Rami Kallala

Publications (2)6.03 Total impact

• Article: The in vitro and in vivo effects of nicotine on bone, bone cells and fracture repair.

  Rami Kallala, Jonathan Barrow, Simon Matthew Graham, Nikolaos Kanakaris, Peter V Giannoudis
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  ABSTRACT: Introduction: Cigarette smoke has negative effects on bone metabolism and fracture repair. However, no study has reviewed effects of nicotine on bone and fracture repair independent of other constituents of cigarette smoke. The authors review the existing evidence of the effect of nicotine on 'bone' and 'bone cells' and fracture repair, drawing conclusions relevant to clinical practice and future research. Areas covered: A literature review was conducted using PRISMA guidelines and PubMed, Cochrane, MEDLINE/OVID, EMBASE, NHS Evidence and Google scholar databases. Articles were included if they specifically investigated the effects of nicotine on 'bone' or fracture repair in animal or human models or in vitro effects on 'bone cells'. A total of 64 papers were included in this review, of which 15 were human in vitro studies and 49 animal studies wherein 9 were in vitro and 40 in vivo. In vivo studies of the effects of nicotine in animals demonstrated widespread effects on bone including osteoneogenesis, osseointegration, steady-state skeletal bone and genes and cytokines relevant to bone cell physiology and bone homeostasis. In these studies, nicotine's effects are predominately negative, inhibiting bone cell metabolism and fracture repair, whereas most in vitro studies reported biphasic responses in all bone cells except osteoclastic cells. Expert opinion: The review suggests that nicotine has effects on osteoneogenesis, osseointegration and steady-state skeletal bone in animal in vivo models, as well as effects on all 'bone cells', via several mechanisms in both animal and human cell in vitro studies. The effect of nicotine is dose-dependent, with higher concentrations having predominantly negative effects, whereas at low concentrations a stimulatory effect is seen. Stimulatory effects on certain cells may indicate a possible, limited therapeutic role; advice regarding smoking cessation perioperatively should remain due to the other harmful components of cigarette smoke, but there may be scope for allowing the use of nicotine patches instead of complete abstention. Further research into clinical outcomes is required before the exact response of bone and fracture repair in humans to nicotine is known.
  Expert Opinion on Drug Safety 03/2013; 12(2):209-33. · 3.02 Impact Factor
• Source

  Available from: Dariush Nikkhah

  Article: In vitro and in vivo effects of antibiotics on bone cell metabolism and fracture healing.

  Rami Kallala, Simon Matthew Graham, Dariush Nikkhah, Margaritis Kyrkos, Manolis Heliotis, Athanassios Mantalaris, Eleftherios Tsiridis
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  ABSTRACT: INTRODUCTION: Recent evidence suggests that antibiotics exert direct effects on bone at a cellular level, disrupting mitochondrial function and cell activity. This comprehensive literature review aims to evaluate evidence for the effects of antibiotics and antimicrobials on bone and discuss the clinical implications. AREAS COVERED: A literature search was conducted on electronic databases covering a period from 1969 to 2010. Studies were included if they reported in vivo and in vitro experimental findings regarding the use of antibiotics and synthetic antibacterials in both animals and humans, focusing on bone cell function and especially fracture repair. EXPERT OPINION: Current research suggests that these negative results could be due to direct effects of antibiotics on mitochondrial physiology within mammalian cells. Treatment doses of antibiotics, especially those released from topical delivery systems such as bone cements, result in antibiotic concentrations thousands of times higher than those required to inhibit bacterial growth. Our findings suggest a need to develop current antibiotic delivery systems to elute sufficient doses to inhibit bacterial growth without negative effects on bone physiology and fracture repair processes.
  Expert Opinion on Drug Safety 12/2011; 11(1):15-32. · 3.02 Impact Factor