Dr Nirala Jacobi:

Welcome to another episode of the SIBO Doctor Podcast. With me today is Dr Mark Pimentel who really needs no introduction to the SIBO community. He's the executive director of the MAST program or Medically Associated Science and Technology. He's professor of medicine at Geffen School of Medicine at Cedar-Sinai Medical Center in L.A. A few of Dr. Pimentel's most significant accomplishments include the discovery of rifaximin as a treatment for IBS. He also developed the first blood test for IBS based on IBS being derived from acute gastroenteritis; the antibody testing. He described the association between IBS and bacterial overgrowth, which forms the basis of microbiome therapies in this condition, as well as uncovering that methanogens are causing constipations in humans.

Dr Nirala Jacobi:

Thank you so much for joining me today, Dr. Pimentel. I've been looking so forward to this interview because we've been waiting for the release of this study that you've been hinting at for quite some time. And finally, you've published it, this long-awaited study on comparing the small intestinal microbiome in SIBO versus non-SIBO patients. So, tell us what you found.

Dr Mark Pimentel:

This has been actually a very, very good year for SIBO in a lot of respects because of the SIBO guidelines being published, the first large-scale, well, not the first, second med analysis, but the first large scale med analysis of over 25 papers showing the SIBOs presence in IBS. And then, finally, this paper, which we've been working on for a number of years through the REIMAGINE study to show that what is the right breath test cutoff, what is SIBO. And we have a lot of that we have reported even two weeks ago at the ACG, but let me just start with your question about that particular paper. So the key is a particular fig table in that paper, which shows that a breath test at 90 minutes with lactulose, if it rises more than 20, correlated with having SIBO by culture, so that is the first time we have a direct correlation and a specificity of over 80% against culture.

Dr Mark Pimentel:

The second was it was associated with elevations in Proteobacteria, which is what we see is part of SIBO, E. coli, Klebsiella. The third was that it was associated with increased gas by the patient. So we correlated with the patient's symptoms. But the fourth and the most, I think, meaningful result is that there are those out there, skeptics who say, "Well, but all of this hydrogen is coming from the colon." What we showed is that at 90 minutes, 20 part per million rise correlated with upregulated systems for producing hydrogen in the small intestine, because the upsurge were first from small intestine. So for the first time, we're showing that this isn't coming from the colon. This is coming from the small intestine. Those systems are upregulated in the metabolomics, and that's the right cutoff. So, that's one of the key points of the paper. The other key point is the type of bacteria that are part of SIBO, which is very interesting as well.

Dr Nirala Jacobi:

Yeah, moving right into that in terms of the Gammaproteobacteria, can you just explain to the listener what the difference between regular Proteobacteria, Gammaproteobacteria? What are we talking about here?

Dr Mark Pimentel:

Well, you remember those levels of life from the kingdom all the way down to species level, and Gammaproteobacteria is at one of those levels. But under Gamma, there is a series of different types of bacteria, but Proteobacteria is the next level down. And under Proteobacteria, there's also a series. But if you look at healthy controls, they don't have much E. coli or Klebsiella at all. But in SIBO, there is a tremendous amount of E. coli and Klebsiella. Everything has shifted to E. coli and Klebsiella. Even in the Proteobacteria phylum, it takes up almost half of the organisms in the small bowel when it comes to SIBO. In the normal, in a patient, it takes up maybe, I don't know, 10%, 15% of the organisms. So, it really is what we thought. It's weeds in the garden, and the two weeds every single time are Klebsiella and E. coli. Now, there's a few other players that if you want to get into, we can have some more interesting dialogue, but those are the key culprits.

Dr Nirala Jacobi:

And the other fascinating finding was that you could attribute certain symptoms to some of these Gammaproteobacteria, in particular, the Enterobacteriaceae being more associated with bloating. How did you actually manage to find that out?

Dr Mark Pimentel:

Well, these are very difficult statistical analysis because of the way that the data are structured, but we were able to correlate internally all those different things. So, what you want in science, and this is something that when we do science, we want to do it five different ways to prove that it's correct. So if they lines up as correct in five different ways, then it's more likely to be true. And in this case, the breath test lined up with the culture, lined up with the symptoms, lined up with hydrogen excess. Its metabolic production lined up with Proteobacteria or Enterobacteriaceae and E. coli. And so, everything lined up together. And so, that convergence means that it's more likely to be true.

Dr Nirala Jacobi:

Okay. So the other very fascinating finding that we've been all waiting for is looking, what does a normal microbiome supposed to look like? And what you found is that Firmicutes tend to make up the majority of the bacteria in non-SIBO patients. In terms of percentage-wise, over 60% of the normal microbiome tends to be short-chain fatty acid producers, and so in the Firmicutes phylum or... And then Actinobacteria happened to be 13%, and Proteobacteria, as you mentioned, about 10 to 11%, versus SIBO patients, which have this incredible predominance of Proteobacteria. And I was wondering because you released another study on functional dyspepsia that also had different ratios of these phyla in terms of Bacteroidetes and Proteobacteria. I mean, that's what we were really waiting for, is something to really understand, is the microbiome really associated with some of these disease states, especially functional dyspepsia as well? So what are we starting to understand in terms of an emerging picture of microbiome imbalances in these conditions?

Dr Mark Pimentel:

That's a great question. I'll point to a third paper, which is a paper that we're very fortunate to have published, and it made the cover of the figure that's the money shot made the cover of the journal in Digestive Diseases and Sciences. And what we did through the REIMAGINE study is we looked at all the patients study for non-SIBO and patients where we did double-balloon endoscopy. So we were able to culture and sequence duodenum, the jejunum, the ileum, or furthest distance we could get, and then the stool. And what we see is that the stool has no relationship to the small bowel. The stool is nearly half Bacteroidetes, another 40% Firmicutes and then a smattering of other things. But in the small bowel, there was almost no Bacteroidetes, so less than 10%. Firmicutes, actinomycetes or Actinobacteria, and Proteobacteria make up the bulk of that area, of that part.

Dr Mark Pimentel:

The other thing that was so interesting in that study was people say, "Well, the closer you get to the colon, the more it's going to look like." So that was another myth that we busted. The second is that the bacteria get exponentially higher the closer you get to all the stool in the colon. No, it's almost the same all the way down. There's incremental slight increases, but the small bowel is almost uniformly the same, which means that potentially, you could sequence to duodenum, and that represents the entire small intestine, so because that's what we were seeing. But the point is we have a very, very good sense of what is normal and we're getting closer and closer to that. In regards to your functional dyspepsia, which has more to [inaudible 00:10:05], we're moving on a particular area as well.

Dr Nirala Jacobi:

That's great. One question about what you just said about the uniformity of the microbiome in the small intestine, I had listened to your co-presenter or co-investigator, I think she was part of your team, Dr. Leite, who presented at the DDW the year prior to you publishing the story. And one thing that I heard from that, and correct me if I'm wrong, is that they only really sequenced the duodenum because there was such difference in duodenum and ileum in these patients. Did I misunderstand that?

Dr Mark Pimentel:

So in certain patients, we do see some remarkable differences, but in the general pool, we see not as many differences. Of course, if you start to look at the species level or the genus level, you're going to see differences as you go down. But the basic structure of the microbiome in the phylum and some of the... Not quite down to genus level. Because when we do sequencing, we can't always get to species level. So we get a little bit shaky ground when we get to that level anyways, but there are differences if you really dig deep. But principally, the structure is the same. You can see that in the figure on the Digestive Disease and Sciences paper.

Dr Nirala Jacobi:

Okay. Great. Thank you. Of course, your study begs the question, where is Methanobrevibacter fitting into all this and why was this not also assessed at the same time?

Dr Mark Pimentel:

So without Methanobrevibacter doesn't get picked up very easily in conventional sequencing. So we're actually doing qPCR for M. smithii right now, and we will have an abstract at DDW that describes its location. So I can't say what it is yet, but we have all of that and then the colon or stool, then we'll have that result then.

Dr Nirala Jacobi:

You always have been one of those cards you have thought or 10 up your sleeve when it comes to hydrogen sulfide and releasing certain data to us. So we're still be waiting with bated breath. But do you think that SIBO will be reclassified when it comes to methanogens?

Dr Mark Pimentel:

Well, I think we did reclassify it with the SIBO guidelines in February. The American College of Gastroenterology published the first, and this is the first time they've endorsed a guideline on small intestinal bacterial overgrowth. It says two things. It says that everybody recognizes SIBO is important. Everybody recognized in that guideline that SIBO was common in IBS as well. So that guideline, the evidence for that is very strong or accumulating. So we suggested in the guideline, even that IBS patients should be tested for SIBO because it would be beneficial to them. But I guess when I'm thinking about your question, you were asking... I lost track of your initial question.

Dr Nirala Jacobi:

That's okay. Well, maybe just talk to us about the guidelines because there was a new intestinal methanogen overgrowth proposed change to the SIBO-C designation or the constipation-dominant, which is obviously related to methane. And we always grouped SIBO-C in alongside SIBO-D. And you, from the very beginning, have alluded to this idea of really separating these two conditions out. And my question I guess is are we any closer to that? And will there be two different guidelines? Is SIBO-C a real thing? Is it actually just IMO?

Dr Mark Pimentel:

Yeah, I did recall just as you were talking about the IMO. Yes, the SIBO guidelines basically did break SIBO down into two categories, IMO, which is not really... So because methanogens are not bacteria, they can't be called B bacteria. So the SIBO didn't work, and we don't know if it's small intestinal or [inaudible 00:13:58] for methanogens, so we kept it generic as intestinal. So it could be large intestinal. It could be small intestinal. So IMO is the new acronym for methanogens. But yeah, you're right. I mean, I think what we've tried to say is that we know food poisoning and this autoimmunity that we've been talking about, the CdtB toxin, the antibodies to CdtB, the antibodies to vinculin or autoimmunity that gets created, that really creates the IBS-D and mixed. And then the C, it doesn't work that way. That's not how it originates. And the methanogens seem to be an important player there.

Dr Mark Pimentel:

We don't understand why people have too many methanogens, so it doesn't quite fit in the scheme of food poisoning, then too many methanogens. That doesn't work. We can't find that happening. So we have two categories, but H2S was launched two or three weeks ago. So we have lot of things we can talk about now if you want to.

Dr Nirala Jacobi:

Yes, I really do. I would like to talk about this. And what Dr. Pimentel is alluding to is, of course, the release of the trio test, which includes measuring levels of hydrogen sulfide, as well as methane and hydrogen. So, tell us more about this test that is now available in America only.

Dr Mark Pimentel:

Yeah. Well, I'm sorry for that, but it shortly will be available elsewhere. So the thing about developing H2S, it was very complicated because H2S is a reactive chemical, so it can convert into other things. It can stick to things. So it was a lot of things that had to be done to create the appropriate transport for it using very high tech materials. You had to also create new valves on the bags. You had to then develop a whole new instrument because you can't retrofit other instruments for H2S. And then you had to do clinical trials. We did two. We did one clinical trial. So now we're getting to data. One clinical trial that said that if you just want it to measure hydrogen and methane, the instrument is exactly giving you the same results as prior instruments. So that the linearity of that is over 90%. So that's perfectly works just as well as anything else.

Dr Mark Pimentel:

The question is, which is more accurate? Well, the sensors on this are accurate to 0.2 ppm. On other instruments, it's two ppm. So it's more accurate, more sensitive to this, to the methane and hydrogen. But H2S was added, and so we had to do a second study to clinically validate what is the level of H2S that characterizes healthy, that characterizes constipation patients with methane, and that characterizes the diarrhea patient coming to your office. And we determined that with the new technology, with the new bag system, with the new instrument, and with the new process, it's five parts per million. So over five parts per million, you are H2S positive. And the higher you are on H2S, the more diarrhea you have. And we're already starting to see some very interesting patterns and examples of what happens when you combine this into a three gas breath test or what we call trio-smart.

Dr Nirala Jacobi:

Before this trio test was available or the hydrogen sulfide assessment was available, as practitioners, we've only really ever had this flat-lining test result as a guide, general guide, which really was not always accurate. So, what are you seeing with the results that you find? When hydrogen sulfide is above five parts per million, how often is hydrogen actually flat-lined and methane flat-lined in those cases?

Dr Mark Pimentel:

Well, there's a number of things we're seeing. If you don't measure the third gas, you're missing about 20 to 25% of people who might be abnormal, especially in the diarrhea category. The second thing is flat-liners are indeed hydrogen sulfide. The third part, which is interesting, and all these years of doing SIBO work, I've had this question come to me many times, "Well, my patient had a hydrogen of 30 at 90. It was positive. I gave them antibiotics and they came back and then we just didn't see it." So what they did with the antibiotics is they got rid of the hydrogen sulfide producers, and now all the hydrogen goes up. Those are the kinds of things we were seeing, and now we can see it real time.

Dr Mark Pimentel:

One interesting anecdote is that it's very rare, but we do see patients with all three gases. I had one of my sickest patients finally did the trio-smart just a few days ago. She has very high levels of all three gases, hard to understand what that means, I mean, why she is so profoundly affected. But generally when methane is present, regardless of the H2S, you're constipated. Methane is superior in producing the phenotype. So we haven't decided whether we should be doing the breath tests with looking specifically for hydrogen sulfide in patients with constipation, but there are examples. But either way, it measures hydrogen and methane, so you'll get your methane enhancer, and now you're adding the hydrogen sulfide to it.

Dr Nirala Jacobi:

So how often are you finding hydrogen sulfide be elevated and the patient has more of a mixed pattern and not diarrhea? Are they're always diarrhea-dominant?

Dr Mark Pimentel:

So the amount of hydrogen sulfide is proportional to the patient's diarrhea. So the higher the hydrogen sulfide, the more dominant the diarrhea is. In what we saw, and we haven't published this yet so I can't give you the exact ranges, but we did see higher hydrogen sulfide in patients with IBS that were higher than normal, but they weren't more than five. So more than five is the threshold to push the patient over into the diarrhea category. And I can't be more specific than that because we're submitting that to DDW, but there's a lot of details in all of that, that will be published in April, May, but hydrogen sulfide adds a lot to the test.

Dr Mark Pimentel:

There was a doctor from Northern California called me and had a hydrogen sulfide in his patient that was off the chart, literally at the highest number on the scale. And the patient had lymphocytic colitis. So we know hydrogen sulfide is proinflammatory and can be associated with ulcerative colitis and other inflammatory bowel diseases as well. I think we're going to get a lot of interesting research out of looking at hydrogen sulfide further, besides just what we already know in IBS and SIBO.

Dr Nirala Jacobi:

And that's really fascinating actually. I mean, there's a lot of, yeah, as you mentioned, research on ulcerative colitis. There's a recent study on some dietary factors in that, but in terms of hydrogen sulfide. About gas dynamics, really, because in one of your talks, you mentioned it takes actually quite a lot longer time to produce methane from hydrogen. Are we seeing that same time issue with hydrogen sulfide or is that perhaps converted faster to hydrogen sulfide?

Dr Mark Pimentel:

You see the exact same thing with hydrogen sulfide. So it fits in the notion that the lactulose speeds the hydrogen producers. Hydrogen producers would be hydrogen and then down the line, [inaudible 00:21:07]. And then they produce hydrogen sulfide or methane. In general, most patients are either methane or hydrogen sulfide, not both. It's just the rare occasion when they're all there. But yeah, I mean, it works and behaves just like methane.

Dr Nirala Jacobi:

This is a question that I've pondered for a while is should we extend the time period or the window of positivity in a test for methane and for hydrogen sulfide? In other words, should we go beyond 90 minutes knowing that it takes a bit longer to actually produce these gases?

Dr Mark Pimentel:

So I got to base my comments on what science we have so far. So you might be right, maybe we should go longer. What we did in our testing is we did two hours. That's what the North American Consensus suggests. And the test results that we were getting correlated perfectly with diarrhea. So with that science, it seems like what we're doing currently with two hours appears to work and appears to discriminate the diarrhea patient and the non-diarrhea patient. However, as you put it, it could be that three hours might be better. So we'll leave it to scientists. Maybe we'll do it. Maybe somebody else will do it to see if three hours might be better, but we think it behaves like methane and we don't need the extended time.

Dr Nirala Jacobi:

And when hydrogen sulfide is above five parts per million at any point in the test, would you consider that to be significant? In other words-

Dr Mark Pimentel:

Correct.

Dr Nirala Jacobi:

... timing just like with methane, in the end, it might not really matter. It might be more of an intestinal hydrogen sulfide overgrowth rather than just small intestinal hydrogen sulfide overgrowth.

Dr Mark Pimentel:

Right. And that's the other thing we're going to have to figure out, is it intestinal or large intestinal, or where is that? But I think it's the same as methane. Any point in time, more than five, any point in time, more than 10, you're a methane producer or you're a hydrogen sulfide producer. But remember, hydrogen sulfide and methane fight each other. They're fighting for the same ingredient, which is hydrogen. So data from the '90s, and I'm not a fan of quoting the '90s because a lot of what we've shown now disproves some... I mean, there were data, but the comments from the '90s and review articles on methane from the '90s that said methane was in Earth, it didn't cause anything, and that's not true. We now know that's not true. But data from the '90s do suggest that H2S is contributing to diarrhea and inflammation and all of this stuff, and we just have to continue to confirm it, but we don't know where it's located, whether it's small intestine or large intestine.

Dr Nirala Jacobi:

I'm sure you are also probably going to say you're withholding that information about who actually or what organism produces the hydrogen sulfide. Is that correct? You know what it is?

Dr Mark Pimentel:

I'm holding that information. Yes, [crosstalk 00:24:20].

Dr Nirala Jacobi:

Okay. All right. Is it perhaps a situation where it is the same culprit, where we're seeing also Proteobacteria? I know you can't really talk about it, but I'm just cogitating out loud because under certain circumstances, Klebsiella can produce all sorts of metabolites. Is it more of a milieu type of situation, where organisms that are in that phylum are also perhaps producing hydrogen sulfide? I mean, am I making sense?

Dr Mark Pimentel:

Yeah. Well, I can't give you an answer to that question. Not yet. Not yet.

Dr Nirala Jacobi:

Okay. All right.

Dr Mark Pimentel:

It might be answered, but I mean, the problem is we won't be able to publish it if we divulge all these things that we already know.

Dr Nirala Jacobi:

Okay.

Dr Mark Pimentel:

But let's say it this way, it's not what you expect.

Dr Nirala Jacobi:

Ooh, the [crosstalk 00:25:09] plot thickens. Yes.

Dr Mark Pimentel:

Exactly.

Dr Nirala Jacobi:

Okay. All right. [crosstalk 00:25:13].

Dr Mark Pimentel:

It's never what you expect. That's what I found in science is it's never what you expect. But my train of thought got run over when I was started speaking, but I did want to say that the hydrogen sulfide and the methanogens are like coyotes and wolves trying to eat the hydrogen, and somebody's got to win. Somebody's got to be the dominant organism. And so when the methanogens, when generally speaking, there's no room for the hydrogen sulfide producers and they diminish in your microbiome or vice versa. But on the rare occasion, which I did mention that they can all be there together, the methane dominates the symptoms causing constipation.

Dr Nirala Jacobi:

And just as a last also thought on the question I had about different gas levels, how often do you see hydrogen elevated in SIBO range, but also hydrogen sulfide present?

Dr Mark Pimentel:

Quite often. Quite often. So we see a lot of patients like that because we see a lot of patients like that with methane also, that the hydrogen is not zero or one, one, one, one. Some patients are like that with methane, but others are not. And so you need to fuel, so you need hydrogen. So it's pretty common that you get hydrogen and hydrogen sulfide together. And it goes back to something I said earlier, where you see hydrogen, so you know there's the fuel for hydrogen sulfide. You give the antibiotic and the hydrogen goes up because you didn't know there was hydrogen sulfide there. And so now we know everything.

Dr Mark Pimentel:

So as we start to treat with antibiotics and we follow the breath test, we're going to start to see what we're doing and how it's changing the dynamic of the patient. I'm going to give you an example. So sometimes you give antibiotics to a patient, then they get diarrhea. Is that because you got rid of the methane and the hydrogen sulfide goes up and hydrogen sulfide causes diarrhea? Is that what's happening? I mean, all of these things now become an opportunity for understanding the microbiome better.

Dr Nirala Jacobi:

And in terms of treatment of hydrogen sulfide, what are you finding to be very effective?

Dr Mark Pimentel:

Well, that's the mystery. We're still testing.

Dr Nirala Jacobi:

Okay.

Dr Mark Pimentel:

We do use rifaximin. We are starting to get some of our first patients back and we haven't gotten the second breath test. That's only been available for two, three weeks here. So we are treating and we're seeing what works and what doesn't. So in a few weeks, we'll have some idea of what's working for that particular gas, but we are also starting a new trial. It's supposed to start today actually, the IRB got approved yesterday on a whole new formulation that we think is five to 10 times better than what we've been doing before. That I can't talk about also.

Dr Nirala Jacobi:

Of course not.

Dr Mark Pimentel:

But I think for next time, right?

Dr Nirala Jacobi:

Okay. Yes.

Dr Mark Pimentel:

I'm super, super excited. I'm super excited because I think that we need to do better. I mean, rifaximin is great, but when only 44% of IBS patients get better, we can do better than that. And I think we've got something that will, so let's see.

Dr Nirala Jacobi:

Very, very exciting

Dr Mark Pimentel:

You won't know until you study it.

Dr Nirala Jacobi:

Mm-hmm (affirmative). Going back to the study that I mentioned before on the functional dyspepsia, I'm a little bit fascinated with functional dyspepsia because it is a bit of an elusive condition that has many different etiologies and contributing factors. But in this study that I mentioned entitled Gut Microbiota Dysbiosis in Functional Dyspepsia that you released earlier this year in May, you also found higher levels of anti-CdtB antibodies actually be present in functional dyspepsia. How do you explain that in terms of these patients are not necessarily having SIBO, they actually have more of a dysbiosis or an imbalance of microbiota, yet they have also potential motility disorders based on these antibodies?

Dr Mark Pimentel:

Yeah. What we're understanding, and a lot of people around the world who study functional dyspepsia more than I do recognize that there's a subset of functional dyspepsia that started from food poisoning. So you mentioned in your questions, CdtB antibodies may be important in that subset. So again, suggesting that that toxin is important there as well. There's a tremendous overlap between functional dyspepsia and IBS. So many people with functional dyspepsia and IBS and vice versa, and so there wasn't like a magic dividing line of the pylorus that says, "Hey, damage to the nerves stops up here." So often, it overflows into the small bowel. There's also growing evidence of SIBO in functional dyspepsia. And so, it's another area that continues to be looked at, and there's more and more data coming. So, stay tuned for that.

Dr Mark Pimentel:

But I did want to mention that we had this other paper that finally this summer is another seminal piece of work that continues to prove the field is that we injected rats with cytolethal distending toxin, and they developed IBS, and they developed SIBO, and they developed anti-vinculin antibodies. So it's the first comprehensive study in animals to show that we can create IBS with just CdtB toxin, and that's in Neurogastroenterology and Motility. So I think lots happened this year, despite COVID, to advance the field of SIBO and these patients who struggle with this condition.

Dr Nirala Jacobi:

Yeah, it's been a really busy year in that regard. Another question on the anti-vinculin and anti-CdtB antibody tests, and actually, I had this conversation with Alison and she asked me to ask you this question, which was about levels of these two antibodies and severity of illness and length of time that people may need to be on prokinetics. Is that proportionate to the amount of antibodies that we find? In other words, the higher the antibodies, the longer people have to be on prokinetics. Do you see that correlation?

Dr Mark Pimentel:

There are patients who have just anti-CdtB positive, and I've seen those patients resolve their IBS over time. And so, that's really good. Good to know. The second is when anti-vinculin is high, that's one thing. When it's really high, it's more severe. Those patients tend to be more refractory. And so, yes, they're more likely to use a prokinetic. They're more likely to need chronic prokinetic in my experience. So this is not published science, this is just experience. And some of them at the highest levels are more likely to require chronic rifaximin even, because I am not able, even with prokinetics, to keep it from coming back. So we do a number of things in that situation.

Dr Nirala Jacobi:

Okay. Just a couple more questions, and we're done. One was actually I forgot to follow up your methane conversation with, have you seen any kind of correlation with SIFO be more prevalent in people with high methane? There's some thought that they might be mutual growth promoters. And is there any science to back that up at this point?

Dr Mark Pimentel:

So there was no science to back that up that I'm aware of. We do have sequencing data and we're able to look for fungus, but we haven't actually done libraries with this fungus yet. So I would not venture a guess at this point.

Dr Nirala Jacobi:

Just clinically I do seem to see some correlation. And I had a really interesting conversation with Dr. Sam Rahbar down in your neck of the woods about this topic that we're seeing just clinically, but obviously more research is needed in that area. The lovastatin study, where are we at with that, lovastatin and methane?

Dr Mark Pimentel:

So the results of that study where there was a futility analysis done, and it didn't show much benefit between placebo and the two arms of the lovastatin. We know lovastatin works. So it could be a formulation issue. It's not going to where it's supposed to get to. We're not sure, but we have to go back to the drawing board. In the lab, it works perfectly, but sometimes what works in the lab doesn't work in the human. And so the question is, does it not work at all in humans, or we just need to redesign it so that it's delivering more carefully or more closely to where the methanogens are? So disappointing, it was a lot of work, a lot of work to get to that point.

Dr Nirala Jacobi:

That was a lot of work. And listeners, we've been talking like you've all been in the loop for the last 10 years. And it was basically a study that looked at time-release lovastatin in the treatment of methane-dominant or IMO, intestinal methanogen overgrowth. Right. So concluding this conversation, it really sounds like we are one step further in really fully understanding the different states that exist in the small intestine in terms of promoting Proteobacteria overgrowth, hydrogen sulfide, hydrogen, and methane. Methane, I'm super curious what you're going to find out in terms of location and interplay between different phyla, really. So thank you, Dr. Pimentel. As always, it's always so enlightening to talk to you, and thank you so much for all you do for the field of IBS. And do you have any last minute clinical nuggets, pearls, anything?

Dr Mark Pimentel:

Well, I think you dug pretty deep for the nuggets. So I think we're good, but there's always more coming. There's always more work we're trying to achieve. Our goals are a little more concrete than they used to be, which is a good thing. It means we're honing in on better ways to treat. We know the organisms now. And so, we're getting better at targeting how we treat this condition.

Dr Nirala Jacobi:

Wonderful. Thank you so much. And until next time, stay safe and stay busy with what you're doing as it's all really fascinating.

Dr Mark Pimentel:

Thank you. Good to see you again.