Preeclampsia and the Kidney: Pathophysiology and Clinical Implications

Preeclampsia and other hypertensive disorders of pregnancy are major contributors to maternal morbidity and mortality worldwide. This group of disorders includes chronic hypertension, gestational hypertension, preeclampsia, preeclampsia superimposed on chronic hypertension, and eclampsia. The body undergoes important physiological changes during pregnancy to allow for normal placental and fetal development. Several mechanisms have been proposed that may lead to preeclampsia, including abnormal placentation and placental hypoxia, impaired angiogenesis, excessive pro-inflammatory response, immune system imbalance, abnormalities of cellular senescence, alterations in regulation and activity of angiotensin II, and oxidative stress, ultimately resulting in upregulation of multiple mediators of endothelial cell dysfunction leading to maternal disease. The clinical implications of preeclampsia are significant as there are important short-term and long-term health consequences for those affected. Preeclampsia leads to increased risk of preterm delivery and increased morbidity and mortality of both the developing fetus and mother. Preeclampsia also commonly leads to acute kidney injury, and women who experience preeclampsia or another hypertensive disorder of pregnancy are at increased lifetime risk of chronic kidney disease and cardiovascular disease. An understanding of normal pregnancy physiology and the pathophysiology of preeclampsia is essential to develop novel treatment approaches and manage patients with preeclampsia and hypertensive disorders of pregnancy. © 2023 American Physiological Society. Compr Physiol 13:4231-4267, 2023.

The Effect of Gender-Affirming Hormone Therapy on Serum Creatinine in Transgender Individuals

OBJECTIVE

To describe the changes in serum creatinine (Cr) levels after the initiation of gender-affirming hormone therapy (GAHT) in transgender individuals to better understand the expected changes and interpretation of laboratory values in this population.

METHODS

A retrospective chart review of all adult transgender patients initiated on GAHT at Mayo Clinic from January 2011 to October 2019 was completed. Laboratory values were obtained prior to initiating GAHT and at 3, 6, and 12 months after initiating GAHT. Baseline Cr values were compared with Cr values at 3, 6, and 12 months after initiating GAHT in transgender men (TM) on testosterone and transgender women (TW) on estradiol and antiandrogens.

RESULTS

A total of 84 TW (median age of 30 years) and 24 TM (median age of 23 years) were included for analysis. Following a matched pair analysis of TW, Cr values were found to be significantly decreased by -0.03 at 3 months (P = .04), -0.10 at 6 months (P < .01), and -0.07 at 12 months (P < .01) compared with baseline values. Following a matched pair analysis of TM, Cr values were found to be significantly increased, on average, by 0.14 at 3 months (P = .04), 0.21 at 6 months (P = .016), and 0.15 at 12 months (P = .003) compared with baseline values.

CONCLUSION

In TW and TM, a change in Cr level was seen as early as 3 months toward their affirmed gender after initiating GAHT. Clinicians can use Cr levels established at 6 months as new baseline values, as these changes continue to persist up to 12 months.

Parental health in fellowship trainees: Fellows' satisfaction with current policies and interest in innovation

BACKGROUND

Parenthood during medical training is common and impacts trainee well-being. However, current graduate medical education parental health policies are often limited in scope. We explored current fellowship trainees' knowledge of/satisfaction with current policies as well as interest in potential changes/additions to existing policies.

METHODS

Fellowship program directors/coordinators at a three-site academic institution were surveyed and information was collected from 2015 to 2019 regarding fellow demographics and parental health policies. We distributed an electronic survey to fellows containing Likert-type-scale questions rating knowledge/level of satisfaction with current parental health policies and interest in potential additions/modifications to current policies.

RESULTS

Thirty-five of 47 (74%) fellowship programs responded. An average of 11% of female fellows and 15% of male fellows took parental leave during the study period. Three (9%) of the programs had at least one additional parental health policy beyond institutional graduate medical education policies. In the fellow survey, 175 of 609 fellows responded (28.7%), of which 84 (48.6%) were female. Although 89.1% agreed/strongly agreed that parental health is an important part of health and well-being for fellows, only 32% were satisfied/very satisfied with current policies (no significant sex-related differences). Fellows reported the following potential interventions as important/very important: 79.2% increased (paid) maternity leave (72.7% male, 86.7% female, p = 0.02), 78% increased (paid) paternity leave (76.4% male, 81.9% female, p = 0.37), 72.3% part-time return to work (60.2% male, 84.3% female, p = 0.0005), 63% coverage for workup/management of infertility (52.3% male, 74.7% female, p = 0.002), and 79.9% on-site day care (70.7% male, 89.2% female, p = 0.003).

CONCLUSIONS

Parental health includes multiple domains, not all of which are covered by current policies. Fellows feel that parental health is an important part of overall health and well-being, but most are not satisfied with current policies. Expanded access to parental leave and new policies (part-time return to work, infertility management, and on-site day care) are opportunities for innovation.

Effect on Kidney Function During Gender Affirming Hormonal Treatment in Transgender Individuals

Background: Accurate interpretation of laboratory values with sex-specific reference ranges presents a challenge in transgender individuals on gender affirming hormone therapy (GAHT). Creatinine (Cr), the most common marker used for kidney function, varies significantly with body mass and composition. Both Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-Epi) equations account for sex in estimating glomerular filtration rate. GAHT can effect Cr values in 2 potential ways: 1) by causing changes in muscle mass and body fat redistribution as early as 3 months after GAHT initiation and 2) by direct effects of sex hormones on kidney function. Previous studies have shown Cr values approaching affirmed gender identity as early as 6 months when on GAHT without mention of sex steroid levels. In this study we sought to describe the changes in serum Cr after initiation of GAHT in an effort to better understand expected changes and interpretation of lab data in TG individuals.

Methods: A retrospective chart analysis on all adult TG patients initiated on GAHT at our institution from January 2011 to 2020 was completed. We reviewed demographics, baseline health information, body mass index, and lab values including Cr, sex hormone levels, A1C, and fasting blood glucose. Lab values were obtained prior to GAHT, at the start of GAHT, at 3, 6, and 12 months after GAHT. Matched pair testing was conducted with sex steroid levels and Cr values in transgender men (TM) on testosterone and transgender women (TW) on estradiol in order to compare the median pre GAHT Cr to median Cr levels at 3, 6, and 12 months.

Results: 84 TW with a median age of 30 and 24 TM with a median age of 23 were included for analysis. TW and TM had a low rate of existing kidney disease (4.9%, 0%), diabetes mellitus (4.8%, 0%), and hypertension (10.8%, 4.5%) respectively. TW on GAHT achieved a goal estradiol level (≥100 pg/ml) at a rate of 37.3%, 51.7%, and 71.1% and suppressed testosterone to a goal level (<60ng/ml) at a rate of 44.4%, 54.7%, and 76.5% at 3, 6, and 12 months respectively. There was no significant change in Cr values at 3 months, but significantly decreased on average by -0.07 (p<0.001) at 6 months, and by -0.09 (p<0.001) at 12 months. TM on GAHT achieved a goal testosterone level (≥240 ng/dl) at a rate of

64.3%, 80.0%, and 72.3% at 3, 6, and 12 months respectively. Cr values increased significantly on average by 0.14 (p=0.036) at 3 months, by 0.21 (p=0.004) at 6 months, and by 0.15 (p=0.003) at 12 months.

Conclusions: In TW on GAHT, clinicians can consider using affirmed gender Cr reference ranges as early as 6 months. Similarly in TM on GAHT, affirmed gender Cr reference ranges can be used as early at 3 months. It remains to be seen whether changes in Cr levels reflect changes in sex steroid levels or sex steroid direct effects. Additionally, research is needed to determine if change in Cr levels reflect true changes in GFR.

Hypertensive Disorders of Pregnancy

Hypertensive disorders of pregnancy are increasing in incidence and are major causes of maternal morbidity and mortality both in the United States and worldwide. An understanding of these diseases is essential for the practicing nephrologist, as preexisting kidney disease is an important risk factor. In addition, the development of hypertensive disorders of pregnancy has important implications for long-term risk of kidney disease and cardiovascular disease. The definition and diagnostic criteria has changed in recent years as our understanding of the disease entity has progressed. Currently, proteinuria is no longer a necessary diagnostic feature of preeclampsia. Preeclampsia and gestational hypertension may develop through multiple different mechanisms. Current research suggests contributions of both placental factors and maternal factors contribute to the disease and represent different phenotypic presentations of preeclampsia.

The role of kidney biopsy in diagnosis of preeclampsia in kidney transplant patients

OBJECTIVE

The aim of this report is to review two patients who developed proteinuria in pregnancy after kidney transplant in order to highlight the importance of maintaining a broad differential and the diagnostic utility of kidney biopsy in this clinical scenario.

METHODS

Two cases of women with kidney transplants who presented with proteinuria in pregnancy are described and the literature is reviewed.

RESULTS

In both cases, a kidney biopsy allowed for prompt diagnosis and treatment.

CONCLUSION

Kidney biopsy should be considered an important diagnostic tool in this clinical scenario.

ABBREVIATIONS

ACE: angiotensin-converting enzyme; ESKD: end-stage kidney disease; FSGS: focal segmental glomerulosclerosis; RAAS: renin aldosterone angiotensin system.