Saturday, November 11, 2017

Free Online Learning Module: Hemodialysis Kinetics 101 The ‘key’ to KT/V urea


Hemodialysis 101: The "key" to KT/V urea

Namrata Krishnan, Assistant Professor of Medicine at Yale has hit it out of the park. She has a fantastic online module to understand hemodialysis kinetics. This module is jam packed with clinical vignettes, well produced videos, explanatory posts, and links to primary literature. I would highly recommend this module to anyone wanting to know more about how hemodialysis works. You can all follow Namrata on Twitter.

Matt Sparks

Monday, November 6, 2017

Fellow Travel Award Opportunity to the Annual Dialysis Conference 2018, Orlando Fl


The Annual Dialysis Conference 2018 that will be held in Orlando, FL March 3-6, 2018.

This conference has an excellent opportunity for fellows to present cases, both posters and oral presentation.

Fellows can apply for a grant for registration and travel. 

Case Summary Grants Nephrology 
Fellows are invited to submit a 1-page case summary of a challenging or unusual dialysis experience. A $1000 grant will be awarded to the best 20 cases submitted. In addition, the authors of the top 6-8 cases will be selected to present their cases in the Fellows Forum Session of the main conference. Case summaries should be organized like abstracts and be written in a manner to entice audience interaction.

Requirements for Grant Consideration
  • Must be a nephrology fellow in an ACGME approved nephrology training program.
  • A letter must be submitted indicating your desire to apply for the case summary grant. The letter needs to be signed by your nephrology fellowship program director and verify that you are a second year fellow. 
  • A conflict of interest form needs to be submitted. You may download a COI form here.
  • A 1-page case summary.
  • All documents need to be submitted by the submission deadline to Claire Oser via email (oserc@health.missouri.edu) or fax (573-884-4820). 
The case summary submission deadline is November 30, 2017. 

Kunal Malhotra MD FNKF
Assistant Professor of Clinical Medicine (Nephrology)
Director, Chronic Dialysis Unit
University of Missouri Hospitals and Clinics
Columbia, MO 65212.

Tuesday, October 31, 2017

ASN #KidneyWk Tweetup 2017 New Orleans


Before there were Tweetups there were blogger nights. The contributors to RFN and other early blogger formed the very first internet based gatherings in nephrology at Kidney Week. This year NephJC has taken over the reigns and will be hosting this even along with Satellite Healthcare.

When: Friday Nov 3rd from 6:30-9:30

Where Deanie's Seafood French Quarter
841 Iberville Street, New Orleans, LA

more info at www.nephjc.com

Thursday, October 26, 2017

November Nephrology Web Episode - Myeloma Cast Nephropathy

The November 2017 nephrology web episode from Washington University is available for viewing a bit early to avoid conflicts with the upcoming #KidneyWk!  This webisode is a short and basic lecture looking at myeloma cast nephropathy.  We start with a case, discuss the classic pathology, and go over the controversial role of plasma exchange for light chain removal.



Monday, October 2, 2017

October Nephrology Web Episode Available!

The monthly Wash U Nephrology Web episode for October is available and is back to basic renal pathology teaching after a couple of esoteric CPC cases.  You can check it out below:


Sunday, October 1, 2017

Interstitial Nephritis in the Renal Allograft: Rejection, Infection or Both?

In renal transplant recipients with allograft dysfunction, differentiating between a viral infection or acute cellular rejection as the etiology of interstitial nephritis can be difficult – especially as they can commonly occur concurrently.

We recently saw a 40-year-old woman who received a deceased donor kidney transplant less than one year ago who presented with an initial complaint of gross hematuria and an elevated creatinine (2.2 mg/dL from nadir of 1.4 mg/dL). The allograft ultrasound showed thickening of the urothelium. Prompt biopsy of the allograft revealed acute cellular rejection (ACR 1B), and she was treated with high dose steroids and anti-thymocyte globulin.  

Over the next several weeks, she continued to complain of intermittent gross hematuria. Cystoscopy was unremarkable. One month later she presented with worsening renal function, cough and shortness of breath. A nasopharyngeal respiratory viral panel ultimately revealed…adenovirus – which was also then found both the blood and urine (millions of copies in each). A repeat allograft biopsy was consistent with adenovirus nephropathy.

Adenovirus is a double-stranded DNA virus with more than 50 distinct serotypes. Though adenovirus infection is relatively common, adenoviral infection of the renal allograft is rare and also difficult to diagnose if viral inclusions are not present in the biopsy (see image above, black arrows indicating nuclear viral inclusion bodies). Based on a limited number of reported cases, patients typically present with fever, hematuria, dysuria, and acute kidney injury. Adenoviremia and viruria are present, as well as decoy cells similar to those seen with BK virus infection. Though it is possible that this patient may have had only ACR from the beginning (a close re-review of the 1st biopsy revealed no viral inclusions), it’s plausible that the adenovirus was responsible for the gross hematuria and thickened urothelium that were present from the start.

Adenoviral infection usually affects multiple organs and can be life threatening, though some patients are able to clear the virus and recover complete allograft function. After anti-viral treatment with intravenous cidofovir, our patient’s creatinine rose to 9 mg/dL. Unfortunately, she remains dialysis dependent and is undergoing re-evaluation for a second transplant.  This challenging case is a reminder that both rejection and infections must be considered when interstitial nephritis – and that one may be a decoy for the other!

Posted by Samira Farouk
Chief Fellow, Division of Nephrology
Icahn School of Medicine at Mount Sinai

Saturday, September 30, 2017

Nephrology Business Leadership University – A Fellow's Review.

Small Group Los Angeles Dialyspa NBLU 2017
In any academic fellowship, fellows receive excellent clinical training. However, the business aspect of practice often gets less attention. Before you know it you are scrambling to understand contracts, negotiate for a job, figure out billing/coding/reimbursement, understand market trends/growth, and figure out how to market your practice. Nephrology Business Leadership University or NBLU, aims to fill in this gap with a comprehensive 5-day course on understanding the business of Nephrology.

During our five days at NBLU, we learned the basics of insurance, 'red flags' of practices, the future of reimbursements, different practice environments (ie. academic, private, rural) and how to effectively interview/network among a variety of business related topics. Fellows were broken up into small groups and learned concepts in a variety of different teaching environments utilizing multiple interactive tools. In our small groups, we were assigned to a city and came up with a practice name as well as a mission statement. We were provided with an interactive map of our practice area and assessed growth rates to determine where we would open a clinic, which hospitals and dialysis units we planned to affiliate with. By far our favorite session was on billing/coding. This was an interactive session in which fellows were taught to 'think like a coder'; where we critiqued and assigned a level notes of other physicians.

By the end of NBLU, we were both feeling much more at ease about transitioning from fellowship to practice. I am ready to begin interviewing to find a practice that fits my needs. We highly recommend this conference to all freshly minted 2nd year Nephrology fellows interested in learning more about business and Nephrology.

However, the best part of NBLU is meeting and interacting with fellows from all over the country. We gained so much knowledge and now future friends and colleagues. How could you miss this opportunity? It is so much different than a brief meeting at Kidney Week or NKF as this is a 5 day immersion.

If you are interested in attending NBLU, pre-registration is now open for August of 2018, apply here

take some time to listen to the video testaments from this year’s attendees

Natasha Dave, Nephrology Fellow, Baylor Houston

Mona Shaban, Nephrology Fellow, University of North Carolina, Chapel Hill

From the Nate Hellman Unpublished Archive: Renal Ammonia Handling

Each day the average American creates 1 mEq/kg of acid which needs buffering. Most of the acid comes from protein. Our kidneys normally do all the buffering through 2 main systems – titratable and non-titratable acids Titratable acids (phosphates and sulfates) are relatively fixed in buffering capacity. Non-tritatable acids (ammonium – NH4+) does vary appropriately in patients having normally functioning kidneys. Thus, we adjust our buffering using ammonium.

If we cannot produce enough ammonium, then we develop a normal gap metabolic acidosis. Understanding the physiology of ammonium excretion helps us understand the possible problems.

  1. in the proximal tubular cells, glutamine converts to alpha ketoglutarate to produce NH3 (ammonia). Ammonia goes into the tubule and converts to NH4+. Thus, as patients lose proximal tubular cells they may lose buffering capacity because they cannot make enough ammonia.
  2. in the ascending limb of the loop of Henle, NH4+ goes into the intersitium by means of the sodium potassium 2 chloride cotransporter (this is the site which loop diuretics block). The NH4+ then converts back to NH3 and becomes part of the countercurrent multiplier system. Thus the medullary part of the kidney has very high concentrations of NH3.
  3. in the distal tubule, we acidify the urine. Here NH3 diffuses into the distal tubule, converts back to NH4+, creating the desired buffer effect.
Renal acidosis (normal gap) can occur for 3 major reasons.

  1. Distal RTA – inability to acidify the urine – cannot excrete the ingested acid if we cannot make mEq portions of NH4+ (which requires an acidified urine)
  2. Type IV RTA – this one is interesting. The problem in type IV RTA is primarily hyperkalemia (most commonly called hyporenin/hypoaldo). Increased potassium levels inhibit the enzyme glutaminase which is responsible for the production of ammonia. Thus if we correct the hyperkalemia, we usually resolve the acidosis.
  3. The acidosis of CKD – two problems for these patients – decreased production of ammonia and decreased concentration in the medulla. As CKD worsens, the countercurrent mechanism does not function as efficiently, decreasing the concentrations of solutes in the medulla. Thus, less ammonia is available to enter the distal tubule for buffering.

I hope these explanations make sense.

Friday, September 22, 2017

From the Nate Hellman Unpublished Archive: microRNAs and the Kidney

MicroRNAs: one of the sexiest topics in the science community these days! Pick up a copy of Science, Nature, or Cell and you can usually find something to do with microRNAs within. What do these have to do with the kidney? Well, it's still a little premature, but there are certainly microRNAs present in the kidney, and recent studies have demonstrated that specific microRNAs are upregulated in conditions such as polycystic kidney disease and renal cell carcinomas, for instance.

How microRNAs work: microRNAs are single-stranded RNA molecules of between 21-23 nucleotides in length which are partially complementary to regions in multiple mRNAs. Once they bind to these mRNAs, the microRNAs either inhibit translation or completely degrade their target RNAs. A specific enzymatic machinery--comprised of the proteins Dicer and the RISC complex--is responsible for inhibiting mRNAs via microRNAs.

In essence, the power of microRNAs are that a single microRNA can regulate the expression of multiple genes working in parallel to achieve a similar biologic effect. This technology is of particular use to the pharmaceutical industry: one can envision targeting a particular microRNA which inhibit several pathways to prevent a disease process, such as atherosclerosis, renal fibrosis, or cyst formation to think of a few possibilities. The field is still very new. I wouldn't be surprised if a future Nobel Prize came out of this work. Three scientists (Drs. Ruvkun, Baulcombe, and Ambros) working on microRNAs recently won the 2008 Lasker Prize--considered by many to be the "precursor" prize to the Nobel.

Thursday, September 21, 2017

Nephrology Fellows: last call to join an online focus group on palliative care


Calling all Nephrology fellows!

Duke University School of Medicine is seeking to understand barriers and facilitators to palliative care conversations between nephrology fellows and their patients. The study, funded by the Agency for Healthcare Research and Quality, is led by Jennifer St. Clair Russell, PhD, MSEd, MCHES, a social and behavioral scientist in the Division of General Internal Medicine with over 11 years of experience in nephrology.

 If you are eligible to participate in our online focus group (on September 28), you will be compensated for your study participation. It is estimated that the online focus group will only take approximately 120 minutes.

We would be honored to have you participate in this exciting research!

To learn more or complete the eligibility questionnaire, please contact Nikita Shah at Nikita.Shah@duke.edu.

Monday, September 18, 2017

A Primer on Primary Hyperoxaluria

Primary hyperoxalurias are a group of autosomal recessive disorders characterized by excess hepatic oxalate production and reduced kidney excretion.

They are classified into three types based on their enzymatic defect in glyoxylate metabolism
  • Type 1 (80%): alanine glyoxylate aminotransferase (AGT) 
  • Type 2 (10%): glyoxylate reductase/hydroxypyruvate reductase (GRHPR) 
  • Type 3 (10%): mitochondrial 4-hydroxy-2-oxoglutarate aldolase enzyme (HOGA1)
Variable in presentation and severity, its true prevalence is likely underestimated. While it can occur at any age, the median age of onset is 5.5 years. In Europe, it has an estimated prevalence of 1-3 cases per 1 million, incidence of 1 case per 120,000 live births and account for 1-2% of pediatric ESKD Unfortunately 20-50% of patients have advanced CKD at diagnosis and 10% are diagnosed only after disease recurrence following transplantation.

Excreted almost entirely by the kidney, oxalate can cause kidney tubular toxicity, nephrocalcinosis and obstruction with superimposed infection. In type 1 primary hyperoxaluria as eGFR falls below 30, plasma oxalate rises resulting in oxalate deposition in various organs including the kidney, heart, joints, retina, skin, bone marrow, heart and CNS.

Given its rarity, clinical suspicion is required for diagnosis. Definitive diagnosis requires genetic testing. Clinically it presents with urolithiasis (greater than 95% calcium oxalate monohydrate), recurrent UTIs, metabolic acidosis, acute kidney failure or oxalate crystals on kidney biopsy. Labs can be notable for persistently elevated urine oxalate, serum L-glycerate or serum oxalate. For persons with a family history, prenatal diagnosis can be obtained through genetic screening in the first trimester.

Conservative treatment strategies should be employed early and include aggressive hydration and potassium citrate to inhibit crystallization. Pyridoxine supplementation can be used for primary hyperoxaluria type 1 Gly170Arg and Phe152Ile genotypes. Intestinal oxalate has limited effects on disease progression as oxalate is largely produced endogenously and studies using oxalate-metabolizing probiotics like Oxalobacter formigenes have been disappointing.

In primary hyperoxaluria type 1 conventional HD and PD are ineffective at removing sufficient levels of oxalate for patients with ESKD due to ongoing liver production. While the ultimate management is transplantation, dialysis may be required as a temporary therapy to reduce plasma oxalate levels. Strategies include short daily sessions of high-flux dialysis, nocturnal dialysis, or combinations of hemodialysis and nocturnal peritoneal dialysis.

Isolated liver transplantation corrects the enzyme defect and can be used in early stages of kidney disease. Isolated kidney transplantation can reduced plasma oxalate, but disease recurrence often leads to poor graft survival. Dual liver-kidney transplantation is thus commonly performed for patients with CKD stage 4. Limited data exists for organ transplantation in primary hyperoxaluria type 2 and type 3 has not yet been associated with ESKD.

Sapna Shah, MD
Nephrology Fellow
Mount Sinai, New York

Tuesday, September 12, 2017

Prune Belly Syndrome and Kidney Disease


Prune Belly Syndrome (PBS) is a very rare (3.8/100,000 live births) congenital disease that predominantly affects males.

PBS is characterized by a triad of
  • Anterior abdominal wall muscle deficiency 
  • Urinary tract abnormalities
  • Bilateral cryptorchidism. 
Termed prune belly due to the wrinkled appearance of the abdominal wall at birth, it is a multisystem disease that can affect the genitourinary tract, cardiopulmonary, GI and musculoskeletal systems. Some studies and the inheritance pattern suggest that the disease is due to a recessive X-linked defect.  However, other studies have demonstrated a deletion in the the hepatocyte nuclear factor 1 beta (HFN1B) gene on chromosome 17q12 resulting in defective mesenchymal development, thus suggesting autosomal dominant inheritance. A clear genetic basis for PBS has not yet been established.

As per Seidal et al., nearly one-half of patients surviving infancy will develop CKD and nearly one third will develop ESRD and require RRT. This is thought to occur largely due to incomplete nephron differentiation, dilation of tubules, interstitial fibrosis and eventual glomerulosclerosis. Clinically PBS can be associated with reflux nephropathy and recurrent pyelonephritis.

Often diagnosed at birth or in early childhood, PBS can be diagnosed by antenatal ultrasound between weeks 20-30 with features including hydroureteronephrosis with or without echodense kidney parenchyma, oligohydramnios, hypoplastic lungs and bulging abdomen.

Therapy in childhood remains controversial, but can require early surgery for urine drainage in order to prevent recurrent infections or antibiotic prophylaxis. Maintenance CAPD and HD are equally effective in the management of ESKD and kidney transplantation has been successfully performed with excellent long-term prognosis.

Sapna Shah, MD
@NephShah
2nd Year Nephrology Fellow
Icahn School of Medicine, Mount Sinai, New York


Monday, September 11, 2017

Attn Fellows: Participate in an Online Focus Group on Palliative Care

Calling all nephrolgoy fellows!

Duke University School of Medicine is seeking to understand barriers and facilitators to palliative care conversations between nephrology fellows and their patients. The study, funded by the Agency for Healthcare Research and Quality, is led by Jennifer St. Clair Russell, PhD, MSEd, MCHES, a social and behavioral scientist in the Division of General Internal Medicine with over 11 years of experience in nephrology.

If you are eligible to participate in one of our two online focus groups (either September 17 or September 28, 2017), you will be compensated for your study participation. It is estimated that the online focus group will only take approximately 120 minutes.

We would be honored to have you participate in this exciting research!

To learn more or complete the eligibility questionnaire, please contact Nikita Shah at Nikita.Shah@duke.edu

Saturday, September 9, 2017

Origins of Renal Physiology at MDIBL Continues to Inspire Nephrology Fellows

2017 MDIBL Origins of Renal Physiology National Renal Fellows Course
I first discovered the Origins of Renal Physiology course on Renal Fellow Network as a medicine intern, and ever since that time, dreamt of going to the course as a renal fellow. Nate’s picture in front of the “Kidney Shed” was seared in my mind. The dream finally came true two weeks ago when I set foot on the Mount Desert Island Biological Lab (MDIBL) in Coastal Maine, and the first place I visited was indeed the Kidney Shed.

In his opening address to the fellows attending the course, Dr. Ziedel rightly said “Physiology is the pride of Nephrology”. He went on to mention the names of several luminaries who have worked at the MDIBL leading to many important discoveries. The lab has been a cornerstone of nephrology research and has been a home for the work of Homer Smith, E.K Marshall, David Evans, Franklin Epstein, and many others who have spent years working on and elucidating the fundamental concepts on kidney physiology.

In modern day practice of nephrology, we are less exposed to these fundamentals of kidney physiology that initially piqued our interest in nephrology. The Origins course is one of the many efforts made by the renal community to reconnect nephrolgoy fellows to physiology. It’s a very unique course which gives the fellows an opportunity to rub elbows with senior and distinguished renal physiologists from esteemed institutions and work with them on experiments to understand the different aspects of kidney biology.

The course consisted of 7 modules, each focusing on a functional unit of the nephron- the glomerulus, proximal tubule, thick ascending limb, distal tubule, acid-base, water homeostasis, and chloride secretion. We studied animals like zebrafish, turtles, and toad bladders. We also explored how ENaC and NKCC channels work. We delved into discussion about morpholinos and so much more. Over the duration of the course, we developed a new-found appreciation for the beauty and wonder of exploring how the kidney regulates homeostasis. We also got a sense for the profound impact MDIBL has had on the field of nephrology and physiology.

As MDIBL is in such close proximity to Acadia National Park- one of the most beautiful national parks in the world, nature is inherently embedded in the process of learning here. Most days started off with a refreshing early morning short hike which energized us to spend the entire day in the lab. On alternate days, amazing outdoor activities were planned for us after presentations of the earlier day’s work. My week at the MDIBL during this course was very memorable.

I was honored to be working closely with great mentors and met nephrology fellows from all over the US and abroad, shared interests and future aspirations and found new friends. 

All in all, an incredible experience! I would wholeheartedly endorse this conference for future fellows.

Manasi Bapat
@manasib33
2nd year Nephrology Fellow
Mount Sinai Hospital, NY

Tuesday, September 5, 2017

September Wash U Nephrology Webisode available - an unusual case of AKI!

Another great episode on the road, as I packed up my gear and headed to Rush University Medical Center in Chicago, IL.  Discussants joining me for this case are Dr. Roger Rodby, Dr. Pravir Baxi, and Dr. David Cimbaluk.  More complicated histology in a very unusual case of AKI:

"73 year old Caucasian female with hypertension, remote history of breast cancer, and NSAID use, presents with incidental AKI"


Tuesday, August 22, 2017

A few months ago, we posted about an acid-base primer that was being offered free for fellows in the US.

During the 5-day period from Wednesday, August 23 - Sunday, August 27, you can get a free copy of this ebook (kindle) edition of The Painless Guide to Mastering Clinical Acid-Base. Simply go to Amazon, search the title of Amazon ID number (B06XRM56TY), or click here, and you will find the ebook priced at $0.00 during those 5 days. Once you "purchase" the book, it will remain permanently in your Amazon library and you will be able to load it onto any device that has a Kindle app linked to your account. Feel free to notify students, residents, nurses or any others who might benefit. There is no limit to the number of persons who can get the download.

Posted by Ben Abelow

Tuesday, August 8, 2017

August Wash U Nephrology Web Episode now available

The monthly nephrology webisode from Wash U is posted and available for your viewing pleasure!  For August, we went on the road and recorded with some special guests from Rush University Medical Center in Chicago.  Try your hand at unraveling this tricky CPC with some complicated histology:

"32 year old African American male with uncontrolled hypertension, HIV, and a positive RPR presents with AKI and shortness of breath."


Monday, August 7, 2017

Midwest Point of Care Ultrasound Workshop

Washington University School of Medicine 
Point of Care Ultrasound Workshop  
Sunday, September 10, 2017
 Institute of Public Health
600 S.Taylor Ave.



Dear Friends. 
Point of care ultrasound has emerged as a powerful tool to assess volume status. This workshop will be part of the Midwest Nephrology + Transplant Symposium.  In this workshop we will review the fundamentals of beside US including heart, lung, and IVC assessment along with US-guided line placement and solid organ biopsy (kidney). 
For more info.

Thursday, August 3, 2017

Panda Eyes

I recently saw an elderly woman in clinic. She had a background history of migraine headaches and had been investigated over the past 18 months for recurrent syncopal episodes. She had at least 5 episodes that began with palpitations usually on minimal exertion. Apart from these episodes, she was fit and active. Her ECHO showed only mild LV hypertrophy and mild pulmonary hypertension. EKGs were unrevealing.

Two years ago she had been seen by a dermatologist for sun-related skin lesions and had mentioned that she had recurrent bruising around her eyelids. She had taken a photo of these lesions and they were noted to be purpuric. They would come and go and usually last for a couple of months when they were there.

She was referred to my clinic for investigation of mild albuminuria. She had ~500mg albumin for approximately 5 years with no significant change. Her renal function had always been otherwise normal apart from one single increase in creatinine was unexplained and returned to normal in a few days. She had no significant risk factors for kidney disease apart from long term NSAID use for her migraines.

As part of her investigations, she had an SPEP and free light chains. The results showed that she has an IgG lambda paraprotein likely related to an underlying multiple myeloma. Re-review of her ECHO images showed that they were consistent with infiltrative disease and she is currently undergoing work-up for AL-amyloidosis.

Periorbital purpura is a rare finding in patients with amyloidosis occurring in about 15% of patients. It is thought to be a result of Factor X deficiency due to binding of Factor X by the amyloid fibrils. It is generally atraumatic and tends to recur without treatment of the underlying amyloid. It is almost pathognomic of amyloid and its presence should prompt testing for AL amyloid.

Image from NEJM

Dialysis for dementia?


When I first began learning about Nephrology, I came across ‘dialysis dementia’, a progressive and fatal condition described in hemodialysis patients. Several studies in the 1970s implicated aluminium found in phosphorus binders and dialysate water as the cause. However, owing to modern techniques of water purification and the use of non-aluminium phosphorus binders, ‘dialysis dementia’ is now considered a rare adverse effect of dialysis, with a current estimated prevalence of 0.6–1.0%.

Nonetheless, moderate to severe cognitive impairment may affect 30–60% of patients undergoing hemodialysis (HD), and two-thirds of patients undergoing peritoneal dialysis (PD). The current pathophysiology of cognitive impairment in patients on dialysis might be mediated by traditional risk factors, such as older age, sex, diabetes mellitus, hypertension and cardiovascular disease; non-traditional factors, including hyperparathyroidism, elevated FGF-23 levels, vitamin D deficiency, anemia, malnutrition, inflammation, and oxidative stress; and dialysis-associated factors, such as adequacy, dialysis modality, hemodynamic instability during the procedure and solute shifts.

It was with interest then that I read recent research suggesting that peripheral clearance of amyloid-β (Aβ) by PD could help to reduce the amyloid plaque burden in the brain, potentially representing a new therapeutic approach for Alzheimer disease (AD). In this study, plasma Aβ levels before and immediately after PD in patients with CKD and in APP/PS1 mice (a standard animal model of AD) were measured. In both cases, plasma Aβ40 and Aβ42 levels were significantly reduced after dialysis. In the animal model, PD resulted in a decrease in Aβ levels in the brain interstitial fluid with reduced deposition even if plaque formation was well underway. The dialysis-treated mice showed reduced levels of hyperphosphorylated tau in the brain, suggesting a slowing of neurodegeneration along with decreased inflammation and increased microglial phagocytosis of Aβ in the brain. Attenuated cognitive decline was demonstrated by improved performance on the Y-maze and open-field tests.

According to the authors, this was a proof-of-concept study that restoration of the AD brain microenvironment and clearance of brain Aβ could be achieved by peripheral approaches. Yet how do we reconcile this promising experimental model with the high incidence of dementia in our PD patients? Although the USRDS data reports the risk of incident dementia to be lower for patients who started on PD than for those who started on HD, it still higher than the age-matched non-dialysis cohort. The tentative conclusion that we may draw from this is that vascular dementia is likely a far greater contributor to cognitive impairment in this population than AD.

In this study PD was very potent in removing Aβ from the blood in CKD patients. The authors highlight key differences in the PD procedure used in this study compared to standard practice. While CKD patients usually receive continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD) with long dwell times of 8 hours or more, the AD mice received only 2 hours of dialysis per day. This suggests that CAPD may be even more effective at depleting the brain Aβ burden in AD patients. Similarly brain Aβ deposition appears to be lower in patients who receive hemodialysis. 

What are the implications of this study for us as nephrologists? Will we be dialyzing people for ‘dementia’ in the future? Or for other neurodegenerative diseases that may benefit from peripheral clearances such as Huntington disease or motor neuron disease?  More research is definitely needed and there will be side-effects that non-nephrologists may not appreciate but it could be an exciting area in the future.



Post by Dearbhla Kelly