears to be a role for IL-1, which is also produced in human testis. We have analysed transcripts of IL-1 gene system (IL-1alpha, IL-1beta, IL-1RI, IL-1RII and IL-1RA) to evaluate the possible link between the level of gene(s) transcription and their function.

METHOD OF STUDY

To determine the activity of gene transcription, a quantitative PCR with isotopic and/or nonisotopic detection was applied.

RESULTS AND CONCLUSIONS

We have detected differential expression of IL-1alpha and IL-1beta genes in separate functional compartments of a male gonad. A strong expression of IL-1alpha gene in an intratubular cell fraction was shown, while the IL-1beta expression seemed to be dominant in extratubular compartment of the male gonad. Abundant amounts of IL-1RA mRNA in gametogenic cells fraction slightly higher than in interstitium have also been found. IL-1RA is the most important regulatory molecule in IL-1 system, which down-regulates activity of both interleukins. Looking more closely at gene(s) differential expression it appears that IL-1alpha can be preferentially down-regulated by IL-1RA gene in intratubular fraction while the IL-1beta, through the "false" IL-1RII receptor in the interstitium. Genes coding for both receptors (IL-1RI and IL-1RII) showed, however, relatively low levels of transcription in both studied compartments. IL-1 genes system creates a complex intragonadal environment and the function of these genes is reflected by their respective distribution in the two main functional compartments of the testis.