statins talk 2009
TRANSCRIPT
Investigation of the effects of Simvastatin and other statin drugs on gut Microbiome with regards to clinical obesity
Investigation of the effects of Simvastatin and other statin drugs on gut Microbiome with regards to clinical obesity
Rhonda Garza Akrum Dhaifullah Biochemistry Department
Supervisors Dr. Robert Akins, PhD Dr. Jack Sobel, MD (ID DMC)
OutlineOutline
Introduction Hypothesis Methods Results Conclusion
Serum cholesterol-lowering statins act by competitive inhibition of the rate-limiting enzyme in cholesterol biosynthesis, hydroxymethylglutaryl-CoA (HMG-CoA) reductase.
Hydroxymethylglutaryl-CoA (HMG-CoA) reductase is essential in prokaryotes for biosynthesis of isoprenes, not sterols.
Central questions. Central questions. The main issue to be addressed by this The main issue to be addressed by this project is to what extent statins inhibit growth of bacteria in project is to what extent statins inhibit growth of bacteria in vitro.vitro.
Investigation of the effects of Simvastatin and other statin drugs on gut Microbiome with regards to clinical obesityInvestigation of the effects of Simvastatin and other statin drugs on gut Microbiome with regards to clinical obesity
Investigation of the effects of Simvastatin and other statin drugs on gut Microbiome with regards to clinical obesityInvestigation of the effects of Simvastatin and other statin drugs on gut Microbiome with regards to clinical obesity
The human gut is dominated by species in the Fimicutes and Bacteroides phyla.
Several studies indicate that the balance of these two groups is surprisingly important in obesity. Obese individuals who enroll in diets and successfully reduce body fat progress from Fimicute dominant to Bacteroides dominate gut species.
Obese mice that have disruptions in the obesity gene (ob/ob) show Fimicutes-dominant gut microbiota compared to Bacteroides rich
populations in lean mice
HypothesisHypothesis
My hypothesis is that a subset of six commercially used statins will selectively inhibit gut-associated bacteria in the Fimicutes phylum, predominantly Clostridium species.
In order to maintain this balance, obese individuals may benefit from specific statins in assisting or maintaining weight loss.
The study will have an impact on the choice of statins, if
some prove to be superior in bacterial management but equally effective in lowering serum cholesterol.
MethodsMethods• Enterobacteria associated with sepsis, were obtained from a variety of
sources and their species was verified by sequencing of their 16S rDNA genes.
• Statins: Lovastatin, Zocor, Fluvastatin, were dissolved from tablets at 10 mg active ingredient per ml of 15% ethanol, 0.25% NaOH and activated by heating at 60°C for 2 hours. Lipitor and Crestor were dissolved at 10 mg/ml in DMSO, Lovastatin l at 10 mg/ml in ethanol.
ResultsResults
Individual statins varied in the range of species affected
Lovastatin, Lipitor, and Zocor all inhibited B. subtilis, none inhibited E. coli, Lipitor and Zocor inhibited P. mirabilis, and only Zocor inhibited S. epidermidis.
Effective statins inhibited B. subtilis at 10 g/ml. Fluvastatin inhibited MRSA and MSSA strains of S. aureus, but was not effective against E. coli, K. pneumoniae, E. aerogenes, or S. marcescens
Table 1. Variable susceptibilities of bacterial species to individual statins by agar-based assay
SpeciesTaxonomic
groupZocor Fluvastatin Lipitor Lovastatin Crestor
B. subtilis Fimicute S S S S R
P. mirabilis Enterobacteria S S S S s
S. aureus (MRSA&MSSA)
Fimicute S S S R R
E. coli Enterobacteria S S S R R
S. epidemidis Fimicute s s s R R
K. pneumoniae Enterobacteria R R s R R
S. marcescens Enterobacteria R R R R R
E. aerogenes Enterobacteria R R R R R
Clostridium sordellii Fimicute S S R s R
Candida albicans Fungi S S S S S
See Fig. 3 and comments. R: Resistant, little or no zone of inhibition; S: susceptible, clear zone of inhibition; s: slightly susceptible, hazy zone of inhibtion
Bacillus subtilisBacillus subtilis
Zocor
LovastatinLovastatin
(1:10)
Zocor (1:10)
Fluvastatin Fluvastatin(1:10)
Clostridium sordellii
Clostridium sordellii
Zocor
LovastatinLovastatin
(1:10)
Zocor (1:10)
Fluvastatin Fluvastatin(1:10)
Clostridium sordelliiClostridium sordellii
Crestor
DMSO Act.Buffer
Crestor (1:10)
Lipitor Lipitor(1:10)
C. albicans S. aureus MRSA B. subtilis
S. marcescens S. epidermidisE. coli S. aureus MSSA K. pneumoniae
E. aerogenes P. mirabilis
S. aureus MSSA
Zocor Crestor
Lovastatin Fluvastatin
Lipitor Solvent
StatinsC. albicans S. aureus MRSA B. subtilis
S. marcescens S. epidermidisE. coli S. aureus MSSA K. pneumoniae
E. aerogenes P. mirabilis
E. coli S. aureus MSSA K. pneumoniae
E. aerogenes P. mirabilis
S. aureus MSSA
Zocor Crestor
Lovastatin Fluvastatin
Lipitor Solvent
Zocor Crestor
Lovastatin Fluvastatin
Lipitor Solvent
Statins
Future ExperimentsFuture Experiments
• An in vivo approach was started that will investigate fecal DNA from a donor who was treated with Simvastatin. Samples were taken pre-treatment, during treatment and post-treatment respectively. The GI flora was expected to shift from Fimicutes and Bacteroides flora to Bacteroides-dominant gut microbiota. This is being determined with successful Q-PCR testing. The effectiveness of Simvastain relative to other anti-obesity drugs is currently unclear and will be pursued in future experiments.
ConclusionConclusion
The subset of six commercially used statins did selectively inhibit gut-associated bacteria in the Fimicutes phylum, predominantly Clostridium species.
The in vivo approach is suggesting that there is a shift in gut microbiota with the treatment of Simvastatin.
• A epidemiological study will further enhance the expectation of statins as a drug that targets the Fimicute population in obese patients.