1. Ochiba Lukandu & Koech Lionel
Chronic khat chewing induces abnormal keratinization of the buccal oral mucosa
Ochiba Lukandu & Koech Lionel
Dept. of Oral & Maxillofacial Surgery Oral Pathology, Medicine and Radiology
School of Dentistry
MOI UNIVERSITY

2. Overview Introduction General aim Materials and Methods Results
Conclusion

3. Introduction
Khat (miraa) is an evergreen shrub grown in the Middle East and the horn of Africa

4. Introduction
Khat use is common in the regions where it is grown. (Over 70% of men in Yemen routinely chew khat)

5. Introduction Reasons for chewing khat: Pyscho-stimulant Medicinal
Recreational
Khat is an important cash crop whose economic value in some regions exceeds coffee and tea.

6. Introduction Adverse effects of khat use – General
Psychotic disorders (Odenwald et al 2005)
Myocardial infarction (Al-Motarreb et al 2002)
Adverse effects of khat use – Oral
Hyperkeratosis (Ali et al 2004, 2006, Gorsky et al 2004)
Genotoxicity (Kassie et al 2004)
Oral cancer?? (Soufi et al 1991, Nasr et al 2000)

7. Introduction Antibiotic properties Al-Hebshi 2005 Apoptosis Dimba 2004
Lukandu 2008
Lower caries rate
Hill 1987
ROS
Aleryani 2010
Oral white lesions
Ali 2004
Dry mouth
Acanthosis
Hyperkeratosis
Ali 2006
Dental staining
Cellular atypia
Ahmed
2010
Tooth wear
Micronucei
Kassie 2001

8. Rationale of study
Generally, studies on the effects of khat on humans are still scarce (Carvalho F. 2003)
Despite reports on the potential adverts effects of khat use on oral soft tissues, only a few previous studies have looked at histopathological changes induced by chronic khat chewing.

9. General aim of the study
Broad objective
To describe pathological changes induced by khat on the buccal oral mucosa
Specific objectives
To describe clinical changes induced by chronic khat use on the buccal oral mucosa
To describe histological changes induced by chronic khat use on the buccal oral mucosa

10. Materials and methods Participants Characteristics of participants
35 volunteers from Meru and Eldoret
8 non chewers (controls)
10 khat chewers who did not smoke
17 khat chewers who also smoked tobacco
Characteristics of participants
All were male (did not get female volunteers)
Mean age 24 for controls, 33 for khat chewers and 30 for khat chewers who also used tobacco
No differences other than for the two habits

11. Materials and methods Participants Inclusion criteria for khat chewers
Khat chewers for more that more than 5 years
Detectable oral white lesion based on a common protocol and willing to sign consent form
Inculsion criteria for control group
Patient undergoing surgical removal of wisdom tooth.
Free of pathological oral white lesions
Must be willing to sign consent form
Never used khat

12. Materials and methods Clinical procedures Non-khat chewers
Excess tissue trimmed off from the margins of the incision made on the buccal mucosa during surgical removal of wisdom teeth
Khat chewers
Biopsy from the centre of the white lesion on the buccal mucosa where the participant places the bolus of khat during khat chewing
Clinical photographs
Description

13. Materials and methods Laboratory procedures
Formalin fixed paraffin-embedded
Standard Hematoxylin and eosin staining
Light microscopy
Histological assessment
Photography (Lieca DM 750 with camera and LASEZ leica application Suite E2 software)
Histomorphometry (Dinocapture 2.0 version 1.5.0)

14. Materials and methods Data management and analysis
Statistical analysis using Sigma Plot Software
One way ANOVA with multiple group comaprisons using Holm-Sidak method
OR Kruskal-Walli’s with multiple comparisons using Dunn’s method
Graphics done using Sigma Plot Software
Presentation
Proportions or means and their standard error
p-values less than 0.05 considered significant

15. Materials and methods Histomorphometry Keratinised Superficial
Non-keratinsed
Epithelial thickness
Spinous
Basal
Rete peg

16. Materials and methods
Histomorphometry

17. Results
Clinical changes
Control Chronic khat chewers

18. Results
Clinical changes
Control Chronic khat chewers

19. Results
Clinical features
Control µg/ml

20. Results
Clinical features
Control µg/ml

21. Results Color Texture White Creamy white Brown Mixed white and brown
(erythematous ones were not seen)
Texture
smooth
Wrinkled

22. Results
Histopathological changes
Control Chronic khat chewers

23. Results
Histopathological changes
Control Chronic khat chewers

24. Control Chronic khat chewers
Melanin, fibrosis, vascular changes, inflammatory cells
Control Chronic khat chewers

25. Results Analysis of whole epithelium (includes rete pegs)
Thickness in µm

26. Results Analysis of whole epithelium (without rete pegs)
Thickness in µm

27. Results
Analysis of rete pegs

28. Results
Analysis of basal cell layer
Thickness in µm

29. Results
Analysis of spinous cell layer
Thickness in µm

30. Results
Analysis of superficial cell layer
Thickness in µm

31. Results
Analysis of keratinized layer

32. Results
Thickness of keratinized layer
Thickness in µm

33. Results Proportion superficial layer keratinized
Percent of total superficial layer

34. Discussion Findings seen here that agree with previous studies;
Induction of keratosis
Induction of Acanthosis (increased spinous layer)
Induction of spongiosis (edema- intra and extracellular)
Findings reported by others, but not seen in this study
Differential inflammatory infiltrate (need for IHC)
Abnormal rete pegs
Severity with use of tobacco (not significant here)

35. Discussion
Findings seen here but contrary to those reported in previous studies;
For chronic khat chewers, smoking does not induce further (significantly different) phenotypic effects. Probably a larger sample size would be helpful.
Findings seen here but never reported before in previous studies;
Extend of melanosis seen especially in khat chewers who do not smoke
Differential effects on each layer of the epithelium – specific effect on superficial cell layer

36. Conclusion Mucosal white/discolored lesions seen in
buccal mucosa of chronic khat chewers are
due to specific khat induced tissue changes such as abnormal keratinization and increased epithelial thickness.

37. Acknowledgement KMA conference organisers Volunteer participants IREC
Administrations of MTRH and Meru level 5 hospitals
Clinical staff at School of Dentistry and Meru level 5 Hospital dental clinic
Lab technicians at MTRH Histopathology lab
The study was supported by:
-Moi University Research fund 2012 to the School of Dentistry