Wednesday, August 31, 2016

Article Review (2013) - Renal Transplantation in Systemic Amyloidosis -- Importance of Amyloid Fibril Type and Precursor Protein Abundance

Today's post will be a quick update on me, followed by an article review, ending with the always exciting blog status update at the end.

As mentioned in the previous post, on July 28 I had my second capsule endoscopy due to a malfunction with the first one. The gastroenterologist, Dr. E, called me early the next week and said no abnormalities were found. We then discussed what the next step should be, and we agreed that I would see my primary physician to discuss whether to refer me to a hematologist, have me start taking an iron supplement, or do something else.

I saw my primary physician on Thursday, August 25, and as I expected he wanted to do some blood work to see where my hemoglobin level is now. I asked him to also have my creatinine and GFR measured with that blood work and explained why. My most recent lab work was done in March of this year, so this set of numbers will give another data point 5 to 6 months after that. I do not have those results yet, so we will have to wait until the next blog post to see what happens next. Now to the article review . . .

Title: Renal Transplantation in Systemic Amyloidosis  --  Importance of Amyloid Fibril Type and Precursor Protein Abundance (1)

Authors: Pinney, Lachmann, Sattianayagam, Gibbs, Wechalekar, Venner, Whelan, Gilbertson, Rowczenio, Hawkins, and Gilmore (UK National Amyloidosis Centre, London, UK; UCL Centre for Nephrology, London, UK)

Journal: American Journal of Transplantation (February 2013)

Abstract:

Renal transplantation remains contentious in patients with systemic amyloidosis due to the risk of graft loss from recurrent amyloid and progressive disease. Outcomes were sought among all patients attending the UK National Amyloidosis Centre who received a renal transplant (RTx) between January 1978 and May 2011. A total of 111 RTx were performed in 104 patients. Eighty-nine percent of patients with end-stage renal disease (ESRD) due to hereditary lysozyme and apolipoprotein A-I amyloidosis received a RTx. Outcomes following RTx were generally excellent in these diseases, reflecting their slow natural history; median graft survival was 13.1 years. Only 20% of patients with ESRD due to AA, AL and fibrinogen amyloidosis received a RTx. Median graft survival was 10.3, 5.8 and 7.3 years in these diseases respectively, and outcomes were influenced by fibril precursor protein supply. Patient survival in AL amyloidosis was 8.9 years among those who had achieved at least a partial clonal response compared to 5.2 years among those who had no response (p = 0.02). Post-RTx chemotherapy was administered successfully to four AL patients. RTx outcome is influenced by amyloid type. Suppression of the fibril precursor protein is desirable in the amyloidoses that have a rapid natural history.

Here is a link to the article: http://onlinelibrary.wiley.com/doi/10.1111/j.1600-6143.2012.04326.x/full

As stated in the abstract, this article reviews the results of renal transplants among UK National Amyloidosis Centre patients between January of 1978 and May of 2011. There were 111 transplants among 104 patients with various types of systemic amyloidosis. The breakdown among the five different types of systemic amyloidosis that were represented is as follows:


AL (primary) - 25 patients
AA (secondary) - 43
AFib (fibrinogen) - 19
AApo (Apolipoprotein A1) - 14
ALys (Lysozyme) - 3


The main focus of this article is to document the results of these kidney transplants and see how the type of amyloid protein and the presence of that protein post-transplant affects how well the transplanted kidney performs. In this review I will only be focusing on the results of the AFib patients.


The introduction of the article provides some basic information about the various types of amyloidosis. It mentions three important points about fibrinogen amyloidosis that differentiate it from the other types:

 - AFib presents with proteinuria and progressive decline in kidney function, usually leading to end-stage renal disease within five years of diagnosis.

 - The fibrinogen alpha-chain is synthesized only in the liver.

 - Since fibrinogen alpha-chain is only synthesized in the liver, liver transplantation completely eliminates the mutant fibrinogen molecules from being produced.


Here are some of the statistics regarding the 19 AFib patients included in this study:

 - There were a total of 21 renal transplants among the 19 patients, indicating some transplanted kidneys failed.

 - Nine patients received combined liver and kidney transplants. (One of those was after a transplanted kidney developed amyloid.)

 - Amyloid did reoccur in seven patients who received kidney transplants, but not in any of the patients who received combined liver and kidney transplants.

 - 4 of the 10 patients who received kidney transplants had died as of the writing of the article. None of those deaths were known to be due to surgical complications. 

 - 3 of the 9 patients who received combined liver and kidney transplants died due to surgical complications.


The discussion section of the article mentions again that liver transplantation removes all of the mutant fibrinogen from the blood, preventing the ongoing accumulation of amyloid in the kidneys. But it states that the risk of combined liver and kidney transplant must be considered when deciding on kidney only vs. combined liver and kidney. This article does not mention anything about liver only transplantation, which is not surprising since it was published in 2013 and came out of the NAC in London.

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This article does not really give us any new information on fibrinogen amyloidosis itself, but it does provide some statistics (from a small population) on the mortality of two treatment options (kidney transplant vs. combined liver and kidney transplant). That serves as a helpful reminder that although we hear about organ transplants quite frequently in the amyloidosis community, organ transplants are certainly not without risk.

Next up will hopefully be an update on me.

=====Monthly Blog Status Update=====

As of July 31, 2016:

Total posts: 169 (1 in July)

Total pageviews: 44,600 (~2300 in July)

Email subscribers: 14 (unchanged)

Total number of countries that have viewed the blog: 128

One new country viewed the blog in July:

Seychelles

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Citation:

(1) Pinney, J. H., Lachmann, H. J., Sattianayagam, P. T., Gibbs, S. D. J., Wechalekar, A. D., Venner, C. P., Whelan, C. J., Gilbertson, J. A., Rowczenio, D., Hawkins, P. N. and Gillmore, J. D. (2013), Renal Transplantation in Systemic Amyloidosis—Importance of Amyloid Fibril Type and Precursor Protein Abundance. American Journal of Transplantation, 13: 433–441. 

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