Effects of commonly used immunosuppressants on graft-derived fibroblasts

Cyclosporin A inhibits PDGF-BB induced hyaluronan synthesis in orbital fibroblasts

Orbital connective tissue changes are contributors to the pathogenesis in thyroid eye disease (TED). Activated fibroblasts respond to immune stimuli with proliferation and increased hyaluronan (HA) production. Cyclosporin A (CsA) was reported to be beneficial in the treatment of TED. PDGF isoforms are increased in orbital tissue of TED patients and enhance HA production. We aimed to study the effect of CsA on HA production and hyaluronan synthase (HAS1, 2 and 3) and hyaluronidase (HYAL1 and 2) mRNA expressions in orbital fibroblasts (OFs). Measurements were performed in the presence or absence of CsA (10 μM) in unstimulated or PDGF-BB (10 ng/ml) stimulated OFs. The HA production of TED OFs (n = 7) and NON-TED OFs (n = 6) were measured by ELISA. The levels of mRNA expressions were examined using RT-PCR. The proliferation rate and metabolic activity were measured by BrdU incorporation and MTT assays, respectively. Treatment with CsA resulted in an average 42% decrease in HA production of OFs (p < 0.0001). CsA decreased the expression levels of HAS2, HAS3 and HYAL2 (p = 0.005, p = 0.005 and p = 0.002, respectively.) PDGF-BB increased HA production (p < 0.001) and HAS2 expression (p = 0.004). CsA could reduce the PDGF-BB-stimulated HA production (p < 0.001) and HAS2 expression (p = 0.005) below the untreated level. In addition, CsA treatment caused a decrease in proliferation potential (p = 0.002) and metabolic activity (p < 0.0001). These findings point to the fact that CsA affects HA metabolism via HAS2, HAS3 and HYAL2 inhibition in OFs. In addition to its well characterized immunosuppressant properties, CsA's beneficial effect in TED may be related to its direct inhibitory effect on basal and growth factor stimulated HA production.

Multiparametric cardiovascular magnetic resonance characteristics and dynamic changes in asymptomatic heart-transplanted patients

OBJECTIVES

To describe the dynamic changes in cardiac deformation and tissue characteristics using cardiac magnetic resonance (CMR) in asymptomatic patients during 12 months after heart transplantation (HT).

METHODS

From April 2020 to January 2021, 21 consecutive HT patients without clinical symptoms were included in this prospective study. Multiparametric CMR was performed at 3, 6, and 12 months after HT. Twenty-five healthy volunteers served as controls.

RESULTS

During follow-up, a decline in left ventricular (LV) global radial strain (GRS) (p = 0.020) and right ventricular (RV) global longitudinal strain (GLS) (p < 0.001) and an increase in post-contrast T1 (p = 0.024) and T2 (p < 0.001) in asymptomatic HT patients occurred at 3 months, which normalized at 6 months postoperatively, compared with those in healthy controls. A decline in LVGLS (p < 0.001) and LV global circumferential strain (GCS) (p < 0.001) and an increase in native T1 (p < 0.001), T2 (p < 0.001), and extracellular volume (ECV) (p < 0.001) occurred at 3 months. Although most parameters improved gradually, LVGLS, native T1, and ECV remained abnormal compared with those in healthy controls at 12 months; only T2 and LVGCS were normalized at 6 months and 12 months, respectively. ECV was significantly correlated with LVGLS, LVGCS, and LVGRS.

CONCLUSION

Cardiac deformation and tissue characteristics were abnormal early after HT, although the patients were clinically asymptomatic. The dynamic changes in CMR characteristics demonstrate a gradual recovery of myocardial injury associated with transplantation during the first 12 months after HT.

KEY POINTS

• Multiparametric CMR can detect the dynamic changes of transplantation-associated myocardial injury. • Post-contrast T1, T2, LVGRS, and RVGLS values are normalized at 6 months after HT. • Native T1, ECV, and LVGLS values remain abnormal compared with those in healthy controls at 12 months after HT.

Nanoparticle formulation of mycophenolate mofetil achieves enhanced efficacy against hepatocellular carcinoma by targeting tumour-associated fibroblast

Hepatocellular carcinoma (HCC) is one of the most aggressive tumours with marked fibrosis. Mycophenolate mofetil (MMF) was well‐established to have antitumour and anti‐fibrotic properties. To overcome the poor bioavailability of MMF, this study constructed two MMF nanosystems, MMF‐LA@DSPE‐PEG and MMF‐LA@PEG‐PLA, by covalently conjugating linoleic acid (LA) to MMF and then loading the conjugate into polymer materials, PEG_5k‐PLA_8k and DSPE‐ PEG_2k, respectively. Hepatocellular carcinoma cell lines and C57BL/6 xenograft model were used to examine the anti‐HCC efficacy of nanoparticles (NPs), whereas NIH‐3T3 fibroblasts and highly‐fibrotic HCC models were used to explore the anti‐fibrotic efficacy. Administration of NPs dramatically inhibited the proliferation of HCC cells and fibroblasts in vitro. Animal experiments revealed that MMF‐LA@DSPE‐PEG achieved significantly higher anti‐HCC efficacy than free MMF and MMF‐LA@PEG‐PLA both in C57BL/6 HCC model and highly‐fibrotic HCC models. Immunohistochemistry further confirmed that MMF‐LA@DSPE‐PEG dramatically reduced cancer‐associated fibroblast (CAF) density in tumours, as the expression levels of alpha‐smooth muscle actin (α‐SMA), fibroblast activation protein (FAP) and collagen IV were significantly downregulated. In addition, we found the presence of CAF strongly correlated with increased HCC recurrence risk after liver transplantation. MMF‐LA@DSPE‐PEG might act as a rational therapeutic strategy in treating HCC and preventing post‐transplant HCC recurrence.

Mycophenolate mofetil, azathioprine and tacrolimus: mechanisms in rheumatology

The introduction of biologic DMARDs into rheumatology has resulted in a substantial reduction of the burden of many rheumatic diseases. In the slipstream of the success achieved with these biologic DMARDs, some conventional immunosuppressive drugs have also found use in new indications. Notably, mycophenolate mofetil, azathioprine and tacrolimus have made their way from solid organ transplantation drugs to become useful assets in rheumatology practice. Mycophenolate mofetil and azathioprine inhibit the purine pathway and subsequently diminish cell proliferation. Both drugs have a pivotal role in the treatment of various rheumatic diseases, including lupus nephritis. Tacrolimus inhibits lymphocyte activation by inhibiting the calcineurin pathway. Mycophenolate mofetil and tacrolimus are, among other indications, increasingly being recognized as useful drugs in the treatment of interstitial lung disease in systemic rheumatic diseases and skin fibrosis in systemic sclerosis. A broad array of trials with mycophenolate mofetil, azathioprine and/or tacrolimus are ongoing within the field of rheumatology that might provide further novel avenues for the use of these drugs. In this Review, we discuss the historical perspective, pharmacodynamics, clinical indications and novel avenues for mycophenolate mofetil, azathioprine and tacrolimus in rheumatology.

Mycophenolic acid reverses TGF beta-induced cell motility, collagen matrix contraction and cell morphology in vitro

The aim of this study was to elucidate functional and molecular effects of mycophenolic acid (MPA) on non-lymphatic, kidney epithelial cells treated with transforming growth factor (TGF). MPA effects were studied using HK2 cells incubated with EGF and TGF. The reversibility of these effects was verified using guanosine and 8-aminoguanosine. The following assays were applied: cell proliferation, viability, collagen matrix contraction, scratch wound closure, spindle index, FACS with anti-CD29 and anti-CD326, promoter demethylation of RAS protein activator like 1 (RASAL1), as well as gene expression of RASAL1, integrin 1ß (ITGB1) (CD29) and epithelial cell adhesion molecule (EpCam) (CD326). Cell proliferation was inhibited by increasing concentrations of MPA, whereas neither apoptosis nor cytotoxicity was detected. Stimulation with EGF and/or TGF led to a significant collagen matrix contraction that was successfully inhibited by MPA. In addition, scratch wound closure was inhibited by incubation with TGF alone or with EGF. Under the same conditions, cell morphology (spindle shape) and molecular phenotype (ITGB1(High)EpCam(Low)/ITGB1(Low)EpCam(High)) were both significantly changed, suggesting an epithelial to mesenchymal transformation. Cell morphology and motility, as well as molecular phenotype, were reversible after MPA treatment with TGF transformation in both presence/absence of EGF, thereby suggesting a correlation with the previously described antifibrotic effects of MPA. Dysregulation of TGF signal transduction appears to be related to progression of fibrosis. A TGF-transformed kidney epithelial cell line derived from human proximal tubules was used to study whether the immunosuppressive drug: MPA possesses any functional or molecular antifibrotic effects. Functional and morphological in vitro changes induced by both the TGF and epithelial-growth-factor were reversible by treatment with MPA. An inhibitory effect of MPA on the TGF pathway appears to be responsible for the previously described antifibrotic effects of the MPA in the COL4A3-deficient mouse model of renal fibrosis.

Effects of mycophenolate mofetil on kidney function and phosphorylation status of renal proteins in Alport COL4A3-deficient mice

Background

We investigated the effects of mycophenolate mofetil (MMF) on kidney function and on protein phosphorylation in a mouse model for the human Alport syndrome.

Methods

COL4A3-deficient (COL4A3−/−) mice were randomly allocated to receive a placebo (PLC COL4A3−/−) or MMF treatment (MMF COL4A3−/−). Wild type mice (WT) were used as controls. Changes in serum creatinine, total protein and blood urea nitrogen (BUN), concentrations of mycophenolic acid (MPA) and its glucuronide metabolite (MPAG), serum protein electrophoresis, urine dipstick chemistry and sediment were measured. Changes in the phosphorylation status of renal proteins and histology were analyzed.

Results

MMF influenced kidney function and protein phosphorylation. Serum creatinine and BUN were lower in MMF treated compared to PLC treated COL4A3−/− mice. Serum albumin and alpha-1 globulins were significantly decreased while serum creatinine, alpha-2 globulins, urine dipstick protein, leukocyte esterase, hemoglobin and red blood cells were all increased in both COL4A3−/− groups compared to WT. Differential 2DE-gel analysis identified six phosphorylated kidney protein spots that were significantly altered by MMF.

Conclusions

These data suggest that the MMF treatment in this murine model moderately improved kidney function and reversed the phosphorylation status of six renal phosphoprotein spots to that seen in WT mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-014-0056-z) contains supplementary material, which is available to authorized users.

Tacrolimus fails to regulate collagen expression in dermal fibroblasts

BACKGROUND

The purpose of this study was to investigate the effects of tacrolimus on human fibroblasts derived from unwounded skin, hypertrophic scars (HTS), and keloids. We hypothesized that tacrolimus, a potent anti-inflammatory and immunosuppressant drug known to attenuate solid organ transplant fibrosis, would block collagen expression in human dermal fibroblasts.

METHODS

We performed genomewide microarray analysis on human dermal fibroblasts treated with tacrolimus in vitro. We used principal component analysis and hierarchical clustering to identify targets regulated by tacrolimus. We performed quantitative polymerase chain reaction to validate the effect of tacrolimus on collagen 1 and 3 expression.

RESULTS

We identified 62, 136, and 185 gene probes on microarray analysis that were significantly regulated (P < 0.05) by tacrolimus in normal, HTS, and keloid fibroblasts, respectively. Collagen pathways were not blocked after tacrolimus exposure in any of the fibroblast groups; we validated these findings using quantitative polymerase chain reaction for collagen 1 and 3. Microarray gene expression of NME/NM23 nucleoside diphosphate kinase 1 and heterogeneous nuclear ribonucleoprotein H3-2H9 were significantly downregulated (P < 0.05) by tacrolimus in both HTS and keloid fibroblast populations but not normal fibroblasts.

CONCLUSIONS

Tacrolimus does not modulate the expression of collagen 1 or 3 in human dermal fibroblasts in vitro. Microarray gene expression of NME/NM23 nucleoside diphosphate kinase 1 and heterogeneous nuclear ribonucleoprotein H3-2H9 are blocked by tacrolimus in pathologic fibroblasts but not normal fibroblasts, and may represent novel genes underlying HTS and keloid pathogenesis. Tacrolimus-based anti-fibrotics might prove more effective if non-fibroblast populations such as inflammatory cells and keratinocytes are targeted.

Mitochondrial cyclophilin-D as a potential therapeutic target for post-myocardial infarction heart failure

The pharmacological inhibition or genetic ablation of cyclophilin-D (CypD), a critical regulator of the mitochondrial permeability transition pore (mPTP), confers myocardial resistance to acute ischemia-reperfusion injury, but its role in post-myocardial infarction (MI) heart failure is unknown. The aim of this study was to determine whether mitochondrial CypD is also a therapeutic target for the treatment of post-MI heart failure. Wild-type (WT) and CypD(-/-) mice were subjected to either sham surgery or permanent ligation of the left main coronary artery to induce MI, and were assessed at either 2 or 28 days to determine the long-term effects of CypD ablation. After 2 days, myocardial infarct size was smaller and left ventricular (LV) function was better preserved in CypD(-/-) mice compared to WT mice. After 28 days, when compared to WT mice, in the CypD(-/-) mice, mortality was halved, myocardial infarct size was reduced, LV systolic function was better preserved, LV dilatation was attenuated and in the remote non-infarcted myocardium, there was less cardiomyocyte hypertrophy and interstitial fibrosis. Finally, ex vivo fibroblast proliferation was found to be reduced in CypD(-/-) cardiac fibroblasts, and in WT cardiac fibroblasts treated with the known CypD inhibitors, cyclosporin-A and sanglifehrin-A. Following an MI, mice lacking CypD have less mortality, smaller infarct size, better preserved LV systolic function and undergo less adverse LV remodelling. These findings suggest that the inhibition of mitochondrial CypD may be a novel therapeutic treatment strategy for post-MI heart failure.

Graft morphology correlates with fibroblast activity in cardiac allograft rejection

Several extracellular matrix substances, such as hyaluronan and fibronectin, may affect graft viability by their involvement in cell adhesion and in migration. These substances are produced locally in the tissue by fibroblasts. The aim of this study was to investigate the activation state of intragraft fibroblasts under various immunosuppressive treatments and to correlate these with morphological parameters. Syngeneic (n = 5) and allogeneic rat (n = 5-6/group) heterotopic heart transplantations were performed. Allogeneically transplanted animals were immunosuppressed with cyclosporine, mycophenolate mofetil or prednisolone. After 10 days, the transplanted hearts were removed for subsequent isolation of intragraft fibroblasts and for evaluation of graft morphology. The hyaluronan synthesis of graft fibroblasts correlated with the cellular infiltration (p < 0.05) and the interstitial oedema (p < 0.05) of the cardiac grafts. In general, proliferation rate and hyaluronan production were of the same magnitude in fibroblasts from allogeneic hearts under immunosuppression with cyclosporine, mycophenolate mofetil or prednisolone as in fibroblasts from syngeneic grafts. A pool of fibroblasts isolated from cardiac grafts of non-immunosuppressed, allogeneically transplanted rats (n = 4) showed considerably higher levels. We concluded that fibroblast activity correlates to the viability of the tissue rather than to the specific drug used for immunosuppression.

Effects of postoperative cyclosporine ophthalmic emulsion 0.05% (Restasis) following glaucoma surgery

PURPOSE

To determine if postoperative topical cyclosporine 0.05% has any beneficial effect following trabeculectomy.

METHODS

This was an interventional, randomized, prospective, double-masked clinical trial of 44 consecutive patients with uncontrolled glaucoma requiring filtration surgery. Ocular surface disease index questionnaire and comprehensive ocular exam, including Schirmer's tear test 1, were performed. Patients underwent routine trabeculectomy, with or without phacoemulsification. The study group (n = 22) received cyclosporine 0.05%, and the control group (n = 22) received artificial tears. Patients were evaluated at 1 and 6 months post surgery. Outcome measures were intraocular pressure, success rate, bleb appearance, ocular surface disease index, Schirmer's tear test 1 and conjunctival inflammation.

RESULTS

Thirty-nine patients completed the study (19 in the study group, 20 in the control group). The mean baseline intraocular pressure was 23.8 +/- 12.6 mmHg in the study group and 25.9 +/- 10.6 mmHg in the control group (P = 0.513). Mean intraocular pressure at postoperative month 6 was 14.88 +/- 6.2 and 14.62 +/- 5.46 mmHg in the study group and control group, respectively (P = 0.837). There was no statistically significant difference in the mean values of Schirmer's tear test 1 and the level of conjunctival hyperaemia between the two groups at baseline, months 1 and 6 post surgery. The treatment group had a statistically significant decrease in ocular surface disease index score at 6 months (P = 0.003), indicating less severity of dry eye symptoms and significant reduction in ocular pain.

CONCLUSIONS

Topical cyclosporine 0.05% had no effect on postoperative bleb function and intraocular pressure following trabeculectomy, but improved subjective ocular surface symptoms in these patients.

Effects of mycophenolic acid on human fibroblast proliferation, migration and adhesion in vitro and in vivo

Mycophenolic acid (MPA) is a potent inhibitor of the inosine monophosphate dehydrogenase and used as an immunosuppressive drug in transplantation. MPA inhibits proliferation of T- and B-lymphocytes by guanosine depletion. Since fibroblasts rely on the de novo synthesis of guanosine nucleotides, it is assumed that MPA interacts with fibroblasts causing an increased frequency of wound healing problems. We show a downregulation of the cytoskeletal proteins vinculin, actin and tubulin in fibroblasts exposed to pharmacological doses of MPA using microarray technology, real-time polymerase chain reaction (PCR) and Western blot. This reduction in RNA and protein content is accompanied by a substantial rearrangement of the cytoskeleton in MPA-treated fibroblasts as documented by immunofluorescence. The dysfunctional fibroblast growth was validated by scratch test documenting impaired migrational capacity. In contrast, cell adhesion was increased in MPA-treated fibroblasts. The results of the cultured human fibroblasts were applied to skin biopsies of renal transplant recipients. Skin biopsies of patients treated with MPA expressed less vinculin, actin and tubulin as compared to control biopsies that could explain potential wound healing problems posttransplantation. The perspective of MPA-induced cytoskeletal dysfunction may go beyond wound healing disturbances and may have beneficial effects on (renal) allografts with respect to scarring.

Hormonal regulation of renomedullary hyaluronan

AIM

Hyaluronan (HA) is involved in renomedullary water handling through its water-binding capacity. This study addressed the effect of hormones involved in regulating fluid-electrolyte homeostasis on renomedullary HA content in vivo and in vitro.

METHODS

The kidneys from rats treated with L-NAME, indomethacin, vasopressin (AVP) or methylprednisolone (MP) during euvolaemia or water loading were analysed for HA by RIA, ELISA and histochemical staining. HA was measured in renomedullary interstitial cells treated with AVP, angiotensin II (Ang II) or a combination of AVP and Ang II.

RESULTS

Baseline renal cortical and medullary HA content was unaffected by 2 h of intravenous treatment with L-NAME (NOS inhibitor) or indomethacin (cyclo-oxygenase inhibitor), whereas AVP reduced medullary HA by 33%. During 2 h of acute water loading, diuresis was accompanied by an increase in renomedullary HA (+45%), but cortical HA was unaffected. In both L-NAME- and indomethacin-treated animals, the water loading-induced increase in renomedullary HA was absent, indicating involvement of NO and prostaglandins. After 7 days of MP treatment, medullary HA was reduced by 40%, but the water loading-induced elevation in HA remained. In cultured renomedullary interstitial cells, AVP reduced the HA content in the supernatant by 63%, and simultaneous treatment with Ang II reduced the HA content even further (95%).

CONCLUSION

AVP reduces HA content, and NO and prostaglandins are needed for the increase in HA during water loading.

Antifibrotic actions of mycophenolic acid

Mycophenolic acid (MPA) is a highly selective, non-competitive and reversible inhibitor of the inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme in the de novo biosynthesis of guanosine nucleotides. Mycophenolate mofetil (MMF, the ester prodrug of MPA) strongly inhibits both T- and B-lymphocyte proliferation and has now been widely used in the prevention of acute and chronic allograft rejection. Recent evidence, however, suggests that MMF is also capable of inhibiting the proliferation of non-immune cells. In various cell lines, e.g. smooth muscle cells, renal tubular cells, mesangial cells, and fibroblasts, MPA reduced or even abrogated proliferation in response to proliferative stimuli. In animal studies, MMF ameliorated renal lesions in immune-mediated disease, e.g. in the Anti-Thy 1.1 model and experimental lupus nephritis, but was also effective in non-immune-mediated renal damage, e.g. in the rat remnant kidney model or in a model of chronic cyclosporine nephrotoxicity in the rat. In humans, MMF reduced proteinuria in steroid-resistant nephrotic syndrome and had beneficial effects in the prevention and treatment of chronic allograft nephropathy and calcineurin inhibitor toxicity through the reduction of immune- and non-immune-mediated renal damage. MMF is well tolerated and has proven to be a relatively safe drug. Taken together, there is a growing body of evidence pointing to therapeutic applications of MMF other than immunosuppression, in particular the prevention of fibrosis.

Sirolimus impairs wound healing

BACKGROUND AND AIMS

Clinically, the immunosuppressive drug sirolimus, used in organ transplantation, appears to impair wound healing. Little is known about the mechanisms of action. We investigated the effect of sirolimus on wound healing, and we analyzed the expression of stimulating mediators of angiogenesis (VEGF, vascular endothelial growth factor) and collagen synthesis (nitric oxide) in wounds.

MATERIALS AND METHODS

Groups of ten rats underwent dorsal skin incision, and polyvinyl alcohol sponges were implanted subcutaneously. Beginning at the day of wounding, rats were treated with 0.5, 2.0, or 5.0 mg sirolimus/kg/day. Animals were killed 10 days later to determine wound breaking strength and reparative collagen deposition. Expression of VEGF and nitric oxide was studied in wounds.

RESULTS

Splenic lymphocyte proliferative activity was significantly decreased by sirolimus (p < 0.05). Sirolimus levels in wound fluid were found to be approximately two- to fivefold higher than blood levels (p < 0.01). Sirolimus (2.0 and 5.0 mg kg(-1) day(-1)) reduced wound breaking strength (p < 0.01) and wound collagen deposition (p < 0.05). This was paralleled by decreased expression of VEGF and nitric oxide in wounds.

CONCLUSION

Experimentally, our data show that sirolimus impairs wound healing, and this is reflected by diminished expression of VEGF and nitric oxide in the wound.

Inhaled delivery of aerosolized cyclosporine

Aerosolized cyclosporine was the first calcineurin inhibitor to be developed for inhaled administration. Its use as a topical immunosuppressant after lung transplantation is reviewed. Animal studies in transplant and non-transplant models are considered, as is nebulized delivery of the drug, including the results of scintigraphy and pharmacokinetic studies. Open label clinical studies of the drug for the treatment of chronic and acute lung transplant rejection are detailed. Placebo controlled trials for rejection prophylaxis are described and future directions for the drug are considered. Aerosol cyclosporine provides an excellent example of how inhaled aerosol delivery can provide therapeutic concentrations of drug in the lungs while minimizing the side effects associated with high systemic concentrations. In the case of lung transplantation, the drug is delivered directly to the airways, the location of the pathology resulting in most mortality in this population (chronic allograft rejection), maximizing the efficacy of this dose-dependent immunosuppressant.

Regulation of fibroblasts by activated and non-activated immune cells

BACKGROUND

Rejection of transplanted tissue is characterized by cell infiltration and interstitial edema. Graft fibroblasts and fibroblast products are partly involved in the regulation of both these phenomena. Knowledge about the mechanisms behind fibroblast activation may lead to new strategies to prevent rejection. This study investigated whether cells of the immune system have the capacity to regulate fibroblast activation.

METHODS

Fibroblasts isolated from rejecting heart transplants or from normal heart tissue were cultured in the presence of supernatants of stimulated or non-stimulated immune cells. The immune cells were challenged either in vitro (incubation with phytohemagglutinin) or in vivo (organ transplantation). Fibroblast proliferation and hyaluronan production were measured.

RESULTS

Normal, sub-confluent heart fibroblasts showed an increased proliferation rate in the presence of supernatants of activated immunocompetent cells, irrespective of if these cells had been stimulated in vitro or in vivo. As expected, proliferation rate and hyaluronan production were upregulated in fibroblasts isolated from rejecting tissue. However, supernatants of biopsy specimens obtained from non-rejecting organs (syngeneic transplants or normal hearts) had an inhibitory effect on the growth rate of confluent fibroblasts isolated from rejecting tissue.

CONCLUSIONS

We conclude that graft-infiltrating cells and immune cells activated in vitro have the capacity to stimulate fibroblasts, most probably as a result of the production and secretion of fibroblast-stimulating factors.