Review for 10.1186/1471-230X-5-8 (2005)

Reviewer's report 
 The role of mast cells in the pathogenesis of pain in chronic pancreatitis Title: 
 1  11 November 2004 Version: Date: 
 Kimberly Kirkwood Reviewer: 
Reviewer's report: 
General 
The authors have demonstrated that mice genetically deficient in mast cells (MCDM)with 
experimental chronic pancreatitis have reduced abdominal hyperalgesia (an index of pain) than do 
wildtype controls. The primary pain endpoint is von Frey Filament (VFF) abdominal withdrawl 
response pre- and post- induction of chronic pancreatitis using trinitrobenzene sulfonic acid (TNBS). 
The response of knockout and wt mice to hindpaw VFF testing serves as an appropriate control. The 
study represents new work from a group with several prior publications in the field of visceral pain. 
Autopsy data are also included from patients with diagnoses of chronic pancreatitis and archival 
pancreatic tissues were compared among 8 patients determined to have had painful and 6 patients 
with non-painful chronic pancreatitis. 
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Major Compulsory Revisions (that the author must respond to before a decision on publication can 
be reached) 
1. The inclusion of the autopsy data/archival tissue examination detract from the manuscript. 
Although it is an intriguing idea, retrospective analysis is inadequate to distinguish among 
postmortem groups of patients with "painful" and "non-painful" chronic pancreatitis. Defining a 
category of patients with non-painful chronic pancreatitis is frought with uncertainty given that pain is the hallmark symptom of the condition of chronic pancreatitis. Furthermore, the presence or absence of mast cells in pancreas tissue specimens could,in theory, be affected by non-pancreatic 
conditions such as hepatitis or systemic sepsis at the time of death. 
2. Although the authors have validated the use of VFF stimulation in a rat model of acute necrotizing 
pancreatitis, they have not done so in the mouse model of chronic pancreatic inflammation. To do so 
they need to correlate the results of VFF testing with another established endpoint, such as 
frequency of abdominal contractions, or staining for fos-like immunoreactivity in the spinal cord. At a 
minimum, one could infer that VFF hypersensitivity was a nociceptive endpoint in this model by 
pre-treating the animals with an opiod analgesic to block the response. 
3. The primary result presented in the manuscript is the reduced frequency of responses to VFF 
stimulation of the abdominal wall in MCDM vs control animals following induction of chronic pancreatitis using TNBS. Each animal serves as its own control. Several points re: the data are 
confusing and require clarification: 
a. MCDM exhibited hypersensitivity to hindpaw stimulation following either saline or TNBS b. in contrast to a. MCDM had reduced sensitivity to abdominal stimulation after either saline or TNBS 
c. TNBS appears to have blocked the increase in frequency of responses to hindpaw stimulation 
with the 1 mN filament, although no statistical comparison is offered 
d. some mechanism for reporting uncertainty in the data needs to be included (error bars or std.dev.) 
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Minor Essential Revisions (such as missing labels on figures, or the wrong use of a term, which the author can be trusted to correct) 
1. my downloaded version of the ms had no table 1. 
2. p. 10, 2nd full paragraph, change "mice" to "mouse" 
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Discretionary Revisions (which the author can choose to ignore) 
1. The ms would be stronger with raw data for fig. 3 in addition to the derivative result presented 
("mean change in response frequency, %"). I would also expand the discussion of this data set in 
Results and in the Discussion since it's the major important finding. 
2. If available, levels of a putative downstream mediator, a product of mast cell degranulation, would 
add mechanistic strength. 
3. The authors raise the concern that since MCDM carry a spontaneous mutation for c-kit which 
could affect sensory neuronal function, it is possible that an aberration in c-kit, and not the depletion 
of mast cells, could explain altered nociception. One way to examine this possibity would be to 
include pharmacological inhibition/degranulation of mast cells as an alternative complimentary approach to genetic deletion of mast cells. 
 Unable to decide on acceptance or rejection until the authors have responded to the What next?: 
major compulsory revisions 
 An article whose findings are important to those with closely related research Level of interest: 
interests 
 Acceptable Quality of written English: 
 No Statistical review: 
Declaration of competing interests: 
I declare that I have no competing interests.