Pentoxifylline and skin inflammation

Pentoxifylline in the Treatment of Cutaneous Leishmaniasis: A Randomized Clinical Trial in Colombia

Addition of the immunomodulator pentoxifylline (PTX) to antimonial treatment of mucosal leishmaniasis has shown increased efficacy. This randomized, double-blind, placebo-controlled trial evaluated whether addition of pentoxifylline to meglumine antimoniate (MA) treatment improves therapeutic response in cutaneous leishmaniasis (CL) patients. Seventy-three patients aged 18−65 years, having multiple lesions or a single lesion ≥ 3 cm were randomized to receive: intramuscular MA (20 mg/kg/day × 20 days) plus oral PTX 400 mg thrice daily (intervention arm, n = 36) or MA plus placebo (control arm, n = 37), between 2012 and 2015. Inflammatory gene expression was evaluated by RT-qPCR in peripheral blood mononuclear cells from trial patients, before and after treatment. Intention-to-treat failure rate was 35% for intervention vs. 25% for control (OR: 0.61, 95% CI: 0.21−1.71). Per-protocol failure rate was 32% for PTX, and 24% for placebo (OR: 0.50, 95% CI: 0.13−1.97). No differences in frequency or severity of adverse events were found (PTX = 142 vs. placebo = 140). Expression of inflammatory mediators was unaltered by addition of PTX to MA. However, therapeutic failure was associated with significant overexpression of il1β and ptgs2 (p < 0.05), irrespective of study group. No clinical benefit of addition of PTX to standard treatment was detected in early mild to moderate CL caused by Leishmania (V.) panamensis.

The effect of caffeine on orthodontic tooth movement in rats

OBJECTIVES

to determine the effect of different doses of caffeine on orthodontic tooth movement (OTM) in rats.

MATERIALS AND METHODS

Forty male 250-300 g Sprague-Dawley rats were randomly divided into four groups of ten animals each and received 0 (control), 1 g/l, 2 g/l and 3 g/l caffeine in tap water for 3 days. Orthodontic appliances were ligated between the maxillary first molars and incisors on the 4th day of the study period. All rats were sacrificed after 2 weeks of treatment after which OTM was measured. Hematoxylin/eosin-stained sections of the molars were prepared and the mesial roots were examined for resorption-lacunae depth and osteoclast number. ANOVA was used for statistical analysis (P<0.05).

RESULTS

A significant decrease in OTM was observed only in the 2 g/l (P=0.043) and 3 g/l (P<0.01) caffeine-receiving rats compared to the control animals. Osteoclast counts and resorption-lacunae depths demonstrated significant differences between each of the caffeine groups and control rats (P<0.05). None of the variables showed significant differences between the caffeine groups (P>0.05).

CONCLUSION

According to our findings, one of the effects of caffeine consumption during orthodontic treatment in rats was decreased root resorption. Additionally, concentrations of 2 g/l and 3 g/l inhibited OTM which seems to be due to its influence on osteoclast numbers.

Effects of pentoxifylline on immediate and late-phase cutaneous reactions in response to anti-immunoglobulin E antibodies in clinically normal dogs

OBJECTIVE

To characterize the effects of pentoxifylline on the gross and microscopic variables associated with immediate and late-phase inflammation following injection of IgE-specific antibodies in the skin of clinically normal dogs.

ANIMALS

6 healthy adult mixed-breed dogs.

PROCEDURES

Intradermal injections (0.1 mL each) of PBS solution, histamine phosphate, and cross-linking rabbit-origin anti-canine IgE antibodies (3 injections/dog) were administered at 0 hours on day 0; wheal sizes were evaluated at 20 minutes, 6 hours, and 24 hours. Biopsy specimens of injected and noninjected skin were collected 24 hours after injection. On day 2, treatment with pentoxifylline (20 mg/kg, PO, q 8 h) was initiated and continued until day 30. For each dog, injection, measurement, and biopsy procedures were repeated on days 30 to 31 and on days 37 to 38 (ie, after discontinuation of pentoxifylline administration).

RESULTS

Pentoxifylline administration was associated with a significant decrease in wheal size at 6 and 24 hours (but not at 20 minutes) after injection of anti-canine IgE. Repeated injections performed 1 week after drug discontinuation revealed partial recovery of the 6-hour cutaneous reaction and complete recovery of the 24-hour cutaneous reaction. Pentoxifylline administration was also associated with inhibition of mast cell degranulation and significant decreases in the total numbers of cutaneous inflammatory cells and eosinophils, compared with pretreatment findings.

CONCLUSIONS AND CLINICAL RELEVANCE

In clinically normal dogs, pentoxifylline effectively impaired late-phase reactions but not immediate reactions at sites of intradermal injection of IgE-specific antibodies by inhibiting mast cell degranulation and recruitment of cutaneous inflammatory cells, especially eosinophils.

Pentoxifylline augments TRAIL/Apo2L mediated apoptosis in cutaneous T cell lymphoma (HuT-78 and MyLa) by modulating the expression of antiapoptotic proteins and death receptors

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) is a promising anticancer agent but cutaneous T lymphoma cells (CTCL) are less sensitive to TRAIL-induced apoptosis. Here, we report that pentoxifylline (PTX), a phosphodiesterase inhibitor, augments TRAIL-mediated apoptosis in HuT-78 and MyLa cells through modulating extrinsic death receptors and intrinsic mitochondria dependent pathways. Our results clearly show that PTX augments TRAIL-mediated activation of caspase-8 and induces cleavage of Bid, although PTX alone cannot activate caspase-8. This is followed by cytochrome c release and subsequent, activation of caspase-9 and caspase-3 and cleavage of poly (ADP ribose) polymerase (PARP). Combined treatment downregulates the expression of various antiapoptotic proteins including c-FLIP, Bcl-xl, cIAP-1, cIAP-2 and XIAP. PTX induces the expression of death receptors DR4 and DR5 on cell surface of both the cell types where c-Jun NH2-terminal kinase (JNK) pathway plays an important role. Moreover, combined silencing of DR4 and DR5 by small interfering RNA abrogates the ability of PTX to induce TRAIL-mediated apoptosis. Thus, this is the first demonstration that PTX can potentiate TRAIL-mediated apoptosis through downregulation of cell survival gene products and upregulation of death receptors.

Alginate-crosslinked chitosan scaffolds as pentoxifylline delivery carriers

To prevent fibrous encapsulation of implants, measures are taken to suppress inflammatory reactions around them. Sustained anti-inflammatory drug release from the scaffolds can potentially be a way to reduce inflammation around these implants. Alginate-crosslinked chitosan is often used to make biocompatible tissue engineered scaffolds. However, there is a lack of quantitative studies on the drug delivery properties of alginate-crosslinked chitosan scaffolds. For this study, chitosan, crosslinked with different concentrations of alginate, was made into porous scaffolds. Infrared and thermal gravimetric analyses showed polyelectrolyte complex formation between chitosan and alginate units. The alginate-crosslinked chitosan scaffolds were more hydrophilic, showed less swelling, had lower pentoxifylline (PTX) release efficacies, were more favorable for initial cell attachment, and were mechanically stronger and more resistant to enzymatic degradation when compared to non-crosslinked chitosan scaffolds. The differences became more significant as the concentrations of chitosan and alginate increased. Furthermore, in vitro tests showed that when PTX was slowly released from the scaffolds, it became more effective in suppressing the production of TNF-alpha and IL-6 by stimulated macrophage cells.

Chronic morphine administration enhances nociceptive sensitivity and local cytokine production after incision

BACKGROUND

The chronic use of opioids prior to surgery leads to lowered pain thresholds and exaggerated pain levels after these procedures. Several mechanisms have been proposed to explain this heightened sensitivity commonly termed opioid-induced hyperalgesia (OIH). Most of these proposed mechanisms involve plastic events in the central or peripheral nervous systems. Alterations in the abundance of peripheral mediators of nociception have not previously been explored.

RESULTS

In these experiments mice were treated with saline (control) or ascending daily doses of morphine to generate a state of OIH followed by hind paw incision. In other experiments morphine treatment was initiated at the time of incision. Both mechanical allodynia and peri-incisional skin cytokine levels were measured. Myeloperoxidase (MPO) assays were used to determine neutrophil activity near the wounds. The cytokine production inhibitor pentoxifylline was used to determine the functional significance of the excess cytokines in previously morphine treated animals. Mice treated chronically treated with morphine prior to incision were found to have enhanced skin levels of IL-1beta, IL-6, G-CSF, KC and TNFalpha after incision at one or more time points compared to saline pretreated controls. The time courses of individual cytokines followed different patterns. There was no discernable effect of chronic morphine treatment on wound area neutrophil infiltration. Pentoxifylline reduced cytokine levels and reversed the excess mechanical sensitization caused by chronic morphine administration prior to incision. Morphine treatment initiated at the time of incision did not lead to a generalized enhancement of cytokine production or nociceptive sensitization in excess of the levels observed after incision alone.

CONCLUSION

The enhanced level of nociceptive sensitization seen after incision in animals chronically exposed to morphine is associated with elevated levels of several cytokines previously reported to be relevant to this incisional pain model. The cytokines may be functional in supporting nociceptive sensitization because pentoxifylline reverses both peri-incisional skin cytokine levels and OIH. Opioid administration beginning at the time of incision does not seem to have the same cytokine enhancing effect. Approaches to postoperative pain control involving a reduction of cytokines may be an effective way to control excessive pain in patients chronically using opioids prior to surgical procedures.

Significance of endothelial dysfunction in the pathogenesis of early and delayed radiation enteropathy

This review summarizes the current state of knowledge regarding the role of endothelial dysfunction in the pathogenesis of early and delayed intestinal radiation toxicity and discusses various endothelial-oriented interventions aimed at reducing the risk of radiation enteropathy. Studies published in the biomedical literature during the past four decades and cited in PubMed, as well as clinical and laboratory data from our own research program are reviewed. The risk of injury to normal tissues limits the cancer cure rates that can be achieved with radiation therapy. During treatment of abdominal and pelvic tumors, the intestine is frequently a major dose-limiting factor. Microvascular injury is a prominent feature of both early (inflammatory), as well as delayed (fibroproliferative) radiation injuries in the intestine and in many other normal tissues. Evidence from our and other laboratories suggests that endothelial dysfunction, notably a deficiency of endothelial thrombomodulin, plays a key role in the pathogenesis of these radiation responses. Deficient levels of thrombomodulin cause loss of vascular thromboresistance, excessive activation of cellular thrombin receptors by thrombin, and insufficient activation of protein C, a plasma protein with anticoagulant, anti-inflammatory, and cytoprotective properties. These changes are presumed to be critically involved in many aspects of early intestinal radiation toxicity and may sustain the fibroproliferative processes that lead to delayed intestinal dysfunction, fibrosis, and clinical complications. In conclusion, injury of vascular endothelium is important in the pathogenesis of the intestinal radiation response. Endothelial-oriented interventions are appealing strategies to prevent or treat normal tissue toxicity associated with radiation treatment of cancer.

Photoimmunoprotection by UVA (320-400 nm) radiation is determined by UVA dose and is associated with cutaneous cyclic guanosine monophosphate

The immunomodulating properties of UVA radiation remain controversial. Here, we demonstrate in female inbred Skh:hr-1 mice that single subinflammatory UVA exposures between 1.61 and 580.5 kJ/m(2) are not immunosuppressive. Furthermore, UVA exposures between 16.13 and 580.5 kJ/m(2) provided dose-related immunoprotection against UVB-induced immunosuppression. Higher UVA exposures (870.8-1,161 kJ/m(2)) became inflammatory and immunosuppressive alone, and lost the photoimmunoprotective capacity. We previously reported that UVA photoimmunoprotection depends on the induction of cutaneous heme oxygenase-1, particularly its enzymatic product, carbon monoxide (CO). CO was suggested to activate cutaneous guanylyl cyclase (GC), as the specific GC inhibitor, 1H-(1,2,4)oxadiazolo-(4,3-a)quinoxalin-1-one (ODQ), abrogated CO photoimmunoprotection in the mouse. This study shows that cutaneous cyclic guanosine monophosphate (cGMP) concentration increased only following immunoprotective UVA doses, or immunoprotective topical CO treatment, and cGMP production was inhibited by ODQ. Conversely, cGMP concentration was increased by inhibition of its degradative phosphodiesterase (PDE) with topical sildenafil. The PDE-5 isoform was identified in normal mouse skin. Subsequently, a moderate concentration of sildenafil was shown to simulate the effect of UVA in protecting against photoimmunosuppression by solar-simulated UV radiation or its mediator cis-urocanic acid. Thus, cutaneous cGMP, controlled by its synthesis via CO-activated GC and its degradation by PDE-5, is strongly associated with UVA photoimmunoprotection.

Severe acute respiratory syndrome, a pathological immune response to the new coronavirus--implications for understanding of pathogenesis, therapy, design of vaccines, and epidemiology

Findings coming from autopsies and serum of SARS patients suggest an important immune-inflammatory implication in the evolution to respiratory distress. Conditions such as HIV infection or treatment with immunosuppressors (in cancer or autoimmune diseases) are not among the bad prognosis factors for development of distress. To date, there have been no reported case fatalities in children, probably due to their more immature immune system. Our conclusions follow: (1) The milder form of SARS in children and the apparent protective factor that immunosupression represent rules out a significant viral cytopathic effect (they would be the most affected). (2) The evidence for immune implication in distress strongly supports immunomodulators for therapy: phosphodiesterase inhibitors (due to their down-modulating activity on proinflammatory cytokines); inhaled corticoids (aimed at producing a local immunomodulation); teophylline or nedocromil sodium (which prevents inflammatory cell recruitment into the airway wall). (3) An early immunomodulatory therapy, based on the levels of proinflammatory cytokines and clinical parameters to evaluate the respiratory function such as arterial oxygen saturation, could prevent the occurrence of distress. (4) Vaccine design should consider the immune origin of distress. (5) Physicians should be aware of mildly symptomatic patients (children, immuno-compromised hosts) to avoid transmission to immunocompetent adults.

Necrobiosis lipoidica of the glans penis

We report a 65-year-old diabetic man with necrobiosis lipoidica occurring on the glans of penis. He was initially seen with chronic ulcerative balanitis that eventually healed with strict control of diabetes mellitus, cystostomy, and pentoxifylline, leaving heavily depressed scars. Penile necrobiotic palisading granulomas include necrobiosis lipoidica and granuloma annulare. On the basis of the literature review, these 2 diseases manifest different skin lesions.

Rolipram inhibits polarization and migration of human T lymphocytes

Phosphodiesterase inhibitors possess anti-inflammatory and immunomodulatory properties and seem to have a great potential in the treatment of inflammatory skin diseases; however, an overall study on the effects of specific phosphodiesterase inhibitors, such as rolipram on the processes involved in the extravasation of lymphoid cells has not been performed. In this work we have assessed the effect of rolipram on the adhesion, polarization, and migration of normal human T lymphocytes. We found that low concentrations of rolipram were able to inhibit significantly the adhesion of T cells to the beta1 and beta2 integrin ligands vascular cell adhesion molecule-1 and intercellular adhesion molecule-1. Rolipram also interfered with the activation of integrins, and significantly inhibited the homotypic aggregation of T lymphocytes induced by anti-beta1 and anti-alpha4 integrin chain monoclonal antibodies. In addition, rolipram had a downregulatory effect on the activation of T cells, and significantly diminished the expression of the activation antigens CD69, CD25, and CD98 induced by phytohemagglutinin. Finally, this drug inhibited the polarization and transendothelial migration of T lymphocytes induced by the chemokine CXCL12 (SDF-1) and the chemotactic cytokine interleukin-15. The results indicate that rolipram, at low concentrations, exerts an important anti-inflammatory and immunomodulatory effect, and suggest that this selective phosphodiesterase inhibitor may be an effective tool for the therapy of immune-mediated diseases.

A retrospective study regarding the treatment of lupoid onychodystrophy in 30 dogs and literature review

The treatment records of 30 dogs with lupoid onychodystrophy were evaluated retrospectively. Dogs were treated with fatty acid supplementation (n=18), doxycycline and niacinamide (n=12), tetracycline and niacinamide (n=10), pentoxifylline (n=6), prednisolone (n=5), azathioprine (n=1), clofazimine (n=1), or with combinations thereof. An excellent response was seen in almost half of the patients treated with tetra- or doxycycline in combination with niacinamide. Six of the dogs were maintained successfully on fatty acid supplementation. Spontaneous remissions and recurrences made evaluation of success rates difficult and emphasized the varied and often unclear etiology and natural course of the syndrome.

A retrospective study of canine and feline cutaneous vasculitis

Twenty-one cases of cutaneous vasculitis in small animals (dogs and cats) were reviewed, and cases were divided by clinical signs into five groups. An attempt was made to correlate clinical types of vasculitis with histological inflammatory patterns, response to therapeutic drugs and prognosis. Greater than 50% of the cases were idiopathic, whereas five were induced by rabies vaccine, two were associated with hypersensitivity to beef, one was associated with lymphosarcoma and two were associated with the administration of oral drugs (ivermectin and itraconazole). Only the cases of rabies vaccine-induced vasculitis in dogs had a consistent histological inflammatory pattern (mononuclear/nonleukocytoclastic) and were responsive to combination therapy with prednisone and pentoxifylline, or to prednisone alone. Most cases with neutrophilic or neutrophilic/eosinophilic inflammatory patterns histologically did not respond to pentoxifylline, but responded to sulfone/sulfonamide drugs, prednisone, or a combination of the two.

Oral pentoxifylline inhibits release of tumor necrosis factor-alpha from human peripheral blood monocytes : a potential treatment for aseptic loosening of total joint components

BACKGROUND

Pentoxifylline (Trental) is a methylxanthine-derivative drug that has been used for more than twenty years in the treatment of peripheral vascular disease. Pentoxifylline is also a potent inhibitor of tumor necrosis factor-alpha (TNF-alpha) secretion, both in vitro and in vivo, and has demonstrated efficacy in the treatment of certain animal and human inflammatory diseases. Pentoxifylline has a potential therapeutic role in the treatment of aseptic loosening of total joint replacement components because it inhibits TNF-alpha secretion by particle-stimulated human peripheral blood monocytes. The purpose of our study was to determine whether the particle-stimulated secretion of TNF-alpha by peripheral blood monocytes was inhibited in volunteers who had received pentoxifylline orally.

METHODS

Human peripheral blood monocytes were harvested from eight healthy volunteers and were exposed to three different concentrations of titanium particles or to 500 ng/mL of lipopolysaccharide as a positive control. The same volunteers were then given pentoxifylline (400 mg, five times per day) for seven days. Their peripheral blood monocytes were again isolated and exposed to experimental conditions, and the TNF-alpha levels were measured.

RESULTS

The peripheral blood monocytes from all eight volunteers showed a significant reduction in TNF-alpha release following oral treatment with pentoxifylline. This reduction was observed at exposures of 10(7) and 10(6) titanium particles/mL and in the lipopolysaccharide-treated group, but not at 10(5) particles/mL.

CONCLUSIONS

To our knowledge, this is the first study to demonstrate the ability of an oral drug to decrease the release of TNF-alpha from human peripheral blood monocytes exposed ex vivo to particle debris. TNF-alpha is involved in the pathogenesis of osteolysis and subsequent loosening of total joint arthroplasty components. The ability to suppress the release of TNF-alpha in patients with a total joint replacement may help to control osteolysis and to reduce the development of aseptic loosening. This effect could increase implant longevity and decrease the need for revision arthroplasty.

The effect of blood flow promoting drugs on cochlear blood flow, perilymphatic pO(2) and auditory function in the normal and noise-damaged hypoxic and ischemic guinea pig inner ear

The effect of blood flow promoting drugs, such as hydroxyethyl starch (HES) either of low or high molecular weight (HES 70, HES 200), pentoxifylline, ginkgo biloba, naftidrofuryl and betahistine, and various combinations of the drugs was studied in unexposed and noise-exposed (broad-band noise, bandwidth 1-12 kHz, 106 dB SPL, 30 min) guinea pigs. The results were compared without therapy and placebo (isotonic saline, NaCl). The cochlear blood flow (CoBF) and the partial pressure of oxygen in the perilymph (PL-pO(2)) were continuously and simultaneously recorded over a period of 210 min. In addition, cochlear microphonics (CMs), compound action potentials of the auditory nerve (CAPs) and auditory brain stem responses (ABRs) were registered. Noise-induced hearing loss (NIHL) paralleled a decrease of PL-pO(2). Both were found to occur before evidence of reduced CoBF. PL-pO(2) and CoBF declined progressively post-exposure, while CMs, CAPs and ABRs showed no further deterioration or signs of recovery up to 180 min after cessation of noise. Treatment started 60 min post-exposure, respectively after 90 min, without manipulation in unexposed animals, and was then studied for a further 120 min. In unexposed animals, CoBF increased significantly during infusion of HES 70, HES 200, pentoxifylline and betahistine. NaCl, ginkgo biloba and naftidrofuryl did not alter CoBF. PL-pO(2) decreased significantly during infusion of all administered drugs and combinations, except for NaCl. CMs, CAPs and ABRs remained constant, with the exception of increased ABRs after infusion of HES 70 and HES 200. In noise-exposed animals, a sustained therapeutic effect on cochlear ischemia was achieved only by HES 200 and pentoxifylline. HES 70, betahistine and ginkgo biloba compensated cochlear ischemia only during infusion; however, 30-60 min after termination of therapy, no significant difference of values for CoBF was observed compared to the untreated noise-exposed groups. NaCl and naftidrofuryl showed no effect on CoBF. None of the applied drugs had a sustained compensatory effect on cochlear hypoxia. CMs, CAPs and ABRs improved significantly after HES 70, HES 200 and betahistine, resulting in partial recovery of CMs, and partial (betahistine) or even full (HES 70 and HES 200) recovery of CAPs and ABRs. In contrast, NaCl, pentoxifylline, ginkgo biloba and naftidrofuryl had no therapeutic effect on NIHL.