Bradykinin Rosacea Theory

[Guide]

"Gut bacteria, or H. Pylori, help produce a protein known as bradykinin. This protein causes vessels in the blood to dilate, which may be the cause of rosacea in some cases. However, this theory remains to be proven." 12 top tips for treating rosacea, Starts at 60, Everyday Health

Bradykinin "is a peptide that causes blood vessels to dilate (enlarge), and therefore causes blood pressure to fall.....It has long been known in animal studies that bromelain, a substance obtained from the stems and leaves of the pineapple plant, suppresses trauma-induced swelling caused by the release of bradykinin into the bloodstream and tissues." Wikipedia

The effects of bradykinin "causes contraction of non-vascular smooth muscle in the bronchus and gut, increases vascular permeability and is also involved in the mechanism of pain. Bradykinin also causes natriuresis, contributing to the drop in blood pressure." Wikipedia

"As noted, inflammatory mediators may be operative in the vasodilation seen in rosacea patients. Inflammatory mediators such as substance P, histamine, serotonin, bradykinin, or prostaglandins have been implicated." [1]

"It is possible that intestinal bacteria are capable of plasma kallikrein–kinin activation and that flushing symptoms and the development of other characteristic features of rosacea result from frequent episodes of neurogenic inflammation caused by bradykinin-induced hypersensitization of facial afferent neurones." [2]

"Flushing in rosacea has been investigated by means of (a) pharmacological inhibition of some possible chemical mediators and (b) titration of bradykinin as a possible effector directly in the blood. Clonidine-inhibited flushing was seen in all patients (mean 45%), other drugs had poorer results. Bradykinin increased in all patients at the climax of flushing (mean 60%). These findings support the hypothesis that epinephrine promotes a bradykinin release responsible for vasodilation." [3]

"Some research suggests that this bacteria produces a protein called bradykinin that can cause blood vessels to dilate, giving rise to rosacea symptoms." [4]

"It has also been suspected that the Helicobacter pylori strain of bacteria, normally found in the digestive tract, might trigger an increase in the protein bradykinin, which can cause your blood vessels to dilate or expand." [5]

"Disclosed herein are methods for the treatment or prevention of rosacea in a patient, including administering a compound that inhibits one or more components of the bradykinin activation pathway in an amount sufficient to reduce or prevent one or more symptoms of rosacea.....Accordingly, the invention features a method of treating or preventing rosacea by administering a compound that inhibits a component or components of the bradykinin activation pathway." [6]

"However, given the increased numbers of substance P-immunoreactive neurons and the vascular hypersensitivity observed in rosacea skin, it would seem more likely that it is not the direct vasoactivity of bradykinin (as suggested in these studies) that is responsible for rosacea symptoms, but that bradykinin is stimulating and sensitizing afferent neurons and that the resulting neurogenic inflammation is responsible for the expression of rosacea symptoms." [7]

"Alcohol ingestion increases bradykinin levels, which leads to flushing that is blocked by clonidine. This suggests that bradykinin, not alcohol, may be a direct mediator of flushing." [8]

Bradykinin is just one cytokine considered involved with rosacea. 

End Notes
Bradykinin image courtesy of Wikimedia Commons

[1] The Proposed Inflammatory Pathophysiology of Rosacea: Implications for Treatment, Larry Millikan, MD, Skinmed. 2003;2 (1). MedScape 

[2] Clin Exp Dermatol. 2004 May;29(3):297-9.
Remission of rosacea induced by reduction of gut transit time.
Kendall SN

[3] Arch Dermatol Res. 1982;272(3-4):311-6.
Flushing in rosacea: a possible mechanism.
Guarrera M, Parodi A, Cipriani C, Divano C, Rebora A.

[4] Rosacea Causes, By Dr Ananya Mandal, MD,  News Medical Life Sciences

[5] A.Vogel Talks about the causes of rosacea 

[6] Treatment of rosacea , US 7105172 B1

[7] Neurogenic inflammation and involvement of the kallikrein-kinin system

[8] The pathophysiology of rosacea, Patient Care, Modern Medicine Network

[9] Cytokines and Rosacea