L

Nature's Quick Constipation Cure

Constipation Help Relief In Minutes

Get Instant Access

Pseudomelanosis Coli

Figure 9.5 Formation of melanosis coli in the mucosa of the colon or rectum. L, laxative; P, cellular fragment; M, macrophage; Ma, macrophage with apoptotic bodies; Mp, pigmented macrophage; Dl, lysosomal digestion; Vl, lymphatic vessel; LM, mesenteric lymphnode; CE, eptithelial cell; LP, lamina propria; MM, muscularis mucosae. The etiology of pseudomelanosis is still unclear. Laxatives could interact with colonic epithelial cells and induce migration of fragments of these cells into the spaces among the crypts. These cellular fragments would be phagosized by macrophages and converted to lipofuscin-like pigments by enzymes present in lysosomes of the macrophages. As a consequence, the epithelium takes on a brown pigmentation. This is reversible upon removing the laxative because the macrophages with pigmentation will migrate towards the lymph-nodes (From Capasso and Gaginella, 1997).

Figure 9.5 Formation of melanosis coli in the mucosa of the colon or rectum. L, laxative; P, cellular fragment; M, macrophage; Ma, macrophage with apoptotic bodies; Mp, pigmented macrophage; Dl, lysosomal digestion; Vl, lymphatic vessel; LM, mesenteric lymphnode; CE, eptithelial cell; LP, lamina propria; MM, muscularis mucosae. The etiology of pseudomelanosis is still unclear. Laxatives could interact with colonic epithelial cells and induce migration of fragments of these cells into the spaces among the crypts. These cellular fragments would be phagosized by macrophages and converted to lipofuscin-like pigments by enzymes present in lysosomes of the macrophages. As a consequence, the epithelium takes on a brown pigmentation. This is reversible upon removing the laxative because the macrophages with pigmentation will migrate towards the lymph-nodes (From Capasso and Gaginella, 1997).

did not show any significant increase of colon cancer incidence (Nakamura etal., 1984; Kune etal., 1988; Kune, 1993). It has also been demonstrated that a positive correlation between melanosis coli, a marker for chronic abuse of anthranoid laxatives, and colon carcinoma exists (Siegers etal, 1993) but this correlation failed in another retrospective study (Nusko etal., 1993). A study carried out in vivo shows that aloe given alone for 13 weeks did not induce the development of preneoplastic or neoplastic lesions, or Aberrant Crypt Foci (ACF), and therefore this laxative did not display any tumor initiating activity in the rat colon (Capasso, personal communication). In addition, when aloe was administered with AOM (azoxymethane), a carcinogen agent, it did not produce any significant increase of ACF, and tumors. These results are basically in agreement with previous studies carried out with other anthraquinone drugs

Table 9.4 Aloe — drug interactions.

Preparation

Possible conventional drug interactions

Possible reactions

Aloe latex and anthranoid laxatives

Antidiarrhoeals Glucoresins Cardioactive glycosides

Antagonism Synergism

Potassium depletion leading to adverse cardiovascular effects Potassium depletion may be exacerbated Antagonism

Aloe gel

Licorice, corticosteroids,

Diuretics

Non steroidal anti-inflammatory drugs

Vitamins

Minerals

Hydrocortisone

Antidiabetics

UV radiation

Additive effect Additive effect Photodermatitis

Reduced absorption of vitamins Reduced absorption of minerals

(Mascolo etal, 1999; Borrelli etal, 2001). Recent studies have also shown that anthraquinone compounds (i.e. emodin) selectively block the retardation of oncogene-modulated signal transduction through the inhibition of protein kinase. All these results suggest a sufficient margin of safety for aloe and other anthraquinone drugs when used internally (Capasso and Gaginella, 1997). The FDA has recently proposed to stop the use of aloe, the laxative, until further studies can show its benefit and safety.

Toxicity due to oral and topical use of Aloe vera

Several studies have been made to determine whether aloe causes toxicity in animals or humans in gel form or in its various preparations, pure gel, liquid concentrate, etc. Studies in mice revealed no acute toxicity in therapeutic doses. In high doses, however, a decrease of CNS (central nervous system) activity was noticed. During chronic treatment, there was a decrease in red cell count and significant sperm damage. On the other hand if aloe gel contains very large amounts of aloin, it may cause unfavourable side-effects (see above). In spite of its wound-healing and anti-inflammatory properties, the topical application of aloe gel has been reported in the literature to cause contact and photodermatitis and/or erythema with papulous (Hogan, 1988; Morrow etal., 1980; Shoji, 1982a, b; Nakamura and Kotahima, 1984; Hunter and Frumkin, 1991; Dominguez-Soto, 1992). Aloin can certainly irritate the skin. However it has been recently found that painting aloe emodin on the skin of mice in conjunction with exposure to ultraviolet radiation results in the development of melatonin-containing skin tumors (Strickland etal., 2000). The precise contribution of aloe derivatives to the development of cutaneous melanoma requires further definition. In the meantime it is preferable to avoid local application of aloe gel when the skin is exposed to ultraviolet radiation (Table 9.4). One case of cathartic effect after topical application of aloe gel has also been reported (Boon and Smith, 1999).

Vogler & Ernst (1999), by reviewing ten controlled clinical trials—a total of 803 subjects-reported no withdrawals or serious adverse reactions. Some patients experienced burning after topical application, contact dermatitis and mild itching. All adverse effects were reversible and aloe vera was generally well tolerated.

Was this article helpful?

0 0
10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook


Post a comment