Warning all Fat Cells: Tuberculosis is Coming

Tuberculosis (TB) has been causing human suffering for millennia, beginning from the age of the Egyptians. In 19^th century Europe, TB infection was so prevalent that it inspired artistry of the era and became the subject of poetry and literature. John Keats, most notably, described the disease in his poetry, before dying from TB at 25 (Barrett, 2017). Despite a long history, TB is not a disease of the past; currently, one third of the global population harbours latent TB (Ehlers, 2009). These individuals do not demonstrate any symptoms or signs of disease, but remain at risk for severe TB infection later in life. TB is caused by a bacterium called Mycobacterium tuberculosis (Mtb) that primarily infects the lungs. In the lungs, immune cells called ‘macrophages’ attempt to engulf and kill the bacteria. Often, the macrophages fail to kill the bacteria, which allows Mtb to replicate in the macrophage. Healthy macrophages are recruited to the lungs and attack infected macrophages, creating a ‘granuloma’, which is basically a wall of macrophages that encapsulate the Mtb for the long term.

In addition to lung macrophage cells, Beigier-Bompadre, et. al. have found that adipose tissue, or fat tissue, also provides a safe haven for Mtb bacteria. They infected mice with Mtb intranasally (in the nose) and discovered that the bacteria accumulated in adipose tissue. They learned that the bacteria remained infectious and turned on new genes to cope with their new fatty home. Reminiscent of their effects in the lung, the bacteria also caused recruitment of immune cells to adipose tissue, increasing inflammation.

Type 2 diabetes is characterized by changes in adipose tissue. It has long been known that individuals with Type 2 diabetes can suffer from more severe TB infections. This new research sheds light on how Mtb bacteria can colonize and remodel adipose tissue, which may help us understand why diabetes and TB are linked. It may even provide us with ways to make this bacterial safe haven not so safe anymore.

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Summary written by: Katrina Bouzanis

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To read the full article, please click here:

Mycobacterium tuberculosis infection modulates adipose tissue biology

Macarena Beigier-Bompadre, Georgina N. Montagna, Anja A. Kühl, Laura Lozza, January Weiner III, Andreas Kupz, Alexis Vogelzang, Hans-Joachim Mollenkopf, Delia Löwe, Silke Bandermann, Anca Dorhoi, Volker Brinkmann, Kai Matuschewski, Stefan H. E. Kaufmann

Additional References:

Barrett, M. (2017, May 13). The romance of tuberculosis. Retrieved November 17, 2017, from http://theweek.com/articles/692701/romance-tuberculosis

Ehlers S. (2009). Lazy, dynamic or minimally recrudescent? On the elusive nature and location of the mycobacterium responsible for latent tuberculosis. Infection. 37(2). Epub 2009/03/25. pmid:19308316.