27 Milligrams
08/05/10 18:34
Azithromycin is supposed to have some as-yet-to-be-determined anti-inflammatory effects in CF and that’s why it’s supposed to help sufferers of this disease, besides it’s antibiotic properties. But if you look at the studies on AZM, you will find that it is impacting the very same processes that the CFTR or the MRP protein would impact if they were there in the membrane of the CF epithelial cell. See below:
Antimicrob Agents Chemother. 2007 Mar;51(3):975-81. Epub 2007 Jan 8.
Azithromycin selectively reduces tumor necrosis factor alpha levels in cystic fibrosis airway epithelial cells.
Cigana C, Assael BM, Melotti P.
Cystic Fibrosis Center-Azienda Ospedaliera di Verona, piazzale Stefani 1, 37126 Verona, Italy.
Abstract
Azithromycin (AZM) ameliorates lung function in cystic fibrosis (CF) patients. This macrolide has been suggested to have anti-inflammatory properties as well as other effects potentially relevant for therapy of CF. In this study, we utilized three CF (IB3-1, 16HBE14o- AS3, and 2CFSMEo-) and two isogenic non-CF (C38 and 16HBE14o- S1) airway epithelial cell lines to investigate whether AZM could reduce tumor necrosis factor alpha (TNF-alpha) mRNA and protein levels by real-time quantitative PCR analysis and an enzyme-linked immunosorbent assay (ELISA), respectively. We studied the effects on the DNA binding of NF-kappaB and specificity protein 1 (Sp1) by an ELISA. Non-CF cells express significantly lower TNF-alpha mRNA and protein levels than an isogenic CF cell line. In CF cells, AZM treatment causes a 30% reduction of TNF-alpha mRNA levels (P < 0.05) and a 45% decrease in TNF-alpha secretion (P < 0.05), reaching approximately the levels of the untreated isogenic non-CF cells. In CF cells, NF-kappaB and Sp1 DNA binding activities were also significantly decreased (about 45 and 60%, respectively; P < 0.05) after AZM treatment. Josamycin, a macrolide lacking clinically described anti-inflammatory effects, was ineffective. Finally, AZM did not alter the mRNA expression levels of interleukin-6, a proinflammatory molecule not differentially expressed in CF and isogenic non-CF cells. The results of our study support the anti-inflammatory activities of this macrolide, since we show that AZM reduced the levels of TNF-alpha and propose inhibitions of NF-kappaB and Sp1 DNA binding as possible mechanisms of this effect.
Levels of tumor necrosis factor – alpha (TNF-a) and the activity of SP-1 (SP-1 is affected by zinc homeostasis, which is, in turn, affected by glutathione transport –or non-transport in the case of CF) are just two of the players that affect inflammation in CF lung disease. You can’t look at this disease in terms of inflammation and not see the effects of those components on increasing inflammation. And AZM tamps them down. What could AZM be doing that would cause that?
Well, I’ll give you a little hint: AZM also increases chloride ion transport. That should give you an idea right there. If you are increasing chloride transport in these cells, and you’re tamping down inflammatory factors, chances are pretty good that you’re inducing a protein that it functionally redundant to the CFTR protein, such as the MRP proteins. And here you go, boys and girls:
J Chemother. 2005 Aug;17(4):393-400.
Long-term azithromycin in cystic fibrosis: another possible mechanism of action?
Pradal U, Delmarco A, Morganti M, Cipolli M, Mini E, Cazzola G.
Cystic Fibrosis Center, Azienda Ospedaliera di Verona, Verona, Italy. ugo.pradal@azosp.vr.it
Abstract
Azithromycin is used for the treatment of cystic fibrosis lung disease, although its mechanisms of action are not completely understood. Besides its antiinflammatory and antimicrobial activities, one possibility could be the overexpression induction of the multidrug resistance-associated protein (MRP), which could affect chloride transport, thus overcoming the ion transport defect of cystic fibrosis. Seven patients were evaluated before and after 4 weeks of azithromycin treatment (500 mg once daily). Ion transport was studied in vivo by measuring nasal potential difference (NPD). MRP mRNA expression was studied in nasal cells by an internal standard-based semiquantitative RT-PCR assay. NPD was consistent with cystic fibrosis before treatment. After azithromycin treatment, sodium transport was still impaired, whereas a significant increase in chloride conductance was observed (p = 0.03). A significant direct correlation was found between MRP mRNA expression levels and NPD chloride response after azithromycin treatment (p = 0.04, r = 0.78). In conclusion, azithromycin may induce MRP overexpression and restore chloride conductance in the airways of cystic fibrosis patients. These findings suggest a new potential role of azithromycin in the treatment of cystic fibrosis pulmonary disease, i.e. the possibility to upregulate proteins whose function may, at least in part, compensate for the basic defect of cystic fibrosis.
Now, no doubt, AZM plays a role in the treatment of this disease. If it induces the expression of a functionally redundant protein, why are people who are on this drug still suffering exacerbations? Why are they still colonized with those same old nasty pathogens?
The answer to this question lies in the method of delivery of this drug. It’s given orally. And, anything given orally has to go through the liver—it’s called first pass hepatic metabolism. What this means is that if AZM can induce the expression of MRP in the lungs of CF patients (thereby replacing some of the missing CFTR protein with another protein that can do the same job), it can also induce it’s expression in the liver of these patients. Once that happens, less AZM can get into the bloodstream, and get to the lung cells, to induce the MRP. To overcome this, you have to get around first pass hepatic metabolism—in other words, get around the liver. The only way to do that is to administer the drug in a different manner—either IV or transdermally.
Obviously, you don’t want to go the IV route. Cystics have to do enough of that already, and although AZM does induce MRP expression, it is not necessarily the best inducer of it. The chemotoxins that were used in the young man to kill his cancer, that Lallemand wrote about, in 1997, are better at inducing MRP, and the induction lasts a lot longer, too. But, of course, you can’t take chemo drugs on a regular basis. They’re toxic, obviously.
Same story with oral colchicine as a therapy for CF patients. It induces functionally redundant proteins, and restores some of the chloride transport. See here:
Biochem Pharmacol. 2004 Jul 15;68(2):253-61.
Increased chloride efflux in colchicine-resistant airway epithelial cell lines.
Dragomir A, Roomans GM.
Department of Medical Cell Biology, University of Uppsala, Box 571, 751 23 Uppsala, Sweden. anca.dragomir@medcellbiol.uu.se
Abstract
Colchicine has been proposed as a treatment to alleviate chronic lung inflammation in cystic fibrosis patients and clinical trials are ongoing. Our aim was to investigate whether chronic exposure of cystic fibrosis cells to colchicine can affect their ability to transport chloride in response to cAMP. Colchicine-resistant cells were selected by growing in medium containing nanomolar concentrations of the drug. While microtubuli were affected by acute exposure to colchicine, they appeared normal in colchicine-resistant cells. Colchicine-resistant clones had higher expression of multidrug resistance proteins compared to untreated cells. Cystic fibrosis transmembrane conductance regulator (CFTR) labelling by immunocytochemistry showed no significant changes. The intracellular chloride concentration and basal chloride efflux of the cystic fibrosis treated cells increased significantly compared with untreated cells, while for the cAMP-stimulated Cl-efflux there was no significant change. The results suggest that colchicine promotes chloride efflux via alternative chloride channels. Since this is an accepted strategy for pharmacological treatment of cystic fibrosis, the results strengthen the notion that colchicine would be beneficial to these patients.
And here:
Mediators Inflamm. 1999;8(1):13-5.
Interest of colchicine for the treatment of cystic fibrosis patients. Preliminary report.
Sermet-Gaudelus I, Stoven V, Annereau JP, Witko-Sarsat V, Reinert P, Guyot M, Descamps-Latscha B, Lallemand JY, Lenoir G.
Service de Pédiatrie II, Hôpital Necker-Enfants Malades, Paris, France.
Abstract
Cystic fibrosis (CF) lung disease is characterized by persistent inflammation. Antiinflammatory drugs, such as corticosteroids and ibuprofen, have proved to slow the decline of pulmonary function although their use is limited because of frequent adverse events. We hypothesized that colchicine could be an alternative treatment because of its antiinflammatory properties and upregulatory effect on cystic fibrosis transmembrane regulator (CFTR) closely related proteins. We herein present results obtained in an open study of eight CF children treated with colchicine for at least 6 months. Clinical status was better in all patients and respiratory function tests significantly improved in five. Median duration of antibiotherapy decreased significantly. These preliminary results support our hypothesis of a beneficial effect of colchicine in CF patients and stress the need for a controlled therapeutic trial.
But, it’s got the same problems as any other ORAL drug that is used to induce MRP proteins—it also eventually induces these same proteins in the liver, which will then filter out the drug before it can get to the lungs.
So, hopefully, you’re curious enough by now, to ask yourself, “What the heck does ’27 milligrams’ have to do with anything I’ve read here so far”? Why that title?
Stay tuned, cowboys and Indians, and you’ll find out in the next blog post.
Antimicrob Agents Chemother. 2007 Mar;51(3):975-81. Epub 2007 Jan 8.
Azithromycin selectively reduces tumor necrosis factor alpha levels in cystic fibrosis airway epithelial cells.
Cigana C, Assael BM, Melotti P.
Cystic Fibrosis Center-Azienda Ospedaliera di Verona, piazzale Stefani 1, 37126 Verona, Italy.
Abstract
Azithromycin (AZM) ameliorates lung function in cystic fibrosis (CF) patients. This macrolide has been suggested to have anti-inflammatory properties as well as other effects potentially relevant for therapy of CF. In this study, we utilized three CF (IB3-1, 16HBE14o- AS3, and 2CFSMEo-) and two isogenic non-CF (C38 and 16HBE14o- S1) airway epithelial cell lines to investigate whether AZM could reduce tumor necrosis factor alpha (TNF-alpha) mRNA and protein levels by real-time quantitative PCR analysis and an enzyme-linked immunosorbent assay (ELISA), respectively. We studied the effects on the DNA binding of NF-kappaB and specificity protein 1 (Sp1) by an ELISA. Non-CF cells express significantly lower TNF-alpha mRNA and protein levels than an isogenic CF cell line. In CF cells, AZM treatment causes a 30% reduction of TNF-alpha mRNA levels (P < 0.05) and a 45% decrease in TNF-alpha secretion (P < 0.05), reaching approximately the levels of the untreated isogenic non-CF cells. In CF cells, NF-kappaB and Sp1 DNA binding activities were also significantly decreased (about 45 and 60%, respectively; P < 0.05) after AZM treatment. Josamycin, a macrolide lacking clinically described anti-inflammatory effects, was ineffective. Finally, AZM did not alter the mRNA expression levels of interleukin-6, a proinflammatory molecule not differentially expressed in CF and isogenic non-CF cells. The results of our study support the anti-inflammatory activities of this macrolide, since we show that AZM reduced the levels of TNF-alpha and propose inhibitions of NF-kappaB and Sp1 DNA binding as possible mechanisms of this effect.
Levels of tumor necrosis factor – alpha (TNF-a) and the activity of SP-1 (SP-1 is affected by zinc homeostasis, which is, in turn, affected by glutathione transport –or non-transport in the case of CF) are just two of the players that affect inflammation in CF lung disease. You can’t look at this disease in terms of inflammation and not see the effects of those components on increasing inflammation. And AZM tamps them down. What could AZM be doing that would cause that?
Well, I’ll give you a little hint: AZM also increases chloride ion transport. That should give you an idea right there. If you are increasing chloride transport in these cells, and you’re tamping down inflammatory factors, chances are pretty good that you’re inducing a protein that it functionally redundant to the CFTR protein, such as the MRP proteins. And here you go, boys and girls:
J Chemother. 2005 Aug;17(4):393-400.
Long-term azithromycin in cystic fibrosis: another possible mechanism of action?
Pradal U, Delmarco A, Morganti M, Cipolli M, Mini E, Cazzola G.
Cystic Fibrosis Center, Azienda Ospedaliera di Verona, Verona, Italy. ugo.pradal@azosp.vr.it
Abstract
Azithromycin is used for the treatment of cystic fibrosis lung disease, although its mechanisms of action are not completely understood. Besides its antiinflammatory and antimicrobial activities, one possibility could be the overexpression induction of the multidrug resistance-associated protein (MRP), which could affect chloride transport, thus overcoming the ion transport defect of cystic fibrosis. Seven patients were evaluated before and after 4 weeks of azithromycin treatment (500 mg once daily). Ion transport was studied in vivo by measuring nasal potential difference (NPD). MRP mRNA expression was studied in nasal cells by an internal standard-based semiquantitative RT-PCR assay. NPD was consistent with cystic fibrosis before treatment. After azithromycin treatment, sodium transport was still impaired, whereas a significant increase in chloride conductance was observed (p = 0.03). A significant direct correlation was found between MRP mRNA expression levels and NPD chloride response after azithromycin treatment (p = 0.04, r = 0.78). In conclusion, azithromycin may induce MRP overexpression and restore chloride conductance in the airways of cystic fibrosis patients. These findings suggest a new potential role of azithromycin in the treatment of cystic fibrosis pulmonary disease, i.e. the possibility to upregulate proteins whose function may, at least in part, compensate for the basic defect of cystic fibrosis.
Now, no doubt, AZM plays a role in the treatment of this disease. If it induces the expression of a functionally redundant protein, why are people who are on this drug still suffering exacerbations? Why are they still colonized with those same old nasty pathogens?
The answer to this question lies in the method of delivery of this drug. It’s given orally. And, anything given orally has to go through the liver—it’s called first pass hepatic metabolism. What this means is that if AZM can induce the expression of MRP in the lungs of CF patients (thereby replacing some of the missing CFTR protein with another protein that can do the same job), it can also induce it’s expression in the liver of these patients. Once that happens, less AZM can get into the bloodstream, and get to the lung cells, to induce the MRP. To overcome this, you have to get around first pass hepatic metabolism—in other words, get around the liver. The only way to do that is to administer the drug in a different manner—either IV or transdermally.
Obviously, you don’t want to go the IV route. Cystics have to do enough of that already, and although AZM does induce MRP expression, it is not necessarily the best inducer of it. The chemotoxins that were used in the young man to kill his cancer, that Lallemand wrote about, in 1997, are better at inducing MRP, and the induction lasts a lot longer, too. But, of course, you can’t take chemo drugs on a regular basis. They’re toxic, obviously.
Same story with oral colchicine as a therapy for CF patients. It induces functionally redundant proteins, and restores some of the chloride transport. See here:
Biochem Pharmacol. 2004 Jul 15;68(2):253-61.
Increased chloride efflux in colchicine-resistant airway epithelial cell lines.
Dragomir A, Roomans GM.
Department of Medical Cell Biology, University of Uppsala, Box 571, 751 23 Uppsala, Sweden. anca.dragomir@medcellbiol.uu.se
Abstract
Colchicine has been proposed as a treatment to alleviate chronic lung inflammation in cystic fibrosis patients and clinical trials are ongoing. Our aim was to investigate whether chronic exposure of cystic fibrosis cells to colchicine can affect their ability to transport chloride in response to cAMP. Colchicine-resistant cells were selected by growing in medium containing nanomolar concentrations of the drug. While microtubuli were affected by acute exposure to colchicine, they appeared normal in colchicine-resistant cells. Colchicine-resistant clones had higher expression of multidrug resistance proteins compared to untreated cells. Cystic fibrosis transmembrane conductance regulator (CFTR) labelling by immunocytochemistry showed no significant changes. The intracellular chloride concentration and basal chloride efflux of the cystic fibrosis treated cells increased significantly compared with untreated cells, while for the cAMP-stimulated Cl-efflux there was no significant change. The results suggest that colchicine promotes chloride efflux via alternative chloride channels. Since this is an accepted strategy for pharmacological treatment of cystic fibrosis, the results strengthen the notion that colchicine would be beneficial to these patients.
And here:
Mediators Inflamm. 1999;8(1):13-5.
Interest of colchicine for the treatment of cystic fibrosis patients. Preliminary report.
Sermet-Gaudelus I, Stoven V, Annereau JP, Witko-Sarsat V, Reinert P, Guyot M, Descamps-Latscha B, Lallemand JY, Lenoir G.
Service de Pédiatrie II, Hôpital Necker-Enfants Malades, Paris, France.
Abstract
Cystic fibrosis (CF) lung disease is characterized by persistent inflammation. Antiinflammatory drugs, such as corticosteroids and ibuprofen, have proved to slow the decline of pulmonary function although their use is limited because of frequent adverse events. We hypothesized that colchicine could be an alternative treatment because of its antiinflammatory properties and upregulatory effect on cystic fibrosis transmembrane regulator (CFTR) closely related proteins. We herein present results obtained in an open study of eight CF children treated with colchicine for at least 6 months. Clinical status was better in all patients and respiratory function tests significantly improved in five. Median duration of antibiotherapy decreased significantly. These preliminary results support our hypothesis of a beneficial effect of colchicine in CF patients and stress the need for a controlled therapeutic trial.
But, it’s got the same problems as any other ORAL drug that is used to induce MRP proteins—it also eventually induces these same proteins in the liver, which will then filter out the drug before it can get to the lungs.
So, hopefully, you’re curious enough by now, to ask yourself, “What the heck does ’27 milligrams’ have to do with anything I’ve read here so far”? Why that title?
Stay tuned, cowboys and Indians, and you’ll find out in the next blog post.