"Evidence-based innovation in biomedicine: potential and

pitfalls"

Mark M. Rasenick

Distinguished University Professor, Physiology & Biophysics and Psychiatry.

U. Illinois Chicago College of Medicine

Chicago Illinois USA

raz@uic.edu

You can’t always get what you want.

• But in biomedical research, you often do just that.

Requirement of Hippocampal Neurogenesis for the Behavioral Effects of Antidepressants

Luca Santarelli,1* Michael Saxe,1* Cornelius Gross,1 Alexandre Surget,2 Fortunato Battaglia,3 Stephanie Dulawa,1 Noelia Weisstaub,1 James Lee,1 Ronald Duman,4 Ottavio Arancio,3 Catherine Belzung,2 Rene´ Hen1†

Science 8 August 2003

• Since then, at least 8 papers published demonstrating neurogenesis has no causative role in antidepressant action. And just about everything you do to an animal increases neurogenesis.

• Fewer than 1200 citations, cumulatively.• But wait, it gets worse

2611 citations

Only 28% of published data were reproducible by pharmaceutical industry. Inconsistencies included inconsistent drug targets and actions (literature vs, in-house studies).

Prior to this study, it was “common knowledge” that only about 50% of academic studies were able to be validated by Pharma.

Prinz et.al.

Selective Data Collecting:Selective Data Reporting

• Non-random data recording (blind microscopy)—looking where the light is,

• Publish the “good results”

• Nobody wants to know about negative results. (clinical trials.gov/PLOSone)

Increased protein complexes?Depends upon where you look

Selective Data Collecting:Selective Data Reporting

• Non-random data recording (blind microscopy)—looking where the light is,

• Publish the “good results”

• Nobody wants to know about negative results. (clinical trials.gov/PLOSone)

Gs is distributed preferentially in lipid raft fractions in post mortem brain of depressed subjects

Total Gs is not significantly different between suicide and control samples

* P < 0.05

Raft/non-raft Gq is not significantly different between suicide and control samplesOnly the Raft distribution of Gs is variable

Donati et.al, 2008

Gs is distributed preferentially in lipid raft fractions in post-mortem brain of depressed subjects

Total Gs is not significantly different between suicide and control samples

** P < 0.02 * P < 0.05

Raft/non-raft Gq is not significantly different between suicide and control samplesOnly the Raft distribution of Gs is variable

Donati et.al, 2008

Problems with clinical studies

• Placebo response: somatic disease.

• Placebo response: Psychiatry

• Volunteers: some do it for the money: some just enjoy volunteering. This is a problem unique to psychiatry—much more difficult to fake a somatic ailment.

How do we fix this?

• Biomarkers can:

• 1) screen volunteers for presence of disease.

• 2) provide a standardized hallmark of sickness or wellness.

Sensitivity and Specificity of Gs Biomarker

• Sensitivity= .93

• Specificity= .78

• PPV= .88 (LR+ = 4.20)

• NPV= .88 (LR- = 0.086)

Note: these data are obtained by differential detergent extraction; not preparation of rafts by density gradient sedimentation.

LR+ /LR- : likelihood ratio

Lipid Rafts and caveolae act as inhibitory domains, separating Gs from the GPCRs that

activate it.

ATP cAMP

sGTP

GTPs

AR Adenylyl Cyclase

ssss

Lipid Rafts

Chronic antidepressant treatments liberate Gs from caveolae/raft membrane domains and foster coupling to adenylyl cyclase (Zhang and Rasenick, 2010). Depression has the

opposite effect, as Gs is enriched in lipid raft fractions prepared from suicide brains (Donati et al., 2008)

So, can raft localization of Gs be a biomarker for Depression and antidepressant response?

Chronic antidepressanttreatment

Fluorescence Recovery After Photobleaching (FRAP) provides reproducible measurements to study the mobility of GFP-Gαs in C6 glioma cells.

Lipid Rafts and caveolae act as inhibitory domains, separating Gs from the GPCRs that

activate it.

ATP cAMP

sGTP

GTPs

AR Adenylyl Cyclase

ssss

Lipid Rafts

Chronic antidepressant treatments liberate Gs from caveolae/raft membrane domains and foster coupling to adenylyl cyclase (Zhang and Rasenick, 2010). Depression has the

opposite effect, as Gs is enriched in lipid raft fractions prepared from suicide brains (Donati et al., 2008)

So, can raft localization of Gs be a biomarker for Depression and antidepressant response?

Chronic antidepressanttreatment

Factors modifying Gs FRAP

Randomization helps, but not all questions can be randomized….)

• Question: does being physically disciplined as a young child increase the risk of being incarcerated as an adult?

• Without randomization, it is difficult to discern causality from correlation

• those who are disciplined more might be those who are already anti-social!

• Yet one could never randomly assign children to different amounts of physical discipline!

• Besides the ethical issues, the mere act of administering physical punishment in an arbitrary manner changes the entire dynamic of the situation that you want to study.

Sometimes controlled studies are difficult

• Consider the putative therapeutic/palliative effects of marijuana.

• The subjects who do not experience psychoactive effects know that they are the controls (although some of them still get “high”)

Animal studies don’t have these drawbacks

• Animal models exist for many diseases• Genes are relatively easy to manipulate, even in

mammals. But what have we learned from the genome?• Most strains are syngenic, little genetic variation—but

that’s also a drawback– Humans are quite variable. Also, some genes have multiple roles during the course of development (conditional k/o addresses this).

• Do mice have mood? Monkeys do.• Yeast to humans, successive approximation.• Human stem cells, including those derived from blood and

skin (iPSC) allow us to compare neurons from normal vs. disease.

But, at the end of the day:

• We can all get some satisfaction, knowing that we are a bit closer to the truth.