OVERVIEW OF THE DISCUSSION
• A model of true mutualism: the rumen
• How do changes in microecology affect the human host.
-microbial diversity
-host immunity
-metabolism
-susceptibility to pathogens/antibiotic resistance
• Models
-burden of microbial related diseases
-host-microbial interactions
Foregut Microbial Fermenters
DIET
The rumen as a model of true mutualism
DIET
Diet (CHO, protein, lipids)
microbial
fermentation
Volatile fatty acids + microbes
Bacteria
gastric
lysozyme
Energy source
Protein source
Amino acids
Rumen Microbes
Counts/ml
Data courtesy of Mel Yokoyama, Michigan State University
OVERVIEW OF THE DISCUSSION
• A model of true mutualism: the rumen
• How do changes in microecology affect the human host?
-microbial diversity
-host immunity
-metabolism
-susceptibility to pathogens/antibiotic resistance
• Models
-burden of microbial related diseases
-host-microbial interactions
Decrease in H. pylori and GI microbes *
in developed countries
100
Developing
Prevalence
(%)
50
Developed
0
0
10
20
30
40
50
60
Age (Years)
•Documented decrease in parasites (Gale 2002; Vermund et al. 1988)
•bacteria? Viruses?
Indigenous bacteria shape
Intestinal Immunity
?
Indigenous-mutualists?
Parasites?
IgA
Cash and Hooper 2005. ASM News 71:77-83
Effect of GI Microbiome on body morphometry in Amerindians
Proportion of helminth eggs and protozoal cysts in feces from
71 asymptomatic Amerindians
Parasite type
Helminths
Protozoa
Genus/species
Ascaris lumbricoides
Trichiura trichuris
Nematoda
Anquilostomideos
Enterobius vermicularis
Plathyhelminthes Hymenolepsis nana
Entamoeba coli
Chilomastix mesnili
Sarcomastigophora Giardia duodenalis
Entamoeba histolitica/ dispar
Iodamoeba butschlii
Apicomplexa
Blastocystis hominis
Sarcomastigophora Endolimax nana
Phylum
Average parasitic load 2.15 + 1.71 . Range 0-6 (N=71)
.
.
.
.
.
.
.
%
93.1
55.6
30.6
1.4
1.5
59.7
25.0
9.7
8.3
4.2
4.2
2.8
Proportion
of H. pylori by age in 90 Amerindians
Age
2-11
12-20
>20
All
H. pylori positive
41
19
15
7
34
28
90
54
% positivity
46
47
82
60
Number of subjects
examined
Z(Xc)
Bio Impedance Vector Analysis (BIVA)
4
95% tolerance
75% tolerance
3
More cell
mass
athletic
Dehydration
2
50% tolerance
Hpy+
Hpy-
1
lean
0
-4
-3
obese
-2
-1
0
-1
1
2
3
4
Z(R)
Less cell
mass
-2
Edema
malnourish
-3
-4
Piccoli et.al. 1995. Am J Clin Nutr 61: 269-270
Z(Xc)
Effect of GI microbiome on body composition and morphometry
4
95% tolerance
75%
tolerance
75%
tolerance
50%
tolerance
50%
tolerance
Hpy+
H. pylori + N=43
HpyH. pylori - N=29
95% tolerance
athletic
3
2
1
lean
0
-4
-3
obese
-2
-1
0
-1
1
2
3
4
Z(R)
-2
-3
malnourished
-4
H pylori + Æ higher cell mass, subscapular skinfold (p<0.05)
No effect of parasite burden on BMI (p=0.593), triceps skinfold (p=0.312); subscapular
skinfold (p=0.587); or nutritional score (p=0.182).
OVERVIEW OF THE DISCUSSION
• A model of true mutualism: the rumen
• How do changes in microecology affect the human host.
-microbial diversity
-host immunity
-metabolism
-susceptibility to pathogens/antibiotic resistance
• Models
-burden of microbial related diseases
-host-microbial interactions
Evolution of Human Societies and their Diseases
Burden
of
diseases related
to microbes
Autoimmune
Infectious
Modernization
Agricultural Technology
Homogeneous diet
Sanitation
Antibiotics
Longer lifespan
Microbiome-Host interactions shape health and disease
Host
Genetic
Immune
Environment
Endocrine
Diet-antibiotics
Microbes
Symbiosis
Pathogenicity
Health
Disease
Time progression
Endogenous
Pathogens
Microbiota
Colonization